How To Solve The Problem Of Dry-type Transformer Failure

1、 The insulation resistance of the iron core to the ground is zero
The actual connection between metals may be caused by burrs, metal wires, etc., which are brought into the iron core by paint, and the two ends are overlapped between the iron core and the clamp; Damaged insulation at the foot causes the iron core to be connected to the foot; A metal object fell into the low-voltage coil, causing the pull plate to connect with the iron core.
Solution:
Use lead wire to poke down the channel between the low voltage coil core stages, confirm that there are no foreign objects, and then check the insulation of the feet.
2、 What precautions should be taken during on-site power transmission?
Generally, the power supply bureau sends power 5 times, and there are also 3 times. Before power transmission, check the bolt fastening and whether there are metal foreign objects on the iron core; Whether the insulation distance meets the power transmission standards; Whether the electrical functions are operating normally; Whether the connection is correct; Check whether the insulation of each component meets the power transmission standards; Check for condensation on the body of the device; Check if there are any leaks in the casing that can allow small animals to enter (especially in the cable entry area); Is there any discharge sound during power transmission.
3、 During power transmission impact, the shell and ground iron plate discharge
It indicates that the conductivity between the shell (aluminum alloy) plates is not good enough, indicating poor grounding.
Solution:
Use a 2500M Ω megger to break through the insulation of the board or scrape off the paint film on each connection part of the shell and connect it to the ground with copper wire.
4、 Why is there a discharge sound during the power frequency withstand voltage test during the handover test?
There are several possibilities. The pull plate can be positioned at the tension point of the clamp to discharge, and a gun can be used to punch it here to ensure good conductivity between the pull plate and the clamp; The phenomenon of pad creep, especially in high-voltage products (35kV), has occurred, and it is necessary to strengthen the insulation treatment of the pad; The virtual connection between high-voltage cables and connection points, or the insulation distance between high-voltage cables and tap boards or corner connection pipes is too close, can also cause discharge sound. It is necessary to increase the insulation distance, tighten the bolts again, and check whether there are dust particles on the inner wall of the high-voltage coil. Due to the moisture absorption of particles, it may cause insulation reduction and discharge.
5、 Common faults of temperature controller operation
The common faults and handling methods of temperature control during operation are shown in the table below:
6、 Common faults in fan operation
The common faults and handling methods of the fan during operation are shown in the table below:
7、 The imbalance rate of DC resistance exceeds the standard
During the handover test, if the tap bolts are loose or the testing method is incorrect, it can cause the DC resistance imbalance rate to exceed the standard.