Evaluating the metering error of electronic transformers on-line based on VN-MWPCA

Electronic transformers are used to measure the voltage and current signals, which are used to sense the state of the transmission networks. The deterioration of their metering error will affect the stable operation of the power system. The traditional method of evaluating the metering error of electronic transformers is to compare them with the standard transformer. There are outstanding problems such as over inspection and under inspection of the traditional method, which cannot be used for evaluating the metering error for a large number of electronic transformers on-line in a long-term. In this article, the correlation between primary transmission networks is analyzed to establish a new evaluation standard without a standard transformer. The standard can be calculated as a characteristic statistics, by using the measured data based on the VN-MWPCA proposed. Then the metering error of electronic transformers is evaluated by analyzing the abnormal change of the statistics. The field application analysis shows that the method proposed can be used to evaluate the metering abnormal of a Class 0.2 electronic transformer on-line accurately.