RADIAL FEEDER DISTRIBUTION SYSTEM PROTECTION & COORDINATION USING GUI ETAP

Abstract

Growing population, heavily variable load, energy efficiency, supply security, environmental concern, are the main reason of highly dense and complex power system for which highly reliable protective devices is needed called digital\electromagnetic relays and fuses. This thesis discusses about relay coordination of radial distribution system and conditions of miss-coordination using ETAP (Star Protection Coordination). Four radial feeder sections is sketch with suitable values which is coordinated in this thesis. Power system elements is protected with fuses and different types of relays; these are coordinated up to sequence of three which is indicated by number 1, 2, 3 and other relay sequence is also shown with ascending time values. Relay timing can be adjusted by varying current time curve characteristics of any relay type except over\under voltage relay and fuse. ETAP graphical user interface is designed in such a way that each feeder is protected and coordinated. Relay setting, time dial, CT’s Ratio, and curve characteristics can be adjusted that tends to different time delay. Using ETAP different types of fault could be analyzed like 3phase, line to ground, line t line, line to line to ground with ½ cycles KA or 30 cycle KA. In this thesis every bus, transmission line is introduced to fault and are analyzed. Propose model use a generator with 6 MW and 11KV and a utility grid.