基于黑盒子方法的GIS内电压互感器高频电路模型的建立

为了研究气体绝缘变电站内的开关操作产生的陡波前过电压(VFTO)通过互感器对二次设备的影响,需要建立它们的高频电路模型。笔者提出了一种基于黑盒子方法的电压互感器(PT)高频电路模型的建立方法。该方法在应用矢量匹配法逼近PT导纳参数矩阵Y(s)的基础上建立了其π型等效电路,然后运用福斯特型RLC电路综合方法实现了该电路模型。为了保证电路模型仿真时的稳定性,对Y(s)的实部进行了无源性修正。由于该方法保证了所建模型的宏观无源性,所以建立的电路模型可以进行稳定、准确的数值仿真。对一个实际PT的测量和仿真计算验证了该方法的有效性。

A High Frequency Circuit Model for Potential Transformer in Gas Insulated Substation Based on the Black Box Method

In order to study the interference caused by very fast transient overvoltage on the secondary circuit via potential/current transformers(PT/CT) in GIS,a method for building a high frequency terminal model of PT based on the black box technique was presented.An equivalent π circuit model of PT was set up based on the rational function approximation of admittance matrix Y(s) by means of vector fitting method,and a higher order RLC equivalent lumped circuit was constructed based on the Foster synthesis method.To guarantee the simulation stability of the circuit model,a correction of the real part of Y(s) was made,which enforces the positive-definite criterion(passivity) to be satisfied.The simulation and the measurement results of a real PT confirm the validity of the proposed method.