考虑动态频率安全的风电参与负荷恢复优化调度

Optimal Dispatch of Wind Power Participating in Load Restoration Considering Dynamic Frequency Security

针对含大规模风电的电力系统在大停电后负荷恢复阶段的频率安全问题,考虑风电机组的虚拟惯量和一次调频响应过程,基于系统等值摇摆方程构建含风电电力系统动态频率响应模型,推导出初始频率变化率(rate of change of frequency,RoCoF)和最低点频率的解析表达式,并将其作为系统动态频率安全约束;在此基础上,以恢复负荷量最大和恢复时间最短为目标,提出考虑动态频率安全约束的系统多时段恢复优化调度模型,并给出非线性约束的线性化方法,以提高恢复决策的效率;以改进的IEEE-39节点系统进行算例验证,结果表明所提模型能够给出保证频率动态安全的风电、负荷的有序接入及常规机组出力方案,且恢复速度快。

To solve the frequency security problem of a large-scale wind power system during the load restoration period after a blackout,considering the virtual inertia and the primary frequency modulation response process of the wind turbine,a dynamic frequency response model is constructed based on the equivalent swing equation.The analytical expressions of the rate of changes of frequency(RoCoF) and the frequency nadir are derived,which are used as the constraints in the disturbance scenarios.On the basis of these constraints,an optimization dispatch model for the load multi-step restoration is proposed,aiming at maximizing the load restoration and minimizing the operation time.A linearization method of nonlinear constraints is given to improve the efficiency of the restoration decision-making.The case study on the modified IEEE-39 bus system shows that the proposed model can realize the orderly grid-connection for the load and wind power in batches during the recovery process,reasonably dispatching the outputs of the conventional units and ensuring the frequency security and the recovery speed.