链式电网动态稳定下多断面耦合特性研究

Research on multi-sections coupling characteristics of chain network dynamic stability

子系统网架结构及内部潮流对互联系统动态稳定性能有一定影响。针对多断面间呈链式结构的电网,为研究不同断面对系统稳定的影响差异性及断面间耦合特性,提出了动态稳定下链式电网断面相对敏感度与耦合度的计算方法。根据断面潮流与两侧角度差的关系,分析了断面潮流调整下互联系统送受端相对角度与扰动下振荡阻尼比的变化规律。对断面间耦合机理的研究表明,断面敏感度与其等值联系电抗、两侧角度差及送端机群惯量等因素有关。三机系统及实际链式电网算例的分析结果验证了方法的有效性与可行性,能够为实际电网动态稳定运行中断面潮流间的协调控制提供可靠依据。

The network structure and power flow of subsystem have some influence on the dynamic stability of interconnected power system. For power grid with multiple sections chain structure, a calculation method of relative sensitivity and mutual coupling degree between transmission sections in chain grid is proposed, in order to research the difference of effects of sections on power system stability and the coupled mechanism. The change law of system damping ratio after disturbance and relative angles between the delivery end and the receiving end of interconnected system, is analyzed, according to the relationship between interface power flow and angle difference at two terminals. It shows that there are several factors associating with the section sensitivity, such as equivalent reactance, the angle difference and inertia time constants of sending-end units. Based on the coupling relationship between transmission interfaces, it would be easy to coordinate interface power flow control in actual network, and it is proved effective and feasible by the results of three-machine system model and Mengxi chain network.