Research On On-line Monitoring Technique For Key Parameters Of Vacuum Circuit Breaker With Permanent Magnetic Actuator

Vacuum Circuit Breaker (VCB) is widely used in power supply and distribution system, which plays both contol and protection functions in electric network. As a new-type breaker operating mechanism, the exertion property of Permanent Magnetic Actuator (PMA) splendiferously coordinates with load characteristic of VCB, which makes VCB with PMA gradually become the main products in electric power system.To ensure safety and reliability service of electric power system.It is the basis to on-line monitor that the key parameter of VCB equipped with PMA is on-line monitored. The author designed and established Virtual Data Acquisition system based on USB-DAQ, and raised the On-line monitoring system on key parameter of VCB with PMA based on hybrid programs of LabVIEW and MATLAB.The author chose VCB with PMA of 12kV as the target of on-line monitoring, analyzed the process of cut-off and closed moment of VCB,chose electrical endurance as the key parameter,analyzed and summarized the open question and all kinds of methods used in switch electrical endurance. Linking the diagram of current waveform and displacement waveform in the wire when the Breaker was driven,the author raised a improvement algorithm on comprehensive assessment of relatively electrical endurance for three phase's contact terminal, and got some state character quantities such as cut -off current value and arcing time by denoising and analyzing the signals after Data Acquisition using wavelet analysis.Finally,adopting the mind of modular programming ,the author accomplished the hardware implementation on VCB's electrical endurance on-line monitoring system based on USB-DAQ card, and also completed the design of multiuser operat- ing interface and block diagram based on hybrid program in LabVIEW and MATLAB. The result of the instance analysis on electrical endurance illustrated that on-line monito ring on short circuit current and arcing time could timely discover continuous arcing phenomenon,which is propitious to judge synthetically on the status of three phase's contact terminal wear and get the value of VCB's remaining electrical endurance.