Remote earth fault location at 6–10 kV cable line using its models

Abstract

As a rule, electrical values of the transient process that occurs during insulation breakdown are considered to determine the fault location in case of short-term self-eliminating and arc intermittent single-phase earth faults in distribution cable networks of 6–10 kV. The known methods for remote earth fault location based on monitoring the parameters of transient currents and voltages, do not always provide sufficient accuracy to determine the fault location. It is due to the influence of various random factors (the value of the total capacitive current that depends on the network operation mode, the moment the fault occurs, etc.). Thus, the task to improve the accuracy of the remote fault location algorithm under the influence of these factors, as well as the speed to determine the fault location is relevant. Considering the complexity of transient processes in case of single-phase earth faults in 6–10 kV cable networks, simulation in Matlab software package is carried out to study the effectiveness of the algorithm of the operation of a device for remote earth fault location based on the above method. A method to determine remotely the location of an earth fault is proposed. It makes possible to ensure sufficient accuracy and speed based on the analysis of the factors that affect the measurement accuracy and in-depth studies on simulation models of 6–10 kV cable networks in Matlab. It is shown that the total effect of various factors that distort the measurement in case of remote fault location using a controlled line model can cause errors in measuring the distance up to the point of the fault equals to 10–15 % with close earth faults (about hundreds of meters away the busbars of the power source) and no more than 5–10 % at the distances a few kilometers away. The method to determine remotely the fault location using the models of a controlled transmission line provides an increase in the accuracy and speed of measuring the distance to the earth fault location in 6–10 kV cable networks. It is more promising to apply when one develops devices for remote earth fault location.