Changing the working winding configuration of a single-phase magnetically controlled shunt reactor (MCSR) from parallel-connection to series-connection can effectively improve the responding speed of an MCSR. Direct application of this method to a three-phase MCSR

however

would cause serious distortion of the flux in the main cores. By introducing the configuration and operating principle of a traditional three-phase MCSR

this paper analyses the features of the current for each winding and the main flux based on the MCSR structure of series-connected working winding. It is proved that the distortion of main flux is caused by lack of even harmonic excitation current. A new physical design for the control windings of a three-phase MCSR is proposed which creates paths for even harmonic excitation current while keeping dc bias for each control winding unchanged. The fast responding single-phase MCSR structure is successfully applied to three-phase MCSR

verifying theoretical analysis with simulation and test results. This work is supported by National High Technology Research and Development Program of China (863 Program) (No. 2012AA050208) and Fundamental Research Funds for the Central Universities (No. 2014MS06).