LIST OF ELECTRICAL TESTS
SWITCHGEAR - circuit breakers, switches, bus-bars, instruments & instrument
transformers
•TORQUE WRENCH- FOR TIGHTNESS OF SCREWS & BOLTS
•MEGGER- FOR VERIFYING THE ELECTRICAL INSULATION LEVEL
•CONTINUITY- FOR VERIFYING THAT A CIRCUIT IS COMPLETE
•CONTACT RESISTANCE- TO DETECT LOOSE CONNECTIONS ,ERODED CONTACT
SURFACES, CONTAMINATED OR CORRODED CONTACTS
•TIMING- FOR VALIDATING THE CORRECT FUNCTION OF THE CIRCUIT BREAKER
MOTORS
•WINDING RESISTANCE- FOR ENSURING THAT EACH CIRCUIT IS WIRED PROPERLY
AND THAT ALL CONNECTIONS ARE TIGHT
•MEGGER- FOR VERIFYING THE ELECTRICAL INSULATION LEVEL
GENERATOR
• MEGGER- FOR VERIFYING THE ELECTRICAL INSULATION LEVEL
• WINDING RESISTANCE- FOR ENSURING THAT EACH CIRCUIT IS WIRED PROPERLY AND
THAT ALL CONNECTIONS ARE TIGHT
• AC IMPEDANCE- TO FIND INDICATIONS OF SHORTED ROTOR TURNS
• TAN DELTA- TO MEASURE THE QUALITY OF INSULATION
TRANSFORMER
• MAGNETISING CURRENT- TO LOCATE DEFECTS IN THE MAGNETIC CORE STRUCTURE,
SHIFTING OF WINDINGS, FAILURE IN BETWEEN TURN
INSULATION OR PROBLEM IN TAP CHANGERS
• WINDING RESISTANCE- FOR ENSURING THAT EACH CIRCUIT IS WIRED PROPERLY AND
THAT ALL CONNECTIONS ARE TIGHT
• MAGNETIC BALANCE- TO IDENTIFY INTER TURN FAULTS AND MAGNETIC IMBALANCE
• TAN DELTA- TO MEASURE THE QUALITY OF INSULATION
• TURNS RATIO- TO CONFIRM THAT THE TRANSFORMER HAS THE CORRECT RATIO OF
PRIMARY TURNS TO SECONDARY TURNS
• BDV- FOR CHECKING THE DIELECTRIC STRENGTH OF THE OIL OF THE TRANSFORMER
• DGA- TO DETERMINE THE QUANTITY OF GASES IN A SPECIFIC AMOUNT OF OIL &
PREDICT THE INTERNAL CONDITION OF THE TRANSFORMER
OVERHAULING OF UNIT#1
6.6 KV BREAKERS
•MEASUREMENT OF CONTACT RESISTANCE OF THE INDIVIDUAL
MODULE AND COMPLETE BOARD
•CHECKING OF BREAKER CLOSING AND OPENING TIME
GT#1 & UT#1
• REVIEW OF PAST DGA RESULTS
• OTI/WTI CHECK- LOCAL & REMOTE
• IR OF DIFFERENT WINDINGS TO EARTH & BETWEEN DIFFERENT WINDINGS
• MAGNETISING CURRENT
• MAGNETIC BALANCE
• RATIO TEST
• WINDING RESISTANCE TEST
• TAN DELTA TEST
• BUSHING:
CHECK FOR ANY CRACKS / CHIPPINGS
OIL LEAKAGE AFTER APPLYING N₂ PRESSURE ON CONSERVATOR
TAN DELTA TEST
• BUCHHOLZ RELAY- PROTECTION CHECKED BY MANUAL OPERATION
• CORE CLAMP- IR @ 1 KV
• GENERAL ASSEMBLY- CHECK CORRECTNESS, BOLT TIGHTNESS USING TORQUE WRENCH
• OIL FILLING/OIL AFTER FILLING:
CHECK THAT RADIATOR VALVES ARE OPEN, CHECK CONSERVATOR LEVEL,
BDV, MOISTURE CONTENT, GAS CONTENT
• OIL BEFORE ENERGIZING AND 24 HRS AFTER ENERGIZING:
BDV
MOISTURE CONTENT
TAN DELTA
SPECIFIC RESISTANCE
DGA
GENERATOR
•STATOR & ROTOR CLEANING
•STATOR CORE El CID TEST
•SEAL ASSEMBLY CHECK
•INSPECTION OF PARTIAL DISCHARGE OCCURRENCES UNDER THE WEDGE /
PACKERS
•INSPECTION OF OVERHANG SUPPORTS
•GLUE INJECTION ON OVERHANG WINDING
•ROTOR FREE RUN OUT
•ROTOR & STATOR VARNISHING
•IR/PI MEASUREMENT OF WINDING
•DC RESISTANCE AND TAN DELTA OF WINDING
•PARTIAL DISCHARGE TEST
•NFT OF STATOR
•IR AND RESISTANCE MEASUREMENT OF RTDS
•PNEUMATIC TEST
•BEARING CLEARANCES
•AIR GAP CHECK
•HYDRAULIC TESTS OF COOLERS
•FINAL IR/PI MEASUREMENT
•BOROSCOPIC CHECK OF ROTOR & STATOR
GOOD PRACTICES OF AGENCIES
• MATERIALS STACKED ORDERLY ALONG WITH PROPER MARKINGS
• MARKINGS PROPERLY VISIBLE FROM CERTAIN DISTANCE
• FIRE & SAFETY EQUIPMENTS KEPT HANDY IN CASE OF EMERGENCY
• PROPERLY MAINTAINED INCOMING & OUTGOING MATERIALS REGISTER
