Mechanical State Detection of GIS Circuit BreakerBased on Vibration Characteristics

GIS (Gas Insulated Switchgear) is widely used in power system for its advantages. However, there may have some faults in the GIS with the running time increasing. Mechanical defects are the main reasons lead to circuit breaker failure. Therefore, this paper proposed a method to analyze the mechanical state of GIS circuit breaker. The operation process of the transmission mechanism of the circuit breaker. The GIS circuit breaker mechanical vibration system was built in the laboratory. A vibration acceleration sensor was used to detect the vibration signal during the opening and closing operation of the circuit breaker. To study the change rule of mechanical state with the increasing operation times, the vibration tests of the GIS circuit breaker were carried out for more than 100 times on two GIS circuit breakers. The evolution law of the vibration signals was extracted based on the time-frequency analysis. According to the analysis results: at the first 50 times closing operation, the vibration signal is scattered mainly over 400-600Hz, 800Hz and 1100-1300Hz. With the increase of the closing times, the amplitude of vibration signal around 800 Hz gradually decreases. The similarity with the first operation is decreasing with the number of operation increases. After operating for 50 times, the similarity tends to be stable. The similarity of each device is only valid for the certain device. Each equipment needs to be checked before using these similarities. The proposed method lays a foundation for detecting mechanical aging and predicting the life of the circuit breaker.