论文部分内容阅读
目前的交直流交替迭代潮流算法应用于超大规模交直流系统时经常面临收敛性差甚至不收敛的问题,无法有效获取可行解.文中提出基于交直流完全解耦从而获取潮流计算的可行解的方法,可提高超大规模交直流系统潮流计算收敛性,并避免交直流交换功率在交替迭代中发散的问题,文中方法的主要观点是交流换流母线电压在正常运行范围内并且直流运行于正常工况时,直流系统可与交流系统完全实现功率解耦,从而可将直流系统等效为恒定功率注入交流系统;待交流系统潮流计算迭代收敛后再求解直流系统换流变的有关变量.若换流变压器分接头越限,则表明交流换流母线电压不能维持在正常运行范围内,可为交流系统调整提供有效的信息,并能正确反映系统运行状态的突出问题.文中所提方法同样适用于未来含级联直流及多端直流的系统.通过我国多个大规模交直流系统算例,表明算法具有极佳的收敛性和鲁棒性.“,”The convergence of AC/DC alternative iteration power flow algorithm is not satisfying when applied to some large AC/DC systems. This paper proposed an AC/DC power decoupling technique to improve the convergence of ultra-large-scale AC/DC power system load flow calculations. While the converter AC bus voltage and DC systems usually operate in normal state, DC systems can be regarded as constant PQ injection into AC buses and the AC/DC systems can be absolutely decoupled. The iteration process can be only involved with the AC system, and DC variables can be solved after the AC power flow converged. This technique can completely avoid the numerical oscillation problems which usually appear in AC/DC alternating iterations. When solving the DC variables, the converter transformer ratio is flexible and out-of-range of ratio only occurs while the AC convertor bus voltages violate normal operation. The DC variables can correctly reflect the AC system operation status. The AC/DC power decoupling technique can also be adequate for multi-terminal and cascading DC systems. Many ultra-large -scale AC/DC power system cases of China verify the high convergence and robustness of the technique.