Effect of series FACTS devices on distance protection

The increase in the line complexity, configuration and the power transmitted has introduced a number of problems in relation to protection. New techniques have become necessary to tackle these problems. Firstly it has become necessary to see that lines are not unnecessarily disconnected, but at the same time shorter operating times from protective relays are demanded on faulted sections to preserve the system stability. In this paper, discussion is made on the basic needs of protective systems, the various schemes of protection and the importance of distance protection in power system. Next it deals with various distance relay characteristics such as Mho, Ohm, Quadra mho, Quadrilateral, Elliptical, lentical and Ova. The constructional features of each type of distance re lay, the behavior and performance of various distance relays had been analysed. The variation in the operation of Distance Relay for multi-terminal configuration, effect of arc resistance, tower footing resistance, resistive reach is obtained. Finally the effect of Series Flexible Alternating Current Transmission System(FACTS) devices on the performance and operational characteristics of the Distance Relays will be observed. The entire simulations are done by using Mipower software to incorporate all the above features and graphical display in transient stability analysis. These studies give us the latest trends in the transmission line protection.