Development of Distance Relay Based on Wide-Area Protection for Transmission Systems of Provincial Electricity Authority

Recently, distance relays are used in conventional protection to protect the transmission system, which consists of primary and back up protections. However, the primary protection used in traditional protection cannot be designed to cover the entire length of the transmission line. Moreover, the rapid increase in distributed generations (DGs) connected to the transmission line may increase fault impedance seen through distance relay. It results in an under-reach and miscoordination problem due to incorrect impedance calculation. In this paper, the development of distance relay based on Wide-Area Protection (WAP) for transmission systems is presented. The proposed method enjoins to instantly collect information of the distance relay and the circuit breaker status in local substations and nearby substations. The simulation is developed by using the DigSILENT PowerFactory program. The results present that the proposed method can improve the stability and reliability of the protection system and overcome such a problem.