Research on the Influence of Current Limiter Based on Highly Coupled Split Reactor on Main Circuit Breaker Overvoltage

Abstract

Due to the increasing short-circuit current levels in modern power grids, it is planned to install a current limiter based on a high-coupling split reactor in the 500kV power grid to limit the short-circuit current. However, the connection of the current limiter will cause the transient recovery voltage of the main circuit breaker to exceed the standard envelope, making the breaking conditions of the main circuit breaker very severe. This paper establishes a mathematical model and finds that the oscillating circuit formed by the current-limiting inductance and the stray capacitance of the system is the reason why the overvoltage rise rate of the main circuit breaker is greatly increased. Establish a single-phase equivalent circuit model for simulation. It is found that the rate of rise of the transient recovery voltage decreases with the increase of the stray capacitance of the system. When the stray capacitance takes the estimated value of the system parameters, the transient recovery voltage rise rate reaches its peak when the current-limiting inductance is 9mH.