III. sound and temperature failure
1. Abnormal sound
When the transformer is in normal operation, it will emit a continuous uniform and slight "buzz" sound under the action of AC electromagnetic field. It is considered abnormal if the sound is not uniform or there is a special sound.
The main reasons are:
1) Overvoltage in the system;
2) transformer overload operation;
All the above need to be determined according to the nameplate parameters of the transformer.
3) The internal clamp or the screws and pull belts of the iron core are loosened, and the vibration of the silicon steel sheet of the iron core is increased, and there is an obvious noise; Need to lift cover treatment;
4) Electrostatic discharge, external insulation corona discharge of metal parts with poor contact or ungrounded section switch, accompanied by a "crackling" discharge sound.
5) The nameplate, sign plate, fan motor, and other external accessories will also emit abnormal sounds due to improper fixing.
Handle it according to the specific situation.
2. Abnormal temperature
Many transformer failures are often accompanied by temperature changes, regulations stipulate that the upper oil temperature of the transformer shall not exceed 95 ° C, temperature rise shall not exceed 55 ° C;
The main reasons and measures that cause the abnormal temperature of the transformer are:
1) multi-point grounding of the core, overheating of the bare metal, and other internal faults of the transformer. Screening is required.
2) After the new installation or overhaul, the radiator door is not opened, and the heat dissipation cannot be recycled normally.
Check the operation of the oil pump and flow meter, and open the volve that is not opened.
3) The respirator is blocked or seriously leaking oil affects heat dissipation.
4) The transformer structure is unreasonable, and the local overheating of the box shell is caused by magnetic leakage, and sometimes it will reach 100° C.
Magnetic insulation materials can be installed in specific parts.
5) The cooling device is not operating normally, affecting heat dissipation.
