Differential Technique for Fault Detection and Classification in Distribution System consisting Distributed Generation

The increased penetration of distributed generation resources (DGRs) in the distribution network, to fulfil the increased load demand, has changed the radial power flow nature of existing network in fault conditions. This results in mal-operation of the conventional protection devices. Thus, the existing methods fail to provide reliable protection for modified distribution system consisting DGRs. Moreover, detection of high impedance faults (HIFs) is also very important in such networks. Since, HIFs have very less fault current magnitude with nonlinear nature, it is difficult to detect them using conventional methods. Thus, a novel technique has been proposed in this paper for the fault detection and classification of distribution network under faults (i.e., lower impedance faults (LIFs) or high impedance faults (HIFs)). The fault detection and classification index is calculated in the proposed technique, using the energy obtained from the differential superimposed component of the positive sequence impedance. The proposed method effectively discriminates the internal and external faults, low impedance faults (LIFs), HIFs, switching transients and it distinguishes them as well. The IEEE-13 bus distribution system integrated with DGRs is used for simulation using Real Time Digital Simulator (RTDS).