A Novel Method for Earth Fault Distance Calculation in Compensated Grids Using Symmetrical Components
Michael Steglich, Svenja Joseph, Christian Rehtanz
Abstract
This paper presents a new approach to calculate the fault distance during a single phase to ground fault in compensated grids. An exact localization of the earth fault is highly important to avoid further destruction, unnecessary disconnections and to support a fast repair. The presented method only needs one point of measurement, can be used under stationary fault conditions and the measurement equipment can be installed at any position in the grid. In contrast to the classical distance calculation, the new method does not need to increase the fault current by connecting a low impedance in parallel to the Petersen coil, but it can also handle this classic method. Two compensated medium voltage grids have been simulated in Matlab-Simulink. An inverter and a battery system are part of the simulations as well and are used to support the fault distance calculation. The results show an accuracy in fault distance calculation under different grid conditions of 90 to 99.9%.