Research On On-Line Monitor And Intelligent Fault Dignosis Technology For High Voltage Circuit Breakers

High voltage circuit breakers (HVCBs) play a significant role in controlling and protecting power grid, which are used frequently and in large quantities in power system. Strengthening the research about on-line monitor and intelligent fault diagnosis of HVCBs helps to promote the intellectualization of power equipments, meet the demands of smart grid developments and advance the stability and reliability of power grids. On-line monitor means real time and continuous collection of operating parameters of HVCBS via various kinds of sensors. Intelligent fault diagnosis refers to the procedure of analyzing data with artificial intelligence algorithms, evaluating working condition of breakers and recognizing the potential faults. The combination of both technologies provides support for condition based maintenance and features promising application prospects.The development process and latest achievements of relevant technologies are discussed in detail. Common faults of breaker are concluded by the statistical data in recent years, on the basis of which the on-line monitor signals of breakers are selected and analyzed. To deal with the data obtained by on-line monitor, tables are used to formalize the knowledge. According to the rough set theory, the improved greed algorithm is applied to discretize the data and reduct the knowledge. As the result, the characteristic information is brought out, the redundant information is deleted and key rules are extracted. A simple decision table is then built. To construct a model for fault diagnosis, the fuzzy Petri net is chosen. Nets are built according to decision tables. The MYCIN method is applied to accelerate the inference and increase the efficiency and accuracy of fault diagnosis. Common faults during the closing procedure of HVCBs are taken as examples to validate the establishment of decision tables and the fulfillment of fault diagnosis.A comprehensive system for HVCB on-line monitor and fault diagnosis is built which contains a host computer and a slave computer. The host computer is an industrial control system with a LCD screen, which calculates and displays the data. The slave computer contains mainly ARM and FPGA chips which conducts the collection and transmission of data. The software planted in the host computer is written in advanced programming language C#. It has a friendly human-computer interaction interface and plays functions such as real time monitor, history inquiry and fault diagnosis. The prototype has passed the practical trial operation and shown satisfactory effects.