Research On Synchronous Switching Of Shunt Capacitor Banks

Controlled switching, also called synchronous switching or phasing-control switching, is a terminology applied to the principle of coordinating the instant of opening or closing of a circuit with specific target point on an associated voltage or current waveform. Controlled switching has become an economical solution and commonly used to reduce switching surges. This paper lays a strong emphasis on controlled capacitor switching, and represents the reactive power compensation of power system. The main contents are composed of the principle of synchronous switching of capacitor banks with controlled switching, and controlled switching strategies of capacitor banks. The paper analyzes transient phenomena of traditional capacitor switching, and presents the principle of controlled switching. The obtained results in this thesis supply references to future research on the controller of synchronous switch.PMA (Permanent Magnetic Actuator) has small mechanical scatter due to its fewer moving parts, and its output characteristics can perfectly match vacuum switch. PMA has been used more and more widely. Controlled vacuum switch is supplied, with independent-pole operated PMA, and capacitor discharge supply can be chosen in the PMA exciting circuit. Thus the operation is controlled by high-current power electronic devices. Test results demonstrate that PMA can satisfy with the request of the controlled switching, and it is the ideal choice of synchronous switching.As a new type of high-power switching component, IPM (Intelligent Power Module) has been widely used. Because of its simple design (built-in drive and protection circuit), low power consumption and switching speed characteristic, IPM has been chosen as the first choice by more and more designers. The paper mainly discusses the control strategy of IPM in the system, the isolation actuation with the photoelectric coupler, the overcurrent and overtemperature protection of IPM and the function of IPM in overall system. Here, the design of software and hardware for synchronous control system of permanent magnetic actuator, in which the digital signal processor TMS320LF2407A is used as the kernel, is presented. In this system the real-time acquisition of the electrical parameters is adopted, and the crossover point of reference signal is detected by FIR digital filter. The system controls the large-capacity capacitor discharge to actuate the PMA through IPM, and makes the circuit breaker open or close in an ideal phase in order to reduce the transition impact. The stored energy capacitors charged once can complete an O-C-O operation in the system. The experiment results indicate that this system already achieves the anticipated effect, and provides some useful experience and the reference for the future research. The system is useful to optimize the synchronous control system.