Continuous monitoring of circuit breakers using vibration analysis

This paper reports the results from three years of continuous condition monitoring of high-voltage circuit breakers (CBs) using vibration analysis. More than 1000 vibration patterns from the operating mechanism of three different spring-operated SF6 breakers in normal service are analyzed. The patterns are recorded during each opening/closing operation and compared with references to identify timing and frequency deviations. Two of the three investigated CBs were operating well, while the third suffered from several severe problems. A developing failure that caused this breaker to not open on command was identified in advance. The reproducibility of the vibration patterns is high for a faultless CB and this makes it possible to separate faulty conditions from natural variations. The vibration analysis method is, however, dependent on a well-conditioned vibration pattern without noise and with distinct events. If the instrumentation is made sufficiently robust to withstand both the electrical disturbances in a substation environment and the mechanical shocks during CB operation, vibration analysis seems to be a promising technique that can be used on a continuous basis to detect malfunctions in the operating mechanism.