针对当前电力系统暂态稳定控制措施耗时长,难于在线应用的情况,提出了一种基于广域测量系统(WAMS)预测的电力系统优化切负荷策略。利用WAMS提供的数据列,对系统中各发电机功角δ进行数值处理预测故障发生后未来时刻δ的运行轨迹;提出利用功角预判轨迹计算不平衡功率的新思路,量化故障造成的系统不平衡功率;借助改进的FVSI电压稳定指标Vindex,确定实施减载的地点和各点的减载量,在系统未失稳前主动减载保证系统暂态稳定和电压稳定,并通过智能算法优化故障后的系统运行状态和电压稳定裕度。IEEE-14节点系统仿真计算表明所提方法有效提高了系统的暂态稳定性和故障后的电压稳定性,实现系统在严重故障时的全局/局部控制。
Considering the current control measures of power system transient stability are time-consuming and difficult to apply online,this paper presents a control strategy based on Wide Area Measurement System(WAMS) prediction.The control strategy can be fulfilled in steps.Firstly,on the basis of the data columns provided by WAMS,the power angle δ of each generator in the power system is processed numerically.Thus the future trajectory of power angle δ after fault can be predicted.Then this prediction of power angle trajectory gives birth to the new idea to calculate disturbance power and quantify the severity of the disturbance by using SFR model.Thirdly,optimal locations and magnitude of the load curtailment are defined according to the improved FVSL voltage stability index(Vindex),and load is shed actively to guarantee system transient stability and voltage stability prior to the collapse of system.Finally,system operation condition and voltage stability margin after fault are optimized through the intelligent algorithm.The simulation computation on IEEE-14 system illustrates that after fault the system transient stability and voltage stability can be effectively maintained through these steps.This strategy makes the power system globally or locally under control in case of severe fault.