New principles to detect faults during power swing

This paper presents new principles to detect power line faults during power swings. Faults during power swings can be classified as nonearth faults and earth faults. Since the difference in fault resistance between two types of faults could be very large, different principles are applied to detect different types of faults during power swings. This paper presents a new principle to detect nonearth faults during power swings by describing the waveform of swing center´s voltage (WSCV). It also presents a new principle to detect earth faults during power swings by introducing a new concept, the synthetic negative sequence vector (SNSV), which is derived by combining the three phase negative sequence components. Studies show that WSCV and SNSV can be used as ideal fault exponents to detect faults during power swings, even for condition where three phases faults occur at swing centers and earth fault resistance reaching 300 ohm at the remote end of transmission line during power swings. The technique is also able to provide fast and reliable fault detection. Results from simulation studies using EMTP are presented in the paper