Study on Hot-line Calibration for 10kV Watt-hour Metering Device

Fewer power losses are required for transmission lines; thus, the need for improving the operating and maintenance level of power loss is becoming an urgent need. Although the design and layout standards for the high-voltage electric energy metering device in the distribution network have gradually become complete and competent, still some defects exist in the high-voltage metering device. First, owing to the higher requirements for the power-cut, the replacement speed of 10kV high-voltage power metering devices is much slower than that of low-voltage meters. Second, due to the failure of power-cut, the on-site calibration of high-voltage metering electric energy devices can only measure the low-voltage part, while the on-site calibration of high-voltage PT and CT cannot be implemented. In this case, there is no reliable measurement to obtain the overall site error of high-voltage electric energy metering device, and flashovers would be generated. In this paper, a novel device of on-site calibration for the 10kV watt-hour metering devices was proposed. The live operation of the proposed device and the analysis of the device compared with the existing meters in the 10kV distribution network is illustrated. Compared with existing devices, the novel device not only performs the on-line verification test for the existing metering devices but also achieves the accuracy of measurement of the active power to 0.1 level at the dynamic range of 5A- 500A.