Study On On-line Monitoring And Fault Diagnosis System For High Voltage Circuit Breaker

On-line monitoring of power equipment is the precondition of predicting maintenancejt is the key element to the reliable running of equipment,Also it is the important supplement to the traditional preventive maintenance.High voltage circuit breaker is one of the most important and the most complex electrical device.lt played an important role to guarantee the safe operation of electrical power system.When it breaks down,it may cause serious economic loss,and it even cause the accidents expand.The accidents of high voltage circuit breaker in the electric power equipment failure is of high proportion. Therefore, the real-time monitoring of high voltage circuit breakers to keep abreast of the working status of the high voltage circuit breaker has a very important significance to improve the reliability of power supply.First,this paper studied the use, classification, structure, typical fault of high voltage circuit breaker.And it details the high voltage circuit breaker monitoring parameters which has breaking and closing coils current,breaking current,energy storage motor current and the temperature signal.Secondly, this paper discusses the measurement,calculation and analysis methods of electrical parameters of high voltage circuit breaker.These parameters includeing breaking current, relative remaining life of the high voltage circuit breaker and breaking and closing coils current.Because of the location of the equipment installation,the outside electromagnetic interference or other factors, noise will superimposed on the current signal when measuring the breaking current. Therefore, the wavelet threshold denoising principle applied to the measurement of the breaking current.lt will eliminate the noise interference and improve the measurement accuracy of the breaking current. Subsequently,this paper introduce the method of maximum slope method to calculate the breaking current. The calculated breaking current will be used in the calculation of the relative life of the high voltage circuit breaker. Also this paper gives the empirical formula to calculate the electrical wear of the oil-minimum breaker breakers, SF6circuit breakers, vacuum circuit breaker.Thirdly,this paper raises the method which use the slope of breaking and closing coils current to extract the features of each time in opening and closing.And the simulation experimental result shows that this method can extract opening and closing time characteristics effectively,which provide the basis for the judgment of the high voltage circuit breaker failure.This paper also propose the reliability analysis of High Voltage Circuit Breakers based on the quality of grid power supply. And do a preliminary study prepared for the follow-up study.Finally, Using NI acquisition card PLC and GPRS modules to build a high voltage circuit breakers online monitoring and fault diagnosis experiment platform.Then,programming the data acquisition program in the PLC,and using the GPRS module for remote data acquisition.Using NI data acquisition card to achieve high-speed acquisition of field data, and using Lab VIEW to write a user-friendly high voltage circuit breaker user management and monitoring interface.This paper has complete part of theoretical study on the On-Line monitoring and fault diagnosis of high voltage circuit breaker.It has complete the part of hardware and software design and the development of the high-speed data acquisition based on the NI data acquisition card and the remote data acquisition based on PLC and GPRS module.