Effect of Fault Resistance on the Operating Behavior of Distance Relay

This book presents an arc resistance calculation, measuring tower footing resistance, protection zone setting and application of distance protection relay Siemens 7SA522 with a quadrilateral characteristic approach for protection on a 110kV Duy Xuyen - Thang Binh transmission line in Viet Nam, which using measured data from one terminal line. Afterward, we propose to focus on the building process of MATLAB SIMULINK model for this relay that combines fault detection and classification block, apparent impedance calculation block for all types of faults, and a trip logic block of three protection zone coordination. Further, the proposed relay model is tested by using various fault scenarios (fault types, fault locations, and fault resistance) on the transmission line. It is important to assess what happened, the actual conditions, the causes of mal-operation. Finally, detailed explanation results by MATLAB CODE indicate that the proposed model behavior will help students, technicians, and operators to understand and properly interpret test results and troubleshoot distance function problems when results are not as expected in real-world conditions.