Research On Faults Diagnosis Of Electric Equipment Based On Relay Protection System

Protection relay is the important tool that ensures safe operation of power systems and improves the quality of power energy and with the expansion of the power system, the consumer's requirement for quality of power energy is rising. As the result, protection relay must be improved greatly and fulfill the high requirement. On-line monitoring and fault diagnosis electrical equipment can record various data relevant to the life of breakers immediately and continuously, and deal with these data automatically. So potential fault can be detected and basic maintenance can be putted in practice. This thesis analyses the development of computer protection relay and fault diagnosis, and compares many computer protection equipments made in domestic, based on which, a method that embedding fault diagnosis function into computer protection relay system. The main researching object is high-voltage breaker, and the goal is to implement monitoring, diagnosis and protection integrating into a whole system.This paper firstly presents the fundamental principle of computer protection relay and integration automation, and analysis relevant variables including analogy, switching and pulse variables, which is collected in existing protection equipments. Later, protection and measurement function of several computer protection relay is introduced detailed.Secondly, this paper introduces the methods of electrical equipment on-line monitoring and fault diagnosis nowadays, and detailed expounds the variables' distilling principle in fault diagnosis.Finally, this paper commits to high-voltage breaker fault diagnosis system based on protection system. The main work is Embedding fault diagnosis function into protection relay, with no change of existing hardware platform, and the emphases is embedding fault diagnosis knowledge set into existing software. In this paper 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.