Abstract:

Vacuum circuit breakers (VCBs) are widely used in power systems to control and protect power lines and power equipments under the conditions of normal, overload, short circuit and other faults. Once a VCB is unable to interrupt or make a current as designed, especially for the short circuit current, heavy losses would be brought about to both the power system and the consumers. In order to reduce the number of accidents and prevent possible troubles due to the failures of VCBs, one valid way is to monitor their performance and condition on-line. Based on the understanding and development of condition based maintenance (CBM) of high-voltage circuit breakers, the authors give some general introduction to electrical endurance on-line condition monitor for VCBs, in which the stress put on the non-intrusive method and device for determination of the arcing duration. The principle and configuration for arcing duration detect are emphatically expounded in our research, in which the electromagnetic induction theory is adopted for the arcing initialization and duration detect. The simulation and experimental results of the arcing detect device are provided in detail. The accuracy and stability of the arcing detect device have been demonstrated and it can distinguish co-existing arc signals in three-phase of circuit breakers. In the end, an algorithm for the electrical endurance of vacuum circuit breakers on-line condition monitoring system is proposed, which based on TMS320F2812 one type of DSP281X series produced by texas instruments semiconductor. The universally accepted approach of accumulative breaking current of high voltage circuit breaker contact to diagnose electrical endurance is used in the high-voltage circuit breakers electrical endurance on-line monitor system.

Key words: Vacuum circuit-breakers, electrical endurance, on-line monitoring, contact system