考虑风电机组运行差异化的低电压穿越分散预防控制

Decentralized Prevention and Control of Low Voltage Ride Through Considering Differential Operation of Wind Turbines

针对跟网型双馈风电场配置的传统低电压控制策略在多电压扰动场景下普适性差的问题,该文提出一种考虑机组状态差异化的风电场短期电压分散预防控制策略。首先,分析配置无功控制、Crowbar保护电路的双馈风电场低电压穿越动态特性,获取各风电机组低电压穿越期间电流及阻抗特性;然后,借助考虑风电场内阻抗变化的节点电压法,构建机组注入电流与机端电压间的动态关系,确定各机组低电压穿越期间对场站内节点电压的影响程度;进一步,设计不同电压扰动场景下的风电场电压控制目标,构建适应多种电压跌落深度的风电场预防控制策略;最后,在Simulink及RTLABOP5600实时数字仿真平台中搭建含4台双馈风电机组的风电场和某实际风电场电磁暂态模型,验证所提风电场控制策略有效性。

This paper proposes a short-term voltage dispersion prevention control strategy for wind farms that considers the differentiation of unit statuses to address the issue of poor universality in the traditional low-voltage control strategies for the grid-connected doubly-fed wind farms under the multi-voltage disturbance scenarios.Firstly,the dynamic characteristics of low-voltage ride-through for the doubly-fed wind farms equipped with the reactive power control and the Crowbar protection circuits are analyzed to determine the current and impedance characteristics of each wind turbine unit during the low-voltage ride-through.Subsequently,the node voltage method,by considering the impedance variation within the wind farm,is employed to establish a dynamic relationship between the injected current of each unit and the terminal voltage,thereby determining the impact level of each unit on the node voltages within the station during the low-voltage ride-through.Furthermore,the voltage control objectives for wind farms under different voltage disturbance scenarios are designed,and a prevention control strategy for wind farms adaptable to various voltage sag depths is formulated.Finally,a wind farm consisting of four doubly-fed wind turbine units and a realistic electromagnetic transient model of an actual wind farm are built in the Simulink and RTLAB OP5600 real-time digital simulation platform to validate the effectiveness of the proposed wind farm control strategy.