Research on the measurement error of capacitor voltage transformer under various insulation characteristics

Capacitor voltage transformer (CVT) is one of the most important measuring and protecting devices in power system, whose measurement error is relevant with insulation characteristics of voltage divider. In daily operation, dielectric aging, moisture, dielectric breakdown etc. will exert a mixing effect on its insulation characteristics, changing voltage divider's equivalent parameters, further resulting in the measurement error. This paper proposes a more accurate model to represent CVT, which takes insulation characteristics of voltage divider into consideration. After theoretical analysis and software simulation, the relationship between measurement error and insulation characteristics is obtained. It indicates that varying of insulation characteristics in CVT will cause a reasonable measurement error.