Performance evaluation of distance relay with CT saturation

The decision of digital distance relay is very important for making the protection scheme in the transmission system more reliable. As the current signal is taken from the output of the current transformer, the distortion introduced by the saturation in it affects the performance of the distance relay. In this context proper nonlinear modeling of current transformer is necessary and a suitable compensation eywords: iles–Atherton CT model lman neural network -transform mpedance trajectory should be carried out to nullify the distortion introduced by it. In this paper Elman neural network based compensation scheme is proposed and the trip decision due to distorted secondary and compensated secondary current is made to have a comparative assessment of the trip decision of the relay is also done. The impedance trajectory with and without the compensation with quadrilateral trip boundary is also shown in this paper using S-transform to have an understanding of the proposed approach. The series of simulation result reflects the improved performance of the distance relay.