How to prevent outdoor high-voltage vacuum circuit breakers from lightning?

The overall structure of the porcelain bushing pillar type outdoor high-voltage vacuum circuit breaker is: the upper porcelain bushing is an arc extinguishing chamber bushing with a built-in vacuum arc extinguishing chamber, and the lower porcelain bushing is a pillar bushing. The arc extinguishing chamber casing and pillar casing are filled with vacuum insulating grease with excellent insulation properties. During lightning activity, if the 35 kV line surge arrester is damaged or has poor lightning protection characteristics, overvoltage will invade the substation equipment along the line. If there is a weak point in the insulation of the circuit breaker, a short circuit will occur, and a lightning strike will damage the equipment. In this regard, the following preventive measures can be taken.

(1) Strengthen the operation and maintenance of high-voltage vacuum circuit breakers, especially during inspection operations. Check whether there are any abnormalities in appearance and whether silicone grease leaks. In case of power outage, check the internal corrosion and silicone grease status through the observation hole to find problems. Deal with it promptly.

(2) Strictly test and inspect the incoming lightning arresters of the substation. Before the thunderstorm season, all lightning arresters need to be inspected again to see if there is any damage and whether the action indicator has water. Lightning protection equipment with poor lightning protection characteristics should be replaced in time. Process and eliminate the inducing factors of insulation breakdown failure of high-voltage vacuum circuit breaker. At the same time, the grounding resistance value of the grounding grid in the substation must be tested to ensure that its resistance value is qualified.

(3) Improve condition monitoring and fault analysis capabilities, actively carry out equipment condition maintenance, carefully check the insulation withstand voltage, leakage current and dielectric loss test results of high-voltage vacuum circuit breakers, make vertical and horizontal comparisons, and discover potential defects in a timely manner.

(4) Use double-channel sealing design to select equipment, rationally select sealing materials and sizes, and control the compression amount of the sealing ring.

(5) Optimize the installation and maintenance process, create a group of maintenance teams with rich maintenance experience and superb maintenance skills, improve the installation and maintenance process of high-voltage vacuum circuit breakers, arresters, fuses, aluminum bars, etc., and strictly control quality.