一种基于有序二元决策图的低频减载新方案

摘要

For controlling problem of frequency decreasing when high-capacity unit of power system tripping,it is required to design reliable low-frequency load shedding scheme.Aiming at existing shortages of traditional schemes,this paper de-signs a kind of low-frequency load shedding scheme considering of load model and active power reserve.This scheme is able to estimate system power vacancy by system frequency fluctuate rate after fault occurs and fully considers impacts of load model and system reserve so as to determine load shedding.Meanwhile,it is able to confirm shedding priority level according to load frequency regulation characteristics.By using ordered binary decision diagram,it is able to search feasible solution to shedding scheme.Aiming at the feasible solution and considering load control price,it is able to determine the optimal con-trol strategy.This scheme is tested and verified on IEEE 9 node system and the result indicates its feasibility to estimate fault,effectiveness of acquiring the optimal load shedding scheme rapidly.In addition,compared with traditional low-fre-quency load shedding scheme,the new scheme is provided with advantages such as strong self-adaptivity and small control price.%为控制电力系统大容量机组跳闸时频率下降的问题,需要设计可靠的低频减载方案。针对传统方案存在的不足,设计了一种考虑负荷模型和系统有功备用的低频减载方案。该方案通过故障后系统频率变化率来估算系统功率缺额,充分考虑负荷模型、系统备用的影响,确定切负荷量；根据负荷的频率调节特性确定切除的优先级；利用有序二元决策图(ordered binary decision diagram,OBDD)搜索切除方案可行解,针对可行解,考虑负荷的控制代价,确定最优的控制策略。该方案经在 IEEE 9节点系统上测试验证,能准确估算故障大小,并能快速得到最优切负荷方案,相比于传统的低频减载方案,具有自适应性强、控制代价小等优势。