Unfairly Faulty Energy Meter Reading due to Inappropriate Use of the Blondel Theorem

Energy measurements are done according to the Blondel theorem, which states that in a system containing N conductors, N-1 current sensing elements are needed to measure the energy. In energy metering for billing purposes at residences only the line current is measured. However, in this paper it is shown experimentally that discrepancies can occur, because current can flow through the protective earth. This occurred in a real one-phase low-voltage distribution system where a residual current device was not functioning properly and a leakage current could flow. This resulted in an unbalance between the line and neutral conductor and thus an inappropriate use of the Blondel theorem.