Results of earth fault measurements in an earth fault compensated 110 kV system

The earth fault compensation has well known favourable effects on the operation of distribution networks. The biggest benefit is the fact that an arc-over vanishes automatically in general, i.e. without intervention of the operation personnel, and thus remains without affecting the customers. The exact knowledge of the damping factor, the detuning and the unbalance as well as the harmonics in the residual current are substantial prerequisites for safe ground fault extinction and thus for a reliable line operation. These quantities are the basis for the planning of further network expansion. To get reliable information, earth fault measurements in the described 110 kV system were carried out. In this paper the evaluations of the above-mentioned parameters via operational indicators are compared with the results of direct earth fault measurements.