Rated Capacitance Determination of a New 1000 kV Equipotential Shielding Capacitor Voltage Transformer Under the Interference of Stray Capacitance

The determination and optimization of the rated capacitance of a capacitor voltage transformer (CVT) is very valuable for the optimal design of a CVT since it is a fundamental parameter for solving many problems such as minimizing the effect of stray capacitance (SC), ensuring a high accuracy of voltage measurement, and fast transient response. SC is known to seriously affect the capacitance of an ultra-high-voltage (UHV) CVT resulting in a larger additional measurement error and a higher false operation rate of relay protection; it is usually unknown or poorly quantified and cannot be measured directly. A new effective and reliable method for rated capacitance design of a new UHV equipotential shielding CVT under the interference of SCs is proposed and successfully demonstrated in this work. An equivalent mathematical model is established to derive the CVT rated capacitance and the SCs are extracted using a finite element method. The performance of this method is verified in the experiment to demonstrate the effectiveness of the method.