防止输电断面连锁过载的快速控制算法

切除过载支路可能会引发相关输电断面内连锁过载,应在过载保护延时动作时限内,采取快速控制措施消除过载。文中保护对象为断面整体,保证降低断面整体潮流的同时断面内无支路过载。现有改进算法的综合灵敏度计算或忽略正常支路,或仅为过载线路及接近极限线路灵敏度的代数和,不能更为合理地体现节点消除断面整体过载的能力;且其节点优先级划分及调整节点对选择、调整量约束条件仍不完善。文中继承了现有综合灵敏度算法的总体思想并加以改进,认为综合灵敏度应为断面内过载支路与正常支路灵敏度的加权和,以此对控制节点进行分类和排序;划分节点优先级时综合考虑节点对支路的灵敏度及断面的综合灵敏度;根据反向等量配对法选择调整节点对时增加"保证断面整体安全"原则,且增加平衡机出力的处理避免越限;完善调整量约束条件,加入潮流反向约束避免调整量过大时潮流反向增长。对某省电网系统的仿真计算表明了算法的快速有效性。

Fast Control Algorithm for Preventing Cascading Overload on Transmission Section

If the trip of overload branch should cause cascading overload inside the corresponding transmission section, rapid overload control should be executed within the time delay of overload protection. The protected object is the whole transmission section, and it is ensured that no branch in the section will be overloaded while power flow of the whole section is decreased. The calculation of integrative sensitivity either neglects normal branches, or is just the algebraic sum of sensitivity of the overload branch and branches near the limit, which cannot reflect the node''s capability to alleviate overload on the whole section more reasonably. In addition, prioritization of control nodes, selection of node pairs and constraint conditions of the adjustment amount are still imperfect. Thus, in inheriting the general idea of integrative sensitivity algorithm and making up for the defects, this paper holds that integrative sensitivity is the weighted sum of sensitivity of overload branches and normal branches. Then the classification and operation sequence of control nodes should be determined. And the sensitivity of node to branch and integrative sensitivity are all used to prioritize control nodes. In addition, the principle of ensuring safety of the whole section is added to the selection of node pairs and the power limit of the slack generator is considered. Reverse constraints are added to keep power flow from increasing reversely with too much adjustment. The rapidity and validity of the proposed algorithm is verified by calculation results of a certain actual system.