The electricity measuring system and calibration technology in the new smart substations

The application of digital measuring devices in the new generation of smart substation has increased greatly year by year. Electronic transformers export the samples in format of IEC61850-9-1 signal frame. And smart electricity meters measure electricity via this signal frame. The principle and interface of electricity measuring have changed fundamentally. Therefore, traditional field calibration method can't be applied to the new digital measuring system any more. This paper compares the measuring system between traditional substation and digital substation, analyses the components of digital electricity measuring system in the new generation of smart substation, and describes the technical principle and characteristic of electronic transformer, merging unit and digital electricity meters. Finally, considering the problems existed in present digital electricity system of field calibration, some measures and suggestions are proposed in this paper.