Investigation of fault analysis and protection employing wavelet transform for parallel transmission lines incorporating UPFC

Abstract

The requirement and continuity of electric power supply to all the consumers are very much important for the growth of any country. Due to the growing demand, economic and environmental constraints equipments used in power system are utilized to their maximum limits. FACTS devices not only regulate the voltage profile but also increase the power transfer capability and defer the transmission network expansion. It is necessary to improve the power transfer capacity of the existing transmission system with improved durability, reliability and controllability. To achieve this, various Flexible AC Transmission System (FACTS) devices such as Static var Compensator (SVC), Static Synchronous Compensator (STATCOM), Static Synchronous Series Compensator (SSSC), Thyristor Controller Series Capacitor (TCSC), Unified Power Flow Controller (UPFC) and Interline Power Flow Controller (IPFC) have been installed in the transmission lines. When the series FACTS controllers are used in the existing transmission lines, despite many advantages, it creates problem to the distance protection relay by means of affecting its reach and directionality. The impedance of the transmission line would vary according to the degree of series compensation which would in turn make the conventional distance protection relay to mal-operate. Thus, the mal-operation of the distance protection relay would lead to instability of the grid network. newline