Optimization of stray capacitance based on CVT harmonic voltage measurement

Abstract

With the wide application of nonlinear power electronic devices in power systems, the problem of harmonic pollution is becoming more and more serious, which significantly affects the measurement accuracy of voltage transformers (especially capacitive voltage transformers, CVT). The existing research focuses on the performance optimization of CVT under power frequency conditions, and the research on measurement error under harmonic conditions is insufficient. In particular, the influence of stray capacitance on harmonic transmission characteristics has not been fully paid attention to. Therefore, this paper aims to solve the problem of CVT measurement error in harmonic environment. By proposing an optimization method based on equivalent circuit model, the key stray capacitance parameters are accurately identified and corrected, to improve its measurement accuracy. Firstly, the equivalent circuit model of CVT is established, and the resonance phenomenon data is captured by Simulink simulation technology. The objective function based on the relative error of voltage transfer coefficient is defined, and the Pareto solution set is calculated by optimization algorithm to identify the optimal stray capacitance parameters. After applying this parameter to the circuit model, the voltage transfer coefficient of CVT is corrected, which significantly reduces the measurement error in harmonic environment. This study not only provides a theoretical basis for the high-precision measurement of CVT in power system, but also provides a reference for practical technical application.