송전선로에 있어서 Mutual Coupling을 고려한 디지털 거리계전기의 신뢰도 향상

An Improvement of Digital Distance Relay Reliability considering Mutual Coupling in Transmission Lines

In this paper, the digital distance relay of transmission lines under fault conditions is discussed. Distance relay is used to protect transmission lines. The principle of distance relay is well-known ; the impedance measured by a relay is Proportional to the distance from the relay to the fault. Hence, by measuring the impedance, it can be determined whether the line is faulted or not. Unfortunately, the measurement of the fault distance is distorted by Mutual Coupling. To implement more reliable and practical digital distance relay, the mutual coupling effect has to be considered.