ON-SITE ACCURACY COMPARISON OF CAPACITOR AND INDUCTIVE VOLTAGE TRANSFORMERS

Abstract

In this paper an on-site accuracy comparison of capacitor and inductive voltage transformers is presented. A 400/110 kV transformer substation in Croatia has been chosen as an appropriate location for the comparison as both types of transformers (capacitor and inductive) operate there simultaneously. Each transformer type is a part of one of the two existing measuring chains for measurement of electrical energy. Their accuracy comparison is, therefore, carried out indirectly, by actually comparing the energies measured by the first and the second measuring chain and then estimating the measurement uncertainty of their difference. Without measurement uncertainty, a parameter that shows the quality of any measurement result, it is generally not possible to conclude about the accuracy of measurement or to compare measurement results mutually. In this measurement uncertainty estimation real on-site conditions in transformer substation, especially those which effect voltage transformer accuracy, have been taken into account (voltage, transformer load, frequency, temperature, etc.)