Faulty feeder identification in high impedance grounded network using charge–voltage relationship

The zero sequence impedance of a healthy feeder seen from the feeding bus bar in a network that is isolated or grounded by arc suppression coils is approximately equivalent to a capacitance. The instantaneous value of the integral of current (i.e. the charge) is then close to a linear function of the zero sequence voltage. One proposal in the literature is to identify the faulty feeder during a single phase to ground fault by the shape of the charge–voltage curves. A simple numerical criterion for identifying the faulty feeder has been established in this paper and it has successfully been applied to measurements obtained by a field test. The test did not include the most difficult identification conditions and those conditions have been analyzed by a computational model. The identification must be based on transients only when the network is overcompensated but the duration of the transients is sufficient for a reliable identification.

► This paper applies to a single phase ground fault. ► The zero sequence impedance of a healthy feeder is equivalent to a capacitance. ► A faulty feeder can be identified by comparing the shape of charge-voltage curves. ► The method has successfully been applied to measurements obtained by a field test.