基于灰色关联分析的自适应低频减载

Adaptive UFLS scheme based on grey correlation analysis

针对当前低频减载方案常按频率跌落延时切除离线整定的负荷量、缺少对负荷特性的综合考虑而引起的欠切、过切等问题,提出以负荷频率效应系数、单位电能损失和负载率为决策指标对不同重要性级别下的负荷节点进行灰色关联分析排序,按关联度由大到小确定切负荷顺序。基于广域测量的系统初始频率变化率自适应估计系统功率缺额,在计及发电机和负荷的调节作用的同时计算切负荷总量,并按减载顺序主动分配。四种典型故障场景下的仿真结果表明所提方案能有效决策减载策略,以最小的减载量和减载代价获得了最优的频率动态恢复曲线,验证了可行性。

The current under frequency load shedding （UFLS） scheme usually cuts the load of offiine setting according to the frequency drop delay, and it ignores the load characteristics, which leads to the overcut and undercut problems. Grey correlation analysis is proposed to calculate correlation degree of shedding load with different importance level based on the indexes of load frequency regulation factor, unit power outage loss, and load rate. The load shedding order depends on the correlation degree. Considering system spinning reserve capacity and load regulation characteristics, the total shedding capacity is decided after using initial frequency change rate measured by WAMS technology to adaptively evaluate the system power gap. The total shedding capacity is assigned to corresponding load automatically in the order of load shedding. Four typical fault scenarios validate that the proposed scheme can decide the intelligent UFLS adaptively and obtain the optimum system dynamic frequency recovery characteristic curve with the minimum load shedding.