Transformers play a crucial role in the power system, and their operating status is directly related to the stability of power supply. This content focuses on the maintenance and fault repair methods of transformers. Firstly, it introduces the basic principles, components, functions, and common classifications of transformers.
Then, it elaborates on the key points of maintenance: In terms of capacity, the normal operating load should preferably be 75 - 90% of the rated capacity. The temperature needs to be recorded regularly, and the three-phase load of distribution transformers should be paid attention to during the period of maximum load. For insulation monitoring, the insulation resistance of the coils should be measured after installation, maintenance, and long-term outages. In terms of the current range, the maximum unbalanced current on the low-voltage side should not exceed 25% of the rated value, and the change in the power supply voltage should be within ±5% of the rated value. If it exceeds this range, a tap changer should be used for adjustment. In the case of overload, it is allowed for a short time under special circumstances, but there are different limits for winter and summer.
Finally, it explains the fault repair. Common faults include short circuits, open circuits, and leakage, which are caused by design errors, poor manufacturing quality, and exceeding the designed operating conditions. The repair steps are to disassemble the iron core, heat it to melt the poured materials, and carefully remove the silicon steel sheets. Then, disassemble the coils, inspect the appearance and the faulty coil, record key data, deal with the fault, rewind it according to the original method, and conduct a comprehensive test. It can be put back into use only after passing the test.