Research On High-voltage Switch With Power Diode Based On Motor Actuator

With the demand for the development of intelligent power industry, high- voltage switchgear as essential mechanical parts in power system, which intelligence affects the intelligence level of the whole system. Meanwhile, the normal operation of the power system not only requires active power for electrical equipment, but also need reactive power to keep some devices such as transformers normal running, it is used to establish and maintain the conversion between the internal electric fields and the magnetic fields. The reactive power distribution seriously affects on voltage levels and generator efficiency in grid, therefore, reactive power compensation is an effective method for reduction line losses, increase power factor and improvement power quality. Capacitor banks as a usual reactive power compensation device is widely used in 6~35 kV medium pressure systems and industrial power systems, it has simple structure and convenient operational features. May cause inrush current or over-voltage problem when capacitor banks input into the grid or remove from the grid, these issues will seriously damage the insulation and pressure of the primary equipment etc. In order to solve the above problems, studying new switchgear to operate capacitor banks is necessary. This paper presents a hybrid high- voltage switching systems based on diode with an actuator motor to switch capacitor banks. It is not only to achieve the intelligent control switchgear, also reduces the inrush current and over- voltage. Hybrid high- voltage switchgear uses the static characteristics of diode to achieve current transfer between the switch fracture and the diode when operating capacitor banks. Diode is turned off when the voltage of diode turn from positive biased to negative biased by the zero-crossing point, at this time to operate switch fracture with arc-free.Firstly, these theories of hybrid high- voltage switchgear are in-depth study such as structure, working principle, current transfer mechanism and mathematical model of permanent magnet synchronous motors, servo control strategy etc. Secondly, construct 10 k V power system simulation models to simulate the arc voltage and current transfer process when the diode hybrid high-voltage switchgear operating capacitor banks in MATLAB. Compare vacuum switch with the new switch in the switching capacitor bank resulting surge and transient over-voltage conditions. Again, establish a permanent magnet synchronous motor servo control system simulation model depend on the control scheme, respectively use PID and fuzzy PID two kinds of controllers in the position controller to verify the servo control system performance whether meets the requirements. Finally, establish the experimental platform to program, debug and verify simulation results in the digital signal processor. The results showed that the motor actuator control strategy in paper adopted can meet the basic requirements of the application and the diode hybrid high-voltage switchgear in paper presented can effectively reduce inrush current and transient over- voltage when switch capacitor banks. Results of this study have important implications for the development of capacitor switching switchgear and intelligent grid.