Research And Realization Of Permanent Magnetic Vacuum Circuit Breaker Intelligent Control Technoloay

With the rapid development of economy, the requirement of power quality is higher and higher, and the application of vacuum circuit-breaker in medium voltage distribution network is generally. Permanent magnetic vacuum circuit-breaker in the proportion of medium vacuum circuit-breaker is increasing because of its advantages, such as simple structure, less components, small dispersibility action, high reliability, long life and so on. This paper studies a new intelligent control technoloty of monostable permanent magnetic actuator, which is based on the coil current and the switch signal of circuit-breaker to comprehensive judge whether the circuit-breaker is in place, this can avoid misjudgement caused by micro-switch or proximity switch failure; At the same time can calculate the closing time according to the coil current waveform, providing the data support for delay time calculation of circuit-breaker closing to achieve the initial synchronous closing control.Firstly, this paper introduces the research status of permanent magnetic vacuum circuit-breaker, analyzes the working principle, dynamic characteristics, coil current characteristics and the synchronous closing technology of monostable permanent magnetic mechanism. Secondly, an intelligent controller is designed for monostable permanent magnetic vacuum circuit-breaker. The hardware circuit design and software flow diagram of the intelligent controller are completed. This intelligent controller can achieve the following functions of circuit-breaker’s intelligent control, protection, status monitoring fo circuit-breaker, communication, LCD display and so on. The intelligent controller uses LPC2294 microprocessor of Philips corporation as core processor in hardware, the hardware circuit including CPU minimum system, voltage, current and other analog signal acquisition circuit, closing and opening control circuit, IGBT driver circuit, environment temperature measurement circuit, communication circuit and so on. The software part completes the transplantation μC/OS-II operating system on the LPC2294 microprocessor, the application procedures contains the AD sampling procedures, the closing and opening control procedures, status inspection procedures, serial communications procedures and so on. In order to realize the accurate measurement of the voltage and current signal, the signal de-noising algorithm and FIR filter are designed to remove the noise. The linear interpolation algorithm can effectively extract the zero crossing point, and initially realize the synchronous closing of permanent magnetic vacuum circuit breaker.