AC-DC power flow calculation is the basis for studying HVDC system. Since the traditional iterative methods need alternative iteration for many times and have convergence problem, this paper analyses the causes of many iterations firstly, and then proposes a new AC-DC power flow calculation method that is suitable for AC-DC power grid with voltage source converter (VSC). The algorithm re-divides AC-DC power system, incorporates interface equation into AC power system, and augments AC Jacobi matrix with variable of DC system. This algorithm can realize AC-DC decoupled power flow calculation, and has the convergence property of unified method while inheriting convenient control mode strategy of traditional alternating iterative method. The examples of modified IEEE 30-node system and IEEE 57-node system show the correctness and effectiveness of the method.%交直流潮流计算是研究交直流系统的基础,传统交替迭代法需要交、直流依次迭代多次并且有不易收敛的问题.首先分析传统交替迭代法需要多次迭代的原因,在此基础上提出一种适用于含电压源换流器(VSC)的交直流电网的改进潮流新算法.该算法通过重新划分交直流系统和归并换流器接口方程至交流系统,建立含部分直流侧变量的增广交流雅可比矩阵模型,进而实现直流系统潮流与交流系统潮流的独立解耦计算.该算法继承了传统交替迭代法控制方式切换方便的优点,又同时具有统一迭代法的收敛性.经修改的IEEE 30节点与IEEE 57节点算例仿真,证明了该方法的正确性与有效性.
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