气体绝缘变电站内PT的特快速暂态仿真建模

为了计算气体绝缘变电站(简称GIS)内由开关操作等对二次设备产生的传导干扰，必须建立电压互感器(简称PT)、电流互感器(简称CT)的高频模型(≥10MHz)。为此，提出了建立PT高频电路模型的新方法。首先根据互感器输入、输出端口之间的实测频率响应，用矢量匹配法(Vectoi Fitting Method)采用有理函数拟合其频域传递函数；然后根据实际需要，对该传递函数进行降阶处理；最后，应用一种特定的RLC电路综合方法建立了该PT的电路模型。该方法具有简单、有效和通用的特点，对于任何形式、任何电压等级的互感器均可使用。

MODELING OF POTENTIAL TRANSFORMERS IN GAS INSULATED SUBSTATION FOR THE VERY FAST TRANSIENT SIMULATION

For an accurate simulation of the voltage stress in secondary circuits caused by Very Fast Transients Overvoltage (VFTO) in Gas Insulated Substation (GIS), a sophisticated modeling of the potential and current trans-formers (PT/CT) is of vital importance. In this paper, a new method for modeling high frequency PT is proposed and the high frequency (10MHz) circuit model for an inductive Potential Transformer in GIS is set up. Firstly, the transfer function model for the PT is set up by means of Vector Fitting using rational function consisting of real poles as well as complex conjugate poles and zeros to approximated the frequency response based on testing data. Secondly, the order of the transfer function is reduced according to the practical needs and only important poles are selected to construct the transfer function .At last, a special method of RLC synthesis for transfer function is used to set up the circuit model of PT. The proposed method for modeling of high frequency PT is simple, effective and general and can be used to the modeling of any kind of instrument transformer as well.