CAPACITOR BANK
SCOPE:
This method statement covers the procedure for doing site tests to be carried out on Capacitor Bank.
OBJECTIVE OF THE TEST:
The objective of the test is to verify the readiness & healthiness of the Capacitor units and Damping Reactor.
SAFETY PRECAUTIONS
Standards rules for working on high voltage equipment will be followed.
Company’s safety codes will be followed.
Never Over tight the Capacitor Units , Follow the installation drawings for tightening torque.
Confirm magnetic clearances mentioned in the drawing is followed.
STANDARD/SPECIFICATION REFERENCE OF THE TEST:
Capacitor BANK specification and approved drawings. IEC 60871-1 & 4
List OF TEST:
Below Tests to be Carried out in Capacitor Bank.
1. CAPACITOR INSULATION RESISTANCE TEST
2. CAPACITOR - CAPACITENCE MEASUREMENT
3. DAMPING REACTOR WINDING RESISTANCE
4. DAMPING REACTOR HV TEST
5. DAMPING REACTOR -INDUCTANCE MEASUREMENT
6. CAPACITOR BANK UNBALANCE CURRENT MEASUREMENT
11 KV CAPACITOR INSULATION RESISTANCE TEST
OBJECTIVE OF THE TEST :
The purpose of the test is to verify the healthiness of insulation of the capacitor units.
STANDARD/SPECIFICATION REFERENCE OF THE TEST :IEC 60871-1 & 4
PROCEDURE OF TEST:
1. Keep the terminals of capacitor unit shorted and the IR value between terminals to
container is measured with 2500V IR tester.
2. The above step to be repeated for all capacitor units.
ACCEPTANCE CRITERIA:
1. IR values must be above 100 MOhms.
11 kV CAPACITOR ‐ CAPACITENCE MEASUREMENT
OBJECTIVE OF THE TEST:
The purpose of the test is to verify the capacitance value of the capacitor units are within the factory data.
STANDARD/SPECIFICATION REFERENCE OF THE TEST: IEC 60871-1 & 4
PROCEDURE OF TEST
1. Connect the LCR tester / Suitable device across the Capacitor Unit and measure the
Capacitance
2. Record the capacitance measured each unit.
3. All capacitence values should be compared with factory test reports.
ACCEPTANCE CRITERIA:
./ All capacitence values should be comparable with factory value and within tolerance recommended by the factory.
11 KV DAMPING REACTOR WINDING RESISTANCE
OBJECTIVE OF THE TEST:
The purpose of the test is to verify that there is no internal short circuit in the winding and the winding resistance of the damping reactor units is within the factory data.
STANDARD/SPECIFICATION REFERENCE OF THE TEST : IEC 60076‐6
PROCEDURE OF TEST
1. Measure and record the ambient temperature and humidity in the test format.
2. Measure the Winding resistance across the terminals using a micro ohm meter.
3. Convert the winding resistance measured to 750 C.
ACCEPTANCE CRITERIA:
./ All resistance values should be compared with the factory test reports
11 kV DAMPING REACTOR HV TEST
OBJECTIVE OF THE TEST:
To verify the dielectric strength of damping reactor
STANDARD/SPECIFICATION REFERENCE OF THE TEST: IEC 60076‐6
PRE-REQUISITES:
1. Isolate the Power Cable before HV Test.
2. The jumper between damping reactor and Capacitor Bank must be removed
before HV Test.
3. Valid calibration certificates for testing instrument must be available.
PROCEDURE OF TEST :
1. Measure Insulation Resistance before and after HV test.
2. Apply 22.4 kV (AC) for 1 minute to each terminal and earth.
3. Leakage current shall be recorded.
ACCEPTANCE CRITERIA:
1.All reactors should withstand the HV for 1 minute. (Note: There is no criteria for leakage
current. The measured record is a reference for future)
11 kV DAMPING REACTOR ‐INDUCTANCE MEASUREMENT
OBJECTIVE OF THE TEST :
The purpose of the test is to verify that the inductance of the damping reactor units is within the GTP and factory data.
STANDARD/SPECIFICATION REFERENCE OF THE TEST:IEC 60076‐6
PREREQUITE:
1. Isolate the Power Cable before the Test.
2. The jumper between damping reactor and Capacitor Bank must be removed
before the Test.
3. Valid calibration certificates for testing instrument must be available.
PROCEDURE OF TEST
Y Measure the Inductance across the terminals using a inductance measurement meter.
ACCEPTANCE CRITERIA:
1.All inductance values should be compared with the factory test reports.
2.Allowable tolerances are mentioned in the factory test reports.
11 KV CAPACITOR BANK UNBALANCE CURRENT MEASUREMENT
OBJECTIVE OF THE TEST:
Determine the unbalance current in the capacitor bank and ensure that the
unbalance current is within the protection setting.
STANDARD/SPECIFICATION REFERENCE OF THE TEST:
NO specific specification. This test
is to ensure that unbalance value is less than 20% of Trip settings.
OBJECTIVE OF THE TEST:
Determine the unbalance current in the capacitor bank and ensure that the
unbalance current is within the protection setting.
PRE REQUISITE:
1. Ensure that capacitor unit tests are completed and interconnections between capacitor units and damping reactor.
2. Ensure valid calibration certificates for test instruments (Digital Multi-meter, Clamp
meter), are available.
PROCEDURE OF TEST:
1. Calculate the total capacitance in each phase of the capacitor bank.
2. Compare the difference in total capacitance across the phases. It must be
within the alarm setting of the unbalance relay. In case the unbalance is more than the setting, rearrange the capacitor units to balance the capacitance fairly equal in all phases.
3. Ensure the interconnection between capacitor units and reactor is available.
4. Apply 380V 3 Phase AC Supply to Capacitor Banks.
5. Measure current in each phase and neutral.
6. Compare the measured neutral current with setting of the out of balance protection relay. No further action required if the neutral current is within the relay setting.
7. Rearrange capacitor unit if the neutral current is more than the alarm setting of
the out of balance protection relay.
8. Measure the phase and neutral current again after rearranging capacitor unit and
ensure the unbalance current is less than the alarm setting of out of balance protection relay (OBR).
ACCEPTANCE CRITERIA:
1.Acceptance criteria: The neutral current should be within the alarm setting of Out of Balance Protection Relay. It shall not be more than 20% of Trip setting