Identification of single leakage currents in the phases of a distribution grid controlled by an automated metering system

The paper dwells upon a 0.4-kV four-wire three-phase distribution grid (DG), where energy consumption is monitored by an automated metering system. Phase wires are assumed to have equal unknown non-neutral resistance in each inter-customer section of the DG; the metering system measures the operating voltage, current, and phase angles between the customers as well as at the DG entry point. The paper dwells upon finding the values of, and locating the leakage currents resulting from unauthorized power outtake. It analyzes an earlier proposed method that relies on phase (linear) wire voltage increments to simulate disturbed and desired state of the DG; analysis reveals the disadvantages of this method. The paper further presents a novel solution based on calculating the grid parameters (resistances) and currents in real time. The paper also proposes an algorithm for calculating the grid parameters, which samples data from two different modes of DG operation. Mathematical expressions are shown herein that implement this method and have been tested by computational experiments. The results could be of use in the design of non-process electricity loss metering systems for distribution grids.