Research On Control Technology Of Reducing Impact Magnet Vacuum Circuit Breaker

Reclosure technology is often used to improve the reliability of power supply when power system fails.However,when a permanent fault occurs in the system,the circuit breaker reclosing will make the power system suffer from the impact of fault current again,resulting in damage to power equipments and affecting power quality.To solve this problem,a kind of reducing impact circuit breaker(RICB)is proposed,in which new permanent magnet actuator(PMA)is adopted to support the phase-controlled reclosure strategy.This paper studies the control method for RICB and designs the corresponding control system.Firstly,this thesis compares the working principles and modes of the double monostable PMA suitable for RICB with traditional single and bistable PMAs.The research status on the control methods for PMA and PM vacuum circuit breaker at home and abroad is then analyzed.The basic principle of phase selection control technology and the factors affecting the effect of phase selection control are introduced.The method for calculating the parameters of power grid by using the sampled data of power grid is given.The method of determining the capacity of energy storage capacitance used to drive the PMA in RICB is also introduced.By analyzing the working principle and dynamic characteristics of double monostable PMA,a control system of RICB is designed in this thesis.The control system takes DSP as the processing core and modularization as the design idea.The hardware zero-crossing detection circuit,communication circuit,high-precision A/D sampling circuit,capacitance charging and detection circuit and drive circuit are respectively designed.At the same time,this thesis designs the corresponding software for the hardware system,including an underlying program embedded in the DSP and an upper computer control program located in the remote computer,and introduces the workflow of the software in detail by using a flow chart.Finally,an experimental platform for RICB is built,and the reliability of each functional module in the designed control system is tested.Under laboratory conditions,the dynamic characteristics of the breaker are tested,the short-term closure experiments related to phase-controlled reclosure,the phase separation and closing experiments are carried out,and the experimental results are also analyzed.