How to prevent oil-immersed transformer explosion
Prevent the accident of oil-immersed transformer explosion
Accidents of oil-immersed transformer explosions occur repeatedly. Because the explosion process of oil-immersed transformers is a relatively slow development process, once the explosion occurs, there will be casualties and huge economic losses. It can be said to be very scary. Because the oil-immersed transformer is more operable during the explosion process, it is a more important place. In order to prevent the explosion of oil-immersed transformers, we must start with prevention.
1. Prevent overload operation of oil-immersed transformers: If the overload operation is carried out for a long time, it will cause the coil to heat up and gradually deteriorate the insulation, short-circuit between boxes, short-to-phase or short-to-ground and oil decomposition;
2. Prevent aging and damage of oil-immersed transformer core insulation: aging of core insulation or damage of clamping bolts and sleeves will cause a large eddy current in the core and long-term heating of the core will cause insulation aging.
3. Prevent accidental damage to the insulation during maintenance: Pay attention to protect the coil or insulation sleeve when repairing the hanging core of the oil-immersed transformer. If abrasion damage is found, deal with it in time.
4.The maximum unbalanced current of the low voltage of the oil-immersed transformer must not exceed 25% of the rated value; the allowable range of the power supply voltage change of the oil-immersed transformer is plus or minus 5% of the rated voltage.
5. Ensure that the wires are in good contact: poor contact inside the coils, poor contact between the connection points between the coils, the leads leading to the high and low voltage side bushings, and the fulcrum points on the tap changer will cause local overheating, damage to insulation and short circuits or open circuit. The high-temperature arc generated at this time will decompose the insulating oil, generate a large amount of gas and increase the pressure in the oil-immersed transformer. When the pressure exceeds the protection value of the gas breaker without tripping, an explosion will occur.
6. Maintain good grounding: For low-voltage systems with protective zero connection, (examination. Large) the neutral point of the low-voltage side of the oil-immersed transformer should be directly grounded. When the three-phase load is unbalanced, a current will appear on the neutral line. When this current is too large and the contact resistance is high, the ground point will become hot and ignite the surrounding flammable materials.
These measures to prevent explosion in oil-immersed transformers must be kept in mind at all times, and preventive measures must be taken to prevent them.