Analysis and mitigation of stray capacitance effects in resistive high-voltage dividers

Abstract

This work analyzes the effects of the parasitic or stray distributed capacitance to ground in high-voltage environments and assesses the effectiveness of different corrective actions to minimize such effects. To this end, the stray capacitance of a 130 kV RMS high-voltage resistive divider is studied because it can severely influence the behavior of such devices when operating under alternating current or transient conditions. The stray capacitance is calculated by means of three-dimensional finite element analysis (FEA) simulations. Different laboratory experiments under direct current (DC) and alternating current (AC) supply are conducted to corroborate the theoretical findings, and different possibilities to mitigate stray capacitance effects are analyzed and discussed. The effects of the capacitance are important in applications, such as large electrical machines including transformers, motors, and generators or in high-voltage applications involving voltage dividers, conductors or insulator strings, among others. The paper also proves the usefulness of FEA simulations in predicting the stray capacitance, since they can deal with a wide range of configurations and allow determining the effectiveness of different corrective configurations.