非对称故障下基于功率平衡的双馈风机暂态电压协调控制策略

Transient Voltage Coordination Control Strategy for Doubly-fed Wind Turbines Based on Power Balance under Asymmetric Faults

  • 摘要: 新型电力系统对新能源机组在电网暂态过程中的支撑作用提出更高的需求。通过分析双馈风电机组不对称故障期间的暂态特性,揭示暂态直流分量和不对称分量的影响权重和演化规律。结合双馈风机故障穿越新标准,提出故障穿越期间双馈风机的协调控制准则和方法。针对转子侧换流器,在考虑网侧换流器功率平衡的基础上,提出基于定子电流微分的转子反电势前馈补偿和负序电流坐标变换控制方法,降低转子侧控制的复杂度,保证故障期间的无功调节;针对网侧换流器,提出负序分量抑制,降低负序分量对电压质量的影响。最后,在PSCAD/EMTDC仿真平台中搭建双馈风电机组接入交流电网送出场景的仿真模型,验证所提控制策略的可行性和优越性。

     

    Abstract: The new power system puts higher demands on the supporting role of renewable energy turbines in the transient process of the power grid. The transient characteristics of doubly-fed wind turbines during asymmetrical faults are analyzed, and the influence weights and evolution laws of transient DC components and asymmetrical components are revealed. Combined with the newly published standard of fault ride-through for doubly-fed wind turbines, coordinated control guidelines and methods for doubly-fed wind turbines during fault ride-through are proposed. For the rotor-side converter, on the basis of considering the power balance with the grid-side converter, the feedforward compensation of rotor counter-potential based on stator current differentiation and the control method of negative-sequence current coordinate transformation are proposed, which reduces the complexity of the rotor-side control and ensures the reactive power regulation during the fault period. For the grid-side converter, the negative-sequence component suppression strategy is proposed, which reduces the effect of the negative-sequence component on the voltage quality. Finally, the simulation model of the doubly-fed wind turbine connected to the AC grid delivery scenario is constructed in the PSCAD/EMTDC simulation platform to verify the feasibility and superiority of the proposed control strategy.

     

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