Analysis of Power Regulation of Magnetically Controlled Shunt Reactor and Its Impacts on Protection

Magnetically controlled shunt reactor (MCSR) is one of the key equipment applied in EHV/UHV transmission systems for reactive power compensation and overvoltage suppression. This paper focuses on the analysis of transient process of power regulation of MCSR and its impact on the protection based on fundamental component of the total control current against turn-to-turn fault. Firstly, the characteristic of steady state of MCSR is analyzed and the concept of the degree of magnetic saturation is introduced. Then the transient process of the power regulation is analyzed through theory and simulation, which shows that the unbalanced currents in three-phase control windings might cause the maloperation of the protection based on the fundamental component of total control current against turn-to-turn fault for MCSR. To solve this problem, an antimaloperation strategy based on the differences among the fundamental components of three-phase control winding currents is proposed and validated by simulation results.