Research On Intellegent Control System Of Permanent Magnet Vacuum Circuit Breaker

Intelligent circuit breaker is an important component of the smart grid. The thesis researches intelligent control technique of the permanent magnet vacuum circuit breaker (PMVCB) including signal sampling and controlled switching technique.The software and hardware of intelligent controller are designed and verified with the experimental results. The thesis can improve the intelligent level of circuit breaker and enhance the construction foundation of the smart grid.Firstly, the thesis introduces the structure and operating principle of mono-stable and bi-stable PMVCBs. The state of the art of PMVCB is reviewed in detail. Based on the key technique above, the controlled switching strategy for different loads is determined by simulating and analyzing the influences of pre-breakdown, control voltage, temperature and aging wear on the controlled switching technique. The Fast Fourier Transform (FFT) principle used in the grid parameter calculation is also introduced.Secondly, the hardware and software systems are designed for intelligent control objectives. The controller using TMS320F2812 as processor includes such modules as power supply, watchdog, external expansion memory, data sampling, driving, zero-cross detection, communication and condition monitoring. The software system includes upper and lower computer ones. The whole workflow is expressed by module flowchart.Finally, an experimental platform for lOkV three-phase PMVCBs is set up. The intelligent control systems based on mono-stable and bi-stable PMVCBs are tested in different experimental environments. The experimental measurement shows that the time error of controlled switching is less than 0.5ms, which means that the controller can work reliably.