NAME OF TEST:
LVAC IR Test.
OBJECTIVE OF THE TEST:
To verify the insulation Resistance of LVAC Bus Bars and Breakers.
PREREQUISITES:
LVAC Panel erection shall be completed in all respect, LVAC bus bar tightness shall be verified by torque checks
PROCEDURE OF TEST:
With all ACBs are in service position and closed, the IR value between phase-to-phase, phase to neutral, phase to earth and neutral to earth is measured with 1000V IR tester.
ACCEPTANCE CRITERIA:
All IR values should be more than 200 Mega ohms.
NAME OF TEST:
LVAC Insulation Resistance & HV Test.
OBJECTIVE OF THE TEST :
To verify the insulation Resistance of LVAC Bus Bars and Breakers.
PROCEDURE OF TEST :
With all ACBs are in service position and closed:
1. 2kV (AC) is applied for 1 minute to each phase and neutral with other phases and
neutral shorted and earthed. Leakage current shall be recorded.
2. IR to be measured before and after HV test.
Note: All the out going feeders shall be in closed condition while doing the HV test. Care
must be taken to ensure that the fuses are capable to withstand the 2kV applied voltage.
ACCEPTANCE CRITERIA :
All Bus bar should withstand the HV for 1 minute.
NAME OF TEST:
LVAC Scheme.
OBJECTIVE OF THE TEST:
The function of this test is to verify the operation logic of the LVAC panel in Auto & Manual mode. The logic is achieved through PLC program.
PROCEDURE OF TEST :
The entire LVAC scheme logic is controlled by PLC. The LVAC panel is provided with three in feeds from earthing transformers. Including two bus couplers there is total five breakers in LVAC panel. Out of five only 3 are permitted to close at a time.
Paralleling of the transformers should never happen.
The major scheme checks are, (When all incomer and Bus section are in service position)
All incomers can be closed in without paralleling.
When any incomer supply fails, that incomer breaker switches OFF, the corresponding
Bus Section closes and maintains the supply to the outgoing feeders.
When the failed incomer resumes supply, first the corresponding Bus section switches
OFF and after a delay incomer breaker switched ON.
Standby incomer cannot be switched on when any of the incomer is in service position and vice versa.
ACCEPTANCE CRITERIA :
All operations shall be according to the scheme.
NAME OF TEST:
LVAC Switch / Lamp Indication.
OBJECTIVE OF THE TEST:
To verify the various indications and their color.
PROCEDURE OF TEST:
Lamps, semaphore indicators etc are provided on the panel to indicate the status of devices, alarms etc. All these indications shall be verified for the correct function. This shall be verified by creating the respective conditions. (For Eg. Bringing the CB in to the test condition can simulate breaker test condition.) . Like that all conditions shall be simulated and verified.
ACCEPTANCE CRITERIA : All indications shall be as per Test Report.
NAME OF TEST:
LVAC Breaker Travel.
OBJECTIVE OF THE TEST:
To verify the travel of breakers form Service to Test- Test to isolated condition with out any tripping of other breakers in service. There should not be any effect on the breakers under operation when other breakers moved from one position to another position.
PROCEDURE OF TEST :
The test shall be carried out for different combinations. While doing the testing the operating mode of the PLC shall be selected to manual. As mentioned in the format different CBs shall be taken for movement & all combinations shall be verified.
ACCEPTANCE CRITERIA :
The Service position breakers should not trip , when other breakers travel from their position.
NAME OF TEST:
LVAC Outgoing feeder identification.
OBJECTIVE OF THE TEST:
To verify the outgoing feeder distribution with respect to the drawing also to ensure the correct termination of the cable at load& Source end.
STANDARD/SPECIFICATION REFERENCE OF THE TEST:
Approved Drawing.
PROCEDURE OF TEST :
All outgoing feeders from LVAC panel must be switched off before proceeding the testing. IR value of the cable shall be measured for each out going feeder. One by one feeders has to be switched ON & the voltage & phase sequence shall be measured at the load end. Correct tightness, Ferrules if any, insulation shrouds etc shall be verified during the testing. The sizing of the cable & voltage drop at the load end etc
shall be in line with the design document.
ACCEPTANCE CRITERIA :
All outgoing feeders shall be terminated as per the drawing. Voltage drop at the load end must be within the allowable limits.
