ELEC MAINTENANCE

1. 10/29/2022 1
SWITCHYARD TRANSFORMER GENERATOR
PROTECTION
& CONTROL
CT
CVT
ISOLATOR
BREAKER
LA
STATOR &
ROTOR
PW SYSTEM
SEAL OIL
SYSTEM
HYDROGEN
COOLING
EXCITATION
SYSTEM
GENERATOR
PROT.
LINE PROT.
TRANSFORM
ER PROT.
MOTOR
PROT.
FEEDER
PROT.
POWER
TRANSFORMER
SERVICE
TRANSFORMER

2. 10/29/2022 2
SWITCHGEAR
HT SWGR
LT SWGR
DC SYSTEM
BATTERY
BATTERY
CHARGER
MOTOR
HT MOTOR
LT MOTOR

3. 10/29/2022 3
• CT: CM/PM, Testing
• CVT: CM/PM, Testing
• Breaker: CM/PM, Testing
• Isolator: PM
• LA: LCM Testing
SWITCHYARD
• CM: Oil tests, Thermo-scanning
• PM: Oil Filtration, Overhaul
• Testing
TRANSFORMER

4. 10/29/2022 4
GENERATOR AND
AUXILIARIES
CM: Shaft voltage, vibration measurement
PM (Medium Scale O/H)
PW system:
• Overhaul of PW coolers and filters
• Inspection of conical filters
• Hydro test on primary water circuit including external piping
• Standard checks on PW water treatment unit (alkalizer unit, Ion exchanger).
Generator Seal oil system :
• Checking clearances, inspection, measurement of dimensions, checking seal surface
condition & checking of insulation
• Overhaul of seal oil pump motors, coolers and filters
• Attending to all TE and EE end seal oil lines pipe leakages.
• Adjust seal oil flows on air side as well as H2 side for both TE and EE end to achieve
proper differential pressure

5. 10/29/2022
GENERATOR AND
AUXILIARIES
Exciter:
• Inspection of rectifier wheels, checking of diodes & fuses, Cleaning of main & pilot exciter
• Inspection gen-exciter coupling, inspection of exciter end bearing
• Checking tightness of Exciter Base frame mounting bolts
• Cleaning of cooler tubes, hydro testing of coolers
• Inspection of brushes for rotor earth fault detection and cleaning surface of the slip rings.
• Overhaul and trials of exciter emergency cooling flaps
• Testing of Main Exciter, Pilot Exciter
H2 system:
• cleaning of cooler tubes, scraping/grit blast cleaning and painting of water boxes by
Epoxy paint, hydro testing of cooler
• Generator air leak test and attending to all leaks including replacement of Generator
Bushing gaskets

6. 10/29/2022 6
GENERATOR AND
AUXILIARIES
PM (Major Scale O/H)
Activities other than medium scale O/H
Gen. Rotor/Stator
• Measurement of air gap clearances
• Cleaning and detailed inspection of Generator Stator Winding and Core
• Inspection of Generator shell end windings, water manifolds, hose connections to stator
bars, phase connectors, bushings, clamps, and inspection for seal oil leaks,
• Cleaning and inspection of rotor (winding and damper bars)
• DP and UT test of retaining ring and bearings
• Stator Core Wedge Tightness and ELCID Test.

7. 10/29/2022 7
• GENERATOR.: Testing,
Protection Trials
• TRANSFORMER: Diff. , O/C ,
thermal O/L, E/F, Device Based
Protection, NDR, Device Trials
• LINE: Distance, Differential,
O/C, E/F, LBBU, Protection
Trials
• MOTOR: Prot. based On Motor
Characteristics
• FEEDER : Overload, SSTD,
Under Voltage, LBBU
PROTECTION

8. 10/29/2022 8
• HT MOTOR:
• Motor tube cleaning
• Bearing inspection
• Vibration measurement
• Overhauling
• LT MOTOR:
• overhauling
MOTOR
• HT SWGR:
• Condition monitoring
• Testing
• Thermo-scanning
• Fast changeover/ slow changeover
• Protection trials
• LT SWGR: Changeover trials,
Maintenance
SWITCHGEAR

9. 10/29/2022 9
• Battery CM
• Sp. gravity & voltage
measurement
• Battery capacity test
• Battery charger R/M
DC SYSTEM