基于CVT宽频传递模型的杂散电容分步辨识方法

Stepwise Identification Method of Stray Capacitance Based on Wideband Transfer Model of CVT

杂散电容是导致电容式电压互感器(CVT)宽频传递特性呈现复杂变化的关键因素,其参数值无法通过直接测量得到,杂散电容的获取一直是个难点。为此,文中提出一种基于CVT宽频传递模型的杂散电容参数分步辨识方法。在分析CVT谐振机理的基础上,以CVT在各谐振点处电压变比误差最小为目标,利用多目标灰狼优化算法,分两步对多个杂散电容进行参数辨识。实际算例测试表明,所提方法仅需根据CVT谐振变比便可实现宽频传递模型中杂散电容参数辨识,且辨识误差小,能够为建立精确CVT宽频电路模型提供理论指导,进一步为暂态电压的测量奠定基础。

Stray capacitance is a key factor causing complex variations in the wideband transfer characteristics of ca-pacitor voltage transformer(CVT).The value of its parameter cannot be obtained by direct measurement and the ac-quisition of the stray capacitance is always a challenge.A stepwise identification method of stray capacitance based on wideband transfer model of CVT is proposed in the paper.The parameter identification of multiple stray capaci-tance is performed in two steps,leveraging the resonance mechanism of CVT and minimizing the voltage ratio error at each resonance point as the objective.A multi-objective gray wolf optimization algorithm has been employed for this purpose.A practical example test shows that the proposed method can achieve the identification of stray capacitance parameters in the wideband transfer model only in accordance with the CVT resonant ratios and has a small identifi-cation error,which providing theoretical guidance for the setting up accurately the wideband circuit model of CVT and further laying the foundation for the measurement of transient voltage.