（ Yinchuan Power Supply Bureau 750001 ）

【Abstract】This paper analyzes several common fault causes of the spring operating mechanism of SF6 high-voltage circuit breaker, points out the problems we should pay attention to in the process of defect handling, and introduces the inspection and treatment methods when the spring operating mechanism of SF6 high-voltage circuit breaker fails.

【Key words】SF6 high-voltage circuit breaker, spring operating mechanism fault, treatment

At present, 110KV, 220KV circuit breakers of most substation are mainly operated by SF6 gas spring energy storage operating mechanism. Some advanced substations have adopted advanced high-voltage circuit breakers produced by Siemens, ABB and other foreign companies. Because it is a new type of circuit breaker different from hydraulic mechanism and electromagnetic mechanism, many operators do not know how to deal with it when a fault occurs. In order to help operators master the treatment method when the air pressure of SF6 high-voltage circuit breaker is reduced, the author, based on years of practical experience, takes LW35-126 circuit breaker as an example, analyzes the cause of the failure, and proposes exploratory treatment plans and preventive measures. Information source: http://tede.cn

1 Reason analysis and treatment methods of SF6 low pressure abnormal alarm during operation of SF6 high voltage circuit breaker spring operating mechanism

1.1Reason analysis of SF6 low pressure abnormal alarm during operation of SF6 high voltage circuit breaker spring operating mechanism

Analyze the reasons why the circuit breaker reports the "SF6 low pressure abnormal alarm" signal. First, the density of SF6 gas is lower than the alarm pressure due to the leakage of SF6 gas; the second is the normal drop in air pressure during long-term operation; the third is the failure of the SF6 gas pressure alarm control circuit, resulting in the phenomenon of false signalling.

1.2Treatment methods of SF6 low pressure abnormal alarm during operation of SF6 high voltage circuit breaker spring operating mechanism

The processing of the "SF6 low pressure abnormal alarm" signal reported by the circuit breaker is divided into two steps: firstly, check the pressure gauge indication, analyze the cause, and determine the plan for eliminating the defect; secondly, restore the normal operation of the equipment as soon as possible after the defect is eliminated. The following are the correct processing steps, methods and precautions for reporting "SF6 low pressure abnormal alarm". Please visit: www.tede.cn for more information

(1)Check the indication of the pressure gauge in time to check whether the signal report is correct and whether there is air leakage.During the inspection, if you feel irritating gas or feel unwell, you should immediately leave the site 10m away, and you must wear protective equipment to approach the equipment.

(2)If there is no air leakage in the inspection, it belongs to the normal drop of air pressure during long-term operation, and should be reported to the superior, and the air should be charged by professionals. After refilling, continue to monitor air pressure.

(3)If there is air leakage in the inspection, report the dispatch immediately, transfer the load or reverse the operation mode in time, and cut off the power of the fault circuit breaker for inspection (at this time, the SF6 air pressure can still ensure arc extinguishing).

(4)If the inspection finds that the SF6 gas pressure alarm control circuit is faulty, resulting in a false signal, the circuit should be checked to eliminate the fault in time.