COMMON PROBLEMS IN ISOLATE SWITCH

In the last article we learned about the characteristics and classification of isolation switches. Do you know the common faults of isolation switches? How should we solve this problem? This article helps you solve this problem.

 
Common problems of disconnectors
 
Q: What are the common faults?
Answer: The common faults of the isolation switch are:

* The contact part is overheated.
* Porcelain insulation damage and flashover discharge.
* Refuse to pull and close.
* Incorrect pulling and closing.
 
Q: Reasons for overheating of the contact part of the isolating switch
Answer: The isolating switch is overheated during operation, the main reason is that the load is too heavy, the contact resistance is increased, and it is not completely closed during operation.
 
Q: What are the reasons for increasing the contact resistance of the isolating switch
Answer: The reason for the increase in contact resistance is that the repulsive force between the blade and the mouth of the knife is very large, and the blade is not tightly closed, which causes surface oxidation and increases the contact resistance. Secondly, the isolation switch will cause arcing during the pulling and closing process, which will burn the contacts and increase the contact resistance.

Q: How to judge whether the contact of the isolating switch is overheated
Answer: It can be judged according to the color change of the contact part of the isolating switch or the change of the color of the temperature test piece, and can also be determined according to the degree of darkening of the blade. It is generally determined based on infrared temperature measurement results.

Q: Isolation switch electrical operation failure
Answer: After the electrical operation of the isolation switch fails, first check whether there is any error in the operation, and then check whether the operation power circuit and power circuit are intact, and whether the fuse is fused or loose. Whether the electrical blocking circuit is normal.

Q: What should I do if the isolation switch is not closed properly?
Answer: The disconnector does not close properly, most of them are caused by the mechanism corrosion, jamming, and maintenance and debugging are not adjusted properly. In this case, the disconnector can be opened and closed again. For the 220KV isolation switch, it can be pushed in with an insulating rod. If necessary, apply for power outage treatment. The high-voltage disconnector should be repaired 1-2 times every 2 years.

Q: How to deal with overheating of isolating switch contacts?
Answer: When it is found that the contact of the isolating switch is overheated, first report the dispatch, try to reduce or shift the load, strengthen the monitoring, and then handle it according to different wiring.

1. Double busbar wiring. If the switch on the side of a busbar is overheated, the overheated disconnector will be taken out of operation by inverting the busbar, and the power will be shut down for maintenance.
2. Single busbar wiring. We must reduce its load, strengthen monitoring, and take measures to cool down, if conditions permit, stop using it as much as possible.

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