A four terminal transmission line protection by wavelet approach in the presence of SVC using hybrid generation

Modern electric supply systems are invariably three phase. The design of transmission and distribution networks is such that normal operations reasonably close to the balanced three phase working conditions to give a complete analysis. A compound generation is a segment of power system in which number of sources commonly attached to a power electronic converter and loads are associated to operate independently. The protection of multi terminal transmission lines is a challenging task due to possible in feed or out feed currents contributed from the tapped lines. The protection scheme is crucial against faults based on traditional over current protection since there are adequate problems due to fault currents in the mode of operation. This paper proposes a novel approach for detection, discrimination of the faults and a control paradigm for four terminal transmission line protection, in presence of PV and wind sources. It deals about transient current based protection scheme for SVC compensated multi terminal transmission system with discrete wavelet transform. Fault indices of all phase currents at all terminals are obtained by analyzing the detail coefficients of current signals using bior 1.5 mother wavelet. This method is analyzed for different types of faults and is found effective for detection and discrimination of fault with various fault inception angle and fault impedance.