ACCURATE FAULT LOCATION METHOD IN DISTRIBUTION NETWORKS CONTAINING DISTRIBUTED GENERATIONS

This paper presents a new fault location method for radial distribution networks with distributed generations. The proposed fault location algorithm uses the voltage and current data obtained by digital fault recorder installed at the head of the network main feeder, with or without the data from any digital fault recorders installed at DG connection points. The algorithm is based on fundamental frequency calculations and includes novel subroutines of current calculation of DG contained laterals and average loading factor and power factor estimation of the network transformers to solve the fault location problem. The method has been tested by simulation studies using EMTP on a 205- node 20kV radial distribution network containing three DG's for different data acquisition scenarios. The results verify accuracy of the method under different fault conditions even with only one measuring point at the head of the main feeder. OWER distribution systems are subjected to fault conditions caused by various sources such as adverse weather conditions, equipment failure and external object contacts. It is important for the electricity companies to locate the fault quickly to improve reliability and quality of the supply to customers. The primitive method of fault location using visual inspection is time consuming and costly as requires extra maintenance staff to patrol outage areas. With the advent of digital relaying, several fault location methods for distribution systems have been proposed in the past couple of decades. Although some of these methods have acceptable accuracy for the application in conventional distribution systems, very few have addressed the fault location problem in the presence of distribution generation (DG). Due to increasing demands for electric power and contradictory environmental concerns, distributed generation is an effective solution which can introduce small power generations from green energy resources into distribution networks. The technical advantages of the DG application can be summarized as backup generation, loss reduction, power quality improvement, grid expansion postponement, peak load service, rural and remote application, combined heat and power (CHP) generation. On the other hand, the increasing use of DG's in the networks makes the system operation more complicated. In this context, one of the most affected areas is the