DIGITAL DISTANCE PROTECTION SCHEME FOR SERIES COMPENSATED TRANSMISSION LINES

Abstract

Accurate, fast and reliable protective scheme is an important operational requirement in modem day power transmission systems. In this thesis, a new digital distance protection scheme for series compensated transmission lines is developed. The proposed distance protection scheme is comprised of three distinct stages, namely, (a) Fault Classification, (b) Selection of Faulted Section (Whether the fault is in front or behind the series capacitor) & (c) Distance Calculation and First Zone Detection. Support Vector Machine (SVM) is used for development of algorithms for all three stages. Performance of the algorithms developed for aforesaid three stages is tested on a large test data set of more than 25,000 cases generated on a model of 400kV, 300 KM transmission line with series compensation placed in the middle of the transmission line having Metal Oxide Varistor (MOV) for the protection of compensating capacitor. The simulation is carried out using well known PSCAD/ EMTDC software package. Further, performance of the developed distance protection scheme has been compared with some of the earlier approaches reported in literature for the same purpose. The results indicate that the proposed SVM based distance protection scheme is fast, accurate and robust among all the approaches discussed in this thesis for a wide variation in system and fault conditions