Analysis of CVT Harmonic Transfer Characteristics and Coefficient Correction Strategy Considering the Circuit Distribution Parameters

Due to the influence of complex distribution parameters, there is a large error in harmonic measurement by capacitor voltage transformer (CVT). According to the typical circuit structure of CVT, this paper firstly establishes an equivalent harmonic transfer model with all distributed parameters considered. And a cascade analysis method based on Y-Δ equivalent transformation is proposed to simplify the equivalent circuit and the calculation of transfer function when considering complex distributed parameters. Then the influence of four key distributed parameters on the CVT harmonic transfer characteristics are analyzed in details, which can provide guidance for optimizing the design of CVT parameters and improving its manufacturing. On this basis, a modified method of harmonic transfer coefficient based on BP neural network algorithm is proposed to recognize and predict the harmonic transfer coefficients, resulting in the improvement of measurement accuracy. Finally, according to the engineering measured data, the validity of proposed method have been verified.