基于虚拟控制单元与启发式搜索的线路过载紧急控制策略

为了快速消除由潮流转移引起的线路过载,给出了基于虚拟控制单元与启发式搜索的紧急控制策略。首先,引入虚拟控制单元的概念:节点的出力调整量等于最大线路过载量时,能够完全消除线路过载的控制单元。然后,给出了最优可控单元的双层搜索策略:第一层,通过设置合理的阈值,筛选减载能力较强的控制节点对构成优先控制单元集;第二层,综合考虑控制单元的减载效果和消除过载能力,给出了基于虚拟控制单元的启发式搜索步骤,得到优先控制单元集中的最优可控单元。若所选的阈值范围内无法找到可控单元,则适当扩大第一层搜索范围,依次类推,直至得到满足要求的控制单元。考虑正常线路冗余量约束来计算调整量,避免了潮流校验。经过一次调整后,依据灵敏度关系修正线路潮流与节点的最大可调整出力,提高控制速度。IEEE 30节点系统的仿真验证了所提算法的有效性。

Emergency Control Strategy Against Line Overload Based on Virtual Control Units and Heuristic Search

In order to quickly eliminate overload caused by power flow transfer, an emergency control strategy based on virtual control units and heuristic search is proposed. Firstly, the concept of virtual control unit is introduced, i. e. the control unit that can completely eliminate the overload, whose bus power adjustment equal to maximum overload of lines. Then, the two-level search strategy is presented to find the optimal control unit. At the first level, by setting a rational threshold, the bus pairs with stronger load shedding capacity is selected to create the priority control unit set. At the second level, the heuristic searching procedure based on virtual control units is given to obtain the optimal controllable unit within the priority control unit set, where the load shedding effectiveness and load shedding capacity are integrated. If the control unit can not be found in the above threshold range, the first level search scope should be appropriately enlarged until satisfactory control units are found. Verification of power flow is avoided by taking into account the normal line redundancy constraining the adjustment calculated. The power flow of lines and bus power are amended after a tune-up according to sensitivity relations, while the control speed is improved. The simulation on an IEEE 30-bus system has verified the effectiveness of the proposed algorithm.