三相四线制配电网络的潮流模型与算法

Power Flow Model and Algorithm for Three-Phase Four-Wire Distribution Network

在三相四线制配电网络中,中性线、大地导线以及中性线的重复接地对潮流分布及潮流算法的收敛性都有较大影响,现有文献对此问题的研究很不充分。文中以配电网络的地理端点为基础,建立了三相四线制配电网络的相分量潮流模型。该模型由端点间的支路电压方程和端点的注入电流方程表示。其中变量包括三相导线、中性线和大地导线的电压和电流。文中采用前推回代法和牛顿法求解配电网潮流,并以IEEE123节点测试系统为例进行了仿真。仿真结果表明,配网中的重复接地对前推回代法的收敛性影响很大,在小接地电阻条件下甚至不收敛,而重复接地对牛顿法的影响较小。

In three-phase four-wire distribution network, the neutral wire, ground wire and repeatedly grounding of the neutral evidently impact the power flow distribution and the convergence of power flow algorithm, however, in existing references the research results in this field is seldom reported. In this paper, based on the geographic terminals of distribution network, a phase component power flow model of three-phase four-wire distribution network is built. This model is expressed by branch voltage equations between terminals and injection current equations of geographic nodes, and in these equations the variables are voltages and currents of three phase conductors, the neutral and the grounding wire. Power flow of distribution network is solved by backward/forward sweep algorithm and Newton-Raphson method based on the current injection. To validate the proposed method, the simulation of IEEE 123-bus test system is carried out, and simulation results show that the repeatedly grounding of the neutral observably affects the convergence of backward/forward sweep algorithm, even under small grounding resistance this algorithm does not converge, whereas the repeatedly grounding of the neutral less affects the convergence of Newton-Raphson method.