Power Factor Correction and harmonic filtering solutions

Power Factor Correction and harmonic filtering solutions
Medium Voltage
Catalogue│2013
Power Factor Correction
and harmonic filtering
solutions
Energy management
How to upgrade electrical network and
improve energy efficiency ?
Energy quality with
Power Factor Correction
and harmonic filtering
Most utilities have specific policies for billing reactive energy.
Price penalties are applied if the active power / apparent power ratio is not
within the guidelines.
• Power Factor Correction solutions modify and control the reactive
power to avoid utility penalties, and reduce overall kVA demand.
These solutions result in lowering utility power bills by
5 to 10 %.
Harmonics stress the electrical network and potentially damage equipment.
• Harmonic Filtering solutions are a means to mitigate the harmonics.
They increase the service life of equipment:
32 % for single phase machines
> up to 18 % for three phase machines
> and up to 5 % for transformers.
> up to
Solutions
1 month
DE90070
payback.
We installed a 5Mvar
capacitor banks.
Annual cost savings
will reach €12m &
implementation costs
€1m.
Portucel Paper Mill
in Portugal
9%
Before
After
¤9m
Power Factor Correction
Every electric machine needs active and
reactive power to operate.
Power factor is used to identify the level of
reactive energy.
If the power factor drops below the limit set
by the utility, then power factor correction
equipment can be installed in order to avoid
penalties.
By correcting a poor power factor, these
solutions also reduce kVA demand.
The results are a 5 to 10% lower electricity
bill, cooler equipment operation and longer
equipment life.
In addition proper power factor correction
helps optimize electrical network loading
and improves reliability.
MV Capacitor banks
installed, cost saving of
€9m, payback in just
2 months.
RFF Railways France
1 year
70 capacitor banks
installed, energy
consumption reduced by
10%, electricity bill
optimised by 18%,
payback in just 1 year.
Madrid Barrajas
airport Spain
Harmonic filtering
Equipment such as drives, inverters,
UPS, arc furnaces, transformers during
energization and discharge lamps generate
harmonic currents and voltage distortion.
reduction in our energy
consumption after we
installed 10 capacitor
banks.
Electricity bill optimized
by 8% and payback in
2 years
Testifies Michelin
Automotive in France
These harmonics stress the network,
overload cables and transformers, cause
outages and disturb many types of
equipment such as computers, telephones,
and rotating machines.
The life of equipment can be greatly
reduced.
5%
LV capacitor bank and
active filter installed,
energy consumption
reduced by 5%.
POMA OTIS
transportation
systems Switzerland
1
Power Factor Correction
Reduce
your electricity bill
by reducing your reactive energy consumption.
Optimize
the size of your electrical
installation
by increasing the available capacity and reducing the dimensions
of your equipment (transformer, cables, etc.).
Improve
energy quality
and the service life of your equipment.
Contribute
PE90086
to environmental conservation by reducing losses in transmission
and distribution networks.
2
Harmonic filtering
Increase
continuity of service
by eliminating risks of stoppages due to nuisance tripping.
Eliminate
malfunctions
of your electrical equipment by reducing overheating,
increasing its lifetime by up to 30%.
Benefit
from the assurance provided
by standardization,
PE90087
by anticipating the requirements of regulations currently being
prepared, deploying environmentally friendly solutions.
3
MV Power Factor Correction and
harmonic filtering
Energy - Production
Wind-power farms
• MV capacitor banks
• MV dynamic compensation
• Blocking circuits
Energy - Transmission
EHV/HV substation
• HV capacitor banks
• HV passive filters
Industry MV/MV
substations
• MV capacitor banks
• MV passive filters
• MV dynamic compensation
• Surge suppressors
4
Energy - Production
Solar power farms
• MV dynamic compensation
• Blocking circuits
Energy - Distribution MV/MV
substation
• MV capacitor banks
• MV passive filters
Infrastructure MV/LV
substation
• MV capacitor banks
5
PE90079
PE90077
PE90081
PE90075
PE90078
PE90080
PE90076
MV Power Factor Correction and
harmonic filtering
To define the solutions to be employed, you must:
• identify and quantify the problems to be
solved (usually by an on-site audit);
• analyse the criticality of the installation and
validate the objectives to be achieved.
The following table shows the typical solutions proposed for installations in various sectors of activity.
Activity
Fixed
banks
Automatic
banks
Dynamic
compensation
Passive
filters
Surge
suppressors
Blocking
circuits
Energy
Transmission
◼
Distribution
◼
◼
◼
◼
Wind-power
Solar power
◼
◼
◼
◼
◼
Infrastructure
Water
◼
Tunnels
◼
Airports
◼
Industry
◼
◼
◼
◼
◼
Plastics
◼
◼
◼
Glass-ceramics
◼
◼
◼
◼
◼
◼
◼
Paper
Chemicals
◼
Iron and steel
◼
◼
◼
Métallurgy
◼
◼
◼
◼
◼
◼
Cement
◼
◼
◼
Mines-quarries
◼
◼
◼
Refineries
◼
◼
◼
Automotive industry
6
◼
Quality & Environment
Quality certified:
ISO 9001, ISO 9002 and ISO 14001
A major strength
In each of its units, Schneider Electric has
an operating organization whose main role is
to verify quality and ensure compliance with
standards.
This procedure is:
• uniform for all departments;
• recognized by numerous customers and
official organizations.
But, above all, its strict application has made
it possible to obtain the recognition of an
independent organization:
French QA management organization AFAQ
(Association Française pour l’Assurance
Qualité).
The quality system for design and
manufacturing is certified in compliance
with the requirements of the ISO 9001
Quality Assurance model.
Stringent, systematic controls
During its manufacture, each equipment item
undergoes systematic routine tests to verify
its quality and compliance:
• measurement of operating capacity and
tolerances;
• measurement of losses;
• dielectric testing;
• checks on safety and locking systems;
• checks on low-voltage components;
• verification of compliance with drawings
and diagrams.
The results obtained are recorded
and initialled by the Quality Control
Department on the specific test certificate
for each device.
ISO 900 1
ISO 9002
ISO 14001
10%
Up to
savings on your
energy bill
Schneider Electric undertakes...
10%
Jarylec*
31%
PE56733
DE90098
to reduce the energy bill and CO2 emissions of its customers by proposing products,
solutions and services which fit in with all levels of the energy value chain.
The power factor correction and harmonic filtering offer form part of the energy
efficiency approach.
Steel
Zinc
Epoxy resin
24%
Brass
Paper, wood, cardboard
Tin-plated copper
2%
7%
1%
19%
5%
1%
Raw materials breakdown for MV capacitors
Polypropylene (film)
Aluminium (film)
* Jarylec: dielectric liquid with no
PCB or chlorine, compatible with
the environment
7
A comprehensive offer
Tools for easier design and setup
The power factor correction and harmonic
filtering offer form part of a comprehensive
offering of products perfectly coordinated
to meet all medium- and low-voltage power
distribution needs.
All these products have been designed to
operate together: electrical, mechanical and
communications consistency.
The electrical installation is accordingly both
optimized and more efficient:
• improved continuity of service;
• losses cut;
• guarantee of scalability;
• efficient monitoring and management.
You thus have all the trumps in hand
in terms of expertise and creativity for
optimized, reliable, expandable and
compliant installations.
With Schneider Electric, you have a
complete range of tools that support you in
the knowledge and setup of products,
all this in compliance with the standards in
force and standard engineering practice.
These tools, technical notebooks and
guides, design aid software, training
courses, etc. are regularly updated
PE90088
A new solution for building your electrical
installations
Schneider Electric joins forces
with your expertise and your creativity for optimized, reliable, expandable and
compliant installations.
Because each
electrical installation
is a specific case,
there is no universal
solution.
8
The variety of
combinations available
to you allows you
to achieve genuine
customization of
technical solutions.
You can express your
creativity and highlight
your expertise in the
design, development and
operation of an electrical
installation.
Power Factor Correction
and harmonic filtering
Main Contents
MV capacitor banks
11
Protection systems
39
Components
47
Special equipment
61
Installation (drawings, dimensions) 67
Services
71
Selection guide
75
Technical guide
81
9
Power Factor
Correction and
harmonic filtering
MV capacitor banks
Contents
Why compensate reactive energy? Choice of compensation type
Choice of compensation location
Choice of protection system type
Choice of coupling mode
Overview of offer
Functions and general characteristics
Banks for motor compensation
12
13
14
15
16
18
20
22
Banks for industrial compensation
26
Banks for global compensation
30
Banks for distribution and large site networks
32
Fixed bank CP 214
Fixed bank CP 214 SAH
Automatic bank CP 253
Automatic bank CP 253 SAH
Fixed bank CP 227
22
24
26
28
30
Automatic bank CP 254
32
Banks for distribution networks
34
Banks for transport and distribution networks
36
Fixed bank CP 229
Fixed bank CP 230
34
36
11
MV capacitor
banks
Why compensate reactive energy?
Every electrical system (cable, line, transformer, motor, lighting, etc.)
employs two forms of energy:
• Active energy consumed (kWh).
This is fully transformed into mechanical, thermal or luminous power.
It corresponds to the active power P (kW) of the loads.
This is the “useful” energy.
• Reactive energy consumed (kvarh).
It serves to magnetize motors and transformers. It corresponds to the
reactive power Q (kvar) of the loads.
It results in a phase difference (ϕ) between the voltage and current.
This is an energy that is “necessary” but produces no work.
DE90071
The reactive energy demanded by the loads is supplied by the electrical
network. This energy must be supplied in addition to the active energy.
This flow of reactive energy over the electrical networks results,
due to a larger current demand, in:
• additional voltage drops;
• transformer overloading;
• overheating in circuits... and hence losses.
Power
generation
Active energy
Reactive energy
Transmission
network
Active energy
Reactive energy
Motor
DE90071
For these reasons, it is necessary to produce reactive energy as close
as possible to the loads, to avoid demand for it on the network,
thereby increasing the installation’s efficiency! This is what is called
"reactive energy compensation" or "power factor correction".
The easiest and commonest way of generating reactive energy is
to install capacitors on the network.
Power
generation
Active energy
Transmission
network
Active energy
Reactive energy
Motor
Capacitors
Compensating reactive energy makes it possible to
increase the capacity of the installation (transformers, cables) by
reducing the load;
reduce losses by Joule effect;
reduce voltage drops;
increase the installation’s service life by reducing overheating;
reduce the electricity bill.
12
MV capacitor
banks
Choice of compensation type
A “capacitor bank” generally consists of several single-phase or three-phase capacitor units
assembled and interconnected to produce very powerful systems.
The capacitor banks are branch-mounted on the network.
They may be of fixed or automatic type.
Fixed bank
The entire bank is put into operation, with a fixed value of kvar.
This is “on/off” type operation.
This type of compensation is used:
• when their reactive power is low (15% of the power of the upstream transformer)
and the load is relatively stable;
• on HV and EHV transmission networks for power values of up to 100 Mvar.
Automatic bank
The bank is divided up into “steps” with capability for switching on or off a smaller or larger number
of steps automatically. This is a permanent adjustment to the reactive power demand, due to load
fluctuations.
This type of bank is very commonly used by certain heavy industries (high installed capacity)
and energy distributors in source substations. It allows step-by-step regulation of reactive energy.
Each step is operated by a switch or contactor.
Capacitor step switching on or off can be controlled by power factor controllers. For this purpose,
the network current and voltage information must be available upstream
of the banks and loads.
Choice of bank type according to the harmonics
The presence of nonlinear loads (variable speed drives, inverters, etc.) creates harmonic
currents and voltages. The compensation equipment will be chosen according to the magnitude
of these harmonics:
• Either the installation has no significant harmonics and there is no risk of resonance.
In this case a bank appropriate for networks with a low harmonic level (standard type) is chosen.
• Or the installation has a significant level of harmonics and/or there is a risk of resonance. In such
cases a bank provided with a detuning reactor, appropriate for networks with a high harmonic
level, is chosen.
13
MV capacitor
banks
Choice of compensation location
DE90072
Individual
Individual compensation is recommended especially when a load
of power greater than 300 kW is present, and if it remains energized
during most working hours. This is especially the case of motors driving
machines with great inertia: centrifuges, compressors and fans,
for example.
Operation of the switch specific to the load in this case automatically
causes capacitor switching on or off. The production of reactive energy
takes place directly at the place where it is consumed.
Individual compensation
For the whole length of the power cable this results in a reduction
in the reactive current load. Individual compensation therefore makes
a major contribution to the reduction in apparent power, losses
and voltage drops in conductors.
Partial/by sector
DE90072
In the case of compensation by sector (or workshop), several loads
are connected to a joint capacitor bank which is operated by its own
switchgear. In large installations, the bank compensates all the reactive
energy consumers in a workshop or a sector.
This form of compensation is recommended for installations
where a number of loads are put into operation simultaneously
and in a manner virtually reproducible over time.
Partial compensation /
by sector
Partial compensation has the advantage of entailing lower capital
investment costs than individual compensation. This is because
calculation of the power of a permanently installed capacitor bank takes
into account expansion of the sector load. However, the load curves
must be well known beforehand in order to correctly size the capacitor
banks and avoid risks of over-compensation (reactive power supplied
exceeding the demand). Over-compensation generally results in the
local occurrence of permanent overvoltages which cause premature
electrical equipment ageing.
Global
DE90072
In the case of global compensation, the production of reactive energy
is grouped in a single place, usually in the transformer substation.
However, it is not necessary for the capacitors to be installed precisely
at the metering level. On the contrary, it is recommended to install
the capacitors in an appropriate location which takes into account
various constraints such as space requirements.
Total compensation
14
The capacitors have a good duty factor; the layout is clear; supervision
of the installation and its various parts is easier than in the case of
compensation by sector. Finally, if stepped automatic adjustment
is adopted, there will in this case be good follow-up of the plant’s load
curve, which avoids operations by personnel (manual switching on/off).
This solution is economically worthwhile if the load variations are not
attributable to specific loads.
Choice of protection system type
MV capacitor
banks
Internal fuses
Each capacitance element of the capacitor is protected by a fuse.
Any fault in this element will result in fuse blowing. The defective element
will thus be eliminated. The result will be a slight capacitance variation and
the voltage will be distributed over the sound elements in series.
Protection by internal fuses increases the availability of capacitor banks,
because the loss of one element no longer systematically results
in tripping of the bank (see details in Propivar NG technical description).
Unbalance protection
The bank is divided into two star connections (see diagram on page 16).
When there is a capacitance unbalance (variation in capacitance
of a capacitor), a current flowing between the 2 neutrals appears.
This current is detected by a current transformer and an unbalance relay.
PE90089
This differential arrangement is a sensitive protection system, independent
of network interference, very suitable whatever the power values.
15
MV capacitor
banks
Choice of coupling mode
To form banks of great power, there are several possibilities for cabling
or connection by combination of capacitor units, namely:
• delta connection: three-phase capacitors (without internal fuse) coupled
in parallel;
• double star connection of single-phase capacitors (with or without
internal fuse);
• H connection.
16
DE90073
DE90073
DE90099
Choice of coupling mode depends on:
• the characteristics, mains voltage and power of the bank;
• the type of compensation, fixed or automatic (stepped);
• the type of protection system:
- capacitor with or without internal fuse;
- differential (unbalance) or with MV fuses;
• economic imperatives.
Example of double star
connection
Example of delta
connection
Example of H connection
(by phase)
Recommended configuration
2 000
2 400
3 000
3 500
YY connection
6 single-phase
capacitors
4 000
6 000
YY connection
9 or 12 capacitors
YY connection of 12 singlephase capacitors (series)
PE90091
PE90090
Q (kvar) / 600
900
1 200
U network (kV)
3,3
4,16
Delta connection
5,5
1 or 2 three-phase
6,6
capacitors
10
11
13,2
13,8
15
20
22
30
33
17
Overview of offer
MV capacitor
banks
Industrial application
Applications
Motor compensation
Industrial compensation Fixed bank
Automatic bank
References CP214 CP214SAH* CP253 Maximum voltage
DE90082
DE90082
DE90082
Three-lines diagrams
Up to 12 kV Up to 12kV Connection mode Three-phase capacitors with delta connection
Three-phase capacitors up to 900 kvar,
single-phase capacitors
with double star
connection above
Type of protection HRC fuses (**) HRC fuses Maximum power****
2 x 450, i.e. 900 kvar Up to 4500 kvar Comments
CP 214
18
CP 227SAH
PB102001_SE
PB102003_SE
PE90107
PB101996_SE
* SAH: Detuning Reactor
** HRC: High Rupturing Capacity
*** CT: Current Transformer
**** For larger power rating, please contact us
CP 253
CP 254
All applications
Energy application
Industrial compensation
Global compensation
Distribution system
Distribution system
Distribution
Automatic bank
Fixed bank
Large sites
Fixed bank
and Transport system
Automatic bankFixed bank
Up to 12 kV Up to 36kV
From 12 to 36 kV CP230
DE90082
CP229 DE90082
CP254 DE90082
CP227 DE90082
DE90082
CP253SAH* Up to 36 kV Three-phase capacitors Single-phase capacitors with double star connection
up to 900 kvar,
single-phase capacitors
with double star
connection above
Above 36 kV
Single-phase capacitors with double star
or H connection
HRC fuses Unbalance by CT***
Unbalance by CT*** and relay
and relay Up to 4000 kvar 12 x 600, i.e. 7200 kvar
12 x 600 kvar, i.e. 7200 kvar Please contact us Please contact us
SAH* on request
SAH* on request
SAH* on request
SAH* on request
PE90084
PE90108
CP 229
CP 230
19
MV capacitor
banks
Functions and general characteristics
CP 214
CP 253
CP 227
CP 254
CP 229
CP 230
Mains voltage
≤ 7.2 kV
bbbbb
≤ 12 kV
bbbbb
≤ 24 kV
bbb
≤ 36 kV
bbbb
≥ 52 kVb
Compensation and Filtering
Bank power*
kvar
900
4 500
7 200
7 200
Steps
quantity
1
5*
1
5*
1
1
type
fixedauto fixedauto fixedfixed
Capacitor connection
delta
bb
double star
v
b
bbb
H vv
Detuning reactor
vvvvvv
Capacitor protection
Inrush reactors (N/A with DR)
b
b
b
b
b
b
Fuse protection
b
b
Blown fuse indicator v
v
Unbalance protection
v
b
b
bb
Quick discharge reactor (< 24 kV) v
v
v
v
v
Switch SF6
v
v
Vacuum interrupter
v
v
Measuring
Current transformer v v
Voltage transformer
v v
People safety
Earthing switch
3-pole v v
5-polev
Line disconnector
v v
with earthing switch
v v
Interlock
v v
Arc fault detector
v
v v
Control and regulation
Control and mounted on door v v
monitoring unit
separated
b b
Automatic controller
standard b b
communication
v v
Auto/local selector switch
v v
Ingress protection
IP
IP00 b
b
IP23 b
b
b
b
IP54 v
v
v
v
Double roof
v
v
v
v
Connection
Cable entry bottom b
b
b
b
b
b
top
v
v
v
v
vv
Access
with door
v
v
v
v
* Standard offer; for other values, please contact us
b: standard
v: optional functions
20
Service conditions
Ambient air temperature
• ≤ 40°C.
• ≤ 30 °C average per 24h.
• ≥ -25°C.
Altitude
• ≤ 1000m.
Atmosphere
Clean industrial air (no dust, fumes, gases or corrosive or flammable vapours, and no salt).
Humidity
Mean relative humidity value over 24h < 95%.
Special service conditions (please, consult us)
Schneider Electric develops solutions to meet the following special conditions:
• Temperature from -40°C to +50°C (derating, ventilation).
• Corrosive atmospheres, vibrations (adaptations where applicable).
• Altitude > 1000 m (derating).
Storage conditions
To conserve all the qualities of the functional unit in the event of extended storage,
we recommend storing the equipment in its original packaging, in a dry location,
sheltered from rain and sun and at a temperature ranging between -25°C and +55°C.
Standards
The equipment proposed in this offer has been designed, manufactured and tested
in accordance with the requirements of the following standards and recommendations:
• High-voltage capacitors: CEI 60871-1&2, BS 1650, VDE 0560, C22-2 N°190-M1985, NEMA CP1.
• High-voltage circuit breakers: IEC 56.
• Current transformers: IEC 60044.
• Earthing switch: IEC 129C.
• Relays, Power factor controller: IEC 60010.
• Quick discharge reactors, Damping reactors: IEC 60076-6.
• Insulators: IEC 168 - 273 - 815.
• High-voltage contactors: IEC 420 / IEC 470.
• High-voltage fuses: IEC 282.1 / IEC 787.
Common electrical characteristics
• Tolerance on bank power rating: 0/+10% (0/+5%, power > 3 Mvar).
• Relative capacitance variation with temperature: -3,5.10-4/°C
Insulation coordination
Highest voltage for the equipment
UM (kV)
7.2
12
17.5
24
36
Power-frequency withstand Impulse withstand
voltage (kV rms, 50 Hz - 1 mn)
voltage (kV peak, 1.2 / 50 μs)
2060
2875
3895
50125
70170
21
Banks for motor compensation
MV capacitor
banks
Insulation up to 12 kV – 50 Hz / 60 Hz
Fixed bank CP214
Application
DE90066
The CP214 banks are used for reactive energy compensation in medium-voltage networks.
This solution is especially suitable for individual motor compensation. The banks are designed
for use in electrical networks up to 12 kV.
5
3
4
2
6
1
1: Frame
2: Insulators
3: Quick discharge reactors
4: Fuses
5: Inrushj reactors
6: Capacitors
The banks are delta-connected (three-phase capacitors). HRC fuses provide protection against
internal faults. The proposed CP214 compensation banks can be installed indoors or outdoors,
mounted in aluminium or steel enclosures.
Références
1
2
22
Description
• SmallChâssis
size / Frame
• Specially designed for motor compensation
Isolateur / Insulator
3
TP de décharge rapide / Discharge Coil
4
Fusible / Fuse HRC
5
Self de choc / Damping Reactor
6
Condensateurs / Capacitor Units
Electrical characteristics
Power (kvar)
DB406316
CP214 - 50 Hz
Mains voltage (kV)
Power (kvar)
DB406317
CP214 - 60 Hz
Mains voltage (kV)
Composition
Each CP214 bank comprises the following components:
• A frame in painted aluminium and steel panels (RAL 9002), IP 23 for indoor installation.
• Propivar NG single-phase capacitors (1 or 2 elements depending on the power of the bank).
• Three inrush current limiting reactors.
• Three HRC fuses (with striker).
Options
• Outdoor type enclosure
(panels in unpainted aluminium).
• Double roof for outdoor type enclosure.
• Set of 2 quick discharge reactors.
• Door with lock.
• Blown fuse indicator.
MT20135
DE90100
General view, dimensions and three-lines diagram
H
L
D
• H: 1700 mm, L: 900 mm, D: 1200 mm.
• Approximate weight: 400 to 560 kg.
23
MV capacitor
banks
Banks for motor compensation
Insulation up to 12 kV – 50 Hz / 60 Hz
Fixed bank CP214 SAH
Application
DE90106
The CP 214 SAH medium-voltage capacitor banks are designed for use in electrical networks
up to 12 kV. The CP214 SAH banks are used for reactive energy compensation
in medium-voltage networks containing harmonics.
This range is especially suitable for individual MV motor compensation.
1
2
5
4
1: Frame
2: Insulators
3: Quick discharge reactors
4: Fuses
5: Detuning reactors
6: Capacitors
3
6
The banks are delta-connected (three-phase capacitors). HRC fuses provide protection against internal
faults. The proposed CP214SAH compensation banks can be installed indoors or outdoors, mounted in
Références
Description
aluminium or steel
enclosures.
1
2
3
24
Châssis / Frame
• Small size
Isolateur / Insulator
• Specially designed for motor compensation
TP de décharge rapide / Discharge Coil
• Suitable
for networks with high harmonic levels
4
Fusible / Fuse HRC
5
Self anti-harmoniques / Detuned Reactor
6
Condensateurs / Capacitor Units
Power (kvar)
DB406334
Electrical characteristics
Power (kvar)
DB406335
Mains voltage (kV)
Mains voltage (kV)
Composition
Each CP214SAH bank comprises the following elements:
• A frame in painted aluminium and steel panels (RAL 9002), IP 23 for indoor installation.
• Propivar NG single-phase capacitors (1 or 2 elements depending on the power of the bank).
• Three HRC fuses (with striker).
• A three-phase detuning reactor (dry type with magnetic core and natural convection cooling).
•
•
•
•
•
Outdoor type enclosure (panels in unpainted aluminium).
Blown fuse indicator.
Sets of two quick discharge reactors: 7.2 - 12 kV.
Door with lock.
Double roof for outdoor type.
General view, dimensions and three-lines diagram
DE90100b
Options
DE90062
80
H
L
D
• H: 1900 mm, L: 2000 mm, D: 1100 mm.
• Approximate weight: 600 to 1000 kg.
25
MV capacitor
banks
Banks for industrial compensation
Insulation up to 12 kV – 50 Hz / 60 Hz
Automatic bank CP253
Application
DE90107
The CP253 medium-voltage capacitor banks are designed for use in electrical networks up to 12 kV.
They are used for total installation compensation, when the load level is fluctuating.
The “1 step” CP253 model is mainly designed for individual compensation of MV motors to avoid
the risk of self-excitation.
2
1
5
7
4
3
6
1: Frame
2: Insulators
3: Quick discharge reactors
4: Fuses
5: Contactors
6: Capacitors
7: Inrush reactors
These banks are delta-connected (three-phase capacitors) and the HRC fuses provide protection
against internal faults. An optional cubicle containing a power factor controller can be used to control
the steps, thus forming an automatic compensation bank. For steps power values greater than 900
Références
Description
kvar, single-phase capacitors connected in double star will be used (maximum of 12 capacitors,
1
Châssis / Frame
maximum power 4500 kvar).
2
•
•
•
•
•
7
26
Isolateur / Insulator
Total installation
compensation
3
TP de décharge rapide / Discharge Coil
Fluctuating
load
level
4
Fusible / Fuse HRC
Ease of access to components
5
Contacteurs / Contactor
Simplified maintenance
6
Condensateurs / Capacitor Units
Easy installation
Self de choc / Damping Reactor
Electrical characteristics
Mains
Steps
voltage (kV)
3.3
1
2
3
4
5
5.5
1
2
3
4
5
6
1
2
3
4
5
6.3
1
2
3
4
5
6.6
1
2
3
4
5
10
1
2
3
4
5
11
1
2
3
4
5
Composition
kvar - 50 Hz kvar - 60 Hz
Min. Max. Min. Max.
100
700
120
840
200
1400 240
1680
300
2100 360
2520
400
2700 480
3240
500
3400 600
4080
100
900
120
1080
200
1800 240
2160
300
2700 360
3240
400
3600 480
4320
500
4500 600
5400
100
900
120
1080
200
1800 240
2160
300
2700 360
3240
400
3600 480
4320
500
4500 600
5400
100
900
120
1080
200
1800 240
2160
300
2700 360
3240
400
3600 480
4320
500
4500 600
5400
100
900
120
1080
200
1800 240
2160
300
2700 360
3240
400
3600 480
4320
500
4500 600
5400
100
900
120
1080
200
1800 240
2160
300
2700 360
3240
400
3600 480
4320
500
4500 600
5400
100
900
120
1080
200
1800 240
2160
300
2700 360
3240
400
3600 480
4320
500
4500 600
5400
Each CP253 bank comprises the following
elements:
• An enclosure in unpainted aluminium or
galvanized steel, IP 23 for indoor installation.
• Propivar NG three-phase capacitors
(1 or 2 elements per step).
• One ROLLARC SF6 contactor per step.
• Three inrush current limiting reactors per step.
• Three HRC fuses (with striker) per step.
Options
• Outdoor type enclosure.
• Double roof for outdoor type enclosure.
• Door with lock.
• Control and monitoring cubicle for "n" steps.
• Step auto/manual selector switch.
• Sets of two quick discharge reactors:
7.2 - 12 kV.
• Blown fuse indicator.
• Earthing switch.
General view, dimensions and three-lines diagram
DE90074
DE90102
80
H
L
H L
1 step 2 000 1 500
2 steps2 000 2 600
3 steps2 000 3 700
4 steps2 000 4 800
5 steps2 000 5 900
D
D
1 600
1 600
1 600
1 600
1 600
27
MV capacitor
banks
Banks for industrial compensation
Insulation up to 12 kV – 50 Hz / 60 Hz
Automatic bank CP253 SAH
Application
DE90108
The CP253 SAH medium-voltage capacitor banks are designed for use in electrical networks
up to 12 kV. The CP253 SAH banks are used for automatic reactive energy compensation in
medium-voltage networks with a high harmonic level. This solution is particularly suitable
for total installation compensation where the load level is fluctuating.
2
3
1
4
6
1:
2:
3:
4:
5:
6:
5
Frame
Insulators
Fuses
Contactors
Capacitors
Detuning reactors
These banks are delta-connected (three-phase capacitors) and the HRC fuses provide protection
Références
Description
against internal faults. An optional cubicle containing a power factor controller can be used to control
1
Châssis / Frame
the steps, thus forming an automatic compensation bank. For steps power values greater than
2
Isolateur / Insulator
900 kvar, single-phase capacitors connected in double star will be used (maximum of 12 capacitors,
3
Fusible / Fuse HRC
maximum power 4500 kvar).
4
•
•
•
•
•
•
28
Contacteurs / Contactor
Condensateurs / Capacitor Units
Total 5installation compensation
6
Self anti-harmoniques / Detuned Reactor
Fluctuating
load level
Ease of access to components
Simplified maintenance
Easy installation
Suitable for networks with a high harmonic level
Electrical characteristics
Mains
Steps
voltage (kV)
3.3
1
2
3
4
5
5.5
1
2
3
4
5
6
1
2
3
4
5
6.3
1
2
3
4
5
6.6
1
2
3
4
5
10
1
2
3
4
5
11
1
2
3
4
5
Composition
kvar - 50 Hz kvar - 60 Hz
Min. Max. Min. Max.
100
700
120
880
200
1450 240
1750
300
2200 360
2650
400
2800 480
3500
500
3400 600
3400
100
950
120
1150
200
1900 240
2250
300
2800 360
3400
400
3800 480
4536
500
4700 600
5700
100
950
120
1150
200
1900 240
2250
300
2800 360
3400
400
3800 480
4536
500
4700 600
5700
100
950
120
1150
200
1900 240
2250
300
2800 360
3400
400
3800 480
4536
500
4700 600
5700
100
950
120
1150
200
1900 240
2250
300
2800 360
3400
400
3800 480
4536
500
4700 600
5700
100
950
120
1150
200
1900 240
2250
300
2800 360
3400
400
3800 480
4536
500
4700 600
5700
100
950
120
1150
200
1900 240
2250
300
2800 360
3400
400
3800 480
4536
500
4700 600
5700
Each CP253SAH bank comprises the following
elements:
• An enclosure in unpainted aluminium or
galvanized steel, IP 23 for indoor installation.
• Propivar NG three-phase capacitors
(1 or 2 elements per step).
• One ROLLARC SF6 contactor per step.
• A detuning reactor (dry type, with magnetic
core, air cooling) per step.
• Three HRC fuses (with striker) per step.
Options
• Outdoor type enclosure.
• Double roof for outdoor type enclosure.
• Door with lock.
• Control and monitoring cubicle for «n» steps.
• Step auto/manual selector switch.
• Sets of two quick discharge reactors:
7.2 - 12 kV.
• Blown fuse indicator.
• Earthing switch.
General view, dimensions and three-lines diagram
H
L
H L
1 step 2 000 1 500
2 steps2 000 2 600
3 steps2 000 3 700
4 steps2 000 4 800
5 steps2 000 5 900
DE90102b
DE90075
80
D
D
2 400
2 400
2 400
2 400
2 400
29
MV capacitor
banks
Banks for global compensation
Insulation up to 36 kV – 50 Hz / 60 Hz
Fixed bank CP227
Application
DE90067
The CP227 medium-voltage capacitor banks are designed for use in electrical networks
up to 36 kV. This range is mainly used for total installation compensation.
4
2
5
1
3
1: Frame
2: Quick discharge reactors
3: Unbalance CT
4: Inrush reactors
5: Capacitors
Références
Description
Châssis
/ Frame
These banks are connected
in double star and the
unbalance
current detection system
1
provides protection against
internal
faults.
The
proposed
CP227
banks
TP de décharge rapide / Dischargecompensation
Coil
2
can be installed outdoors or indoors, mounted in aluminium or steel enclosures.
TC de déséquilibre / Unbalance CT
3
NB: CP 227 SAH fixed banks with detuning reactor are designed and proposed on request.
4
•
•
•
•
5
30
Self de choc / Damping Reactor
Total installation compensation
Ease of access to components
Simplified maintenance
Easy installation
Condensateurs / Capacitor Units
Power (kvar)
Power (kvar)
DB406318
Electrical characteristics
Mains voltage (kV)
Mains voltage (kV)
Composition
Each CP227 bank comprises the following elements:
• An enclosure in unpainted aluminium or galvanized steel, IP 23 for indoor installation.
• Propivar NG capacitors (6, 9 or 12 elements depending on the power of the bank).
• Three inrush current limiting reactors.
• A current transformer for unbalance protection.
Options
• Outdoor type enclosure (panels in
unpainted aluminium).
• Double roof for outdoor type enclosure.
• Door with lock.
• Sets of two quick discharge reactors by steps.
• Unbalance protection relay (supplied
separately).
• Earthing switch.
General view, dimensions and three-lines diagram
• Insulation up to 24 kV: H: 2000 mm, L: 1400 mm, D: 1400 mm.
• 36 kV insulation: H: 2000 mm, L: 3000 mm, D: 2100 mm.
• Approximate weight: 450 to 1550 kg.
DE90064
DE90101
80
H
L
D
31
Banks for distribution
and large sites networks
MV capacitor
banks
Insulation up to 36 kV – 50 Hz / 60 Hz
Automatic bank CP254
Application
DE90109
The CP254 medium-voltage capacitor banks are designed for use in electrical networks up to
36 kV. They are used for total installation compensation, when the load level is fluctuating.
7
4
3
1
2
6
1: Frame
2: Insulators of earthing switch
3: Quick discharge reactors
4: Inrush reactor
5: Unbalance CT
6: Capacitors
7: SF6 switch
These banks are connected in double star and the unbalance current detection system provides
protection against internal faults. Several banks (in that case called “steps”) can be controlled by
a power factor controller to form an automatic capacitor bank. The steps are connected in parallel
with power cables (outside our scope of supply).
NB: CP 254 SAH fixed banks
with detuning reactor are designed
and proposed on request.
Références
Description
•
•
•
•
•
32
Total
installation compensationChâssis / Frame
1
Fluctuating load level
2 of access to components
Isolateur / Insulator
Ease
Simplified maintenance
3
TP de décharge rapide / Discharge Coil
Easy installation
4
Self anti-harmoniques / Detuned Reactor
5
TC de déséquilibre / Unbalance CT
6
Condensateurs / Capacitor Units
Electrical characteristics
Mains voltage (kV)
13.8
15
20
22
30
33
kvar - 50 Hz kvar - 60 Hz
Min. Max. Min. Max.
720
4800
300
4500 300
6000 300
6300 600
7200 600
7200 720
8640
Composition
Each CP254 bank comprises the following elements:
• An enclosure in unpainted aluminium or galvanized steel, IP 23 for indoor installation.
• Propivar NG capacitors (6, 9 or 12 elements per step depending on the power of the bank).
• An SF6 switch.
• Three inrush current limiting reactors.
• A current transformer for unbalance protection.
Options
•
•
•
•
•
•
•
•
•
•
Outdoor type enclosure.
Double roof for outdoor type enclosure.
Door with lock.
Unbalance protection relay (supplied separately)*.
Three-pole / Five-pole earthing switch.
Ligne Current Transformer.
Voltage Transformer.
Sets of two quick discharge reactors.
Control and monitoring cubicle for «n» steps.
Step auto/manual selector switch.
* 2 relays are used for banks having capacitors with internal fuses; a single relay is required when there are no
internal fuses. If the monitoring and protection cubicle option is selected, the relays are installed in the cubicle.
General view, dimensions and three-lines diagram
DE90103
DE90076
80
H
L
D
• Insulation up to 24 kV
H: 2000 mm, L: 2600 mm, D: 1400 mm.
• 36 kV insulation
H: 2100 mm, L: 3000 mm, D: 2100 mm.
• Approximate weight: 450 to 1550 kg.
33
MV capacitor
banks
Banks for distribution networks
Insulation up to 36 kV – 50 Hz / 60 Hz
Fixed bank CP229
Application
DE90068
The banks of the CP229 range are mounted in aluminium racks.
They are used for reactive energy compensation in medium-voltage networks.
This high power range is designed for total compensation of large industrial plants
and power distribution systems.
5
1
2
6
3
7
1:
2:
3:
4:
5:
6:
7:
Frame
Insulators
Unbalance CT
Supporting stands
Capacitors
Copper busbar
Connection pad
4
These banks are connected in double star (up to 36 capacitors) and the unbalance current
detection system provides protection against internal faults.
NB: CP 229 SAH fixed banks with detuning reactor are designed and proposed on request.
•
•
•
•
•
34
Références
Description
Total plant compensationChâssis / Frame aluminium
1
Suitable for high power
2
Isolateur / Insulator
Ease of access to components
TC de déséquilibre / Unbalance CT
3
Simplified maintenance
Pieds support / Base support aluminium
4
Easy installation
5
Condensateurs / Capacitor Units
6
Jeu de barre CUIVRE / COPPER busbar
7
Plage de raccordement / Available connexion
Electrical characteristics
•
•
•
•
•
Rated frequency: 50 Hz or 60 Hz.
Insulation up to 36 kV.
Reactive power of 5.4 to 18 Mvar; maximum of 30 capacitors in standard configuration.
For higher power values, please contact us.
Tolerance on capacitance value: 0, +5%.
Options
• Inrush reactors (supplied separately).
DE90104
DE90065
General view and three-lines diagram
35
MV capacitor
banks
Banks for transport and distribution
networks
Insulation up to 245 kV – 50 Hz / 60 Hz
Fixed bank CP230
Application
DE90069
These capacitor banks are custom designed, in accordance with customer specifications.
Generally, they are used on high-voltage networks to increase the lines’ transmission capacity and
reduce voltage drops.
7
6
3
10
2
9
8
1
11
4
5
1: Frame
2, 3 & 4: Insulators
5: Supports
6: Lifting rings
7: Connection pad
8: Capacitors
9: Inrush reactors
10: Neutral busbar
11: Unbalance CT
Références
Description
1
Châssis / Frame aluminium
2
banks
Isolateur
/ Insulator
The
of the CP230 range
are
mounted in aluminium or galvanised steel frames. Schneider
Electric can
propose
capacitor
banks
for networks up to 230 kV.
3
Isolateur / Insulator
4
5
6
7
8
36
Isolateur / Insulator
• HV
and EHV compensation
Support / Support
• Special
design adapted to customer specifications
• Adaptation
to eyes
site conditions
Anneaux
de levage / Lifting
• Simple, robust installation
Plage de raccordement / Terminal pads
Condensateurs / Capacitor Units
9
Self de choc / Damping Reactor
10
Jeu de barre neutre / neutral busbar
11
TC de déséquilibre / Unbalance CT
Electrical characteristics
• Rated frequency: 50 Hz or 60 Hz.
• Insulation: up to 245 kV.
• Maximum reactive power: 100 Mvar, for higher values, please contact us.
• Tolerance on capacitance value: 0, +5%.
• Inrush current limiting reactors: single-phase reactors, dry type
air core.
DE90105
DE90077
General view and three-lines diagram
37
Power Factor
Correction and
harmonic filtering
Protection systems
Contents
Types of faults in capacitor banks
People safety
Protection of capacitors
Arc fault detector
40
41
42
44
39
Protection
systems
Types of faults in capacitor banks
DE90057
The main faults that can affect a capacitor
bank are:
• Element short circuit in a capacitor.
• Overload.
• Short circuit (two- and three-phase).
• Phase-to-earth fault.
1.33 IN
Element short circuit in a capacitor
Without internal protection (Fig. 1)
Elements wired in parallel are therefore bypassed by the short circuited
unit (cf. Propivar NG capacitors, p.46).
• The capacitor’s impedance is modified.
• The voltage applied is distributed over one set less in series.
• Each set is therefore subjected to a higher voltage stress, which may
cause other element failures in cascade until complete short circuit.
Initial voltage of element, UNE (equal to UN/4) becomes, after fault, equal to
UN/3, either 1.33 UNE.
With internal protection (Fig. 2)
Blowing of the internal fuse linked in series eliminates the short circuited
element.
• The capacitor stays in service.
• Its impedance is "slightly" modified accordingly.
1.33 UNE
If=1.33 IN
1.33 UNE
1.33 UNE
Figure 1: Wafer short circuit without
internal fuse protection
Overload
Overload is due to a permanent or temporary overcurrent:
• permanent overcurrent due to:
- a rise in the supply voltage;
- the circulation of a harmonic current due to the presence of nonlinear
loads such as static converters (rectifiers, variable speed drives),
arc furnaces, etc.;
• temporary overcurrent due to energizing of steps of a bank.
An overload results in overheating which is harmful to dielectric strength,
and causes premature capacitor ageing.
DE90056
Short circuit (two- and three-phase)
The short circuit is an internal or external fault between live conductors,
either phase-to-phase (delta-connected capacitors), or phase-to-neutral
(star-connected capacitors). External short circuits may be due to
external overvoltages (lightning stroke, switching surge) or insulation
faults (foreign bodies modifying clearances).
They result in electric arcs causing material peeling, overpressures
and electrodynamic forces. Internal short circuits result in electric arcs
in the oil, which causes the appearance of gas in the sealed enclosure
leading to violent overpressures which can cause rupture of
the enclosure and leakage of the dielectric.
0.978 IN
0.978 UNE
0.978 UNE
1.067 UNE
0.978 UNE
Figure 2: Wafer short circuit
with internal fuse protection
40
Phase-to-earth fault
The earth fault consists either of an internal fault between a live part of
the capacitor and the frame consisting of the metal enclosure which is earthed
(for protection of human life), or an external fault between live conductors and
the frame.
The effects of the short circuit depend on the sum of the fault impedance and
the loop impedance (which depends on the network’s earthing system). The
resulting current may be very low and inadequate to cause blowing
of external fuses, which may result in a gradual overpressure (accumulation
of gases) and heavy stresses on the enclosure.
Protection
systems
People safety
The main devices contributing to people safety
in reactive energy compensation equipment are:
• Digital protection relay
(phase-to-earth fault, short circuit).
• Quick discharge reactors.
• Earthing switch.
• External fuses.
Digital protection relays
It performs protection against the various types of fault.
• Phase-to-earth fault by earth overcurrent protection (ANSI 50N-51N)
which allows detection of overcurrents due to phase-to-earth faults.
It uses measurement of the fundamental component of the earth current.
• Overload by thermal overload protection (ANSI 49 RMS) which
can protect capacitors against overloads based on measurement
of current drawn.
• Short circuit by phase overcurrent protection (ANSI 50-51) which
allows detection of overcurrents due to phase-to-phase faults. It uses
measurement of the fundamental component of the currents coming
from 2 or 3 “phase CT” current transformers.
Quick discharge reactor
PE90102
The installation of two quick discharge reactors (“PT” potential
transformers) between phases of the bank allows capacitor
discharge time to be reduced from 10 minutes to about 10 seconds.
This reduction in discharge time provides:
• safety for personnel during any servicing operations;
• a reduction in waiting time prior to earthing (closing of the earthing
switch).
No more than 3 consecutive discharges are acceptable
and it is essential to comply with a 2-hour rest period (for cooling) before
starting a sequence again.
Earthing switch
This is a safety-critical component, designed to ground and discharge
capacitors prior to maintenance to allow human intervention
on the installation in complete safety.
The capacitor terminals must be earthed and kept earthed while
the servicing operation is in progress.
PE90101
Quick discharge reactors
Line disconnector
The disconnector is an electromechanical device allowing mechanical
separation of an electric circuit and its power supply, while physically
ensuring an adequate isolation distance. The aim may be to ensure
the safety of personnel working on the isolated part of the electrical
network or to eliminate part of the network at fault.
Medium-voltage line disconnectors are often combined with
an earthing switch.
Earthing switch
41
Protection
systems
Protection of capacitors
The main capacitor protection devices are:
• Internal fuses.
• External fuses.
• Inrush reactors.
• Unbalance protection relays.
• Digital protection relay (overload).
Internal fuses
Propivar NG capacitors (single-phase capacitors) can be supplied with
protection by an internal fuse combined with each element.
In the event of failure of one element, it will be disconnected and
isolated. Failure of an element can occur:
• when the capacitor’s voltage is close to maximum magnitude. In this
case, power stored in the capacitances of the parallel elements causes
blowing of the internal fuse (Fig. 1);
• when the capacitor’s voltage is close to zero. Circulation of total
capacitor current causes blowing of the internal fuse (Fig. 2).
DE90078
• Instantaneous disconnection of the short-circuited element
• Lower maintenance costs
• Continuity of service maintained
• Possibility of planned preventive maintenance operation
(monitoring of the capacitor element)
DE90079
Fig. 1: Internal fuse blowing caused by discharge of
the energy stored in the capacitor elements coupled
in parallel
Fig. 2: Internal fuse blowing caused when
the capacitor’s voltage is close to zero
42
PE90092
External fuses
HRC fuses
The external fuses for capacitors are designed to eliminate capacitors
at fault, so as to allow the other steps of the bank to which the unit is
connected to continue to operate. They also eliminate external sparkover
on capacitor bushings. The operation of an external fuse
is generally determined by the fault current supplied by the network
and by the discharge energy coming from the capacitors connected
in parallel with the capacitor at fault.
The initial failure is usually an individual element (wafer) of
the capacitor. This failure results in a short circuit which applies to
all the elements in parallel and thus eliminates a series set of elements.
If the cause of the initial failure remains, failure of the successive series
sets (which sustain a voltage increase with each elimination of a series
set) will occur. This causes a current increase in the capacitor until
the external fuse operates, eliminating the failed capacitor from
the circuit.
PE90103
Protection by external HRC (High Rupturing Capacity) fuses
incorporated in the bank is very suitable (technically and economically)
for capacitor banks of:
• low power (< 1 200 kvar);
• provided with three-phase capacitors;
• mains voltage < 12 kV.
The fuse rating will be chosen with a value ranging between 1.7 and 2.2
times the current rating of the bank (1.5 to 2.2 with detuning reactors).
Blowing of HRC fuses is generally caused by a non-resistive short
circuit. The blown fuse indication is a visual means of checking
the state of the fuse.
Inrush reactors
PE90104
Inrush reactors
Inrush reactors are connected in series to each step and serves to limit
the current peak which occurs during switch-on operations.
The inductance value is chosen to ensure that the peak current
occurring during operations always remain less than 100 times
the current rating of the bank.
Main characteristics:
• Air-core reactors, dry type.
• Single-phase configuration.
• Indoor or outdoor installation.
• In compliance with IEC or equivalent standards.
Unbalance protection
This protection generally applies to banks of:
• medium or high power ( > 1200 kvar);
• provided with single-phase capacitors;
• double star connection compulsory.
Unbalance or differential protection is a protection system capable
of detecting and responding to a partial capacitor fault.
It consists of a current transformer connected between two electrically
balanced points combined with a current relay. In the event of a fault
in a capacitor, the result is an unbalance, hence a circulating current
in the current transformer which will cause, via the relay, opening
of the bank’s switchgear (circuit breaker, switch, contactor, etc.).
Note: there is no unbalance protection with three-phase capacitors.
Current transformer for unbalance protection
43
Protections
Arc fault detector
Vamp 120
Benefits
•
•
•
•
•
•
Personnel safety
Reduces production losses
Extended switchgear life cycle
Reduced insurance costs
Low investment costs and fast installation
Reliable operation
Functions
Vamp arc flash protection maximizes the personnel safety and
minimizes the material damage of the installation in the most
hazardous power system fault situations. The arc protection unit
detects an arc flash in an installation and trips the feeding breakers.
On detection of a fault the arc flash protection unit immediately trips
the concerned circuit breaker(s) to isolate the fault.
An arc flash protection system operates much faster than
conventional protection relays and thus damage caused by an arc
short circuit can be kept to a minimum level.
PE90501
System features
• Integrated 19 - 256 V AC/DC aux. supply.
• Up to 4 arc sensors.
• Selective trip for 2 zones and possibility for generator set emergency trip
(separate contact).
• Operation time 7 ms (including the output relay).
• Non-volatile trip status.
• NO and NC trip outputs:
- self-supervision,
- straight-forward installation,
- cost efficient solution.
Sensors
• Point sensor:
- arc detection,
- self-monitored,
- cable length adjustable from 6 m to 20 m.
Standards
Disturbance standards
Electromagnetic compatibility
Test voltage standards
Electrical security tests
Mechanical standards
Shock response
Shock withstand
Bump test
Vibration
Environmental conditions Operating temperature
Transport and storage temperature
Relative humidity
Degree of protection (IEC 60529)
Emission
Immunity
Insulation test voltage
Impulse test
Sinusoidal response
Sinusoidal endurance
EN 61000-6-4
EN 61000-6-2
IEC 60255-5
IEC 60255-5
IEC 60255-21-2, class I
IEC 60255-21-2, class I
IEC 60255-21-2, class I
IEC 60255-21-1, class I
IEC 60255-21-1, class I
-10 to +55°C
- 40 to +70°C
< 75% (1 year, average value)
< 90% (30 days per year,
no condensation permitted)
IP20
• Schneider Electric VAMP’s arc flash fault protection functionality
enhances the safety of both people and property and has made
Schneider Electric VAMP a pioneer in the field of arc flash protection
with more than 10.000 VAMP arc flash systems and units with over
150.000 arc detecting sensors in service worldwide.
44
45
Power Factor
Correction and
harmonic filtering
Components
Contents
MV Propivar NG capacitor
Varlogic power factor controller
Current Transformer
Potential Transformer
Detuning or filtering reactor
Rollarc contactor SF1& SF2 circuit breakers Vacuum contactor CBX3-C
SF1& SF2 circuit breakers Control and monitoring unit
Digital protection relay: Sepam
48
50
51
51
52
53
54
56
57
58
47
Propivar NG capacitor unit
Components
PB108153
PB108151
Propivar NG capacitors are used to
build capacitor banks for reactive energy
compensation on medium- and high-voltage
networks. Through various assemblies,
they can cover various reactive power ratings
according to the mains voltage, frequency
and level of harmonic distortion of the network.
Description
A high-voltage Propivar NG capacitor takes the form of a metal
enclosure with terminals on top.
This enclosure contains a set of capacitor elements. Wired in seriesparallel groups, they can form unit elements of high power
for high network voltages. Two types are proposed:
• with internal fuses (Single Phase Capacitor, Double Capacitor),
available with Q > 100 kvar, some possible limitations according to
voltage level;
• without internal fuse (Three Phase or Single Phase Capacitor,
Double Capacitor).
These capacitors are provided with discharge resistors to reduce
the residual voltage to 75 V, 10 minutes after their switching off.
On request, the capacitors can be supplied with resistors to reduce
the residual voltage to 50 V in 5 minutes.
Composition
Three phase and double
capacitor
DB108807
Single phase capacitor
The capacitor elements forming the Propivar NG capacitor are made of:
• folded aluminium electrodes;
• polypropylene films;
• non PCB (chlorine free) dielectric fluid (Jarylec C101).
Main characteristics
Propivar NG capacitors have an exceptional long service life increased
by their low losses, their chemical and heat stability and their resistance
to overvoltages and overcurrents, as well as their withstand to
environment (salt mist, sulphurous atmosphere, vibrations).
Heat stability
At low temperature, these capacitors are able to withstand switching
transient. At higher ambient temperatures, they provide very limited heating,
so that there is no risk of modification of the dielectric insulation properties.
Chemical stability
Transient surges in networks and partial discharge levels cause
accelerated ageing of capacitor elements. The exceptionally long service
life of Propivar NG capacitors is due to the intrinsic properties
of the dielectric fluid, namely:
• very high chemical stability;
• high power of absorption of gases generated during partial discharges;
• very high dielectric strength.
Propivar NG capacitor with internal fuse, built with
4 series group of 12, parallel elements complete
with discharge resistors
Overvoltage and overcurrent resistance
Capacitors can accept:
• an overvoltage of 1.10 UN, 12 h per day;
• an overvoltage at power frequency of 1.15 UN, 30 minutes per day;
• a permanent overcurrent of 1.3 IN.
Their resistance is tested according to IEC 60871-2:
• 850 cycles at an overvoltage level of 2.25 UN
(cycle duration 15 periods);
• ageing tests at 1.4 UN (1000 hours).
Salt mist
The capacitors have been tested to salt mist according to IEC 60068-2-11
(672 hours) with temperature criteria from NPX 41-002.
Sulphurous atmosphere
The capacitors have been tested to sulphurous atmosphere according to
NFT 30-055 (30 days).
Vibrations
The withstand of the capacitors have been tested according to
IEC 60068-2-6 up to 3M4 level.
48
Standards
IEC 60871-1, 2 and 4, NEMA CP1 (other standards on request).
Quality assurance and environment
Propivar NG complies with ROHS regulations and is declared
in REACH.
Schneider-Electric capacitor plants are certified according
to ISO9001 (Quality) and ISO14001 (Environment).
Other characteristics
Operating frequency
Temperature range
Average loss factor at 20 °C after
stabilization
Maximum nominal reactive power
Capacitor voltage range
Three Phase Capacitor
Single Phase Capacitor
Double Capacitor
Three Phase Capacitor
Single Phase Capacitor
Double Capacitor
Indoor/outdoor
Location
Tolerance on capacitance value
Relative capacitance variation ∆C/C per °C
Capacitor tank
Material
Thickness
Surface treatment
180
QN (kvar)
349
Single Phase Propivar NG
(BIL max / 170 kV)
A
B
50 Hz 60 Hz (mm)(mm)
50
60
157 300
100 120 157 300
150 180 157 300
200 240 157 350
250 300 157 450
300 360 157 500
350 420 187 500
400 480 187 550
450 540 187 600
500 600 187 650
550 660 187 700
600 720 187 800
700 840 207 800
800 960 207 900
900 207 y 950
20
20
110
432
Three Phase
Propivar NG
110
QN (kvar)
180
Single Phase
Propivar NG
432
220
B
DB406182
A
-5 % to +10 %
-3.5 . 10-4/°C
Stainless steel
1.5 mm
Stainless steel ball blasted surface, one layer of two component
paint plus one layer of hydro paint.
Grey RAL 7038
One per side
Porcelain, grey colour
Two M16 x 2
Nickel-coated brass, max 2 cables (external diameter 10 mm max)
Two 13*24 mm holes, 395.5 mm centers
B
Terminations
DB406183
Colour
Fixing brackets
Bushings
Terminals
Clamps
Fixing
50 Hz or 60 Hz
-25 °C to +50 °C (-40 °C to +55 °C on request)
0.16 W/kvar with internal fuses
0.12 W/kvar without internal fuse
600 kvar
900 kvar
800 kvar
1-12 kV
Ph/Ph
1-17.3 kV
Ph/N
1-9 kV
Ph/N
=
=
349
A
Three Phase Propivar NG (BIL max / 75 kV) and
Double capacitor Propivar NG (BIL max / 95 kV)
50 Hz
50
75
100
125
150
175
200
250
300
350
400
450
500
550
600
60 Hz
60
90
120
150
180
210
240
300
360
420
480
540
600
-
A
B
(mm)
157
157
157
157
157
157
157
157
157
187
187
187
187
187
187
(mm)
300
300
300
300
300
350
350
450
500
500
550
600
650
750
850
A
B
(mm)
157
157
157
187
187
187
207
207
(mm)
300
350
500
550
650
800
800
900
Double Capacitor Propivar NG
QN (kvar)
• These dimensions are given for indicative
purposes, some possible "modifications"
according voltage level.
50 Hz
100 (2 x 50)
200 (2 x 100)
300 (2 x 150)
400 (2 x 200)
500 (2 x 250)
600 (2 x 300)
700 (2 x 350)
800 (2 x 400)
60 Hz
120 (2 x 60)
240 (2 x 120)
360 (2 x 180)
480 (2 x 240)
600 (2 x 300)
720 (2 x 360)
800 (2 x 400)
-
49
Varlogic power factor controller
Components
PB100032_SE
PB100033_SE
Varlogic controllers constantly measure
the installation’s reactive power
and manage connection and disconnection
of capacitor steps to obtain the desired
power factor.
The NRC12 can manage up to 12 capacitor
steps and has extensive functionalities
including Modbus communication (optional).
It simplifies the commissioning, monitoring
and maintenance of power factor
correction equipment.
Varlogic NRC12
NRC12 technical specifications
Number of steps Dimensions Frequency Monitoring current Monitoring voltage* Measured power
display Nominal consumption Tensions d’alimentation
Output relay Screen Degree of protection Target pf (cos ϕ) range Response current C/K Reconnection time
Response time Values displayed
Type of installation Enclosure Operating temperature Alarm history Stepped meter Fan control
by dedicated relay Alarm contact
TC range
Detection of voltage dips Communication
12
155 x 158 x 80 mm
50 Hz nominal (range 48...52 Hz)
60 Hz nominal (range 58...62 Hz)
0…1 A or 0...5 A
80…690 V (nominal, max. 115%)
100 000 kVA
13 VA
110 V nominal, (range 88...130 V)
230 V nominal, (range 185...265 V)
400 V nominal, (range 320...460 V)
250 V, 2 A
Graphic display, resolution 64x128 pixels, backlit
IP41 front panel, IP20 rear panel
0.85 ind …1.00 … 0.90 cap
0.01 ... 1.99, symmetric or asymmetric
10…900 s
20 % reconnexion time, min. 10 s
cos ϕ, Iact, Ireact, Iapp, IRMS/I1, P, Q, S, THD (U)
and harmonic voltages, THD(I) and harmonic current, internal and external temperature
Flush mounting or on DIN rail
Impact-resistant PC/ABS, UL94V-0
0…60°C List of the last 5 alarms
Yes
Yes. 250 Vac, 8A
Yes. 250 Vac, 8A
25/1 … 6000/1 or 25/5 … 6000/5
Response time > 15 ms
Modbus protocol with CCA-01 (option)
* Voltage transformer ratio input allows display/monitoring of primary voltage
in MV installation
50
Current Transformer
Potential Transformer
Components
Current Transformer
Composition and types
Current Transformers are designed to perform protection and monitoring
functions.
• Detection of overcurrents in capacitor banks and supply of a signal
to the protection relay.
• Supply of a signal to the power factor controller.
They are of the following types:
• wound (most common type): when the primary and secondary include
a coil wound on the magnetic circuit;
• bushing type: primary formed by a conductor not isolated from
the installation;
• toroidal: primary formed by an isolated cable.
DE52359
DE52344
Current Transformers (CT) meet standard IEC
60044-1.
Their function is to supply the secondary circuit
with a current that is proportional to that of the
MV circuit on which they are installed.
The primary is series-mounted on the MV
network and subject to the same over-currents
as the latter and withstands the MV voltage.
The double star arrangement and unbalance protection require the use
of special current transformers (class X).
Magnetic core
Magnetic core
Closed core type current
transformer
PE56030
Wound type primary
current transformer
Current Transformer
Potential Transformer
Composition and types
Potential Transformers are designed to perform protection and
monitoring functions.
• Detection of over-/under-voltages in capacitor banks and supply
of a signal to the protection relay.
• Supply of a signal to the power factor controller.
PE56700
Potential Transformers (PT) meet standard
IEC 60044-2.
They have two key functions:
• adapting the value of MV voltage on
the primary to the characteristics of metering
protection devices by supplying a secondary
voltage that is proportional and lower;
• isolating power circuits from the metering
and/or protection circuit.
Phase-earth Potential
Transformer
51
Detuning or filtering reactor
Components
Iron-core reactor, “resin-impregnated” technology
1
Iron-core reactor, “resin-encapsulated” technology
•
•
•
•
•
•
•
•
•
•
•
•
•
2
PE90094
PE90093
PE90096
A detuning reactor forms part of the power
factor correction equipment, to prevent
amplification of the pre-existing harmonic in
current and voltage on the network.
There are many types of reactors.
Indoor installation.
Three-phase type.
Max. voltage 12 kV.
Connection to copper pad.
Weight up to 2000 kg.
Indoor installation.
Three-phase type.
Max. voltage 24 kV.
IEC 60076-6 standard.
Fire resistance.
Temperature class F.
Connection to copper pad.
Weight up to 2000 kg.
Iron-core reactor, “oil-immersed” technology
•
•
•
•
•
Indoor or outdoor installation.
Max. voltage 36 kV.
Hermetically sealed type with integral filling.
Connection to porcelain or plug-in bushings.
Weight up to 3500 kg.
Air-core reactor (coreless), “resin-impregnated” technology
3
Air-core reactors are characterized by a reactance which does not depend
on the current passing through them (constant permeability of air).
These reactors are generally installed in substations or in static
compensation equipment (SVC - Static Var Compensator).
The “dry” type design is characterized by high reliability, no maintenance
and great adaptability to environmental constraints.
• Mainly outdoor installation.
• Max. voltage up to 245 kV.
PE90095
4
1: Iron-core reactor, “resin-impregnated” technology
2: Iron-core reactor, “resin-encapsulated” technology
3: Iron-core reactor, “oil-immersed” technology
4: Air-core reactor (coreless), “resin-impregnated”
technology
52
Components
Rollarc contactor
The Rollarc three-pole type contactor,
for indoor use, employs SF6 for insulation
switching.
The breaking principle is that of the rotating
arc. The basic device consists of three pole
units mounted in a single insulating enclosure.
The insulating enclosure containing the live
parts of these poles is filled with SF6
at a relative pressure of 2.5 bar.
The Rollarc contactor is available in two types:
• R400 contactor, with magnetic holding.
• R400D contactor, with mechanical latching.
Applications
Control and protection of
• MV motors.
• Capacitor banks and power transformers.
Reference standards
• IEC 60470 standard: High-Voltage Alternating Current Contactors
and Contactor-Based Motor-Starters.
• IEC 62271-105 standard: High-voltage switchgear and controlgear,
Alternating current switch-fuse combinations.
Electrical characteristics
Rated
Insulation level
Breaking capacity
Rated
Making capacity Short-timeMechanical
voltage current
thermal
endurance
UR (kV) Inpulse 1 mn
with
IRwith
current
50/60Hz 1,2/50μs 50/60Hz
fuses
fuses
3s
kV
kV peak kV rms kA
kA
A
kA peak
kA
kA rms
7,2602010 50 400
25
125
10100 000
operations
12 60288 40 400
20
100
8
Maximum operable power
Voltage (kV)
Without fuse
With integrated fuse
Power (kvar)
Power (kvar)
3,3 1255790
4,161585800
6,6 25101270
10 3810960
12 45701155
Equipment requiring no maintenance on live parts.
High mechanical and electrical endurance.
Insensitivity to the environment.
Gas pressure can be monitored constantly.
PE56761
PE90105
•
•
•
•
1: MV connections
2: LV connections
3: Auxiliary contacts
4: Pressure switch
5: Electromagnetic control
mechanism
6: Mechanical latching
device (R400D)
7: Opening release
8: Mounting points
9: Insulating enclosure
10: Rating plate
Rollarc contactor (connections)
Rollarc contactor (cutaway)
53
Composants
Vacuum contactor CBX3-C
PE90243
The three-phase CBX3-C contactor, designed
for indoor applications, uses vacuum
technology for insulation and arc-breaking.
It is specifically designed for breaking
capacitive loads.
Applications
The design and contact materials fulfil the general requirements for
contactor applications of capacitor bank feeders in various industrial
sectors, such as:
• metallurgy,
• mining,
• oil and gas,
• electrical distribution.
CBX comes with an electronic auxiliary supply (EAS) as standard
equipment for easy configuration and low consumption.
Standards
Schneider Electric vacuum contactors have been designed to meet or
exceed the requirements of international standards:
• CEI 60470,
• ANSI C37,
• BS EN 60470,
• NEMA ICS,
• GB (Chinese).
Electrical characteristics
CBX3-C
Rated Voltage (kV)
Power frequency withstand
voltage (kV)
Impulse withstand voltage (BIL) (kV)
Capacitive load
Rated operating current (A)
Maximum capacitor bank
rating (kvar)
Inrush current (kAp)
Short time withstand current
1 s (kA)
Peak on ½ cycle (kAp)
Mechanical endurance (N°)
Electrical endurance at
rated current (N°)
Temperature range (°C)
Number of poles
54
7.2 / 12
20 / 28
60 / 75
400
3360 /
5600
20
4
25
3 millions
500 000
-5 to +40
1P - 3P
Control
Closing coil supply voltage (V)
Latch supply voltage (V)
Power consumption (W)
Latch voltage supply
DC: 24, 48, 60, 110, 125, 220, 250
AC: 110, 120, 220, 240
DC: 24, 48, 110, 240
AC: 110, 240
CBX
Closing
Magnetic holding
Magnetic holding with EAS
Power consumption (W)
Endurance (N°)
500
150
80
240
200000
Electronic Auxiliary Supply (EAS)
A selection of only two standard electronic circuits are required to
manage all usual auxiliary voltages:
• 24 to 60 V DC,
• 110 to 250 V AC/V DC.
Benefits
• Low power consumption.
• Improved reliability.
• Operation counter (optional).
• Optional 100 ms delay to open.
• Reduced thermal dissipation.
• Standardized schematics.
Options
CBX
Auxiliary contacts
Electronic supply (EAS)
Opening delay 100 ms
Operation counter
Insulation level at 42 kV
Mechanical latch
5 NO + 5 NC
Yes
Option
Option
Option
Option
Dimensions
• Fast switching rate.
• Long mechanical life.
• Low power losses thanks to
electronic auxiliary supply.
Width (mm)
Length (mm)
Height (mm)
Weight (kg)
343
333
258
28
55
Components
SF1 & SF2 circuit breakers
PE56501
The SF circuit breaker of the Schneider Electric
equipment range is used for switching on
capacitor banks or steps.
This circuit breaker uses SF6 as dielectric.
It has been especially tested for the specific
operation of capacitor banks.
Description
The SF circuit breaker, in its basic fixed version, consists of:
• 3 main poles, linked mechanically and each comprising an insulating
enclosure of the “sealed pressure system” type. The sealed enclosure
is filled with SF6 at low pressure.
• A spring type energy storage manual control (electrical on option). This
means the device’s making speed and breaking speed
are independent of the operator. When it is provided with electric control,
the circuit breaker can be remotely controlled and resetting cycles can
be performed.
• Front panel with the manual control and status indicators.
• Downstream and upstream terminals for power circuit connection.
• A terminal block for connection of external auxiliary circuits. Depending
on these characteristics, the SF circuit breaker is available with a front or
side control mechanism.
Options
PE56503
SF1 circuit-breaker
• Electric control
• Supporting frame fitted with rollers and floor mounting brackets
for a fixed installation.
• Circuit breaker locking in open position by lock installed
on the control front plate.
• SF6 pressure switch for highest performance.
Applications
The SF devices are three-pole MV circuit breakers for indoor use.
They are chiefly used for switching and protection of networks
from 12 to 36 kV in the distribution of primary and secondary power.
With self-compression of the SF6 gas, which is the switch-off technique
used in these circuit breakers, the establishment or interruption
of any type of capacitive or inductive current is performed without
any dangerous overvoltage for the equipment connected to
the network.
The SF circuit breaker is therefore highly appropriate for the switching of
capacitor banks.
SF2 circuit-breaker
SF1 fixed
Side or front operating mechanism
Rated voltage Ur (kV, 50/60 Hz)
SF2 fixed
Front operating mechanism
36 kV
24 kV
36 kV
40.5 kV
24 kV
17.5 kV
12 kV
Rated short-circuit breaking current (Isc )
25 kA
from 12.5 to 25 kA
from 12.5 from 25
31.5 kA
to 40 kA
to 40 kA
Rated current (Ir )
630 A
from 400 to 1 250 A
from 630 to 3 150 A
Rated switching capacitive current (Ic )
440 A
from 280 to 875 A
from 440 to 2 200 A
56
2 500 A
1 750 A
Components
Control and monitoring unit
The function of these units is to control
and protect capacitor banks.
Description
These enclosures are designed for indoor installation.
They comprise the following elements:
• A Varlogic power factor controller;
• A Sepam digital protection relay:
• Unbalance protection relays;
• Indicator lamps
- “ON”
- for each step, “Step ON”, “Step OFF”, “Unbalance alarm”,
“Unbalance trip”.
Option
PE90106
A three-position selector switch:
• “Auto”: The steps are controlled automatically by the power factor
controller;
• “Manual”: The steps are controlled manually by means of a 2-position
selector switch located on the enclosure (1 selector switch per step);
• “0”: The steps are disconnected (no control, automatic or manual,
is possible).
1
2
1
2
Monitoring and control unit
1. Varlogic power factor controller
2. Sepam digital protection relay
57
Components
Sepam protection relay
PA40431
Sepam protection relays maximise energy
availability and the profits generated by
your installation while protecting people
and property.
Stay informed to manage better
With Sepam, get intuitive access to all system information in
one’s own language to manage the electrical installation
effectively. If a problem occurs, clear and complete information
puts everyone in a position to make the right decisions immediately.
Maintain installation availability
Sepam maintains high energy availability thanks to its diagnostics
function that continuously monitors network status.
In-depth analysis capabilities and high reliability ensure that
equipment is de-energized only when absolutely necessary.
Risks are minimized and servicing time reduced by planned
maintenance operations.
Enhance installation dependability
Sepam protection relays
Sepam series 80 is the first digital protection relay to deliver
dependability and behaviour in the event of failure meeting
the requirements of standard IEC 61508.
Sepam manufacturing quality is so high that the units can be used in
the most severe environments, including off-shore oil rigs and chemical
factories (standard IEC 60062-2-60).
Communicate openly
In addition to the DNP3, IEC 60870-5-103 and Modbus standards,
Sepam complies with IEC 61850 and uses the communication
protocol that is today’s market standard to interface with all brands
of electrical-distribution devices.
Respect the environment
•
•
•
•
Compliance with RoHS European Directive.
Low energy consumption.
Manufacturing in plant certified ISO 14001.
Recyclable over 85% (Sepam S10).
Modular range structured; Capacitor application
S20
S24
Protection of a capacitor
bank (delta connection)
without voltage monitoring
• capacitor bank shortcircuit protection
58
S40
C86
Protection of a capacitor
bank (delta connection)
without voltage monitoring
• capacitor bank sc
protection
• U et f monitoring
• overload protection:
(Sepam C86)
C86
Protection of a double star connected capacitor bank
with 1 to 4 steps
• capacitor bank short-circuit protection
• U et f monitoring
• overload protection
• unbalance protection
Technical specifications
b : standard
v : option
* Figures indicate
the number of protection
functions available
Code ANSI
S10A
S10B
S20S24S40C86
Protections*
Phase overcurrent
50/51
224448
Earth fault
50N/51N
224448
Sensitive earth fault
50G/51G
224448
Breaker failure
50BF1
1
1
Negative sequence / unbalance
46
1
1
2
2
Thermal overload for capacitors
49RMS
1
1
1
Capacitor-bank unbalance
51C8
Positive sequence undervoltage
27D2
Remanent undervoltage
27R2
Undervoltage (L-L or L-N)
272
4
Overvoltage (L-L or L-N)
592
4
Neutral voltage displacement 59N2
2
Negative sequence overvoltage
471
2
Overfrequency
81H
2
2
Underfrequency
81L4
4
Temperature monitoring (16RTDs)
38/49Tv
Measures
Phase current RMS I1, I2, I3
b
b
bbbb
Measured residual current I0Σ b
Demand current I1, I2, I3
bbbb
Peak demand current IM1, IM2, IM3
bbbbbb
Measured residual curent I0, I’0
bbbbbb
Voltage U21, U32, U13, V1, V2, V3
bb
Residual voltage V0bb
Fréquencybb
Active power P, P1, P2, P3
bb
Reactive power Q, Q1, Q2, Q3
bb
Apparent power S, S1, S2, S3
bb
Peak demand power PM, QM
bb
Power factorbb
Active and reactive energy
bb
Network, switchgear and capacitors diagnosis
Tripping current
bbbb
tripI1, tripI2, tripI3, tripI0
Harmonic distortion (THD) current
b
and voltage THDi, THDu
Phase displacement φ0, φ'0, φ0Σ
b
Phase displacement φ1, φ2, φ3bb
Disturbance recording
bbbb
Thermal capacity usedb
Capacitor unbalance b
current and capacitance
CT/PT supervision
60/60FLbb
Trip circuit supervision
74vv
Auxiliary power supply monitoringb
Cumulative breaking current
bbbb
Number of operations
vvvv
Control and monitoring
Circuit breaker/contactor control
94/69
vvvv
Logic discrimination
68
b
vvvv
Latching/acknowledgement86
bbbbbb
Annunciation30
bbbbbb
Communication protocols S-LAN
Modbus RTU
b vvvv
Modbus TCP/IP
v vvvv
DNP3vvvv
CEI 60870-5-103
vvvv
CEI 61850
vvvv
59
Power Factor
Correction and
harmonic filtering
Specific equipments
Contents
Hybrid Var Compensator (HVC)
Passive harmonic filters Blocking circuits
62
64
65
61
Specific
equipments
Hybride Var Compensator (HVC)
HVC (Hybrid Var Compensator) equipment
is designed to perform economical reactive
energy compensation in real time.
Its use can:
• improve the quality of public and industrial
networks by reducing or eliminating voltage
fluctuations, power fluctuations, etc.;
• increase the capacity of existing networks
by compensating losses due to reactive
energy;
• allow optimum coupling of renewable
energies (wind-power, solar power) to
the network through an appropriate response
to normative constraints
Hybrid Var Compensator (HVC)
Description
The equipment comprises a fixed MV bank of shunt capacitors with
detuning reactor, and an AccuSine electronic device combined with
an LV/MV step-up transformer.
DE90083
25 / 4.16 kV
25 / 4.16 kV
2000 A
2000 A
CT (3) 1000/5
CT (3) 1000/5
1200A
4.16kV
4.16kV
CT (3) 1000:5
2000A
6 x 250kvar
Accusine
Example of implementation
62
PE90082
PE90046
4.16 / 0.48 kV
1225 kvar
MV bank
with detuning
reactors
DE90084
Operation
The fixed capacitor bank constantly injects a capacitive reactive current
into the network. The electronic device injects a reactive, capacitive
or inductive current, continually and in less than one period (20 ms 50 Hz), to compensate the major rapid fluctuations in reactive power
consumption due to the load.
Characteristics
fixed kvar
load
AccuSine
result kvar
•
•
•
•
•
•
Injection of reactive energy in “leading” or “lagging” mode.
Response time less than one cycle.
Power factor adjustable up to unity.
Reactive energy compensation without transient.
Continuous compensation.
Separate monitoring of each phase for unbalanced loads.
Applications
PE90074
• Energy
- Connection of wind-power or solar farms.
• Industry
- Arc furnaces: voltage regulation and flicker attenuation.
- Welding machines: voltage regulation and flicker attenuation.
- Crushers: flicker attenuation.
- Pumping stations: starting assistance for high-powered MV motors.
- Cold/hot rolling mills: attenuation of harmonics and improvement of the
power factor of rapidly fluctuating loads.
AccuSine range
63
Specific
equipments
Passive harmonic filters
PE90097
Schneider Electric can propose numerous
passive harmonic filtering solutions in medium
and high voltage, for 50 or 60 Hz networks.
These solutions are custom designed on
a case by case basis. A preliminary site audit
and a precise definition of needs (objectives
to be achieved, etc.) are essential to guarantee
the performance of this type of solution.
Passive harmonic filter
64
Passive harmonic filters
Technical characteristics
• Rated frequency: 50 Hz or 60 Hz.
• Insulation: 72.5 kV (for other values, please consult us).
• Maximum reactive power: 35 Mvar (for other values, please consult us).
• Reactors: single-phase, dry, air-core; they are most commonly used for
passive filters.
• Other components, such as resistors, can also be used in the design of
passive filters.
• Tuning frequencies: chosen according to the harmonics to be filtered
and the performance to be achieved (a preliminary site audit is crucial
to make the right choices).
Blocking circuits
Principle
In its range of solutions, Schneider Electric
has low-frequency passive blocking circuits
which can prevent disturbance by musicalfrequency remote control signals emitted by the
power distributor, especially in the context of
installation of an autonomous production unit.
DE90054
Reactor
Reactor
1640
To meet the conditions required by the power
distributor, the blocking circuit is defined
on a case by case basis according to
the characteristics of:
• the HV power supply line of the source
substation;
• the HV/MV transformer of the source
substation;
• the remote control order injection device;
• the load of the MV feeders;
• the generating sets.
DE90054
These blocking circuits are often used in
installations provided with cogeneration plants.
The blocking circuit is implemented by placing in parallel an reactor and
a capacitor element whose values have been calculated to allow blocking of
a chosen frequency (175 Hz or 188 Hz in France, for example).
400
Specific
equipments
Insulator 24kV
Path AL
6060
900
900
Capacitor
20
300
4ǿ13
1100
20
Superimposed mounting
Juxtaposed mounting
Technical characteristics
(passive blocking circuit for 15 and 20 kV networks )
PE90083
Tuning frequency
Insulation level Available ratings Characteristics of components
of 175 Hz blocking circuits
Single-phase capacitors Single-phase reactors
Characteristics of components
of 188 Hz blocking circuits
Single-phase capacitors Single-phase reactors
Maximum ambient temperature Altitude Mounting
IP 207μF / 2100V, without internal fuses
4mH, without magnetic core
179μF / 2100V, without internal fuses
4mH, without magnetic core
45 °C
< 1000 m
Juxtaposed (capacitors upright, alongside the
reactor) or on top of one another (capacitors
installed in a rack, under the reactor)
00 on unpainted aluminium substrate
4400
1200
1100
1000
1100
Phase 1
In-line arrangement
Phase 2
Phase 3
Phase 2
4150 min.
Phase 1
600
1100 1100
1155
1100
Phase 3
1200
1100
2400
1200
1100
1150
6600 min
min.
1200
DE90055
DE90055
Blocking circuit
175 or 188 Hz
(other frequencies on request)
Up to 24 kV
200, 300 ou 400 A per phase
Delta arrangement
65
Power Factor
Correction and
harmonic filtering
Installation (drawings, dimensions)
Contents
CP 214, CP 214 SAH, CP 227, CP 254
CP 229, CP 230, CP 253, CP 253 SAH
68
69
67
Installation
( drawings,
dimensions)
CP 214, CP 214 SAH, CP 227, CP 254
Drawing
Dimensions and weight
• H: 1700 mm, L : 900 mm, D: 1200 mm.
• Approximate weight: 425 to 560 kg.
80
MT20135
CP 214
H
L
Drawing
CP 214 SAH
Dimensions and weight
80
DE90062
• H : 1900 mm, L : 2000 mm, D : 1100 mm.
• Approximate weight: 600 to 1000 kg.
D
H
L
Drawing
CP 227
Dimensions and weight
80
DE90064
• Isolement 24 kV
H : 2000 mm, L : 1400 mm, D : 1400 mm.
• 36 kV insulation
H : 2000 mm, L : 3000 mm, D : 2100 mm.
• Approximate weight: 450 to 1550 kg.
D
H
L
Drawing
CP 254
Dimensions and weight
80
DE90076
• Insulation up to 24 kV
H : 2000 mm, L : 2600 mm, D : 1400 mm.
• 36 kV insulation
H : 2100 mm, L : 3000 mm, D : 2100 mm.
• Approximate weight: 450 to 1550 kg.
H
L
68
D
D
CP 229, CP 230, CP 253, CP 253 SAH
CP 253
Dimensions
Number of steps
1
H : 2 000, L :
2
H : 2 000, L :
3
H : 2 000, L :
4
H : 2 000, L :
5
H : 2 000, L :
1 500,
2 600,
3 700,
4 800,
5 900,
D
D
D
D
D
:
:
:
:
:
Drawing
1 600
1 600
1 600
1 600
1 600
DE90074
80
H
L
D
CP 253 SAH
Dimensions
Number of steps
1
H : 2 000, L :
2
H : 2 000, L :
3
H : 2 000, L :
4
H : 2 000, L :
5
H : 2 000, L :
1 500,
2 600,
3 700,
4 800,
5 900,
Drawing
D
D
D
D
D
:
:
:
:
:
2 400
2 400
2 400
2 400
2 400
DE90075
80
H
L
D
CP 230
DE90077
DE90065
CP 229
69
Power Factor
Correction and
harmonic filtering
Services
Contents
Schneider Electric expertise Maintenance & end of life
72
73
71
Services
Schneider Electric expertise
For more than 50 years, Schneider Electric
has designed and manufactured power factor
correction and harmonic filtering equipment.
From the beginning, it was clear that on-site
measurements were often decisive.
That is why Schneider Electric set up a team of
specialists to perform measurements,
site audits, simulations and expert appraisals.
Each category of service is organized on
various levels. The level depends on
the equipment used (power factor meter,
harmonic recorder, network analyser, etc.)
and the qualifications of the personnel involved.
The “services” offering includes:
• On-site measurements.
• Installation, supervision and commissioning.
• Repairs.
• Simulations and studies.
• Hire of measuring instruments (network
analysers, etc.).
• Training sessions.
Schneider Electric’s services
Listen, Understand, Act,
is the virtuous circle guaranteeing you the energy efficiency you need.
• Listen
This means collecting information, about symptoms and
other difficulties concerning the operation of the installation.
It requires -> Audit -> specific measurements -> recording
of the characteristic parameters of the network’s key points.
• Understand
Once this information has been collected, the diagnosis must be drawn up,
and the corrective actions must be identified and determined.
• Act
This the decisive phase… removal of network disturbances, correction
of the power factor, installation of standby or battery back-up networks…
and it is also the heart of our expertise.
In all cases, the ideal solution is to correct, but also and above all to
monitor the effectiveness of the installed solutions over a period of time;
an installation is alive, and like any living thing its characteristics change
over time.
In many countries, the local service team of Schneider Electric has
the competencies and equipment needed to perform measurements,
diagnoses, repairs, etc. as required.
PE90100
The Schneider Electric specialists can be called on to provide support or
their expertise for specific or extremely critical cases.
Training sessions can be organized to train or update the knowledge of
your installation or maintenance teams.
Our specialists can also be called on to take part in conferences,
seminars, presentations, etc. concerning power factor correction,
harmonic filtering, quality of power, etc.
Installation diagnosis
•
•
•
•
•
Evaluation of the state of the capacitor banks.
Measurement of operating temperatures.
Recording of voltages, currents, active and reactive power levels.
Recording of harmonic voltage and current spectrums.
Recording of transient voltage and current phenomena.
Solution definition
•
•
•
•
72
Proposal of capacitor replacement and substitution plans.
Management of the destruction process.
Power factor correction upgrade.
Reduction of networks harmonic distorsion.
PE90090
Maintenance & end of life
Maintenance
Routine checks
Check and, if necessary, clean the ventilation systems (frequency
depends on local conditions).
Annual checks
• Check connection clamping.
• Check insulator cleanliness.
• Check bank U, I, C and capacitance C values.
• Measure ambient temperature for the capacitor bank.
• Check operation of the safety features.
Faults and solutions
• Failure of a three-phase capacitor
This is revealed by blowing of one or more HRC fuses. The faulty
capacitor is identified by capacitance measurement (capacitance
fluctuation greater than 10% = faulty).
In this case, the capacitor and the three HRC fuses must be replaced
immediately.
• Failure of a single-phase capacitor
This is revealed by unbalance protection tripping. The faulty capacitor is
identified by a capacitance measurement for each capacitor (capacitance
fluctuation greater than 10% = faulty).
In this case, the capacitor must be replaced immediately (bank
rebalancing is sometimes necessary; please consult us).
PE90091
NB: For internal fuses, we also recommend replacing capacitors having
sustained a capacitance fluctuation of more than 5%.
Propivar NG capacitor end of life
The capacitors of our product range contain a non-PCB dielectric fluid.
Its recovery at end of life must necessarily be performed by
a central waste oils recycling facility according to local
requirements.
If the capacitor is damaged with leaking fluid, it must be placed on a tray
fluid retention and transport to the treatment center must be made by
an approved carrier.
Operations of dismantling and recovery at end of life
(to be done over a holding tank)
• Drill tank capacitor and recover oil impregnant which must follow
an incineration path with energy recover.
• Cut the tank under the cover, and remove the inner part of
the capacitor.
• Drain the inner part and the tank.
• The tank capacitor steel is recyclable.
• Separate cover and bushings from inner part.
• The inner part of the capacitor must follow a shearing path, incineration
and recovery metals.
• The entire cover and bushings must be crushed for recovery of metals
(steel, copper and brass).
73
Power Factor
Correction and
harmonic filtering
Selection guide
Contents
Installation conditions & General characteristics
Frame/enclosure & Propivar NG capacitors Additional equipment 76
77
78
75
Design guide
Installation conditions
General characteristics
This form specifies all the data to be provided to Schneider Electric from the “price quote” phase
to the “order execution” phase.
Site conditions
Country
Altitude v ≤ 1000 m
v > 1000 m
Atmosphere
v Normal
v Saline
v SO2
v Other
Pollution / Creepage v Low I (16 mm/kV)
distance, insulators
v Moderate II (20 mm/kV)
and bushings
v High III (25 mm/kV)
v Very high IV (31 mm/kV)
Short-circuit
current power (kA)
Temperature (°C)
v > -25°C
v ≤ 40 °C
v 45 °C
v 50 °C
v 55 °C
Standards
IEC
v
Others v
General characteristics
Type of bank (STD, DR or filter) v STD v DR v Filter
Rated voltage (kV)
Power (kvar) Rated frequency (Hz) v 50 v 60
Insulation level
Max. voltage for the equipment kV
Power-frequency test voltage (50Hz - 1 mn)
kV rms
Impulse test voltage (1.2 / 50 µs) kV peak
Connection
v Double star
v Delta
v H single-phase
v Single-phase
v Other
Short-circuit current withstand capacity v Depending on site conditions v Other
kA
sec
v 1 v 3
Auxiliary voltages
VDC v 24 v 48 v 60 v 110 v 125 v 220
VAC v 110 v 127 v 220-230
76
Design guide
Frame/enclosure
Propivar NG capacitors
Frame/enclosure
Type v Indoor
v Outdoor
Degree of protection v IP 00 v IP 23
v IP 54 v Other:
Frame material
v Steel v Galvanised steel
v Aluminium
v Stainless steel
Panel material
v Steel v Galvanised steel
v Aluminium
v Stainless steel
Frame coating
v Bare
v Painted
Panel coating
v Bare
v Painted
Double roof v Yes v No
Colour
v Supplier standard v Other
RAL
Door v Supplier standard v Other
Lock (type) v Supplier standard v Other
Propivar NG capacitors
Type
v Three-phase v Single-phase
Design voltage (V)
Rated frequency (Hz)
v 50 v 60
Specification of steps
N°
123456
kvar
sequence
Insulation level
Max. voltage for the equipment kV
Power-frequency test voltage (50Hz - 1 mn)
kV rms
Impulse test voltage (1.2 / 50 µs) kV peak
Internal fuses v Yes v No
Terminal creepage distance
v Supplier standard v Other
mm
mm/kV v 16 v 20 v 25 v 31
Internal discharge resistors V/min v 75/10 v 50/5
Temperature
Max. (°C) v ≤ 40 v 45 v 50 v 55
Min. (°C) v -25 v Other
Gradient
v Supplier standard v Other
V/μm
77
Design guide
Additional equipment
Unbalance relays
v
Relays v Supplier standard v Other
Type
Thresholds v Trip
v Alarm and trip
Mounting
v Supplied separately
v In bank
v In enclosure or cabinet with the control
and monitoring components
Detuning reactors
v
Type v Resin-impregnated v Resin-encapsulated
v Oil-immersed
v Air core
v 1-phase v 3-phase
Installation v Indoor
v Outdoor
v In enclosure v Outside the enclosure
Harmonic order
Measuring PT
Rated voltage (V/V) (primary/secondary)
Discharge function Quantity Protection CT Power (VA)
Precision class Number of protected phases v
v Yes v No
v 2 v 3
v
v 5P v 3P
v 1 v 2 v 3
Switching device
v
Type
v Circuit breaker v Contactor
Breaking technology
v SF6 v Vacuum
Fuses
v
System for protection against
single-phase operation
v
Inrush reactors
v
Quick discharge reactors
v
78
Design guide
Additional equipment
Surge arresters (by default one per phase)
v
Line disconnector v
Earthing switch
v
Type v 3-pole v 5-pole
Earthing switch connection v Line side v Load side
Quantity v 1 per step v 1 per bank
Combined disconnector (line disconnector + ground switch)
Earthing switch connection v
v Line side v Load side
Interlocking system
v
v Supplier standard scheme
v Other, to be defined
Monitoring/Control
v
Number of steps to be controlled
Installation v Cabinet
v Cubicle
v In bank
Controllerv Yes v No
Type
v NR6/NR12 v NRC12
Sequence
Modbus com.
v Yes v No
U (V) measurement
I (A) measurement
v 1 A secondary
v 5 A secondary
Protection relay
Functions
v Unbalance
v Over current
v Over voltage
v Other:
Type
Quantity v Per step v Overall
Auto / 0 / Manual function v Yes v No
Indicator lamps
By default
v Aux. voltage presence
v ON / step
v OFF / step
v Alarm-Unbalance-Blown fuse
Other Accessories
v
Ventilation v Supplier standard Type
Lighting in bank v Yes v Other
v No
79
Power Factor
Correction and
harmonic filtering
Technical guide
Contents
Reminders concerning reactive energy
82
Why compensate?
84
Method for determining compensation
86
Control of capacitor banks 90
Protection and circuit diagrams of capacitor banks
93
Typical cases of compensation
94
Capacitor definitions and terminology 96
Reactive energy
Reactive energy compensation
Reactive energy and network components
Power factors of typical equipment
Economic benefits
Technical benefits
Reduction in transmission losses according to the power factor improvement
Economic evaluation of compensation
Stage
Stage
Stage
Stage
one: Calculation of reactive power
two: Choice of compensation mode
three: Choice of compensation type
four: How to allow for harmonics
General characteristics of switchgear and controlgear
Type of switchgear and controlgear
Switching ON capacitor banks
Switching ON capacitor banks, synthesis
Switching OFF capacitor banks
Switchgear used for capacitor control
Medium voltage switchgear characteristics
Capacitors
Delta-connected bank
Bank connected in double star
MV asynchronous motor compensation
MV transformer compensation
81
Reactive energy
In an electric circuit, the active power P is
the real power transmitted to loads such as motors,
lamps, furnaces, radiators, computers, etc.
The active electric power is converted into
mechanical power, heat or light. The physical unit
is the watt (W), the multiples kilowatt (kW) and
megawatt (MW) being used for convenience.
In a circuit in which the applied rms voltage is Vrms
and in which flows an rms current Irms,
the apparent power S is the product of Vrms x Irms.
The apparent power is therefore the basis
for sizing of electrical equipment. A device
(transformer, cable, switch, etc.) should be
designed on the basis of the rms values of
voltages and currents.
The physical unit of apparent power is the voltampere (VA), the multiples kilovolt-ampere (kVA)
and megavolt-ampere (MVA) being used for
convenience.
The power factor λ is the ratio of the active power
P (kW) to the apparent power S (kVA)
for a given circuit.
λ = P(kW)/S(kVA).
In the specific case where the current and voltage
are sinusoidal and phase-shifted by an angle φ,
the power factor is equal to cos φ, called
the displacement power factor.
For most electric loads such as motors,
the current I lags the voltage V by an angle φ.
In vector representation, the current can therefore
be broken down into two components:
• Ia in phase with the voltage and called
the “active” component;
• Ir in quadrature with the voltage and called
the “reactive” component.
82
DE90086
Reminders concerning reactive energy
The above diagram established for currents also
applies to powers, by multiplying each current
by the common voltage V.
One can therefore define:
• apparent power: S = V x l (kVA);
• active power: P = V x la = V x I x cosφ (kW);
• reactive power: Q = V x lr = V x I x sinφ (kvar).
The physical unit of reactive power is the voltampere-reactive (var), the multiples kilovoltampere-reactive (kvar), and megavolt-amperereactive (Mvar) being used for convenience.
DE90087
Technical guide
The reactive current Ir is the component consumed
by the inductive magnetic circuits
of electrical machines (transformers and motors).
The reactive power is therefore commonly
associated with magnetization of the magnetic
circuits of machines.
Accordingly, the power supply source must provide
not only the active power P but also the reactive
power Q, resulting in an apparent power S.
The function tgφ is often used; it is equal to:
tgφ = Q(kvar)/P(kW).
Over a given period of time, this ratio is also that
of the reactive energy (Wr) and active energy (Wa)
consumed: tgφ = Wr(kvarh)/Wa(kWh).
In some countries, this ratio is used for billing
reactive energy.
DE90088
Reactive energy compensation
The flow of reactive energy has significant
technical consequences for the choice of
equipment, operation of networks and,
accordingly, has economic consequences.
For a given active power P used, the lower
the cosφ, i.e. the larger the angle φ, the more
apparent power S must be supplied.
Qr
Qc
Fig. 1: Principle
of reactive energy
compensation
Accordingly, the flow of reactive energy in
distribution systems results, due to an excessive
current demand, in:
• overloads at the transformer level;
• end-of-line voltage drops;
• overheating of power cables, hence active
energy losses.
DE90089
For these fundamental reasons, it is necessary
to produce reactive energy as close as possible
to motors and transformers, to avoid increased
demand on the network.
Transformer
To avoid over-sizing his network, the power
distributor therefore encourages his customers
to improve the power factor, by billing reactive
energy above a certain threshold.`
The principle of reactive energy compensation
is to generate reactive power in the vicinity
of the load, so as to relieve the power supply.
Capacitors are most commonly used
to supply reactive power. On figure1,
the reactive power Qc supplied
by capacitors allows the apparent power
to be reduced from the value S to the value S’.
Active
power
Reactive energy
and network components
Synchronous machines
These machines have an (active energy) generator
function when they convert mechanical energy
into electrical energy. In the opposite case, they are
motors. By adjusting their excitation, these machines
can supply or consume reactive energy.
In some cases, the machine supplies no active
energy: this is the case of the synchronous
compensator.
Asynchronous machines
These are distinguished from the preceeding
machines in particular by their property of being
always consumers of reactive energy. This energy
is very significant: from 25% to 35% of the active
energy at full load, and much more at partial
load. The asynchronous motor is in common use
universally. It is the main consumer of reactive
energy in industrial networks.
Lines and cables
The inductive and capacitive properties
of overhead lines and cables are such
that they are consumers of reactive energy.
Transformers
Transformers consume reactive energy
corresponding to about 5% to 10%
of the apparent energy passing through them.
Reactors
Reactors are chiefly consumers of reactive energy.
Active energy losses represent only a small
percentage of the reactive energy (QR) consumed.
Capacitors
Capacitors generate reactive energy with very
small losses, hence their use in the reactive
energy (QC) compensation application.
Motor
Before compensation
DE90089
Power factors of typical equipment
Transformer
Power
made
available
Active
power
Reactive
power
supplied by
capacitor
Motor
After compensation
Device
cos φ tg φ
Asynchronous motor loaded at 0%
0.17
5.80
25%0.55
1.52
50%0.73
0.94
75%0.80
0.75
100%0.85
0.72
Incandescent lamps
≈ 1
≈0
Non-compensated fluorescent lamps
≈ 0.5
≈ 1.73
Compensated fluorescent lamps (0.93)
0.93
0.39
Discharge lamps
0.4 to 0.6
2.29 to
Resistance furnaces
≈ 1
≈0
Induction furnaces with integral pf correction
≈ 0.85
≈ 0.62
Dielectric ovens
≈ 0.85
≈ 0.62
Resistance welding machines
0.8 to 0.9
0.75 to
Single-phase stationary arc welding stations
≈ 0.5
1.73
Rotary arc welding sets
0.7 to 0.9
1.02 to
Arc welding rectifier transformers
0.7 to 0.8
1.02 to
Arc furnaces
0.8
0.75
1.33
0.48
0.48
0.75
83
Why compensate?
Improvement of
the power factor of
an installation, known
as compensation,
offers numerous
benefits of
an economic and
technical nature.
Economic benefits
The benefits provided by reactive energy compensation are such that they give a very rapid return
on investment.
These benefits are as follows:
• elimination of billing for excessive reactive energy consumption;
• reduction in subscribed demand in kVA;
• decrease in active energy consumed in kWh
(losses reduction).
Technical benefits
• Attenuation of voltage drops
The flow of reactive currents is responsible for
voltage drops on power supply lines.
These are detrimental to satisfactory operation of
the loads, even if the voltage at the head of the line is
satisfactory. The presence of a capacitor bank at end
of line can reduce this phenomenon.
The relative voltage level at the end of the line
is defined by the following formula:
• Increase in the active power available
at the secondary of transformers
The installation of means of compensation on
the downstream terminals of an overloaded
transformer can release a power reserve that can
be used for a possible extension of the plant without
having to change transformer, thus postponing
a major investment.
• Increase in the active power carried by lines
for equal losses
An increase in the workload often makes it
necessary to carry greater active power in order
to meet the energy needs of the loads.
The installation of a capacitor bank will make it
possible to increase the transmission capacity
without changing the existing electric power lines.
The following chart gives, as a function of
the power factor improvement, the percentage
increase in the power carried for equal active losses.
DE90090
Technical guide
Increase in the active power carried
ΔU(%) ≈ XLxQ/U²
in which:
XL: reactance of the line;
Q: reactive power of the capacitor bank;
U: mains voltage.
• Reduction in transmission losses at constant
active power
Losses due to conductor resistance are included
in the consumption recorded by active energy
counters (kWh). They are proportional to
the square of the current carried and decrease
as the power factor increases.
The table below gives the percentage
reduction in transmission losses according to
the improvement in the power factor.
Example: if, before compensation, cosφ1 = 0.7
and after compensation cosφ2 = 0.9, there is a 35%
increasing in carrying capacity
Reduction in transmission losses according to the power factor improvement
Cosφ1
Reduction in transmission losses at constant active power according to cosφ2 (%)
before compensation Cosφ2 0.8 0.85 0.9 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99
23 32 40 41 42 43 45 46 47 48 49 50
0.70
0.72
19 28 36 37 39 40 41 43 44 45 46 47
0.74
14 24 32 34 35 37 38 39 41 42 43 44
0.76
10 20 29 30 32 33 35 36 37 39 40 41
0.78
5
16 25 27 28 30 31 33 34 35 37 38
0.80
0
11 21 23 24 26 28 29 31 32 33 35
0.82
7
17 19 21 22 24 25 27 29 30 31
0.84
2
13 15 17 18 10 22 23 25 27 28
0.86
9
11 13 14 16 18 20 21 23 25
0.88
4
6
9
10 12 14 16 18 19 21
0.90 2 4
6
8
10 12 14 16 17
0 to 15% reduction in losses
15% to 30% reduction in losses
30% to 50% reduction in losses
84
Economic evaluation
of compensation
The economic benefits of compensation are
measured by comparing the cost of installation of
capacitor banks with the savings they provide.
Cost of capacitor banks
The cost of capacitor banks depends on several
factors, including:
• the voltage level;
• installed capacity;
• number of steps;
• the control mode;
• the protection quality level.
Capacitors can be installed either at low voltage
or at medium voltage.
Note that:
• medium-voltage compensation becomes
economically worthwhile when the capacity
to be installed exceeds 800 kvar;
• below this value, compensation should,
if possible, preferably be performed at low voltage.
Savings obtained
Let us illustrate this by the following example of
an installation comprising a 20 kV/400 V transformer
of power 630 kVA (nominal apparent power).
• Installation without capacitor
Characteristics of the installation: P = 500 kW
at cosφ = 0.75.
Consequences:
- The apparent power S is equal to 667 kVA;
- The transformer is overloaded by a factor
of 667/630, or about 6%;
- The reactive power Q is equal to 441 kvar
(cosφ = 0.75 corresponds to tgφ = 0.882)
and is billed by the power distributor;
- The circuit breaker and cables have to be chosen
for a total current of 962 A;
- The losses in the cables are proportional
to the square of the current, i.e. (962)2.
• Installation with capacitor
Characteristics of the installation: P = 500 kW
at cosφ = 0.928.
Consequences:
- The apparent power S is equal to 539 kVA;
- The transformer is no longer overloaded. There is
a power reserve equal to 630/539, or about 17%;
- The reactive power Q is equal to 200 kvar
(cosφ = 0.928 corresponds to tgφ = 0.4).
This reactive power is billed at a reduced rate
or not at all by the power distributor;
- The losses in the cables are reduced
by a ratio of (778)2/(962)2 = 0.65, i.e. a 35% gain.
The reactive energy is supplied locally
by a capacitor bank of power 240 kvar.
85
Technical guide
Method for determining compensation
Compensation
for an installation
is determined
in 4 stages.
• Calculation of
reactive power.
• Choice of
compensation mode.
- Global for the entire
installation.
- By sector.
- Separate for each
load.
• Choice of
compensation type.
- Fixed by switching
on and off a bank
supplying a fixed
quantity of kvar.
- Automatic by
switching on and off
“steps” dividing up
the bank’s power
and making it possible
to adapt to
the kvar needs of
the installation.
•Allowance for
harmonics.
In what follows,
we describe
these various stages
in greater detail.
Stage one:
Calculation of reactive power
Example: A motor
has a power rating
of 1000 kW and
a cosφ of 0.8
(tgφ = 0.75).
To obtain cosφ = 0.95,
you must install
a reactive power in
capacitors equal to
k x P, namely:
Qc = 0.421 x 1000 =
421 kvar
86
Principle of calculation
The aim is to determine the reactive power Qc (kvar)
to be installed in order to increase the power factor
cosφ and reduce the apparent power S.
For φ’ < φ, we shall have: cosφ’ > cosφ
and tgφ’ < tgφ.
This is illustrated by the figure below.
DE90091
Pa
S’
QR
S Qc
To calculate Qc there are two possible
approaches, depending on the available data:
• Calculation based on billing data;
• Calculation based on the electrical data
of the installation.
Calculation based on billing
The aim here is to eliminate billing by the power
distributor. To do this, proceed as follows:
• Consider the monthly consumption of reactive
energy R in kvarh;
• Assess the period t of operation (in hours)
during which reactive energy is billed during
the month in question.
The hours to be allowed for are peak hours,
i.e. 16 h per day, if there is no billing of reactive
power during off-peak hours. Under these
circumstances, the following estimate of t will be
taken for companies operating in shifts of:
• 1 times 8 hours; t = 176 h (i.e. 22 days);
• 2 times 8 hours; t = 308 h;
• 3 times 8 hours; t = 400 h.
Deduct from this the reactive power
to be installed: Qc= R (kvarh) / t (hours).
Calculation based on the installation data
The power to be installed is calculated from
the cosφ or tgφ measured for the installation.
Qc can be calculated:
• directly from the relationship Qc = P x (tgφ-tgφ’)
which is based on the figure, where
- Qc = power of the capacitor bank in kvar;
- P = active power of the load in kW;
- tgφ = tangent of phase shift angle before
compensation;
- tgφ’ = tangent of phase shift angle after
compensation.
• from the following table, knowing tgφ or cosφ of
the existing installation and the tgφ’ or cosφ’ that
is wanted.
Before
Reactive power (kvar) to be installed per kW of load to achieve the cosφ’ or tgφ’ objective
compensation tgφ 0.75
0.620 0.484 0.456 0.426 0.395 0.363 0.329 0.292 0.251 0.203 0.142 0.000
cosφ 0.80
0.85 0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.000
tgφ
cosφ
2.29 0.4 1.541 1.6721.8071.8361.8651.8961.9281.9632.0002.0412.0882.1492.291
2.16 0.42
1.411 1.5411.6761.7051.7351.7661.7981.8321.8691.9101.9582.0182.161
2.04 0.44
1.291 1.4211.5571.5851.6151.6461.6781.7121.7491.7901.8381.8982.041
1.93 0.46
1.180 1.3111.4461.4751.5041.5351.5671.6021.6391.6801.7271.7881.930
1.83 0.48
1.078 1.2081.3431.3721.4021.4321.4651.4991.5361.5771.6251.6851.828
1.73 0.5 0.982 1.1121.2481.2761.3061.3371.3691.4031.4401.4811.5291.5901.732
1.64 0.52
0.893 1.0231.1581.1871.2171.2471.2801.3141.3511.3921.4401.5001.643
1.56 0.54
0.809 0.9391.0741.1031.1331.1631.1961.2301.2671.3081.3561.4161.559
1.48 0.56
0.729 0.8600.9951.0241.0531.0841.1161.1511.1881.2291.2761.3371.479
1.40 0.58
0.655 0.7850.9200.9490.9791.0091.0421.0761.1131.1541.2011.2621.405
1.33 0.6 0.583 0.7140.8490.8780.9070.9380.9701.0051.0421.0831.1301.1911.333
1.27 0.62
0.515 0.6460.7810.8100.8390.8700.9030.9370.9741.0151.0621.1231.265
1.20 0.64
0.451 0.5810.7160.7450.7750.8050.8380.8720.9090.9500.9981.0581.201
1.14 0.66
0.388 0.5190.6540.6830.7120.7430.7750.8100.8470.8880.9350.9961.138
1.08 0.68
0.328 0.4590.5940.6230.6520.6830.7150.7500.7870.8280.8750.9361.078
1.02 0.70
0.270 0.4000.5360.5650.5940.6250.6570.6920.7290.7700.8170.8781.020
0.96 0.72
0.214 0.3440.4800.5080.5380.5690.6010.6350.6720.7130.7610.8210.964
0.91 0.74
0.159 0.2890.4250.4530.4830.5140.5460.5800.6170.6580.7060.7660.909
0.86 0.76
0.105 0.2350.3710.4000.4290.4600.4920.5260.5630.6050.6520.7130.855
0.80 0.78
0.052 0.1830.3180.3470.3760.4070.4390.4740.5110.5520.5990.6600.802
0.75 0.80
0.1300.2660.2940.3240.3550.3870.4210.4580.4990.5470.6080.750
0.70 0.82
0.0780.2140.2420.2720.3030.3350.3690.4060.4470.4950.5560.698
0.65 0.84
0.0260.1620.1900.2200.2510.2830.3170.3540.3950.4430.5030.646
0.59 0.86
0.1090.1380.1670.1980.2300.2650.3020.3430.3900.4510.593
0.54 0.88
0.0550.0840.1140.1450.1770.2110.2480.2890.3370.3970.540
0.48 0.90
0.0290.0580.0890.1210.1560.1930.2340.2810.3420.484
Stage two:
Choice of compensation mode
Where to install capacitors?
The location of capacitors on an electrical network
is determined by:
• the goal sought (elimination of penalties, relief
for cables, transformers, etc., raising the voltage
level);
• the load conditions (stable or rapidly variable);
• the foreseeable influence of the capacitors on
the network characteristics;
• the cost of installation.
Reactive energy compensation can be:
• total;
• broken down by sector;
• separate for each load.
It is more economical to install capacitor banks
in medium and high voltage for power ratings
greater than about 800 kvar. Analysis of
the networks of the various countries, however,
shows that there is no universal rule.
Global compensation
The bank is connected at the head of
the installation to be compensated and performs
compensation for the entire installation. It is
suitable when the load is stable and continuous.
Example below:
• HV bank on HV distribution system (1);
• MV bank for MV subscriber (2);
• Regulated or fixed LV bank for LV subscriber (3).
Compensation by sector
The bank is connected at the head of
the installation sector to be compensated.
This is suitable when the installation is extensive
and includes workshops having different load
conditions.
Example below:
• MV bank on MV network (4);
• LV bank for each workshop for MV subscriber (5).
Individual compensation
The bank is connected directly to the terminals
of each inductive type load (especially motors).
It should be considered when the motor power
is high relative to the subscribed demand.
This compensation is technically ideal because
it produces the reactive energy at the very place
where it is consumed, and in a quantity adjusted
to the demand. Example below: LV bank for load
compensation (6).
DE90092
HV distribution network
MV distribution network
MV/LV
distribution
transformer
MV/LV
transformer
MV/LV
transformer
LV busbar
LV subscriber
MV subscriber
MV subscriber
Summary of compensation locations
87
Technical guide
Method for determining compensation
Stage three: Choice of
compensation type
Types of MV compensation
The capacitor banks are branch-mounted on the
network. They can be fixed or automatic.
Fixed compensation
The entire bank is put into service, with a fixed
value of kvar. This is “on/off” type operation.
The capacitors have a constant power output
and their switching on and off can be:
• manual, by circuit breaker or switch;
• semi-automatic by contactor;
• servo controlled by the terminals of inductive
loads (motors or transformers).
This type of compensation is used:
• when their reactive power is low (< 15% of
the power of the upstream transformer) and
the load is relatively stable;
• on HV and EHV transmission networks
for power ratings of up to 100 Mvar.
Automatic compensation
The banks are divided up into “steps”
with capability for switching on or off
a smaller or larger number of steps, generally
automatically.
This is an “automatic adjustment” to the load level.
These banks are very commonly used by certain
heavy industries with high power demand
and energy distributors in source substations.
This allows step-by-step regulation of reactive
energy.
Each step is operated by a switch or a contactor
using SF6 breaking technology.
Capacitor step switching on or off can be
controlled by power factor relays. For this purpose,
a current transformer should be positioned
upstream of the loads and banks.
Stage four: How to allow for
harmonics
Harmonic currents flow in an installation due to
the presence of nonlinear loads (e.g. variable
speed drives, uninterruptible power supplies,
arc furnaces, lighting). The flow of harmonic
currents in the network impedances creates
harmonic voltages.
The magnitude of the harmonic disturbance
on a network is measured by:
• the individual harmonic voltage factor u(%),
which gives a measure of the scale of each
harmonic relative to the fundamental.
For the harmonic of order h this factor is:
u(%) = 100xUh/U1, where Uh is the harmonic
voltage of order h at the point in question
and U1 the fundamental voltage;
• the total harmonic distortion THDU (%)
which gives a measure of the thermal influence
of all the harmonics.
Effects of harmonics on capacitors
• Absorption of harmonic currents
Capacitors do not generate harmonic current
but are very sensitive to them.
The impedance of a capacitor
Z c = 1/Cω = 1/C2πf decreases when
the frequency increases. It thus offers, in a certain
way, less resistance to a harmonic current
in the event of a current distortion. This results
in an increase in the current in the capacitor.
• Risk of resonance
The presence of a capacitor in a network may
amplify certain harmonic orders. This is due to
a resonance phenomenon, the frequency of which
depends on the network impedance (or its shortcircuit power).
The resonance frequency (natural frequency)
is equal to:
H
THDU (%) = 100x
U 2h
1
U1
H is generally limited to 40.
In the same fashion, an individual factor and
a total harmonic for current distortion are
defined. Generally, it is considered that the level
of harmonic disturbance is acceptable in an
installation so long as the total harmonic voltage
distortion does not exceed 8%, in accordance with
IEC 61000 -2-4.
88
fnatural =
Ssc
x
f
Q
Ssc: short-circuit power in kVA.
Q: power of the capacitor bank in kvar.
f: power supply frequency.
The resonance’s effect will be all the more
pronounced as fnatural is close to that of one of
the harmonics present. The applied current
overload will cause overheating and then
premature ageing of the capacitor.
Solutions to limit stress due to harmonics
• Oversizing of capacitor links to the network:
cables, lines, switchgear and controlgear should
be sized for at least 1.43 Ic, the value of
the capacitor’s rated current at 50 Hz;
• voltage oversizing of capacitors;
• use of detuning reactors combined with
oversized capacitors.
In MV, the detuning reactor connected in series
with the capacitor is generally designed to form a
capacitor bank tuned to 215 Hz (50 Hz) or 260 Hz
(60 Hz). Since this frequency corresponds to no
harmonic order, it makes it possible to reduce both
the harmonic overvoltages across the terminals of
the capacitor as a result of the resonance, and the
overload currents passing through the capacitor.
Solutions to comply with the permissible
distortion factor in a network
Apart from their effect on the capacitors,
the presence of harmonics in a network generates
a voltage distortion factor. The energy supplier
limits the values of the acceptable distortion factor
at the point of delivery to below a certain threshold.
In addition to systematic oversizing of power
connections, the other measures to be taken
depend on the comparison between:
• Gh: total power in kVA of all harmonic generating
equipment (static converters, UPSs, variable
speed drives). If the power is known in kW, divide
by 0.7 to estimate Gh in kVA.
• Ssc: short-circuit power of the network (kVA).
• Sn: power of the upstream transformer(s).
If several transformers are in parallel, allow for
the possible outage of a transformer.
The choice is summarized in the following table.
Gh ≤ Scc / 120 Scc / 120 < Gh < Scc / 70
Scc / 70 < Gh ≤ Scc / 30
Standard equipment
Equipement
with DR
and oversized
capacitors
Equipement with oversized
capacitors
1.2 x UN
This results in the distortion THDU being limited
to 5% downstream of the transformer.
If these values are not reached, the use
of attenuation devices is necessary.
The choice of these devices depends on
the characteristics of the installation, the power
of the harmonic generators, and the need for
reactive energy compensation. Calculation software
is used to determine the optimal solution.
Choice of solution
Complementary approach is to choose equipments according to industrial process described hereunder:
Activity
Businesses process
Textile
Weaving, print induction
Paper-works
Roll, pumping
Printing
Printing, recording
Chemistry, Pharmacy Dosage, clean rooms, filtration,
concentration, distillation
Plastic
Extrusion, thermoforming
Glass, Céramic
Rolling, furnace
Steel
Arc furnaces, rolling mill,
wiredrawing, cutting, pumping
Metallurgy
Welding, stamping, furnace,
surface treatments
Automotive
Welding, stamping
Cement
Kilns, shredding, conveying, lifting,
ventilation, pumping
Mining, Quarrying
Conveying, lifting
Refineries
Ventilation, pumping
Equipment
Standard Oversized
DR
89
Technical guide
Control of capacitor banks
General characteristics
of switchgear and controlgear
The equipment used is defined by the following
selection criteria:
• rated voltage and current;
• making current;
• capacitive breaking capacity;
• making capacity;
• number of operations.
Precautions should be taken concerning:
• The capacitive breaking capacity (kA rms).
The problem is due to the existence, after
switching off, of a restriking voltage equal to
the difference between the mains voltage
and the charging voltage of the capacitors.
The device must be capable of preventing
this restriking.
• The making capacity (kA peak) which must
be able to withstand inrush currents.
Type of switchgear and controlgear
The choice of switchgear and controlgear
depends on electrical criteria but in particular
on the type of use of the banks. There are several
possibilities:
• Disconnector. Without breaking capacity,
it will be used only for operation of the bank with
the power off. It requires the use of a protection
device (fuse or circuit breaker).
• Switch. It has only a breaking capacity limited
to IN and a moderate making capacity, and does
not allow a large number of operations. Therefore,
it will be used especially in the case of so-called
fixed banks.
• Contactor. This allows a very large number
of operations, but is limited to 12 kV. It can be
coordinated with fuses of "High Rupturing Capacity"
(HRC).
• Circuit breaker. This very efficient device
will be used for general protection of high-power
banks.
90
Switching ON capacitor banks
Switching on a bank Qc (fixed or stepped)
is accompanied by transient current and voltage
conditions. A making overcurrent of short
duration (≤ 10 ms) appears. Its peak value
and its frequency, generally high, depend on
the characteristics of the upstream network
and the number of banks. Where necessary,
a surge reactor may or may not have to be inserted
to limit this overcurrent to the peak resistance of
the capacitors, namely: Imax. peak ≤100 IN, (IN: rated
current of bank Qc) or to a lower value if
the switchgear has limited characteristics.
In the case of a single bank, the overcurrent
is generally from 10 to 30 IN, but for a high Scc
and low Qc it may exceed the limit and require an
inrush reactor. In the case of banks in parallel,
either identical (regulated system) or of different
values (compensation of several motors),
the overcurrent will be very high and will have
to be limited. In making this choice, allow for
the number of possible operations under
the given current.
Switching ON capacitor banks, synthesis
Stepped bank (identical)
DE90093
Fixed bank
Lo
DE90093
U√3
1
2
C
n+1
l
l
l
Lo = S/C inductance of the network
Scc = √3 U Icc with U/√3 = LoωIcc
C
C
n steps switched on when
n+1 is switched on
l = link inductance (0.5 µH/m)
Bank power Q = U2Cω = √3UIcapa
Q = U2Cω = √3UIcapa ;
Q = Power of each step
Peak making current
Ie = 2 x U x n x C
n+1 l
3
Ie = 1 x 1
LoC ω
I
x capa
2
Ie = Icapa x 2 x
n
C
f
Ie = Icapa 2 x Scc
Q
fe = 1
2π LoC
fe = 1
2π lC
Q-factor,
mains
2
(n+2)/(n+1)
Q-factor, bank
2
2n/(n+1)
Inrush reactor
Generally, no need of an inrush
reactor (unless high Ssc and low Q)
Generally, need of an inrush reactor
Calculation inrush reactor
L ≥ 10
ω
Natural frequency
x
n+1
2
2Q
3 Imax peak
x natural
2
fnetwork
L (μH) - Q (Mvar) - Ssc (MVA)
H
I max. peak (kA)*
U
2
h
U 2h
1
U1
2
6
L ≥ 2.10 x Q x
3 ω
U
Scc
H
n
n+1
x
1
2
Imax peak
L (μH) - Q (Mvar) - Ssc (MVA)
Imax. peak (kA)*
1
* Imax. peak is the smaller of the following 2 making values:
U1
• maximum peak current of the bank (i.e. 100xIcapa)
• maximum peak current of the switchgear Imaking max.
Note: For steps not having the same powers, please contact us
H
U 2h
1
U1
Example 1: Fixed bank of 250 kvar
at a phase-to-phase voltage of U = 5.5 kV powered
by a network of maximum short-circuit power Ssc =
250 MVA.
Example 2: Bank of 3 steps each of 350 kvar
at a phase-to-phase voltage of U = 5.5 kV
at a distance of 5 m from their associated cutoff
device.
L0 = 386 μH.
C = 26.3 μF.
Icapa = 26.2 A.
Ie = 1173 A.
fe = 1581 Hz.
C = 36,8 μF.
Icapa = 36.7 A.
● without inrush reactor
l = 2,5 μH.
Ie = 11490 A !!
fe = 16.5 kHz.
● inrush limiting reactor L is mandatory in order to
limit Ie to a value lower than 100 Icapa either:
L = 50 μH.
Ie = 2508 A.
fe = 3619 Hz.
91
Technical guide
Control of capacitor banks
Switching OFF capacitor banks
A capacitor is switched off by a cutoff device
precisely at zero crossing of the current, which
coincides with the instantaneous maximum voltage.
On the one hand, a voltage surge escalation
3 U, 5 U may occur if the device does not have fast
dielectric restoration; this was the case for air cutoff
devices; this phenomenon has disappeared
with SF6 devices.
On the other hand, the capacitor remains charged at
its maximum voltage. In the event of fast reclosing,
an increased transient phenomenon will occur.
The IEC 60871 standard requires a capacitor
discharge device so that the voltage across
the terminals does not exceed 75 V, 10 minutes after
disconnection.
A quick discharge can be obtained using discharge
reactors; however, this system has a limit set of
3 consecutive discharges followed by a rest period
of 2 hours, due to reactor overheating. This will have
to be carefully evaluated when using banks having
regular switchings.
Switchgear
used for capacitor control
Switches are chosen for banks with a low rate
of operations (at most 2 operations per day);
above this, contactors are used.
For the most powerful banks (connected in double
star), the SF6 switch or circuit breaker is the most
appropriate device. All switchgear and controlgear
should be sized for 1.43 times the rated current
of the capacitor bank.
The switched capacitive current values given
by the manufacturer should be complied with
(see table below).
Medium voltage switchgear characteristics
Switchgear designation
Short circuit performance
SF1
25kA/36kV
SF2
40kA/40.5kV
contactor Rollarc R 400
10kA/7.2kV
8kA/12kV
92
Rated normal current
630 and 1250A
630 and 3150A
400A
Capacitive current switched
440 and 880A
440 and 2200A
240A
Protection and circuit diagrams
of capacitor banks
Capacitors
Delta-connected bank
The capacitor is
a reliable component
if it is used in
the conditions for which
it has been designed
and manufactured.
It is formed of elements
placed in series to resist
voltage, and placed
in parallel to obtain
the wanted capacitance.
There are two types of
capacitor at present:
with or without internal
fuses.
This circuit diagram will be used for insulation
voltages of 7.2 kV and 12 kV.
Capacitors
with internal fuses
Each element is
protected by a fuse.
In this case, any fault
in an element will be
eliminated. The defective
circuit will be isolated.
The result will be
a slight capacitance
variation and the voltage
will be distributed over
the sound elements in
series. The setting of
the unbalance relay shall
be such that
the loss of elements
of a given unit in series
causes switching off
of the bank when
the resulting overvoltage
exceeds the limits
determined by the
standard (IEC 60871).
Protection by internal
fuses increases
the availability of capacitor banks, because
the loss of one element
does not systematically
result in switching off of
the bank.
The maximum power is 900 kvar in three-phase
(2 capacitors in parallel). Above this, single-phase
capacitors can be used up to 4000 kvar.
This type of circuit diagram is highly suitable for
MV motor compensation and for automatic total
compensation up to 12 kV.
Protection
Overcurrent protection is provided by HRC fuses.
Important note: Choose HRC fuses with a rating of
at least 1.7 times the rated current of the bank.
In this type of circuit layout, never use capacitors
with internal fuses, because the breaking
capacity of internal fuses is not designed
for network short-circuit currents.
Delta connected capacitor bank
Bank connected in double star
For all power ratings, the bank is divided into two
stars allowing detection of an unbalance between
the two neutrals by an appropriate relay. This type
of bank allows the use of capacitors with or without
internal fuses.
It can be designed for any type of network up to
EHV networks.
The mounting principle is always the same:
to achieve voltage levels of 100 kV or 200 kV,
connect a sufficient number of MV capacitors in
series. This layout will therefore be used for high
powers to be installed, chiefly in fixed banks.
However, regulated steps are used by certain
power distributors with powers ranging up to 8
Mvar at 36 kV, controlled by a special switch for
capacitors.
Protection
Protection is provided by an unbalance relay
detecting a current flowing in the circuit between
the two neutrals of the stars. The unbalance
current is generally less than 1 A. The setting
value will be given after calculation for each bank.
The setting threshold is given by the manufacturer.
It depends on the internal structure of the bank
(series and parallel combination of capacitor units)
and on whether or not internal fuses for capacitor
protection are present.
The time delay is approximately several tenths
of a second. In addition to this protection,
provision should be made for overload protection
on each phase. The value shall be set to 1.43
times the rated current of the bank.
DE90095
Capacitors without internal fuses
Capacitor failure is
the result of failure of
an internal element.
A fault in an element
results in short-circuiting
of a unit in series and
hence a rise in
the voltage on the other
units in series. Having
no protection device
inside the capacitor,
the fault will be eliminated only by cutoff of
the bank or separation
of the circuit in
the defective capacitor.
DE90094
Technical guide
Double star connected capacitor bank
93
Technical guide
Typical cases of compensation
MV asynchronous motor
compensation
Risk of self-excitation of asynchronous motors
in the presence of capacitors
When a motor drives a load of high inertia,
after a supply voltage interruption, it can continue
to rotate due to its inertia. It can in that case be
self-excited by the presence at its terminals of
capacitors that could provide it with the reactive
energy needed for its operation as an asynchronous generator. This self-excitation causes
overvoltages exceeding the maximum voltage Um
of the network.
Capacitor mounting on motor terminals
Practical rule: The capacitive current should be
less than 90% of the motor’s current under
no load. This means compensating only
the reactive energy of the motor “under no load”,
which may represent only 50% of the needs under
load.
Advantage: This requires only switchgear.
The settings of the protection devices must take
into account the reduction in the reactive current
supplied by the capacitor.
Additional compensation may be performed either
at MV at the overall level, or at LV.
Capacitor mounting in parallel with
separate control
In the case of high-power motors, to prevent
any risk of self-excitation, or else in the event
that the motor is started by means of special
equipment (resistors, reactors, autotransformers),
the capacitors will be switched on only after
starting. The reactive power to be supplied can be
calculated according to the improvement in
the power factor wanted.
NB: If there are several banks of this type in
the same network, provision should be made for
inrush reactors, because this is the same case
as a so-called “stepped” system.
94
Nominal
1500
28
34
43
54
68
76
86
97
108
215
430
speed of rotation (rpm)
1000 750
132
313540
384249
475361
596676
748396
8394108
94 106122
106119137
118133153
235265305
470530610
DE90096
Value in kvar of the maximum compensation feasible on
the motor terminals without risk of self-excitation
C
Capacitor mounting on motor terminals
DE90097
Precautions to be taken against this risk
• Whenever a capacitor bank is installed at
the terminals of a motor, it should be ensured
that the power of the bank is less than
the power needed for self-excitation of the motor,
by complying with the following rule: Capacitor
current Ic ≤ 0,9 x Io (motor no-load current). Io
can be estimated by the following approximate
calculation:
Io = 2 x In x (1 - cos φn,)
- In = rated current of the motor under load
- cos φn = power factor of the motor under nominal
load.
• Moreover, in any installation containing motors
with high inertia and capacitor banks, the banks’
switchgear and controlgear shall be designed in
such a way that in the event of a general power
failure, no electrical bonding may remain between
these motors and the capacitors.
Power rating
(kW)
132
160
200
250
315
355
400
450
500
1000
2000
Inrush reactors
where applicable
Capacitor mounting in parallel with separate control
MV transformer compensation
The power rating of a transformer is given
as apparent power (kVA). The greater tg φ
(or the smaller cos φ), the lower the active power
available for a transformer. The transformer and
the installation are therefore poorly optimized.
The connection of capacitors to the MV terminals of
the transformer therefore offers two advantages:
• Compensate magnetic losses and relieve
the upstream installation. This is extremely
interesting, because the transformer generally
stays energized permanently.
For the reactive power values to be compensated,
see table below.
• Increase the active power available on
the transformer secondary. It is worthwhile,
in the event of a current or future extension,
improving the power factor and thus avoiding
investment in a new transformer.
Apparent power
Primary voltage Secondary voltage Short-circuit (MVA)
(kV)
(kV)
voltage Usc (%)
2.5
20
3 to 16
6.5
30
3 to 16
6.5
3.15
20
3 to 16
7
30
3 to 16
7
4
20
3 to 16
7
30
3 to 16
7
5
20
3 to 16
7.5
30
3 to 16
7.5
6.3
10 to 36
3 to 20
8.1
8
10 to 36
3 to 20
8.4
10
10 to 36
3 to 20
8.9
12.5
10 to 36
3 to 20
9.4
16
10 to 36
3 to 20
10.1
20
10 to 36
3 to 20
11
25
10 to 36
3 to 20
12.1
31.5
10 to 36
3 to 20
13.5
40
10 to 36
3 to 20
15.3
Reactive power
to be compensated
unloaded (kvar)
40
50
50
60
60
70
70
80
70
80
90
120
130
140
175
190
240
95
Technical guide
Capacitor definitions and terminology
Scope of application
The standards (IEC 60871) apply to capacitor
units and capacitor banks designed in particular to
be used to correct the power factor
of alternating-current networks having a rated
voltage greater than or equal to 1000 V,
of frequency equal to 16 2/3 , 50 or 60 Hz.
Capacitor element
Device consisting basically of two electrodes
separated by a dielectric.
Capacitor unit
Set of one or more capacitor elements placed in the
same enclosure and connected to output terminals.
Capacitor bank
Set of capacitor units connected so as to act jointly.
Internal protection of a capacitor
Fuse mounted inside a unit and con-nected in series with
an element or a group of elements.
Capacitor discharge device
Device that can be incorporated in the capacitor
and is capable, in a specified time, of reducing
practically to zero the voltage between
the capacitor terminals when the capacitor
has been disconnected from the network.
Rated capacitance (Cn)
Value of the capacitance for which the capacitor
was designed.
Rated power of a capacitor (Qn)
Reactive power output at rated values:
capacitance, frequency and voltage (or current).
96
Rated voltage of a capacitor (Un)
Rms value of the alternating voltage for which
the capacitor was designed.
Rated frequency of a capacitor (Fn)
Frequency for which the capacitor was designed.
Rated current of a capacitor (In)
Rms value of an alternating current for which
the capacitor was designed.
Residual voltage
Voltage which remains on the terminals of
a capacitor for some time after its disconnection.
Highest network voltage (Um)
The highest value of the phase-to-phase rms
voltage which may occur at any time and any point
on the network in normal operating conditions.
This value does not take into account temporary
voltage fluctuations due to faults or sudden
tripping causing the separation of major loads.
Highest voltage for the equipment
The highest voltage for which the equipment of
a network is specified with regard to its insulation
in particular. This voltage must be at least equal to
the highest voltage of the network for which
the equipment is intended.
Insulation level
The insulation level of an equipment is defined,
in the present situation, as the expression of
the values of its impulse withstand voltage
and its power-frequency withstand voltage.
Technical guide
97
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www.schneider-electric.com
CFIED 205098EN
As standards, specifications and designs change from
time to time, please ask for confirmation of the
information given in this publication.
10-31-1247
10-31-1247
Publication: Schneider Electric Industries SAS
Photos: Schneider Electric
Printed:
This document has been
printed on ecological
paper.
07-2013
© 2013 - Schneider Electric - All rights reserved
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