Research On Switching Over-voltage And Synchronous Control Breaking Technology Of Shunt Reactor

With the increasing popularity of shunt reactors in systems,turn-to-turn faults in shunt reactors have become an urgent problem to be solved.During the interruption process of the shunt reactor,the operating over-voltage is common.Especially in the case of the empty busbar,it is extremely dangerous to interrupt the shunt reactor.The over-voltage phenomenon is extremely serious,which is the main factor causing the short circuit between the shunt reactors.At present,the research on the over-voltage of shunt reactors is extremely lacking,and there is no corresponding measures to deal with it.However,the conventional shunt reactor over-voltage protection method can not meet the requirements of GB311 insulation.The phase-controlled switching technology can weaken the transient phenomena such as inrush current and over-voltage during the operation of the circuit breaker.The phase-controlled switching of the shunt reactor by using the fast vacuum switch can reduce the over-voltage during the switching.Focusing on the main research content,the completed work mainly includes the following four parts.Aiming at the over-voltage of shunt reactor operation,a phase-controlled switching strategy of shunt reactor which can reduce the re-ignition probability and suppress the virtual current chopping phenomenon is proposed,and the effect is verified by simulation.It mainly includes: research on the interrupting process of the shunt reactor,the generation mechanism and key parameters of the operating over-voltage;The fast switching and phase-controlled switching techniques are proposed to reduce the re-ignition probability.An asynchronous phase-controlled interrupting strategy is proposed to avoid the occurrence of virtual current chopping phenomenon and simultaneous three-phase interrupting.The fast phase-controlled breaking sequence of shunt reactor under various working conditions is designed.The re-ignition characteristics and critical opening distance at the time of interrupting resistance were studied;According to the actual substation parameters,the model of substation system and the model of 35 kV reactor are established.The simulation of the over-voltage of the substation is carried out,and the effect of the proposed fast phase-controlled interrupting strategy is simulated.The results show that the proposed fast phase-controlled strategy effectively avoids the virtual current chopping phenomenon and simultaneous three-phase interrupting,which can reduce the operating over-voltage when the shunt reactor is interrupted.According to the requirements of the scheme,a fast repulsion mechanism suitable for phase controlled switching of shunt reactors is developed.It mainly includes: Aiming at the problems of long excitation time and slow opening speed of the permanent magnet actuator,according to the characteristics of high reliability of the permanent magnet actuator and fast action speed of the electromagnetic repulsion mechanism,the fast repulsion permanent magnet combined operating mechanism is adopted;the parameters of the operating mechanism are determined to improve the speed of the designed mechanism and meet the requirements of fast phase controlled switching of the shunt reactor.According to the requirements of the scheme,the relevant manufacturers are entrusted to develop and manufacture the vacuum switch of the fast repulsion mechanism,and the functional test is carried out on the switch prototype.The results show that the fast switch developed and manufactured in this paper can meet the expected requirements of fast opening.Based on the above preparations,the interrupting test of shunt reactor was carried out with the help of the perfect experimental platform of Guangdong Product Quality Supervision and Inspection Institute.The experimental results show that the fast phase-controlled asynchronous interrupting strategy proposed in this paper can suppress the operation over-voltage fundamentally.