电力网络频率等值新方法

A New Frequency-Dependent Network Equivalent Method for Power System

提出了一种基于高斯消去法的电力网络新的宽频等值方法。该方法基于高斯消去法获得外部系统网络在频域上导纳传递函数,即外部网络的传递函数,将传递函数进行分式展开并基于简单的RLC支路与分式的对应关系获得等值网络;针对等值网络规模过大而使等值网络过于复杂、计算量过大的问题,进一步提出了等值网络化简方法及大网络分步求解的方法,而实现大系统的等值计算。因外部网络的传递函数包含了外部系统网络在较宽频域内的全部电气信息,故所提出的宽频等值方法获得的外部系统网络的等值电路,可以反映外部系统网络的在较宽频域的电气特性,等值精度较高。算例证明了方法的有效性。

A new frequency-dependent network equivalent method based on Gaussian elimination is presented in the paper.In the method,the external system’s frequency admittance matrix,that is actually the transfer function of external system,is directly calculated by Gaussian elimination method,and the equivalent network is obtained by corresponding relationship between simple RLC branch and fraction gained through the operation of the transfer function.In view of the high complication and huge computation of the equivalent network caused by large-scale power system,a simplification strategy and a step-by-step solution method are further proposed in the paper respectively for the equivalent network and for the large-scale network,which successfully realize the equivalence of a large system.Since the transfer function of external network includes all the electrical information of the external system in a wider frequency range,the equivalent electric circuit of the external system network obtained by the proposed frequency-dependent network equivalent method can reflect the electrical characteristics in a relatively large frequency range with high equivalent precision.Case study has validated the effectiveness of the method.