基于PSASP短路计算的区域电网等值方法

使用PSCAD/EMTDC软件对大型区域电网的局部线路和附近区域进行电磁暂态分析,需要将区域电网分为内部网络和外部网络2部分,对外部网络进行等值简化。传统的网络等值方法需要建立被等值系统的节点导纳矩阵,通过高斯消元法化简网络,计算工作量巨大。为此提出了基于PSASP短路计算的区域电网等值方法。通过全部边界节点的同时短路获得注入电流源参数。然后采用边界节点逐一短路,获得与边界节点数目相同的节点电压方程组,联立求解出节点导纳矩阵。新方法直接求解边界节点对应参数,计算量小。含特高压线路的大型区域电网仿真分析表明,PSASP原网络和PSCAD/EMTDC等值网络的短路电流基本一致,验证了等值方法正确性。最后分析比较了新方法与传统的静态等值方法,探讨了新方法的适用范围。

An Equivalence Method of Regional Power Network Based on Short Circuit Calculation by Power System Analysis Software Package

To perform electromagnetic transient analysis on a part of a large-scale regional power network by PSCAD/EMTDC,the regional power network has to be divided into two parts,namely the internal network and the external network,and then the equivalent simplification of the external power network is carried out.It is necessary for traditional equivalent methods to establish nodal admittance matrix of the external power network and simplify the network by Gaussian elimination,and it leads to heavy calculation burden.For this reason an equivalent method for regional power network based on short-circuit calculation by Power System Analysis Software Package(PSASP) is proposed,that is,by means of simultaneous short-circuit of all boundary nodes the parameters of injection current sources can be obtained;then by means of short-circuiting boundary nodes one by one,the nodal voltage equations,whose number is the same as the number of boundary nodes,are attained,thus the nodal admittance matrix can be simultaneously solved.Adopting the proposed method,corresponding parameters of boundary nodes can be directly solved and the calculation burden is light.Results of simulation of large-scale regional power network containing UHV transmission line show that the short-circuit current of the original regional power network calculated by PSASP basically conforms to that calculated by equivalent network based on PSCAD/EMTDC,thus the correctness of the proposed method is verified.Finally,the proposed method is compared with traditional static equivalent methods,and the application scope of the proposed method is discussed.