Operation and maintenance of transformers

1. Prevent transformer overload operation: If the transformer is operated with overload for a long time, it will cause the coil to heat up, and the insulation will gradually age, causing short circuit between boxes, short circuit between phases or short circuit to ground and oil decomposition.

2. Guarantee the quality of insulating oil: In the storage, transportation or operation and maintenance of transformer insulating oil, if the oil quality is poor or there are too many impurities or moisture, the insulation strength will be reduced. When the insulation strength is reduced to a certain value, the transformer will be short-circuited and cause electric sparks, arcs or dangerous temperatures. Therefore, the oil quality of the transformer should be tested regularly during operation, and the unqualified oil should be replaced in time.

3. Prevent transformer core insulation aging damage: core insulation aging or clamping bolt bushing damage will cause the core to produce a large eddy current, causing the core to heat up for a long time and cause insulation aging.

4. Prevent inadvertent damage to the insulation during inspection and repair: When inspecting and repairing the hanging core of the transformer, pay attention to protecting the coil or insulating sleeve. If scratches are found, they should be dealt with in time.

5. Ensure that the wires are in good contact: the internal joints of the coils are in poor contact, the connection points between the coils, the contacts leading to the high and low voltage sides of the bushing, and the fulcrums on the tap switch are in poor contact, which will cause local overheating, damage the insulation, and cause a short circuit. Or open circuit. The high-temperature arc generated at this time will decompose the insulating oil, produce a large amount of gas, and increase the pressure in the transformer. When the pressure exceeds the protection value of the gas circuit breaker without tripping, an explosion will occur.

6. Prevent electric shock: The power supply of power transformers generally comes from overhead lines, and overhead lines are prone to lightning strikes, and transformers will burn out due to insulation breakdown.

7. Reliable short-circuit protection: If the transformer coil or load is short-circuited, the transformer will withstand a considerable short-circuit current. If the protection system fails or the protection setting is too large, the transformer may be burned. For this reason, a reliable short-circuit protection device must be installed.

8. Maintain good grounding: For low-voltage systems that use protection to connect to zero, the neutral point on the low-voltage side of the transformer should be directly grounded. When the three-phase load is unbalanced, current will appear on the zero line. When this current is too large and the contact resistance is large, high temperature will appear at the grounding point, igniting the surrounding combustible materials.

9. Prevent over-temperature: The temperature change should be monitored when the transformer is running. If the transformer coil wire is A-class insulation, the insulator is mainly paper and cotton yarn. The temperature has a great influence on the insulation and service life. Therefore, when the transformer is running, it must be well ventilated and cooled. If necessary, mandatory Ventilation to achieve the purpose of reducing the temperature rise of the transformer