Double-Circuit Line Adaptive Protection Considering Different Operation and Switching Modes

This paper deals with problems connected to distance protection of double-circuit transmission lines. Because of the zero sequence mutual coupling of parallel circuits, the relay "sees" incorrect impedance. In this paper it was developed adaptive model which solves problems of single-line-to-ground fault on a single line. Different operation modes change short circuit currents (Ik1 - phase-to-earth short circuit current and Ik3 - three-phase short circuit current) on both ends. In fact parameters of the active network will be changed. The idea was to develop adaptive model with more than one different independent Kohonen networks. Each network is trained with short-circuit examples according to the switching mode and operation mode. Input parameters are voltage, current, switching mode and operation mode. By information of the switching mode and operation mode it will be activated belonging Kohonen network. The developed adaptive model was tested on double-circuit 400 kV transmission line.