大型交直流互联电力系统双向迭代连续潮流算法

Continuation Power Flow Method Based on Bi-Directional Iteration in Bulk AC/DC Interconnected Power System

提出一种求解大规模AC/DC互联电网电压稳定极限的双向迭代连续潮流算法。该方法将换流变压器一次侧交流母线电流作为交、直流系统之间的协调变量,分别推导了含该协调变量的交流系统和直流系统牛顿法迭代的修正方程,通过对直流系统修正方程进行线性变换,得到一组换流器母线电压电流的约束方程,通过该约束方程实现大规模AC/DC互联电网预测–校正连续法的双向迭代新算法。该算法不改变AC/DC互联电网全网联立求解潮流牛顿法的迭代次数和计算精度,且具备了交替求解法灵活处理直流系统控制方式的优点。以南方电网2007年夏季大方式运行数据的分析结果说明了所提连续潮流算法的有效性。

A new continuation power flow method for static voltage stability analysis of large-scale AC/DC interconnected power system is proposed.The currents of convector transformer,called coordinate variables,are introduced into both of the power flow equations of AC subsystem and DC subsystem.With the coordinate variables,correction equations of both AC and DC systems in Newton-Raphson method are established.Then the restrict equations between the current coordinate variables and the voltages of the convertor transformer buses is derived,which is used to form a novel bi-directional iteration approach.This method preserves the precision and convergence of AC/DC Newton load flow method and easily to reflect the effects of the control mode changes of DC systems to the voltage stability limit of AC system.Finally,the studies on one representation of the South China AC/DC power grid system are reported which indicate the feasibility and effect of the method.