电流互感器宽频等效电路模型的分频段建模

变电站内开关操作时,会在母线上产生包含着很多高频分量的瞬态过电压和过电流。为了预测这种瞬态过程中某一频段对二次回路的传导干扰电流,需要建立变电站内电流互感器各个频段的模型。先用矢量匹配法拟和测量电流互感器所得到的宽频电流传输特性数据,然后在得到传输函数的基础上介绍了一种输入端接电阻的二端口网络综合方法。为了验证该方法的正确性,对一台500kV的电流互感器用该方法进行了分频段建模,并用PsPice软件对电路模型进行了仿真计算,其结果表明电路模型传输特性和测量得到的电压的传输特性吻合。

Modeling in Different Frequencies for Wide Frequency Equivalent Circuit of Current Transformer

In substation,the switch operation will cause the fast transient overvoltage and high current including a great deal of high frequency components in the bus bar.In order to predict the current stress in secondary circuits caused by the transient process,the model of current transformer in different wide frequency characteristic is necessary to be set up.In this paper,based on matching vector quantity method,characteristic data of current transformer in wide frequency band is obtained firstly.Then with the transfer function,a synthesis method of two terminal network by means of connecting a resistance at the input terminal is introduced.To verify this method,a model of 500 kV CT in different frequencies has been built.A good simulation result using PsPice has been achieved,and the result shows that the method is accurate.