In Transformers 13 General Problems and Possible Causes : General Problems in Transformers
| Nature of Problems | Possible Causes |
| Low IR value | (a) Ageing (b) Ingress of moisture through breather. (c) Sludge formation within transformer (d) Error in measurement such as measuring leads falling on the transformer itself. |
| Oil Leakage in bushing | (a) Crack in porcelain (b) Worn out gasket (c) Ageing / damaged oil seal. (d) Heating the to improper fastening of bushing clamp. (e) Failure of gasket of air release plug. |
| Heating in Bushing clamp | (a) Improper fatening (b) In adequate clamp size (c) Bimetallic action |
| Low oil level indication in conservator | (a) Link through wornout gaskets (b) Loss of transparency in the oil-level view glass. (c) Defective MOG( magnetic oil gauge) |
| Overflow of OLTC oil | (a) Development of contact resistance in the OLTC and consequent heating. (b) Failure of epoxy board barier between the main tank and OLTC. (c) Loose in Kerosine plug of OLTC chamber. |
| Absence of breathing action in breather | (a) Blockage in breathing pipa line (b) Leakage in breathing pipe line. (c) Failure of diaphragm in explosion vent. |
| Failure of Diaphragm in Explosion vent | (a) Blockage in breather / breather pipe line. (b) In advertent closing of valve between explosion vent and main conservator. (c) Inadvertent closing of the valve in the Bucholts pipe line. (d) Mechanical failure. (e) Ageing |
| MOG alarm | (a) Lenk in the transformer. (b) Loss of oil in the conservator due to repeated sampling followed by sudden fall in load and/or ambient temperatura. (c) Detachment of float assembly/entry of oil into the float of the MOG, inside the conservator. (d) Freakish operation due to entry of rain water rodent into the terminal casing of MOG. |
| Temperature Alarm/Trip | (a) Continuous over load. (b) Failure/Inadequate fans/pumps. (c) Mechanical damage to the capillary tube of T.I. (d) Defect in the temperature Indicator. (e) Freakish operation due to antry of water / rodents into the marshalling box (f) Loosening of core assembly in transport. (g) Failure of insulation of the core lamination/core assembly. (h) Inadvertent closing of radiator values. |
General Problems in Transformer and Possible Causes
| Bucholtz Alarm | (a) Incipient fault in side the transformer. (b) Accumulation of air in the Bucholtz chamber, which could have got trapped inside the transformer, due to improper filling of oil. (c) Leak in the radiator / pipe lines of the cooling pump (only in transformers with forced by cooling.) (d) Freakish operation due to entry of rain water/ rodents into the terminal casing of the buchholtz relay. (e) Loss of oil due to leakage. |
| Buchholtz trip | (a) Major electrical fault in side the transformer. (b) Major jolting of the winding assembly for a fault in the feeder or in the LV close bus. (c) In correct indlination/ cross section of the pipe line between the tank and conservator. (d) Freakish operation due to entry of rain water/ rodents into the terminal casing of B.relay. |
| OLTC surgerdy relay trip | (a) Loss of oil due to leak in the OLTC/conservator / Pipe line of the surge relay. (b) Development of contact resistance in the OLTC and consequent heating. (c) Freakish operation due to entry of rain water / rodents into the terminal casing of the surge relay. |
| Pressure Relief Trip Device | (a) Electrical fault inside transformer. (b) In adverttent closing of the valve in the bucholtz pipe line. (c) Freakish actuation due to entry of rain water / rodents into the terminal casing of the PRD |
Also Read : ELECTRICAL FAULT FINDING
Also Read : SUB-STATIONS
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