中文摘要：

目前，风电并入交直流混合系统低频振荡模态研究未见文献报道。在PSASP中搭建了CEPRl36节点系统中含双馈风电场的纯交流系统和交直流混合系统的小信号稳定性分析的详细模型。对计及了风力机传动链、双馈发电机、变换器和直流输电动态模型及其控制策略，且直流系统运行在双极两端中性点接地、单极大地回线、单极金属回线、单极双导线并联大地回线四种不同接线方式下的小信号稳定性进行了仿真。从双馈风电场接入交流或交直流混合系统并参与有功或无功调度两种运行方式角度，采用模态分析法进行了电网区间和局部区域低频振荡模态对比分析。结果表明：双馈风电场接入交直流混合系统的低频振荡特性不仅与直流线路运行接线方式存在关联，而且受接入的风电场运行方式影响。与接入交流系统比较，接入交直流混合系统区间振荡的恶化程度变大、稳定裕度更差。

英文摘要：

Now, the modal research on low-frequency oscillation of AC/DC hybrid system integrated by DFIG-based wind farms has not been reported in literature. Therefore, a detailed pure AC and AC/DC CEPRI36 nodes system with DFIG-based wind farms is established in PSASP in order to do small signal stability analysis. With considering wind turbine drive drain, DFIG model, converter and DC transmission dynamic model and its control strategies, and DC system operating in four connection modes including bipolar neutral grounding at both ends mode, monopole ground return mode, monopole metallic return mode and monopole and two parallel conductor mode with earth return, the corresponding small signal stability is simulated and the characteristics of local oscillation modes and inter-area oscillation modes are contrastively analyzed by using modal analysis method under the two operation modes of wind farms participating active power dispatching and reactive power dispatching. The results show that low-frequency oscillation characteristics of power system with DC transmission when integrated by DFIG-based wind farms are not only closely related to the DC transmission connection mode of operation, but affected by the operation mode of integrated wind farms, compared with integrating to AC system, deterioration degree of inter-area oscillation is expanded and stability margin is decreased.