特快速暂态过电压下变压器绕组高频电路模型的研究

Research on High-frequency Circuit Model of Transformer Windings in VFTO

变压器绕组的高频模型对于分析特快速暂态过电压对变压器的影响是非常重要的。从易于高频测量的散射参数出发,提出了一种建立变压器绕组高频电路模型的方法。该方法首先由散射参数计算绕组各匝的电压传输函数,并利用矢量匹配法对得到的电压传输函数进行有理函数逼近;其次,对得到的有理函数形式的传输函数进行阶数缩减,得到变压器绕组电压传输函数的降阶模型;最后,运用网络综合技术建立变压器绕组的高频电路模型。该电路模型简单、通用,仅由R、L、C和理想变压器构成,其模型参数可以根据电压传输函数的极点和留数非常方便地得出。通过对电路模型的仿真结果与实际测量结果进行比较,验证了文中方法的正确性。

The high frequency circuit model of transformer windings is indispensable in analyzing the transients particularly caused by the very fast transients which occur at the time of disconnecting switch operations in GIS. This paper describes a systematic methodology for establishing the high frequency circuit model of transformer windings based on scattering parameters, the circuit model is composed of R,L, C elements and ideal transformers, and the parameters of the elements can be easily calculated by the poles and residues of the voltage transfer function. The circuit model is simple and robust. The simulation results and measured results are presented, confirming the validity of the proposed model.