线路输电能力与静态电压崩溃的关系研究

Relation between power transfer limits of network branches and static voltage collapse of power system

为了更好地利用线路的输电能力监测系统的静态电压稳定性,本文研究了静态电压崩溃与线路最大有功传输极限间的关系。首先分析了当系统输电容量变化时线路传输的有功功率在其功率圆图上的变化轨迹;然后从线路有功传输极限的角度揭示了系统静态鞍结分岔发生的条件并解释了极限诱导分岔为何在重负荷条件下更容易发生。通过New-England 39节点系统和东北网639节点系统验证了本文提出的静态电压崩溃与线路有功传输极限之间关系的正确性,指出现有的基于线路有功传输极限的一些算法不适用于估算复杂系统的负荷边界,应构建一种能综合反映整个输电系统输电能力的指标来评估系统的电压稳定性。

The relation between static voltage collapse and line static transfer stability limit is researched to assess the static voltage stability using the line transfer capability.First,branch complex power trajectory is described when the load parameter is increased.Second,from the line static transfer stability limit,this paper discovers the condition of saddle-node bifurcation voltage collapse and explains the phenomenon that limit-induced bifurcation is likely to be typical for a sufficiently highly loaded system.The proposed relation is illustrated with the New-England 39-bus system and a real 639-bus system.The proposed theory shows that some methods based on the line static transfer stability limit do not adapt to assessing the load margin for complex system,and a new index based on the transfer ability of a transmission system should be proposed to assess the system voltage stability.