Power Regulation Transient Process of Magnetically Controlled Shunt Reactor and Its Impact on Protection against Turn-to-Turn Faults

Abstract

Magnetically controlled shunt reactor (MCSR) can smoothly regulate its reactive power in a large scale. However, the transient characteristic during power regulation and its impact on the protection of MCSR have not been researched. This paper focuses on the analysis transient process of power regulation of MCSR. Firstly, the steady-state operation characteristics of MCSR are analyzed, where the magnetic saturation concept is introduced. On this basis, the transient process of power regulation and its feature are discussed. During the transient process, due to the difference of magnetic saturation between the limbs, the fundamental frequency component of the control winding current and total control current increase, which may cause a mal-operation of protection against turn-to-turn faults based on the fundamental frequency component of the total control current. According to the characteristics that the fundamental frequency components of the three-phase control windings are approximately equal during the power regulation process, the process can be identified and the possible mal-operations can also be avoided. Based on simulation based on Matlab/Simulink and experimental results, the correctness of the proposed scheme is verified.