Charging current compensation for distance protection

When a distance relay is applied to a long transmission line, the capacitance of the transmission line causes oscillation of the distance measurement, although the exact nature of the phenomenon has never been clearly defined. Our research has shown that the degree of oscillation can be reduced significantly by introducing charging current to the circuit model to be solved by the distance relay. In this paper, the undesirable influence of charging current on distance protection is introduced, after which the effect of charging current compensation for a distance relay is proven by practical simulations. Furthermore, the advantage of this method of charging current compensation as opposed to other methods is also explained.