An improved scheme based on fuzzy logic for EHV transmission line protection

This paper presents an improved scheme for real time fault location and classification in a power transmission system using a fuzzy technique. A protection algorithm is based on the monitoring of the high frequency components on overhead lines caused by a sudden change in the system. This results in a travelling wave combination of aerial and ground modes, initiated from the fault point. A possible application to detect the type of fault based on modal analysis is proposed. This paper shows that a fuzzy approach can be useful in transmission line protection, whenever fuzzy decisions have to be undertaken. Simulation results are used to illustrate the basic features of the performance of the new scheme on a simple 220 kV-transmission line.