海上风电场并网柔直系统的故障穿越协调控制策略.doc

海上风电场并网柔直系统的故障穿越协调控制策略* 刘璇，宋强，刘文华 （ 摘要： 关键词： 中图分类号：TM 文献标识码： 文章编号： A coordinated control strategy for fault ride-through of offshore wind farm connected flexible HVDC transmission system Liu Xuan, Song Qiang, Liu Wenhua (State Key Lab of Control and Simulation of Power Systems and Generation Equipment, Tsinghua University, Beijing 100084, China) Abstract: This paper analyzes multilevel lumped DBR circuits which are based on the H-bridge inverter unit and simple lumped air-cooled resistors, introducing their structural topology, parameter design and control method, and demonstrates the FRT performance of multilevel lumped DBR circuits by comparing with the modular multi-level DBR circuits. For the offshore wind farm connected by flexible HVDC transmission system, combining the AC-voltage magnitude reduction method of double-fed and permanent magnet direct-driven wind farm converter station, the FRT coordination control strategy is designed by using WTGs’ ability of power regulation of wind farms. Under the premise of ensuring FRT performance of system, the study reduces required capacity of DBR circuits, thus to adapt for large-capacity and high-voltage situations. Based on parameters of German Borwin1 project, a flexible three-terminal HVDC system model is established in PSCAD/EMTDC software and simulation results show that the coordination control strategy has good FRT control effect. Keywords: VSC-HVDC, fault ride-through, coordination control, multilevel lumped DBR circuit, offshore wind farm 0　引 言 ，海上(VSC-HVDC)的应用越来越广泛，的海上风电例如orwin1/2、Dorwin1/2/3、HelWin1/2与SylWin1均采用了结构[1]。SC-HVDC在正常运行时，风电机组的与受端网络消耗的保持平衡受端网络发生故障时，能力下降，而送端却未受影响，导致线路上积累换流站直流线路的控制失效，直流持续，严重时线路跳开2]。为避免系统崩溃，需要设计合适的流输电策略，使直流线路的电压维持在一个的范围。 卸荷电路典型的RT策略，通过在线路上并联斩波电阻来消耗多余的，达到功率平衡1,3,8]。的电路会造成较大的功率波动，影响故障穿越性能模块化卸荷电路了模块化多电平换流器结构，配合建立分布式的电阻冷却系统，增加了设备的体积与成本1,5,9]。近来有研究提出全桥结构的换流桥臂与集中卸荷构成电路优点，了分布式电阻的散热问题称为多电平卸荷电路[5]原理结构，的参数设计控制策略只采用卸荷电路，功率将系统额定，不仅极大的能量损失，增加卸荷设备的体积与成本，带