Adaptive centralized protection scheme for distribution systems with DG using risk analysis for protective devices placement

摘要

Conventional electric distribution systems are radial in nature, supplied at one end through a main source. These networks generally have a simple protection system usually implemented using fuses, re-closers, and over-current relays. Recently, great attention has been paid to applying Distributed Generation (DG) throughout electric distribution systems. Presence of such generation in a network leads to losing coordination of protection devices. Therefore, it is desired to develop an algorithm which is capable of protecting distribution systems that include DG, through diagnosis and isolation of faults. A new approach for the protection of distribution networks in the presence of DCs is presented in this paper. The algorithm is based on dividing an existing distribution network into several zones, each capable of operating in island operation. In the suggested method, risk analysis is used to optimize the protection zones by optimal placement of protective devices. Multilayer Perceptrons (MLPs) neural networks are used for determination of faults. The proposed scheme has been implemented on a selected part of a real distribution network of a large city and a MATLAB based developed software has been used to implement the proposed algorithm on the real network data.