The Research On Error Of Secondary-side Electric Energy Metering System In Intelligent Substation

With the experimental units and extension of Intelligent Substation and the development of the technology of monitoring, protection and controlling in Power System, Merging Units and digital watt-hour meter have wide applications in secondary side of Substation, but the accuracy and Reliability of secondary-side electric energy metering will become more strict.There are huge difference between Intelligent Substation and Conventional Substation in structure and function. The system of secondary-side electric energy metering in Intelligent Substation which is made of Merging Units and digital watt-hour meters has substituted traditional AC Electrical Energy Meters, but there are some problems in the accuracy of electric energy metering in practice. Since lacking of equipment and technology of on-line detection, the factors are always difficult to be determined, which effect metering error of the secondary-side electric energy metering system.According to Intelligent Substation, this paper simulated the structure of the secondary-side electric energy metering system of Merging Units, analyzed the possible factors of metering error, finally determined the vital factors and influence degree of them, made the evaluation of measurement uncertainty, drawed a conclusion and proposed some corresponding suggestions on the premise that voltage Merging Units、Current Merging Units and digital watt-hour meter complied with the requirements of the standards.