Study on Change Rule of Metering Performance of Three-wire and Four-wire PowerMetering Device Under Different Single-Phase Ground Fault

Under the background of power interconnection, the accurate measurement of power metering device plays an important role in the lean management of distribution network line loss and the economic benefits of both power suppliers and power consumers. In this paper, the accuracy of electric energy measurement under single-phase ground fault was studied. Meanwhile, a 10 kV distribution network single-phase ground fault test platform was built to analyze the measurement performance changes of three-wire and four-wire power metering device under different single-phase ground fault types. The research results reveal that the single-phase ground fault does not affect the error of voltage transformer. On the power supply side, the power metering device PT adopts the V/v wiring mode, which would cause the energy metering inaccuracy under a single-phase ground fault. In addition, for the unground neutral system, the three-phase and three-wire connection can keep accurate measurement performance. However, for the ground system with neutral point passing through arc suppression coil, there may be measurement error in three-phase and three-wire power metering device.