Determining locations of a double ground fault in networks with isolated neutral
The determining locations of a double ground fault in networks with isolated neutral is much more complicated due to a topographic remoteness of faults places. The necessary level of perfection of methods for determining locations of such faults is ensured through the use of many algorithmic network models. In the proposed method the general algorithmic model of the network is used to calculate the voltage at the supposed place of a fault. At the same time algorithmic models of an undamaged network and models, of a pure fault regime allow distinguishing electrical quantities, associated only with the measurements at the device installation location, from electrical quantities, entirely determined by earth fault currents. Such property of models allows the algorithm to have accuracy in doubleground fault location theoretically independent of short circuit resistances. An important role in fault locations is played by the hypothesis of the resistivity of the ground fault circuit. Following this idea, the purposed method uses an objective function to fault location on the line, which is a measure of the transmitted reactive power in the transverse circuit between phase and ground. The stability and accuracy of the algorithm do not depend on the remoteness of fault places from each other one.