Question { Essar, 109027 }

check list of maintenance of transformer?

Answer

) Power Isolation of transformer with proper permit
2) Earthing of all hv/lv terminal after physical isolation.
3) Cleaning of transformer with lint free cotton.
4) Oil leakages checks for all joint
5) Silica gel re heating if reqd.
6) OLTC/OFTC local operation Check(calibration of motor
over load relay)
7) OLTC continuity check(by connecting analog meter across
across all the phase terminal and OLTC operation)
8) Alarm and trip circuit checking of OTI,WTI, MOLG, Mulsy
fire,Buchholtz of main and OLTC
9) BDV of main Oil and OLTC oil
10) PPM of oil
11) Tan delta of bushing, main Oil and OLTC oil
12) Magnetic balence
13) Ratio test in every tap
14) Winding resistance
15) Insulation resistance after LA disconnection
16) Secondary injection test of protection relays with CT &
PT test
17) Cooling Fan testing by OTI/WTI temprature (manully by
rotating the prob)
18) Other inter lock if any

Note: Normaly Annual maintenance cover most of the the
test, mainly 5 year test contain all the checks depends on
manufacture and customer check list.