考虑谐波功率修正的地铁交直流潮流计算方法

AC/DC Power Flow Calculation Method for Metro System Considering Harmonic Power

地铁牵引供电系统是一个不同于交直流电力系统的交直流混合系统,其潮流计算的难点在于交直流系统的解耦和迭代方法。将牵引变电所的交流侧母线节点视为交流系统的PQ节点,将直流侧节点视为直流系统的恒压节点,从而将交直流系统进行了解耦。直流系统中,将节点分为P节点和V节点,适应了直流牵引网结构特点,提高了收敛速度;交流系统中,利用交叉频率耦合导纳矩阵建立整流器组的谐波模型,建立整流器组谐波电压与谐波电流的关系矩阵。用交流谐波潮流的谐波功率对交流基波潮流的PQ节点进行修正,提高了交流潮流计算的精度。该混合潮流计算方法有机地将交流基波潮流、谐波潮流和直流潮流三者结合起来,收敛性能好,适应性强,实例分析结果验证了该算法的有效性。

Being different from the AC/DC power system,metro＇s traction power supply system（TPSS） is an AC/DC hybrid system,in which the difficulty of load flow calculation lies in the decoupling and iteration method of AC/DC system.In this paper,the bus nodes of traction substations（TSSs） in the AC side were regarded as PQ nodes of AC system,and the nodes in the DC side were regarded as constant voltage nodes of DC system,thus the AC/DC system was decoupled.In DC system,the nodes were divided into P nodes and V nodes in order to adapt to the characteristics of DC traction network and improve convergence speed.In AC system,crossed frequency admittance matrix was used for the harmonic modeling,and the forming of the harmonic voltage and current relation matrix for rectifiers units.Using harmonic power of AC harmonic power flow,the PQ nodes were corrected,which improved the accuracy of AC power flow.This hybrid power flow algorithm organically combined AC fundamental power flow,harmonic power flow and DC power flow and its convergence and adaptability are good.Test on an actual system verified the effectiveness of this algorithm.