The Design Of High Voltage Circuit Breaker On-line Monitoring System

For improving the reliability of high voltage circuit breaker operation and the economical efficiency of the equipment maintenance, carrying out condition-based maintenance better, online monitoring of high voltage circuit breaker can be used to acquire the operating condition of equipment and the change trend, provide a reasonable assessment of the equipment state. Establishing the on-line monitoring system can measure each state parameter of circuit breaker more accurately, and provide more effective information for the failure prediction of the circuit breaker.In this paper, the circuit breaker’s mechanical properties, the contact electric life and the vacuum degree of vacuum circuit breaker are selected as the research object. The physical features of them are summarized and analyzed. The related signal of circuit breaker are collected and processed. The hardware and software of the online monitoring system have been designed and realized to complete the monitoring function.Hall sensor is applied to monitor the current of closing coil and opening coil. The exponent of circuit breaker time travel curve is achieved, the mechanical status of circuit breaker has been measured. The prediction theory of several contact electric life is also discussed in This thesis. The relative electric life method is applied to calculate the contact electric life. According to related theory of vacuum interrupter, the coupling capacitance method has been used to monitor the vacuum degree online.Online detection system of the circuit breaker is designed based on PIC16F887microcontroller. The software consisted of the main program, data acquisition module, data processing module, communication module etc. The structured and modular design is used to realize online monitoring function. The vacuum circuit breaker3AF (ZN12-/1250-31.5) is selected as the tested device. Test results show that the real-time display of time travel curve of circuit breaker can be displayed. The collection of closing time and travel, the calculation of speed, and the vacuum degree of vacuum interrupter can be real-time monitored by means of the design of online monitoring system.In a word, the stability of online monitoring system is high, the test method is feasible, the selected device which have high cost performance are reliable. It is very imperative and significant to carry out on-line monitoring of circuit breaker based on the consideration of reliability and economy.