Analysis Methods and Application of Complex Metering Faults in Three-Phase Four-Wire Smart Energy Meters

Three-Phase four-wire smart energy meters are widely applied in neutral directly grounded systems, neutral resistance-grounded systems, and neutral high-impedance grounded systems. During field operation, metering anomalies such as voltage phase sequence reversal and polarity reversal may occur, leading to measurement deviations that jeopardize the safety, accuracy, and reliability of energy metering. This study investigates a complex fault scenario involving simultaneous voltage phase sequence reversal and polarity reversal in a three-phase four-wire smart energy meter. A systematic methodology is proposed to diagnose active power inversion and phase sequence misalignment. Furthermore, the energy correction value is quantified based on fault data analysis, and comprehensive mitigation strategies are presented to improve operational robustness and measurement integrity.