FAULT LOCATION ON A HIGH VOLTAGE SERIES COMPENSATED TRANSMISSION NETWORK

Abstract

The demand for electrical energy is increasing exponentially and along with this, the size and complexity of the power system is increasing. This requires more compact and flexible equipment to increase the stability In order to minimize the overall cost and to enhance the power transfer limit, series compensation has been a fast growing area since earlier eighties. The obvious fact is that series device helps in achieving steady state limit by damping power oscillations. In addition, the series compensation device compensates for VAR losses by reducing the effective reactance resulting into better efficiency. The series compensation is configured as a fixed capacitor located in series with the line. The capacitor is protected by a connecting a MOV across it. MOV bypasses the capacitor during high voltage conditions protecting the capacitor. The MOV conducts immediately after the voltage drop across capacitor exceeds a certain voltage level (Vref). Due to being non linear in nature, MOV bring instabilities in the system. Also addition of such devices results in inaccuracy in determining the fault location. In this work, the fault and analysis on a high voltage series compensated line is carried out and the data obtained during fault analysis is utilized in determining the fault location The simulation for system under study is carried out on MATLAB/SIMULINK. A two end transmission system with a series compensation unit at the centre is taken and fault analysis on this system is carried out and MOV behavior is studied. Results are evaluated for different types of faults. To overcome the problems associated with series compensated lines, an algorithm is applied on the line to achieve accuracy in fault location. The data obtained during fault analysis is utilized in determining the fault location.