Detection of fault during power swing using superimposed negative sequence apparent power based scheme

Variation of fundamental frequency components of current and voltage during power swing causes the error in phasor estimation. Due to this, many protection relaying schemes as distance, directional etc are badly affected and mal-functioned and this may lead to severe blackout. For series compensated line, the non linear behavior of metal oxide varistor (MOV), current and voltage reversal conditions, and sub-synchronous oscillations are also responsible for erroneous measurements of relay voltage and current during power swing. To overcome all these challenges, a fault detection scheme based on superimposed negative sequence apparent power is proposed which works during power swing for series compensated line. This scheme takes 3 ms-5ms for fault detection. Local end voltage and current data are utilized to execute the proposed algorithm. The 400kV, 50Hz WSCC 9 bus system is simulated using the PSCAD/EMTDC software.