Research On Overvoltage Mechanism And Suppression Method Of Vacuum Circuit Breaker Opening Shunt Reactor

As the demand for electricity continues to rise,the scale of the power grid gradually expands,and the capacity of the power grid continues to increase.In order to stabilize the safe and stable operation of the power grid system,more and more reactive power is being used in the power system.As a particularly important inductive reactive power compensation device in power systems,shunt reactors play an active role in maintaining system stability,optimizing system economic benefits,and increasing line transmission capacity.At present,in order to ensure the stability of the power system,a vacuum circuit breaker is used to break the parallel reactor on the 10 k V line to ensure the reactive power of the system.However,breaking the parallel reactor through the 10 k V vacuum circuit breaker will produce a blocking effect and vacuum interruption The strong arc extinguishing ability of the reactor can cut off the small current instantaneously,so that the current value is reduced to 0,so that the overcurrent voltage is generated on the bus side and the reactor side.In severe cases,it will cause reignition with higher frequency and larger amplitude Overvoltage will eventually lead to short-circuit discharge between the bus phases and damage to the inter-turn insulation of the reactor,threatening the safety of electrical equipment and affecting the safe operation of the system.At present,the material,manufacturing process and application conditions of vacuum circuit breakers are different from those in the past,and the operation transient process of breaking parallel reactors is complicated in form and has many influencing factors.In order to better solve the impact of overvoltage,this dissertation conducts an in-depth study on the 10 k V vacuum circuit breaker in parallel parallel reactive power compensation reactor,and specifically explains the mechanism of overvoltage generated by cutting off the parallel reactor in the 10 k V system.In this dissertation,a test platform is built on the basis of the operation of the power grid accident circuit,and a series of field tests are carried out to conduct a field test and statistical study of the vacuum circuit breaker parallel shunt reactor.Based on the results of the field test data,the circuit breaker is analyzed and fitted The opening and closing curve of the re-ignition state of the reactor is used to build a continuous arc re-ignition and extinction mechanism model of the shunt reactor,and fully consider the main equipment parameters andparasitic parameters in the substation,and build a re-ignition over-voltage simulation model in the ATP simulation program.The simulation model was used to test and analyze the method of suppressing reignition overvoltage,and a mixed method of surge arrester and RC resistance-capacitor absorber for shunt reactor breaking overvoltage was proposed to solve the hazard of overvoltage.