Design and simulation of quadrilateral relays in ac transmission lines with vsc-based hvdc systems under phase-to-ground fault condition

Abstract

Voltage source converters (VSC)-based high voltage direct current (HVDC) transmission system can be used to integrate the offshore wind power generation with an AC grid. Due to the interconnection of VSC-HVDC system with the AC grid, an operation of distance relays might get affected. Also, fault resistance plays a significant role in the performance of ground relays. The ground faults have higher fault resistance causes the accuracy of the ground relay gets affected significantly. In this paper, the three-zone quadrilateral characteristic-based distance relay is designed to protect the AC transmission lines under phase-to-ground fault with fault resistance. Simulation studies are carried out to test the performance of the quadrilateral relay under phase-to-ground fault including various fault resistance cases in an AC transmission line with the effect of VSC-HVDC system. The impact of the dynamic conditions of the VSC-HVDC system on the performance of the quadrilateral relays under phase-to-ground fault with fault resistance cases is presented. Also, the performance comparison of the quadrilateral relay with the mho relay under such conditions is presented. © 2019, Politechnica University of Bucharest. All rights reserved.