大扰动下计及风电场低电压穿越恢复差异的频率响应估计方法OA北大核心CSTPCD

With the increasing penetration rate of the wind power,multiple wind farms entering into the low voltage ride-through(LVRT)at the same time will bring significant impacts to the power system,resulting in temporary drop in active power output,rapid drop in power grid frequency and even the risk of triggering under-frequency load shedding.It is necessary to quickly estimate the frequency curve of the power grid under the temporary power disturbances to develop corresponding control measures.However,due to the difference in power recovery within wind farms,LVRT curves present different shapes.If this impact is ignored,there will be significant estimation errors in the frequency response curve,and traditional time-domain simulation based on detailed model has low efficiency.Hence,a disturbance power analysis method considering LVRT recovery difference of wind farms is proposed.The active power disturbances caused by single-unit wind turbine at each stage of LVRT are described by segment functions,and the total temporary disturbance power of the system is accurately estimated based on energy conservation principle.Considering the frequency regulation characteristics of the wind farm and the virtual inertia effect,an optimized model for system frequency response suitable for power girds with high-proportion renewable energy is proposed.The differental evolution algorithm is used to identify the parameters of the system transfer function based on actual data,and then the frequency response trajectory is fitted.The applicability and reliability of the proposed method in different scenarios are verified by the simulation of IEEE 39-bus system and simplified system for actual power grid.