Fault detection and identification in MVDC Radial and Ring Distribution System by Wavelet decomposition

The use of renewable energy systems (RES), as distributed generation (DG) units, in distribution systems is growing in recent years. DC distribution system is more feasible for the integration of renewable energy-based DGs as compared to the AC Distribution system. In DC distribution protection is the main issue because of low line impedance that causes high fault current. In this paper wavelet decomposition based protection scheme is proposed which identify the fault section in the distribution system and also identify which type of fault is occurred. Voltage and current signals, both are analyzed through wavelet. Sequence voltages are used for the input signal to wavelet decomposition for fault type identification. A communication channel is used between lines relays for the identification of faulty sections in distribution. A bipolar ring and radial type DC distribution systems are modeled on MATLAB/Simulink and different fault events are simulated.