High Voltage Circuit Breaker Monitoring And Diagnosis System

Based on the conception of device maintenance of Electrical Power System , this paper discusses the possibility and necessity of on-line status monitoring and fault diagnosis technology and takes the HV (high voltage) circuit breaker as the example. The HV circuit breaker is one of the major critical components that control and protect power network, so the reliability of the breaker operation is very important. Nowadays the HV circuit breakers are overhauled regularly by the unsuitable routine, so it is necessary to apply on-line monitoring and fault diagnosis on the real-time state of the HV circuit breaker.This paper introduces the situation of current research on equipment state monitoring and fault diagnosis at first, and then presents a variety of technology on monitoring and diagnosis and probes its development tendency. The state monitoring methods of HV circuit breaker are studied and analyzed on mechanism and electricity. The paper also presents the fault diagnosis technology that based on fuzzy theory. In fuzzy diagnosis, all the symptoms at fault time comprise a symptom space, and all the reasons that may lead to the fault comprise a reason space. The related reason must correspond with some symptom masses in the symptom space, and this is generally described by degree of affiliation.HV circuit breaker fault divides into mechanical aspect and electrical aspect, and most research are focus on the mechanical vibration when HV circuit breaker statemonitoring is involved. The author analyzes these two aspects synthetically in this paper, and two methods of the vibration signal processing have been put forward: the development of signal trend and the analysis of the maximum module based on the wavelet transform. Capture the signal's low frequency component according to the wavelet transform which can reflect the signal's developing trend. Then it can estimate the status of HV circuit breaker according to compare the normal condition's waveform with the fault condition's waveform. Process the mechanism vibration signal on the theory of wavelet singularity detection. When the signal occurs singularly, the coefficient's maximum module can appear. It can confirm the time when the fault occur. At the same time, the module can be considered the characteristic parameters for the fault diagnosis.Finally, combined with the actual situation of Shandong Huangtai power plant at which the author works, a on-line status monitoring and fault diagnosis system on HV circuit breaker is developed and embedded in the factory level equipment condition overhaul system. The data used in this system comes from (1) Unit DCS system shared by factory level data highway, relay protection system, fault recorder system data. (2) analog signals from some sensors are transferred and converted to industrial control computer directly (3) equipment manager inputs data manually according to the cycle measure results. This system uses program language of Matlab6.5 directly, and implements data gathering, storing, processing, calculation and communication functions on HV circuit breaker by means of data processing methods and mathematics modules in Matlab, and thereby give the synthetically evaluation of HV circuit breaker's life cycle.