Research On On-line Monitoring Vacuum For Breaker System Based On ZigBee

With the popularization of the oil-free power system, the application of vacuum circuit breaker in low voltage is becoming more and more popular. The stable operation of the power system is directly influenced by the stability of vacuum circuit breakers. The key for vacuum circuit breaker to keep reliable breaking capacity is the high vacuum medium in interrupter. Therefore, the realization of on-line monitoring of vacuum degree becomes more and more important. The on-line monitoring system of vacuum degree based on coupling capacitance method is designed in this paper.In the complex field of working environment, communication effect of traditional cable is not easy to wiring and the circuits are easy to aging. To promote the development of smart grid, the application of wireless sensor network in the power system takes the place of cable transmission signal, becoming a more and more important research topic. This paper analyzes the wireless communication technology and in-depth study of the ZigBee technology networking mode. A small ZigBee star network based on the ZigBee protocol is designed. On the basis of the existing research of the vacuum degree on-line monitoring system, the on-line monitoring system based on ZigBee technology is designed.This paper introduces the principle of the coupling capacitance method. The change of the vacuum degree indirectly reflects the change of the vacuum degree. The coupling capacitor divider probe has been designed to collect the potential changes and a series of signal conditioning circuit has been designed to process the collected signals. This design makes the curve of calibration coupled voltage signal and vacuum degree more accurate. The system realizes the communication of upper computer and lower machine. The PC can display and storage the controller signals transmitted by ZigBee technology to better real-time monitor vacuum degree and analysis the interrupter running state.System software design includes upper computer and lower machine. The lower machine is based on AVR MCU and selects C language as programming language, thus A/D sampling chip data acquisition, data processing, data transmission and other functions can be achieved. The system uses C++to write the host computer software. The design completes the serial communication between the host computer and the coordinator. The function of the system on-line monitoring is realized by combining the software and hardware.The experimental platform is set up to simulate the working environment of vacuum circuit breaker. The corresponding curves of the coupling voltage and vacuum degree are calibrated through experiment. In the field environment, the network parameters of the ZigBee communication network and the signal quality of the transmission are tested. It is proved that the wireless network can realize the data transmission and meet the requirements of the field. The experimental results show that the designed system can complete the on-line monitoring of the vacuum degree.