A study on distance relay overload zone setting for transmission line protection using dynamic line rating

A distance relay overload zone setting for transmission line protection using dynamic line rating considering the ambient temperature around the transmission line is proposed in this paper. If the ambient temperature around the transmission line is high, the proposed overload zone becomes narrower as the line allowable current becomes smaller. If the ambient temperature is low, the overload zone expands as the line allowable current increases. In the same power system situation, the overload zone that depends on the ambient temperature around the transmission line is operated by the apparent impedance calculated at the relay point together with the fault determination zone of the existing distance relay to provide the system operator with the line overload information. To verify the proposed method, air temperature data from regional detailed observation data provided by Korea Meteorological Administration AWS(Automatic Weather System) and real system PSS/E data were used. Copyright © The Korean Institute of Electrical Engineers.