Research On Phase-controlled Switching Technology Of Motor Operating Mechanism In High-voltage Vacuum Circuit Breaker

In order to meet the development needs of China's smart grid,it is extremely urgent to improve the intelligent level of high voltage electrical equipment.In this paper,based on the motor operating mechanism of 126 kV vacuum circuit breaker,the phase-controlled switching technology of motor operating mechanism of high voltage circuit breaker is studied.This paper studies the design of the drive motor,the control system,and the phase-controlled switching operation experiments of the circuit breaker.Main work of this paper includes the following issues:(1)Study on the design method of driving motor of operating mechanism.According to the load characteristics of circuit breakers and the requirements of phase-controlled switching technology,in this paper,the design method of the drive motor of the operating mechanism is presented from the point of tangential electromagnetic force.With the high power density and high response speed,the main parameters of the drive motor are determined;Advantages and disadvantages of different rotor structures are analyzed.The matching schemes of winding wire diameter and turns are designed;The finite element motor model of electric,magnetic and mechanical coupling field is established;The dynamic characteristics of the magnetic flux density distribution,armature winding current,electromagnetic torque and rotational angular displacement of the driving motor during the operation of the circuit breaker are analyzed.Then,the effectiveness of the drive motor design method is verified.(2)Design of the control system of operating mechanism.For high voltage circuit breaker operation speed,short operation time and motion reliability,the control device of motor operating mechanism is designed with the core of high speed and high precision DSP28335,including the main processor unit,the power grid voltage generation unit,the signal acquisition unit,the inverter drive unit and the low voltage power supply module,etc.;Based on the DSP development platform,the main program of the system,the power grid voltage phase detection program,the motor rotation angle displacement acquisition program and the motor winding current acquisition program are compiled and debugged.(3)The tracking control technology of motor operating mechanism is studied.Based on the operating mechanism of 126 kV vacuum circuit breaker operating mechanism and its control system,online experiment platform is built.The influence of mechanical dispersion and environmental temperature on the stability of motor operating mechanism is analyzed.The tracking control technology of motor operating mechanism is presented.Expert PID controller is designed and motor operating mechanism tracking control experiment is carried out.The experimental results show that motor operating mechanism has a good tracking action.Under different experimental conditions,the maximum deviation between the switching time of the circuit breaker and the preset time is 0.72 ms.(4)Phase-controlled switching operation experiment of 126 kV vacuum circuit breaker motor operating mechanism is done.Based on the tracking control technology of motor operating mechanism,under different experimental temperature,phase-controlled switching operation experiment of 126 kV vacuum circuit breaker motor operating mechanism is done.The experimental results show that the maximum deviation of the phase-controlled closing operation of the circuit breaker is 0.75 ms,and the maximum deviation of the phase-controlled opening operation of the circuit breaker is 0.83 ms,which meet the requirements of the International Conference on Large High Voltage Electric System on the phase-controlled switching accuracy within ±1ms.