Frequency-adaptive by-pass filter for saturable reactor compensators

An adaptive form of a bypass filter is proposed. The filter is based on online detection of the subharmonic modes which bypass filters are to counter and a thyristor switching array by which filter parameters are related to subharmonic mode frequencies. Extensive simulation studies have confirmed the significant increases in damping which frequency-adaptive bypass filtering can achieve in comparison with that of the fixed-parameter form of filter so far used, especially when mode frequencies approach the supply frequency