NAME OF TEST: CB INSULATION RESISITANCE TEST
OBJECTIVE OF THE TEST: To measure the insulation resistance between phase to Earth
and phase to phase of Circuit Breaker (R, Y & B phases).
PROCEDURE OF TEST:
1. Record the Circuit breaker name plate details and verify the supplied Vacuum bottle
manufacturer.
2. General visual inspection for circuit breaker fixing , cleaning and damage.
3. Circuit breaker shall be rack-out from the switchgear panel and insulator poles to clean.
4. Ambient temperature must be recorded with a calibrated temperature meter.
5. Circuit breaker shall be closed for measure the IR.
6. Apply 5KV between phase and Earth for 60 second and repeat for the other phase’s
record the values.
7. Apply 5KV between phase and Phase for 60 second and repeat for the other
phase’s record the values.
ACCEPTANCE CRITERIA
Measured Insulation resistance shall be obtained in the unit of Giga ohms.
NAME OF TEST: MV SWGR Circuit Breaker contact resistance measurement
OBJECTIVE OF THE TEST:
This test is carried out to confirm the healthiness of circuit breaker
contact during circuit breaker closed position.
STANDARD/SPECIFICATION REFERENCE OF THE TEST: - IEC 62271-100
PROCEDURE OF TEST:
1.Contact resistance of entire C.B shall be measured. It can be measured in different
ways. Between the points of measurement of contact resistance 100 A DC current
is injected & the voltage drop is measured.
Micro ohm meter shall be used for this
measurement. Voltage measurement probes shall be kept inside the current injecting point.
2.Contact resistance of each phase is measured separately.
3.Record the temperature and humidity during the measuring time.
ACCEPTANCE CRITERIA:
Resistance should be ±5 % of the factory value.
NAME OF TEST: -
MV CB Operational Functional Checks (Mechanical).
OBJECTIVE OF THE TEST: -
This test is primarily carried out to verify the operation of the Circuit breaker tripping & closing by manual commands (pushing manually buttons provided on the circuit breaker). Manual spring charging shall also be verified during this test. All indications like semaphore & mechanical indications shall be verified.
STANDARD/SPECIFICATION REFERENCE OF THE TEST: - IEC 60298
PROCEDURE OF TEST: -
Motor spring charging:-
Switch off the supply to the spring charge motor to prevent spring re charging. Operate the breaker; to make the spring discharged condition. Insert the spring charge handle in to specified place for manual charge and charge the spring.
CB Operation:-
Check the circuit breaker operations by pushing manual close/open buttons provide on the circuit breaker.
CB Indication:-
During the closing /opening operation indications like semaphore, indication lamps, mechanical indications etc shall be checked.
ACCEPTANCE CRITERIA: -
CB manual spring: Operation shall be smooth
CB open / close operations: Operation shall be smooth
CB indication: Indication lamp shall be OK.
NAME OF TEST: -
MV CB Operational Functional Checks (Electrical).
OBJECTIVE OF THE TEST: -
This test is primarily carried out to verify the operation of the Circuit breaker through viz. tripping & closing by electrical commands. Electrical spring charging shall also be verified during the testing.
All indications like semaphore, indication lamps & mechanical indications shall be verified.
STANDARD/SPECIFICATION REFERENCE OF THE TEST: - IEC 60298
PROCEDURE OF TEST: -
Motor spring charging:-
Switch off the supply to the spring charge motor to prevent spring re charging. Operate the breaker; to make the spring discharged condition. Switch on the supply of the spring charge motor and stop watch, immediately the spring get charged and the spring charging time shall be measured by stopwatch. Also record the maximum spring charging current using clamp or ammeter. Compare the charging time with in limit as compared with FAT reports.
CB Operation:-
1. Check the operation of the close coil/ Trip coil at Rated Voltage
2. Check the anti pumping function by enabling close command continuously for that close
circuit breaker wait for spring charge after C.B spring fully charged give close command
continuously and open circuit breaker. Circuit breaker shall not close after opened.
3. Check open-Close- Open (OCO) by close the circuit breaker wait for C.B spring and switch
off C.B spring charge supply. Give open – close – open command.Circuit breaker mechanism shall capable for the OCO operation is verified.
CB Indication:-
During the closing /opening operation indications like semaphore, indication lamps, mechanical indications etc shall be checked.
ACCEPTANCE CRITERIA: -
Motor spring charging time/Current : As specified by the manufacturer
Motor spring charge current: As specified by the manufacturer
CB operation at: Operation shall be smooth
CB indication: Indication lamp shall be OK
NAME OF TEST:
CB Timing Measurement
OBJECTIVE OF THE TEST:
To measure the closing and opening time of main contact of Circuit Breaker (R, Y & B phases) & including the discrepancy among the poles operation timing.
STANDARD/SPECIFICATION REFERENCE OF THE TEST: IEC 62271-100.
PROCEDURE OF TEST:
Timing measurement has to be done for close and trip coils. At first simulate all the field point of CB (After removing CB control plug) by using a simulator.
Usually a PROGRAMMA kit or any other suitable instrument can be used for measuring
close/open timing of Circuit Breaker. At rated voltage we have to give the close/open pulse from that kit. The duration of operation will be recorded in the instrument & it shall be displayed in the form of graph.
Following shall be recorded for open, Close & OCO operation
Duration of operation of individual poles & discrepancy between operation of poles
Close Coil/ Trip coil current.
One set of NO & NC contact operation timing.
Time for CB close /open (individual R, Y & B) can be measured from the graph. Closing and
opening current also we can take along with that graph. Pole discrepancy also we have to check for close/open time. 1 NO & 1 NC auxiliary contact timing also we can take along with that graph.
ACCEPTANCE CRITERIA
Acceptance criteria are as per manufacturer standard.
NAME OF TEST:
MV SWGR Circuit Breaker contact resistance measurement.
OBJECTIVE OF THE TEST: -
This test is carried out to confirm the healthiness of bus bar joints between panels, feeder tapping’s and circuit breaker fixed and moving contact during circuit breaker service closed position.
STANDARD/SPECIFICATION REFERENCE OF THE TEST: - IEC 62271-100
PROCEDURE OF TEST:
Contact resistance of bus bar between 2 panels and 2 circuit breaker service
position measured. It can be measured in different ways. Between the points of
measurement of contact resistance 100 A DC current is injected at 2 panel cable
terminations& the voltage drop is measured. Micro ohm meter shall be used for this
measurement. Care must be taken to avoid wrong measurement by putting leads
wrongly. Voltage measurement probes shall be kept inside the current injecting point.
Bus bar Contact resistance of each phase is measured separately.
Record the temperature and humidity during the measuring time.
ACCEPTANCE CRITERIA: -
Resistance should be ±5 % of the factory value.
NAME OF TEST:-
High voltage test on MV SWG BUSBAR
OBJECTIVE OF THE TEST: -
Ensure the power frequency with standing capacity for support insulator of bus bar.
STANDARD/SPECIFICATION REFERENCE OF THE TEST: - IEC 62271-100.
PROCEDURE OF TEST: -
1. Pre – Requisites:
a) Ensure that all safety signs are put in place and test area is cordoned off. Ensure
that test area is cleaned and free from dust.
b) Ensure that tool box talk is conducted.
c) Ensure that all CT's are shorted and grounded in the LV compartment.
2. HV Test on Bus Bar:
1. Rack in all the circuit breaker in service position. Close all the breakers except Bus –
Section Breaker.
2. Short Y, B Phase of Bus bar of section – 1 and connect to ground.
3. Using 5kV Insulation Tester measure, insulation resistance between R-Phase to
(Y+B+E) and record the values.
4. Insert Incomer and Bus VT of section – 1.
5. Apply AC RMS Voltage across R-Phase to (Y+B+E) and measure secondary output
voltage of all the VT's.
6. Check for correct operation of voltage indicators.
7. Reduce the voltage and remove all the VT's of section – 1.
8. Apply AC High Voltage of 80 % of FAT for 1 minute across R-Phase to (Y+B+E)
and record the leakage current.
9. Repeat point 3 after HV test.
10. Repeat step 2 to 9 for Y- Phase and B – Phase respectively.
11. Repeat the above steps 1 to 9 for Bus – Bars of section – 2 and section – 3
respectively.
12. Normalize all the CT connection.
ACCEPTANCE CRITERIA: -
HV test can be considered as passed if high with stood for 60 second.
NAME OF TEST:-
High voltage test on 11 KV Circuit Breaker
OBJECTIVE: -
Ensure the power frequency with stand for insulator and Vacuum bottle.
STANDARD/SPECIFICATION REFERENCE OF THE TEST: - IEC 62271-100.
PROCEDURE OF TEST: -
3. Pre – Requisites:
1. Ensure that all safety signs are put in place and test area is cordoned off. Ensure
that test area is cleaned and free from dust.
2. Ensure that tool box talk is conducted.
3. Ensure that all CT's are shorted and grounded in the LV compartment.
4. HV Test on 11kV Circuit Breakers: (Open Condition)
1. Open all Circuit Breakers.
2. Draw out the circuit breaker from switchgear by dedicated CB trolley.
3. Position all CB’s in wooden platform.
4. Short top contacts of R, Y, B Phase of all Circuit Breakers and connected to HV
test kit.
5. Short bottom contacts of R, Y, B Phases of all Circuit Breakers and connected to
Earth.
6. Using 5kV Insulation Tester measure insulation resistance between Top contact to
Bottom contacts and record the values before HV.
7. Apply AC High Voltage for 1 minute across Top contacts to Bottom contacts and
record the leakage current.
8. Repeat point 6 and record the values after HV test.
9. This CB HV Test shall be conducted section by section.
5. HV Test on 11kV CB Bus Section 1 & 2: (Close Condition)
1. Draw out the circuit breaker of bus section 1&2 by dedicated CB trolley.
2. Ensure that both Circuit Breakers are kept closed.
3. Short Y, B Phase of Breakers and connect to Earth.
4. Using 5kV Insulation Tester measure insulation resistance between R - Phase to
(Y+B + ground) and record the value before HV.
5. Apply AC High Voltage for 1 minute across R Phase to (Y+B+ ground) and record
the leakage current.
6. Repeat point 4 and record the value after HV.
7. Repeat steps 3 to 6 for Y – Phase and B – Phase respectively.
ACCEPTANCE CRITERIA: -
HV test passed can be considered pass ,if CB’s with stand HV voltage for 60 second .
NAME OF TEST:-
Electro mechanical interlocks feeder earth switch
OBJECTIVE OF THE TEST: -
Interlocking system against putting the feeder earth switch ON is given below.
Earth switch can be possible to operate when the VCB in test position.
STANDARD/SPECIFICATION REFERENCE OF THE TEST: - IEC 62271-100.
PROCEDURE OF TEST: -
General
Check the control circuit and control wiring.
Check the ferrule number on each component and terminal block on the respective circuit
and in capacitor door interlock.
Check the manufacturing details of the component as per approved drawing.
Check the functionality of the earthing switch auxiliary contacts (open/close)
Check that the earth switch cannot be closed when the CB is in service position (should not
try with huge force ut may damage the earth switch mechanism).
Check that the CB cannot be inserted in to the service position when the earthing switch is
closed.
Check the status of the position-indicating device (Semaphore and mechanical indication).
Condition for closing the earth switch.
VCB should be in test position.
Negative check also to be checked by changing all the first condition and check the
operation of the feeder earth switch.
ACCEPTANCE CRITERIA: -
Interlock shall satisfy all the above requirements