Data Bulletin 620-90 [English, 89 KB, 2/13/1995]

Data Bulletin 620-90 [English, 89 KB, 2/13/1995]
S&C Power-Operated
Metal-Enclosed Switchgear
Indoor and Outdoor Distribution (4.16 through 34.5 kv)
Inspection Recommendations for
Switchgear Equipped with
Type AT-2 Source-Transfer Controls
TABLE OF CONTENTS
Section
Page Number
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
TABLE I—Inspection Procedures for S&C Switchgear
Equipped with Type AT-2 Source-Transfer Controls . . . . . . . . 3
Section
Page Number
TABLE II—Inspection and Maintenance Procedures for the
Enclosure and for Components in High-Voltage Bays. . . . . . . .5
INTRODUCTION
Ç CAUTION
The equipment covered by this publication must be
inspected by qualified persons who are thoroughly
trained and who understand any hazards that may be
involved. This publication is written only for such
qualified persons and is not intended to be a substitute for adequate training and experience in safety
procedures for this type of equipment.
This publication contains inspection and maintenance
recommendations for S&C Power-Operated MetalEnclosed Switchgear assemblies. Included in these recommendations are instructions to effect a complete functional inspection of Type AT-2 Source-Transfer Controls
for switchgear having automatic source-transfer capabilities. Type AT-2 controls are used in switchgear config-
Supersedes Data Bulletin 620-90 dated 12-19-88
ured in a common-bus primary-selective arrangement.
For switchgear equipped with Type AT-3 Source-Transfer
Controls, refer to Instruction Sheet 620-591 for inspection recommendations.
To successfully complete the inspection procedures
involving the AT-2 control, the gear must be energized
with adequate voltage available on both power sources. It
is recommended that this inspection be performed at
least every year. Refer to Table I.
It is generally recommended that the metal-enclosed
switchgear enclosure and components located in highvoltage bays be inspected six months to a year after
installation and then every five years thereafter to
ensure continued proper performance of the gear. Each
user’s own experience as well as environmental conditions at the installation will determine whether more or
less frequent inspections are required. Refer to Table II.
c1995
DATA BULLETIN
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S&C ELECTRIC COMPANY
620-90
Page 1 of 8
February 13, 1995
S&C Power-Operated
Metal-Enclosed Switchgear
Indoor and Outdoor Distribution (4.16 through 34.5 kv)
Inspection Recommendations for
Switchgear Equipped with
Type AT-2 Source-Transfer Controls
INTRODUCTION — Continued
A partial visual inspection of the gear for general cleanliness, and to confirm proper alignment and condition of
barriers and terminators may be performed with the gear
energized, if permitted by the user’s own operating practices and provided that standard precautionary practices
are followed. Such visual inspections may be performed
when the gear is visited for other reasons, as well. However, the more detailed inspection and maintenance procedures outlined in this publication may only be
completed when the unit is completely de-energized and
grounded.
Ç
CAUTION
When following the inspection procedures involving the
AT-2 control, decouple all switch operators from their
associated Mini-Rupter® or Alduti-Rupter® Switches.
Switching operations will result in temporary service
interruptions if the operators are coupled.
For instructions regarding switch operators, refer to:
INSTRUCTION SHEET 629-510 (Formerly 855-512):
S&C Switch Operators
Catalog Numbers 38744
Type MS-2
and 38754
INSTRUCTION SHEET 629-500 (Formerly 854-501):
S&C Switch Operators
Catalog Number
Type AS-30
38960
INSTRUCTION SHEET 629-520 (Formerly 855-501):
S&C Switch Operators—Type MS-10
For instructions regarding operation of the AT-2 control, refer to:
INSTRUCTION SHEET 514-501:
S&C Source-Transfer Controls
Type AT-2
For instructions regarding the inspection and maintenance of SPD open-phase detectors and ZSD overcurrent
relays, refer to:
INSTRUCTION SHEET 542-500:
S&C Open-Phase Detector
For use in S&C
Type SPD
Metal-Enclosed Switchgear
INSTRUCTION SHEET 551-500:
S&C Overcurrent Relay
For use in S&C
Type ZSD
Metal-Enclosed Gear
For instructions regarding manually operated S&C
Alduti-Rupter Switches or S&C Mini-Rupter Switches,
refer to:
INSTRUCTION SHEET 783-501:
S&C Alduti-Rupter Switches
Three-Pole
Indoor Distribution (4.8 kv through 34.5 kv)
INSTRUCTION SHEET 785-501:
S&C Mini-Rupter Switches
Manually Operated
Indoor Distribution (4.16 kv through
Styles
25 kv)
Applicable instruction sheets, drawings, and wiring
diagrams for each switchgear assembly, plus similar documents for meters, relays, and other low-voltage components not of S&C manufacture, are in an envelope entitled
“INSTALLATION AND OPERATION INFORMATION KIT.”
This envelope is located in a holder inside the appropriately labeled switchgear-bay door.
If maintenance is required that is beyond the scope of
this publication or if replacement parts are necessary,
contact the nearest S&C Sales Office. Have the complete
catalog number of the gear and date of shipment (as
shown on the nameplate) available for reference.
For Two-Way Transfer,
Catalog Numbers 38881
and 38883
For instructions regarding the operation of the
optional S&C Test Accessory (Catalog Number TA-1316)
refer to:
INSTRUCTION SHEET 514-605:
S&C Source-Transfer Controls
Type AT-2, AT-3, and AT-12
S&C Test Accessory,
Catalog Number TA-1316
For AT-2 troubleshooting, refer to:
INSTRUCTION SHEET 514-520:
S&C Type AT
Troubleshooting
Source-Transfer Controls
Guide
620-90
Page 2 of 8
February 13, 1995
DATA BULLETIN
S&C ELECTRIC COMPANY
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TABLE I
Inspection Procedures for S&C Switchgear Equipped with
Type AT-2 Source-Transfer Controls 1
Item
Inspection Procedures
Voltage-Sensor
Signal Adjustments
and Measurements
1. Place the manual/automatic selector switch in the “MANUAL” position and decouple each operator from its associated
Mini-Rupter or Alduti-Rupter Switches (switching operations will result in temporary service interruptions if the operators
are coupled).
2. If three voltage transformers are used for sensing on each source: The signal-voltage output of the voltage transformers need not be measured or adjusted.
3. If one voltage transformer and two voltage sensors are used for sensing on each source:
a. At the programming panel on the AT-2, measure and record the magnitude of the voltage-transformer output voltage
for the center phase of the preferred source using a voltmeter having an input impedance of at least 5,000 ohms
per volt.
b. Measure and record the magnitude of the voltage-sensor output signal for the other two phases of the preferred
source.
c. If the measured output of any voltage sensor differs from that of the voltage transformer, “scrub” the associated
voltage-sensor potentiometer by rotating the adjustment screw back and forth 10 to 12 times. Then adjust the
setting to match the measured voltage-transformer output voltage.
d. Repeat Steps a, b, and c above for the alternate source.
Switch
Operators
1. With the manual/automatic selector switch in the “MANUAL” position, open the preferred-source operator by pressing
the appropriate “OPEN” pushbutton (or manual trip lever, as applicable). After opening, Type MS-2 Switch Operators
should recharge in 1¹⁄₂ seconds; Type AS-30 Switch Operators do not recharge.
2. Close the alternate-source operator by pressing the appropriate “CLOSE” pushbutton (or manual trip lever, as applicable). This operator should also recharge in 1¹⁄₂ seconds if an MS-2; Type AS-30 Switch Operators do not recharge.
3. Each switch operator should be given an exercising consisting of 5 or more operations, power operated, unless normal
operating duty provides equal or greater exercise.
4. Return both operators to their original positions (preferred closed, alternate open).
Time Delay on Loss
of Source (“62P” and
“62A” Timers)
and Return of
Source (“2P” Timer)
1. Place the manual/automatic selector switch in the “AUTOMATIC” position and note the position of the automatic-hold
return selector switch.
2. If the AT-2 is in the “AUTOMATIC RETURN” mode:
a. Simulate a prolonged loss of preferred-source voltage by pressing and holding in the simulate-loss-of-source test
switch for the preferred source. Verify that the time to initiate transfer is within 620% of the setting on the “62P” timer.
Also, confirm that the associated source voltage lamp extinguishes. Verify, as well, that the switch operator
targets correctly indicate an open or closed position.
b. Release the test switch to simulate a return of the preferred-source voltage. Verify that the time to initiate back
transfer is within 620% of the setting on the “2P” timer. Confirm that the associated source voltage lamp relights.
Again, verify the switch operator targets’ positions.
3. If the AT-2 is in the “HOLD RETURN” mode:
a. Simulate a prolonged loss of preferred-source voltage by pressing and holding in the simulate-loss-of-source test
switch for the preferred source. Verify that the time to initiate transfer is within 620% of the setting on the “62P” timer.
Also, confirm that the associated source voltage lamp extinguishes. Verify, as well, that the switch operator targets
correctly indicate an open or closed position.
b. After releasing the test switch, wait a sufficient length of time to make sure that back transfer does not occur. Confirm
that the associated source voltage lamp relights.
c. Now simulate a loss of alternate-source voltage by pressing the simulate-loss-of-source test switch for the alternate
source. Verify that the time to initiate retransfer is within 620% of the setting on the “62A” timer.
1 If the power-operated switchgear being inspected does not operate as
indicated in these inspection recommendations, refer to the SourceTransfer Controls troubleshooting guide, S&C Instruction Sheet 514-520.
If further assistance is necessary, contact the nearest S&C Sales Office.
Have the complete catalog number of the switchgear, date of shipment
(as shown on the nameplate), operating mode settings, and timer settings
available for reference.
TABLE CONTINUED c
DATA BULLETIN
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S&C ELECTRIC COMPANY
620-90
Page 3 of 8
February 13, 1995
S&C Power-Operated
Metal-Enclosed Switchgear
Indoor and Outdoor Distribution (4.16 through 34.5 kv)
Inspection Recommendations for
Switchgear Equipped with
Type AT-2 Source-Transfer Controls
TABLE I — Continued
Inspection Procedures for S&C Switchgear Equipped with
Type AT-2 Source-Transfer Controls 1—Continued
Item
Inspection Procedures
Reset Time for
Optional
Overcurrent-Lockout
Feature
(“62LR” Timer)
1. With the manual/automatic selector switch in the “AUTOMATIC” position, simulate an overcurrent condition on the
preferred source by momentarily pressing the simulate-overcurrent test switch for the preferred source. Confirm that the
blue overcurrent-lockout indicator lamp lights for a period of time within 620% of the setting on the “62LR” timer.
2. Simulate an overcurrent condition and a loss of source voltage on the preferred source. To accomplish this, momentarily
press the simulate-overcurrent test switch and, at the same time, press and hold in the simulate-loss-of-source test
switch for the preferred source. Confirm that the preferred-source operator opens while the alternate-source operator
remains open and locked out. Release the simulate-loss-of-source test switch when the preferred-source operator
opens.
3. Place the manual/automatic selector switch in the “MANUAL” position and reset the overcurrent-lockout feature. Confirm
that the blue overcurrent-lockout indicator lamp extinguishes. Then close the preferred-source operator by pressing the
appropriate “CLOSE” pushbutton or manual trip lever, as applicable.
Before Leaving the
Gear . . .
1. So that the AT-2 Source-Transfer Control is ready for automatic operation, before leaving the site perform the following:
a. If the operators were decoupled, place the manual/automatic selector switch in the “MANUAL” position, then recouple
each operator to its associated Mini-Rupter or Alduti-Rupter Switches.
b. Return the manual/automatic selector switch to the “AUTOMATIC” position.
c. Confirm that the “READY” indicator lamp is illuminated. (If the “READY” indicator is not illuminated, refer to the
conditions required to light “READY” indicator lamp listed on the faceplate of the AT-2 Source-Transfer Control.)
d. Close and padlock all doors and covers.
1 If the power-operated switchgear being inspected does not operate as
indicated in these inspection recommendations, refer to the SourceTransfer Controls troubleshooting guide, S&C Instruction Sheet 514-520.
If further assistance is necessary, contact the nearest S&C Sales Office.
Have the complete catalog number of the switchgear, date of shipment
(as shown on the nameplate), operating mode settings, and timer settings
available for reference.
620-90
Page 4 of 8
February 13, 1995
DATA BULLETIN
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TABLE II
Inspection and Maintenance Procedures for the Enclosure and for
Components in High-Voltage Bays
Ç WARNING
When access to high-voltage bays is required it must be
restricted to qualified persons only, who must observe
the following procedures:
1. Adhere to prescribed safety rules at all times.
2. Be certain that fuses, interrupter switches, switch
operators, their mechanisms, and any other devices
are disconnected from all power sources and
grounded before that device is inspected, serviced,
or repaired.
3. Discharge all stored-energy switch operators by
using the utility crank (for MS-2 operators), the
manual trip handle (for MS-10 operators), or manual-operating wrench (for AS-30 operators), as
applicable.
4. Always assume that both sets of terminals on any
interrupter switch or fuse are energized unless
proven otherwise by test, by visual evidence of opencircuit conditions on both terminal ends, or by
grounding.
5. Test for voltage. Qualified persons should be certain
that they have and know how to operate the correct
test equipment for determining the voltage on both
sets of terminals on any fuse or interrupter switch.
6. After the switchgear has been completely disconnected from all sources of power and tested, properly connect suitable grounding leads to both sides
of the equipment, that is, incoming and outgoing
phases of the equipment to be maintained.
7. Install dual-purpose front barriers, if furnished, in
the “slide-in” position. If a contact on either side of a
barrier is energized, do not leave the barrier in the
“slide-in” position for longer than one week. These
barriers are intended for temporary use only to isolate the blades of the switch from the main contacts
while work is being performed. If the barriers are left
in the “slide-in” position for extended periods of
time, there is the possibility of corona discharge to
the barriers. Prolonged exposure to corona discharge may damage the barriers and result in a flashover.
8. Padlock and tag equipment in accordance with the
user’s standard operating procedures.
SPECIAL WARNING: All voltage transformers and
voltage sensors must be disconnected when external
voltage is used to test any secondary-side wiring or
devices, to avoid energizing the high-voltage conductors through the voltage transformers or sensors. If
drawout-type voltage transformers are provided,
draw out the transformers and completely disconnect the secondary connections. Otherwise, remove
the primary fuses of the voltage transformers and
disconnect the secondaries by removing the secondary fuses or by disconnecting the secondary leads.
Do not disconnect the burden or the voltage limiter
from the voltage sensor until the switchgear is deenergized; otherwise the voltage sensor will be damaged. For voltage sensors, the secondary leads must
be shorted either by removing the plug from the
input receptacle and transferring it to the shorting
receptacle (for applications involving AT-2 SourceTransfer Control), or by inserting screws into shorting-type terminal blocks.
9. When the equipment to be inspected is not of S&C
manufacture, follow instructions supplied by the
manufacturer of the equipment.
10. Make certain that ground connections from the
ground bus (or ground pad on a single-bay assembly) to the permanent station or system ground facility are made. No equipment should be returned to
service unless such grounds are properly made.
NOTE: Occasionally low-voltage components may
require maintenance. In the servicing or repair of
space heaters, voltage-transformer secondary wiring, and any other components located in a highvoltage bay, all of the preceding safety procedures
apply. The maintenance of other low-voltage components (such as voltmeters, ammeters, relays, etc.),
isolated from high voltage, may be performed under
the safety rules for equipment rated 600 volts or less.
If maintenance is to be performed on ammeters,
short-circuit the secondary connections of the associated current transformer at the shorting-type terminal block prior to removal of the ammeter. This
may require access to a high-voltage bay, in which
case the foregoing procedures apply.
CONTINUED c
DATA BULLETIN
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S&C ELECTRIC COMPANY
620-90
Page 5 of 8
February 13, 1995
S&C Power-Operated
Metal-Enclosed Switchgear
Indoor and Outdoor Distribution (4.16 through 34.5 kv)
Inspection Recommendations for
Switchgear Equipped with
Type AT-2 Source-Transfer Controls
TABLE II — Continued
Inspection and Maintenance Procedures for the Enclosure and for
Components in High-Voltage Bays—Continued
Ç WARNING
When returning the equipment to service, observe the
following procedures:
1. Reconnect any low-voltage terminals that may have
been disconnected when servicing the gear.
2. Withdraw any dual-purpose front barriers, if furnished,
from the “slide-in” position and return them to their
normal, suspended position.
3. Make certain that fuses (or switch blades in lieu of
fuses) are closed and securely latched.
4. Open any grounding switch, or remove other grounding means, before energizing the associated interrupter
switch(es).
620-90
Page 6 of 8
February 13, 1995
5. Close and securely latch each switchgear-bay door
before energizing the circuit or operating any
switching device.
6. Lock interrupter switches in the open or closed
position as dictated by the electric power system
design.
7. Padlock all doors, switch-operating handles, and
covers before leaving the installation site, even
momentarily. Observe this procedure even in those
cases where the gear is accessible only to qualified
persons.
DATA BULLETIN
S&C ELECTRIC COMPANY
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TABLE II — Continued
Inspection and Maintenance Procedures for the Enclosure and for
Components in High-Voltage Bays 1—Continued
Item
Inspect
and Clean
Interior
Procedures
1. Visually inspect the interior of each bay for excess dirt and weeds, and rodent, reptile, and insect intrusion.
2. If cleaning is necessary, S&C recommends using water to wash dirty or contaminated surfaces. Mild soap may be used
to remove particularly stubborn deposits on painted surfaces, barriers, and Cypoxy® parts.m
3. Inspect insulators, surge arrestors, terminators, etc. for physical and electrical damage.
4. Check that gasketing around doors and windows is securely affixed and that grouting around exterior of bays is in good
condition. Verify that there has been no major water ingress.
1. Inspect barriers for signs of tracking and corona discharge. Surface deposits can be wiped off. If surface erosion
is present, the barriers may need to be replaced.
2. Verify that interphase and end barriers hang vertically and that retaining hardware securely holds them in place.
3. Verify, as well, that the clearance from the terminators and other energized parts to the barriers and electrical ground is
maintained to prevent flashover (e.g., fuse silencer to terminator drain wire). Minimum air clearances are listed below.
Inspect
Barriers and
Minimum Air
Clearances
Minimum Air Clearances (Inches) •
Rating, kv
Nominal
BIL
4.8
7.2
13.8
25
25
34.5
34.5
60
75
95
125
150
150
200
Energized Parts
to Barriers
Terminator Skirts
to Barriers
¹⁄₂
¹⁄₂
¹⁄₂
1¹⁄₄
1¹⁄₄ (2)
3
3 (3¹⁄₂)
¹⁄₂
1
1
2¹⁄₄
2¹⁄₄ (31/4)
3¹⁄₄
3¹⁄₄ (43/4)
Energized Parts
to Elec. Ground
Phase-toPhase
3¹⁄₂
4¹⁄₂
6
7¹⁄₂
10¹⁄₂
10¹⁄₂
15
4¹⁄₂
6
6
7¹⁄₂
12
12
15
Inspect and Exercise
Mini-Rupter and
Alduti-Rupter
Switches
1. While switchgear-bay doors are closed and latched, exercise the Mini-Rupter and Alduti-Rupter Switches and verify
proper opening and closing. If dual-purpose front barriers are furnished, be sure that they are not in the “slide-in”
position.
2. Inspect, clean, and re-lubricate the Mini-Rupter Switches.m
a. Check blades for signs of galling and excessive arc interruption. Minor surface imperfections can be burnished out.
Clean the blades and apply a thin layer of lubricant, as necessary.
b. Clean rotating hinge contacts and apply a thin layer of lubricant, as necessary.
c. Check contacts and joints for signs of overheating, as evidenced by distorted or discolored metal.j
3. Inspect, clean, and re-lubricate the Alduti-Rupter Switches.m
a. Check main current-carrying contacts for signs of galling. Minor surface imperfections can be burnished out. Clean
the contacts and apply a thin layer of lubricant, as necessary.
b. Check contacts and joints for signs of overheating, as evidenced by distorted or discolored metal.j
NOTE: S&C recommends cleaning and re-lubrication of Mini-Rupter and Alduti-Rupter Switches every ten years,
regardless of condition, to ensure proper operation or more frequently if the environment tends to be excessively hot, humid,
dry, dirty, or contaminated.
Inspect Fuses
1. Open and close fuses to ensure proper latching. Refer to the applicable S&C Instruction Sheet for fuse handling
instructions.
2. Inspect the fuse contact surfaces for signs of galling and overheating, as evidenced by distorted or discolored
contacts.j Minor surface imperfections can be burnished out. Clean contacts and apply a thin layer of lubricant,
as necessary.m
1 If maintenance is required that is beyond the scope of this publication
or if replacement parts are necessary, contact the nearest S&C Sales
Office. Have the complete catalog number of the gear and date of shipment (as shown on the nameplate) available for reference.
m CAUTION: Do not use industrial strength cleaning solutions (e.g.,
Formula 409®, Simple Green®) or lubricants which contain solvents.
Solvent vapors can attack arc compressor components and fuse pull
rings, resulting in reduced interrupting performance or weakened parts.
NYE Rheolube 368 (available in small ¹⁄₄ oz. tubes from S&C, Part No.
9999-044) is the only approved lubricant.
•
Numbers in parenthesis apply to switchgear furnished with Benelex
barriers. Switchgear manufactured prior to 1982 may utilize Benelex barriers.
j
Note: There may be discoloration of copper and copper alloy surfaces due to oxidation. This, however, does not indicate overheating.
TABLE CONTINUED c
DATA BULLETIN
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S&C ELECTRIC COMPANY
620-90
Page 7 of 8
February 13, 1995
S&C Power-Operated
Metal-Enclosed Switchgear
Indoor and Outdoor Distribution (4.16 through 34.5 kv)
Inspection Recommendations for
Switchgear Equipped with
Type AT-2 Source-Transfer Controls
TABLE II — Continued
Inspection and Maintenance Procedures for the Enclosure and for
Components in High-Voltage Bays 1—Continued
Item
Procedures
Inspect
Mechanical
and Key
Interlocks,
and Door
Latching
Mechanisms
1. Inspect all mechanical interlocks and key interlocks for proper functioning. Refer to S&C Instruction Sheets 621-500 and
622-500 for Custom and System II Metal-Enclosed Switchgear, respectively.
2. Verify proper operation of the door latching mechanisms.
Inspect,
Clean, and
Touch Up
Exterior
1. To maintain the original integrity of the finish, clean the exterior of the gear and touch up scratches and abrasions using S&C
touch-up finish and red-oxide primer, available in aerosol spray cans. Order by Catalog No.: 9999-058 for olive-green finish,
9999-079 for light-gray indoor finish, 9999-080 for light-gray outdoor finish, and 9999-061 for red-oxide primer.
2. Inspect exterior vent filters (if supplied). Replacement fiberglass filters (two per vent required) are available from S&C, Catalog
No. CD-1056-6. If the environment is very dusty, S&C recommends that the filters be inspected several times during the year to
ensure sufficient ventilation in the switchgear.
1 If maintenance is required that is beyond the scope of this publication
Printed in U.S.A.
or if replacement parts are necessary, contact the nearest S&C Sales
Office. Have the complete catalog number of the gear and date of shipment (as shown on the nameplate) available for reference.
620-90
Page 8 of 8
February 13, 1995
DATA BULLETIN
S&C ELECTRIC COMPANY
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