af0100 arc-flash relay

af0100 arc-flash relay
AF0100
ARC-FLASH
RELAY
APPLICATION
GUIDE
AF0100 Arc-Flash Relay
APPLICATION GUIDE
Table of Contents
1 INTRODUCTION3
1.1 Arc-Flash Relay
3
1.2 Optical Sensors
3
2 DESIGN4
2.1 Typical Arc-Flash Protection Applications
4
2.2 Arcing Faults
5
2.2.1 Typical Energy in an Arcing Fault
5
2.2.2 Arc-Flash Relays and PPE
5
2.2.3 Arc-Flash Relays in Engineering Software Packages
5
2.3 Electrical Drawings
6
2.3.1 AF0100 Arc-Flash Relay Back Plate and Sensor Dimensions
6
2.3.2 Connections
6
2.3.3 Symbols
6
3 INSTALLATION7
3.1 Block Diagram 7
3.2 Relay Placement
7
3.2.1 Maximum Distance to Circuit-Breaker
7
3.2.2 Maximum Distance to Sensors
8
3.3 Redundant Trip Path
9
3.4 Sensor Placement
9
3.4.1 Point Sensor Placement
3.4.2 Fiber-Optic Sensor Placement
10
11
4 EXAMPLES
12
4.1 Generator Application 12
4.2 Main–Tie–Main Application
13
APPENDIX A: SUPPORTING MATERIALS14
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
1 INTRODUCTION 1.1 Arc-Flash Relay
The AF0100 is a microprocessor-based protection relay that limits
arc-flash damage by using light sensors to rapidly detect the arc and
then trip a circuit breaker. Sensors, inputs, and trip-coil voltage are
monitored to ensure fail-safe operation. A secondary solid-state circuit
provides a redundant trip path in shunt trip mode. A USB port is used
for configuration.
The AF0100 can be used on electrical systems operating at any voltage
(AC or DC) since it does not directly connect to the system. The small size
of the AF0100 allows installation in any switchgear cubicle, transformer
compartment, generator control panel, or motor control center bucket.
1.2 Optical Sensors
The AF0100 accepts PGA-LS10 (point), PGA-LS20, and PGA-LS30
(fiber) optical sensors. These sensors have been designed to have a
wide detection angle and provide the correct sensitivity for an arc flash.
LEDs on the relay and on the sensors indicate sensor health and which
sensor(s) detected an arc fault. All sensor types include an optical-toelectrical transducer and connect to the AF0100 with copper wire.
Point Sensor (PGA-LS10)
The point sensor has a detection area of a 2 m half-sphere for arcs of 3
kA or more. Each PGA-LS10 features a built-in LED which enables an
AF0100 to verify the function of the light sensor, wiring, and electronics.
If the relay does not detect the sensor-check LED, a sensor-fail alarm
will occur; the ERROR output will change state, the ERROR LED will
begin to flash, and the sensor LED will show short red flashing. The
sensor includes 10 m of shielded three-wire electrical cable which can
easily be shortened or extended to a maximum of 50 m.
Fiber-Optic Sensor (PGA-LS20, PGA-LS30)
The fiber-optic sensor has a 360° detection zone along the fiber’s length
(8 m for the PGA-LS20, 18 m for the PGA-LS30). Each PGA-LS20 and
PGA-LS30 features a built-in LED which enables the AF0100 to verify
the function of the fiber-optic light sensor, wiring, and electronics. If
the relay does not detect the sensor-check LED, a sensor-fail alarm
will occur; the ONLINE output will change state, the ONLINE LED will
begin to flash, and the sensor LED will show short red flashing.
The fiber-optic sensors have three components:
1. A fiber-optic cable bundle terminating on both ends, one end
covered with a black sleeve, and the other is uncovered. Both ends
are terminated at the factory.
2. A transmitter with a white enclosure and a white thumb nut.
3. A receiver with a white enclosure, a black thumb nut, and an
adjustment screw behind an access hole. Both the receiver and
the transmitter connect to a single input on the AF0100 using
shielded three-wire electrical cable. The receiver and transmitter
each include 10 m of shielded three-wire electrical cable that
can easily be shortened or extended to a maximum of 50 m.
All three components are monitored to ensure continuity and
correct operation.
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180˚ 2-meter
Half-Sphere
Sensor
Viewing Angle
Up to
50 m cable
2.5m
2m
Light Sensor
PGA-LS10:
Detection Range of a 3 kA Arcing Fault
Black Shield
(no light detection)
Receiver
Up to
50 m cables
Transmitter
PGA-LS20: Active Length of 8 m
PGA-LS30: Active Length of 18 m
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
Fiber
The fiber is the light-collecting element of the PGA-LS20 and PGA-LS30. It must be installed so it has line-of-sight
to all current-carrying parts. In some cases this may be accomplished by mounting in a position that follows the bus
bars along the back wall of the cabinets.
Connect the black-sleeve-covered end to the receiver using the black thumb nut, and the white uncovered end to
the transmitter using the white thumb nut. Ensure the fiber is inserted completely into the transmitter and receiver
and the nuts are tightened. Pull gently on the electrical cable to verify a secure connection.
The fiber should not be sharply bent or pinched. The minimum bending radius is 5 cm.
Point or Fiber-Optic Sensors?
The AF0100 supports two types of arc-flash sensors, point sensors (PGA-LS10) and fiber-optic sensors
(PGA-LS20 and PGA-LS30). Both sensor types gather light and transmit the intensity of the light back to the
AF0100. The point sensor monitors the light from a single collection point while the fiber-optic sensors collect
light along their entire length. The decision to use point sensors or fiber-optic sensors comes down to the
geometry of the equipment to be monitored and the importance of fault location. In a switchgear installation with
many small cabinets, it may be more cost-effective to pass a single fiber-optic sensor through all the cabinets
than to install one point sensor per cabinet. However, this is done at the expense of using the fault location
features of the AF0100 to determine the location of the arc-flash within those cabinets, not which sensor sees
the fault. Sensor types can be combined to further customize the solution. An understanding of the two sensor
types and their properties is important for selecting the correct sensors.
2 DESIGN
2.1 Typical Arc-Flash Protection Applications Although an arc flash is improbable on systems operating at 208 V or less, systems with higher voltages have
sufficient capacity to cause an arc flash and should use proper protection. Arc-flash protection is especially
important in the following applications:
g
g
g
g
g
g
g
g
olidly grounded electrical distribution systems: It is estimated that over 95% of all electrical faults are, or
S
begin as, a ground fault*. Ground-fault current on a solidly grounded system is only limited by the resistance of
the fault and system impedance, and has the potential to cause an arc flash.
larm-only systems: When ground faults are allowed to persist on a system, particularly in an ungrounded
A
system, the faults can cause rapid deterioration of electrical safety and escalation into an arc flash.
igh-Current Systems: The 2017 US NEC, section 240.87 includes “active arc-flash mitigation system” in a
H
short list of options that shall be used to reduce clearing time “Where the highest continuous current trip setting
for which the actual overcurrent device installed in a circuit breaker is rated or can be adjust is 1200 A or higher.”
ir-cooled transformers: On air-cooled equipment, the winding insulation, terminals, and ground points are
A
exposed to the environment. Pollution, dust, and other contaminants can cause premature insulation failure and
can lower the resistance of the air gap between energized conductors, and between energized conductors and
ground. Insulation failure and lower air-gap resistance increase the probability of an arc flash.
enerators: Incident energy levels are typically very high on generators, and portable generators are often in
G
enclosed trailers which make maintenance difficult and dangerous.
ack-out breakers: As a circuit breaker is racked out, there is a potential for an arc flash to develop when the
R
electrical contacts are disconnected while energized.
evices with high inrush currents: Transformers, capacitor-banks, surge arrestors, large motors, and other
D
reactive loads will cause a high-inrush current when energized. To allow these systems to operate properly,
instantaneous-current settings on circuit breakers will either be set very high or not used, allowing an arc-flash
to remain on the system for longer, or not be detected at all.
ow-voltage equipment: Higher fault currents at lower voltage and a mentality that lower voltages are safer
L
than high voltages mean that many arc-flash incidents actually occur on low-voltage equipment.
*Source: Industrial Power System Grounding Design Handbook by J.R. Dunki-Jacobs, F.J. Shields, and Conrad St. Pierre, page xv.
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
g
g
g
g
Medium and high-voltage equipment: Medium-voltage equipment (4160 V and higher) often uses air insulation.
oveable and mobile electrical equipment: Mobile electrical equipment is subject to physical damage while
M
in motion and has a higher potential for an arc flash. The designs are often more compact, reducing air gap
insulation levels.
reas where work or maintenance is regularly performed on energized equipment: While maintenance
A
personnel are required to wear proper PPE when working on or around energized equipment, an arc-flash relay
can be used to lower the levels of hazard that personnel are exposed to.
Older facilities: Where often, room is not available for any other means of Arc-Flash Hazard mitigation.
2.2 Arcing Faults
2.2.1 Typical Energy in an Arcing Fault
A phase-to-phase fault on a 480-V system with 20,000 amperes of fault current provides 9,600,000 watts of
power. Imagine that there is no arc protection and the fault lasts for 200 milliseconds before the overcurrent
protection clears it. The released energy would be 2 MJ, which corresponds roughly to a stick of dynamite.
The energy formula is as follows:
Energy = voltage x current x time = 480 V x 20,000 A x 0.2 s = 1,920,000 J
For a given system voltage, two factors can be adjusted to reduce arc-flash energy: time and current.
Time can be reduced by using a device such as the AF0100 to rapidly detect an arc flash, thus causing the
connected circuit breaker to trip at its instantaneous speed, overriding any inverse-time delay. Current can be
reduced by using current-limiting fuses or, in case of phase-to-ground faults, by using high-resistance grounding.
2.2.2 Arc-Flash Relays and PPE
Reducing the clearing time is typically a trade-off with system uptime for current-based protection. Sufficient
delay is required to prevent unnecessary tripping on momentary overload or current spikes. Such delay limits how
quickly such a system can react.
Arc-flash relays address this issue by detecting light rather than current, which permits a much faster response
that is independent of current spikes and momentary overloads. The AF0100 relay can detect an arcing condition
and send a trip signal to a circuit breaker in milliseconds. This response time is much faster than standard currentbased protection, which means using an arc-flash relay will lower the incident energy or arc-flash hazard in most
cases. This results in increased worker safety, less fault damage, and improved uptime.
If the arc-flash incident energy has decreased, the associated PPE requirement may also be lowered. The exact
improvement will depend on the installation, so the AF0100 must be modeled in the system to determine
the new incident energy and PPE.
2.2.3 Arc-Flash Relays in Engineering Software Packages
To date, engineering software used for three-phase power system design and analysis (including arc-flash
incident energy calculations) rely on time-current curves for overcurrent protection devices. Examples of this type
of software include SKM, EasyPower, etap, and others.
Because arc-flash relays use light instead of current, the operation time is independent of the current to the extent
that the light produced from the current is above the threshold. The AF0100's time-current curve is a horizontal
line at the response time of the configuration used (5 ms for typical a arc-flash application and configuration).
In order to model the AF0100 in these software packages, the operating time of the breaker connected to the
AF0100 should be adjusted to its instantaneous trip time plus the AF0100 operation time. These times can be
found in the AF0100 manual, but vary from 3 ms to 8 ms and with a typical shunt breaker connected to the
normally open contact is 5 ms. Detailed instructions on modeling an arc-flash relay in various software packages
can be found in the Technical Resources section of the Littelfuse.com website.
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APPLICATION GUIDE
3.02
76.6
1.39
35.3
AF0100 Arc-Flash Relay
S
LE
HO
2.3.1 AF0100 Arc-Flash Relay Back Plate and Sensor Dimensions
2
G
IN
NT 5.2
20
0.
FRONT
U
MO
6.3
SIDE
127.6
95.2
16.2
0.64
3.75
0.64
14.2
(0.56)
2.4
(0.09)
46.0
(1.81)
16.2
8.3
(0.33)
6.3
0.25
2.0
(0.08)
9.6
(0.38)
5.03
0.25
2.3 Electrical Drawings
23.8
(0.94)
WHITE
SHIELD / BLACK
YELLOW
RED
BOTTOM
THUMB NUT
32.0
(1.26)
PGA-LS20 and PGA-LS30
2.3.3 Symbols
L1
L1
G Protection
Active
R Trip
N
DECREASE
SENSITIVITY
24.0
(0.94)
32.0
(1.26)
PGA-LS10
2.3.2 Connections
RECEIVER
SENSITIVITY
ADJUSTMENT
SCREW
42.0
(1.65)
52.0
(2.05)
44.0
(1.73)
6.3
0.25
NOTES:
1. DIMENSIONS IN MILLIMETERS [INCHES].
2. MOUNT USING DIN RAIL OR TWO #6 SCREWS
USB
Note 3
RED LED FOR
CIRCUIT CHECK AND
VISUAL DIAGNOSTICS
MOUNTING DETAIL
Ø4.25(0.167)
MOUNTING HOLES
4.0
(0.16)
46.0
(1.81)
10 m
Ø4.25(0.167)
MOUNTING HOLES
Ø8.3(0.33)
SENSOR LENS
4.0
(0.16)
24.0
(0.94)
4.0
(0.16)
(32.8 ft)
3.02
76.6
3.51
89.2
18.8
(0.74)
N
A B
C
x
x
L1
x
These symbols are to be used in electrical
drawings of the AF0100:
Trip
Coil
N
AFR
PGA-LS20 or PGA-LS30
Fiber-Optic Sensor
AF0100
Arc-Flash Relay
PGA-LS10
Point Sensor
Reset
N
L1
PGA-LS10
Point Sensor PGA-LS20/PGA-LS30
Fiber Optic Sensor
NOTES:
1. RELAY OUTPUTS SHOWN
DE-ENERGIZED.
2. A TOTAL OF TWO POINT OR FIBEROPTIC SENSORS CAN BE CONNECTED.
3. USB ‘B’ CONNECTOR. FOR
CONFIGURATION, SEE SECTION 7.3 OF
THE AF0100 MANUAL.
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Sensor 1 Sensor 2
USB
Note 3
N
6
L1
L1
G Protection
Active
R Trip
N
A
B
C
x
x
x
L1
N
Trip
Coil
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
3 INSTALLATION
3.1 Block Diagram
Digital I/O Connection to other AF0100 or AF0500
24-48 Vdc
Supply
PGA-LS10
(Point Sensor)
+
–
AF0100
or
L1
L2
PGA-LS20/
PGA-LS30
(Fiber-Optic Sensor)
(Arc-Flash Protection Relay)
Unit
Healthy
Trip 1
Trip 2
100-240 Vac/Vdc
Supply
3.2 Relay Placement
3.2.1 Maximum Distance to Circuit-Breaker
In order to determine the maximum permitted distance, the following data is required:
g
Burden of the shunt trip-coil (see data sheet of shunt trip)
g
Available trip voltage in the installation
g
g
ermitted voltage range of the trip coil (lowest permitted voltage for the shunt trip to operate,
P
see data sheet of the shunt trip)
Wire material and specific electrical resistance of that material
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
Calculation Definitions and Example
VARIABLE
S
L
ρ
U
Umin
Udrop
A
DEFINITIONS
Burden of the shunt trip [VA]
Cable length
mm2
Specific electrical resistance (copper is 0.0178) Ω xm
Available trip voltage in the installation
Lowest permitted voltage for the shunt trip to operate
Maximum voltage drop permitted over the cable between the shunt trip and the AF0100
Cable cross section [mm2]
Example Values
S = 185 VA
Ω x mm2
ρ = 0.0178
m
U = 24 V
Umin = 12 V
(Copper Wire)
A = 2.5 mm2
Calculation of the Permitted Cable-Voltage Drop
Udrop = U–Umin = 24 V–12 V = 12 V
Note that the nominal trip current is calculated with the full
24 V. Due to voltage drop across the cable, the full trip voltage
will not be present at the coil. When a lower voltage is
available at the trip coil, the trip coil will operate with a lower
current. This gives some additional safety margin.
Calculation of Nominal Trip Current
S = UxI
I = S = 185 VA = 7.71 A
24 V
U
Calculation of Maximum Allowed Cable Resistance
R=
Udrop
= 12 V =1.55 Ω
I
7.71 A
The maximum distance between the AF0100 trip coil output
and trip coil for above example is 108 m. If the AF0100 is
installed far from the circuit breaker, higher voltage trip coils
can be used to reduce the current draw and therefore the
voltage drop on the wire.
Calculation of Maximum Cable Length
A
L
1.04 Ωx 2.5 mm2
RxA
=217 m / 2 = 108 m
L= ρ =
mm2
0.0178 Ω xm
ρ =Rx
3.2.2 Maximum Distance to Sensors
The maximum length of electrical cable between a PGA-LS10 point sensor and an AF0100 is 50 m.
The maximum length of electrical cable between a PGA-LS20/PGA-LS30 fiber-optic sensor and an AF0100 is 50
m to the transmitter module and 50 m to the receiver module.
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
3.3 Redundant Trip Path
The AF0100 has a secondary solid-state circuit (shunt trip mode only) that provides redundancy in the event of a
microprocessor failure. Less often considered, a microprocessor-based relay can take several hundred milliseconds
to initialize and reach the state where it is able to detect an arc flash. If the system is de-energized for maintenance
(including the AF0100) and then re-energized when the maintenance is complete, this constitutes a risk. A
misplaced tool or incorrect wiring that was changed during shutdown could result in an arc flash immediately
on power up. In this case, the redundant trip path will protect the system against arc flashes during initialization
of the microprocessor as well, thus the system allows a much faster response time on power up than typical
microprocessor-based relays. The response time after power up is less than 10 ms. In contrast, microprocessor
initialization time can be in the order of 500 ms.
3.4 Sensor Placement
To Electrical Bus/Other Generators
The AF0100 Arc-Flash Relay and sensors are easily
installed in retrofit projects and new switchgear with
little or no reconfiguration. Even elaborate systems
with multiple power sources take only minutes to
configure using the relay’s built-in USB PC-interface
software. (No need to install any configuration
software on the PC)
Control Panel
Threading a fiber-optic sensor through the cabinets
and in areas where point-sensor coverage is uncertain
results in complete coverage and an added level of
redundancy (at least 20 cm per compartment, 60 cm
recommended). Even if policy is to only work on deenergized systems, all maintenance areas should be
monitored to prevent potential damage and additional
costs. At least one sensor should have visibility of an
arc fault in the event that someone were to block the
other sensor(s).
Circuit
Breaker
AVR
Trip 1
Trip 2
Incoming from
Generator
Point
Sensor
Additional guidelines
g
g
g
nsure fiber-optic light sensors and electrical
E
cables are not blocked by objects, either fixed
or movable.
o not place point sensors or fiber-optic sensor on
D
live or energized components.
hoose a location that will minimize collection of
C
foreign debris and be easy to inspect/maintain.
g
Use care when handling, pulling, and securing electrical cables and sensors.
g
Avoid sharp bends (<5 cm) and high temperature (>80°C).
g
Consider potential light emitted from air-magnetic circuit breakers when placing sensors.
g
g
Even though the sensors and electrical cables have no exposed live parts and are fully insulated, the placement and
routing must comply with industry-standards for over-surface (creep) and through-air (clearance) requirements.
abel equipment so that workers are aware that light detection technology is present. Avoid direct sunlight,
L
flash photography and welding if the sensors are exposed and current inhibit is not used.
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
Scenario with point sensor placement on the top of
each compartment, looking down. The detection area
for each sensor is shown in green for demonstration
purposes only. For exact sensor range refer to section
1.2. In this case, both Point Sensor 2 and the FiberOptic Sensor detected the flash as it was within their
viewing area (shown in orange).
Scenario with point sensor placement on the wall of
each compartment. The detection area for each sensor
is shown in green for demonstration purposes only.
For exact sensor range refer to section 1.2. In this
case, both Point Sensor 1 and the Fiber-Optic Sensor
detected the flash as it was within their viewing area
(shown in orange).
3.4.1 Point Sensor Placement
The point-sensor (PGA-LS10) housing
directs light from a half-sphere detection
volume onto the light sensor. An arc flash
can conduct tens of thousands of amps but,
for an arc flash of only 3 kA, a PGA-LS10
has a half-sphere detection range of 2 m
or more. A point sensor is apt at indicating
the fault location because the light is only
collected at one location. However, the
requirement for direct line-of-sight can
be a disadvantage in areas with a lot of
equipment and poor sight lines. In most
enclosures, the metallic walls can reflect the
light onto the sensor, thereby amplifying the
light incident on the sensor. However, walls
create an extra safety issue — an arc flash in
a location not directly visible by the sensor
might not be detected.
Examples of appropriate point sensor installation.
The PGA-LS10 point sensors can be installed up to 50 m from the AF0100 Arc-Flash relay with standard shielded
3-wire electrical cable. This is a benefit for retrofit applications as electrical cable is more durable and easier to
install than a fiber-only installation between sensor and relay. Electrical cable has high tolerance for electrical
noise (although not as high as a fiber-optic sensor), and for the purposes of electrical clearances, should be
treated as though it is a bare conductor at ground potential.
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
3.4.2 Fiber-Optic Sensor Placement
TRIP 1
The fiber-optic sensor (PGA-LS20 and
PGA-LS30) has three components. There
is an optical fiber bundle, a transmitter and
a receiver, to convert light collected by the
fiber into an electric signal that can be sent
to the relay. Unlike most fiber-optic sensors
which transmit light from one end to the other
without letting any light escape, the fiberoptic sensor is designed to trap light along its
entire length and then prevent that light from
escaping. One end of the fiber is shielded
for 2 m (minimum) as light entering in this
location will be detected more intensely (than
the same light further down the sensor) which
could cause incorrect measurement.
DE
VI
N CE
SH OT S
OW
N
POINT SENSOR PGA-LS10
DE
VI
N CE
SH OT S
OW
N
M
A
EA IN
KE
R
BR
DE
VI
N CE
SH OT S
OW
N
FIB
ER
S
PG
A- ENS
LS
OR
20
SENSOR 2
Transmitter and receiver modules can be
installed up to 50 m from the AF0100. The
fiber should not be in contact with bare
conductors but can be run much closer
than the electrical cables and point sensor,
which can make it a better choice for small
and dense spaces with lots of shadow
and little clearance. The active lengths of
the PGA-LS20 and PGA-LS30 are 8 m and
18 m respectively.
SENSOR 1
PGA-LS20 10m (8m active)
PGA-LS30 20m (18m active)
Make sure that at least 20 cm of fiber are
exposed in each compartment, in order to
collect sufficient light. Fibers must be handled
with care as they are more fragile than electrical
cable, have a minimum radius for curves, and
may be damaged during installation. A fiberoptic sensor does not detect the exact location
of an arc along the fiber, it just detects an arc.
It may not be immediately clear where the
arc-flash was detected if the sensor is passed
through many compartments. However,
passing the fiber-optic sensor through many
small compartments may result in a significant
cost savings as compared to using an individual
point sensor in each compartment.
Example of appropriate fiber optic sensor installation.
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
4 EXAMPLES
4.1 Generator Application
To protect a generator from an arc fault, the most critical section (because it is otherwise unprotected from any
overcurrent device) is between the generator and the generator breaker. A fault on this location, upstream of the
generator breaker, will be supplied directly from the generator as well as from any connected sources in parallel,
such as other generators and/or the utility. Sensors are mounted to monitor these sections and the AF0100 is
connected to the automatic voltage regulator (AVR) or a control circuit in order to power down the generator and
to the generator breaker to prevent any parallel sources from maintaining the arc flash.
Protecting an enclosed transformer from an arc flash usually means one sensor monitoring the primary side
and another monitoring the secondary side. There must be an upstream device to trip. In this example, the
transformer does have a breaker that can be opened in case of an arc, but otherwise, the AF0100 would connect
to each generator arc-flash relay using its digital I/O to shut down all energy sources to the arc.
Generator Enclosure
Generator
Transformer Enclosure
Sensor
Transformer
Sensor
Breaker
To application
Primary Side Sensor
Secondary Side Sensor
AVR/
Control Circuit
Trip 1 Trip 2
Trip 1
AF0100
AF0100
To other parallel generators or utility
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
4.2 Main–Tie–Main Application
In case a switchboard is divided into separate sections by tie or coupler circuit breaker and fed by more than one
incoming feeder, it can be advantageous to disconnect only the switchboard section where the arc is present,
while leaving the other sections online. In this case it is not enough to trip the incoming feeder alone. The tie
breaker must be tripped as well in order to isolate the section with the arc fault from the rest of the system. In
the event of a fault at the tie breaker, both incoming feeders must be tripped. The single-line diagram shows an
application with two incoming feeders and a tie breaker. All sensors are downstream of the circuit breakers. If
an arc is detected on either side of the tie circuit breaker, the respective feeder circuit breaker and the tie circuit
breaker will be tripped.
This example shows a system utilizing AF0100 and AF0500 relays connected through digital I/O to ensure that
the correct breakers trip for each of the three protection zones.
Source 1
Fiber Sensor
Source 2
Protected Zone 1
Protected Zone 2
Fiber Sensor
Protected Zone 3
Tie Breaker
Sensor
Sensor
Sensor
Sensor
Sensor
Tripped
AF0500
Trip
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Trip
AF0100
Tripped
13
Sensor
Tripped
AF0100
Trip
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AF0100 Arc-Flash Relay
APPLICATION GUIDE
APPENDIX A: SUPPORTING MATERIALS Littelfuse provides many supporting materials in digital format for the function and installation of the
AF0100 Arc-Flash Relay.
Manual
Brochure
Workbook for Estimating Arc-Flash Incident Energy Reduction
Datasheet
Videos
FAQ Booklet
Guideform Specifications
These can be found at: Littelfuse.com/ArcFlash
AF0100 COMMISSIONING INFORMATION
General Installation
Settings
Minimum
Default
Max
Unit
Comments
Date Installed
Operator
Comment 1
Comment 2
General
System Name
Description Of This Unit
AF0100 Arc-Flash Relay
Date and Time
Synchronize to PC Clock
Disabled
o Enabled
o Disabled
Light Sensors
Common Settings
Light Immunity Lower Limit
Arc Detection Time
Before Tripping
10
10
25
klux
klux
0
(Effective
0.8)
1
20,000
ms
ms
Light Sensor 1
Sensor Status
Sensor Description
Change Configuration
o Sensor Present
o No Sensor Detected
o Sensor Missing
o Sensor Tripped
o No Change
o No Sensor Expected
o Sensor Expected
o Sensor Present
o No Sensor Detected
o Sensor Missing
o Sensor Tripped
o No Change
o No Sensor Expected
o Sensor Expected
Sensor 1
No Change
Light Sensor 2
Sensor Status
Sensor Description
Change Configuration
Sensor 2
No Change
Configuration of Failsafe/NFS Outputs
Trip 1
Failsafe
o Failsafe
o Non-Failsafe
Trip 2
Failsafe
o Failsafe
o Non-Failsafe
Error
Failsafe
o Failsafe
o Non-Failsafe
© 2017 Littelfuse Products
14
Littelfuse.com/ArcFlash
AF0100 Arc-Flash Relay
APPLICATION GUIDE
NOTES
© 2017 Littelfuse Products
15
Littelfuse.com/ArcFlash
For more information, visit
Littelfuse.com/ArcFlash
Additional technical information and application data for Littelfuse protection relays, generator and engine controls, fuses and other circuit protection and
safety products can be found on Littelfuse.com. For questions, contact our Technical Support Group (800-832-3873). Specifications, descriptions and illustrative
material in this literature are as accurate as known at the time of publication, but are subject to changes without notice. All data was compiled from public information
available from manufacturers’ manuals and datasheets.
© 2017 Littelfuse, Inc.
Form: PF719
Rev: 1-A-022417
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