弱电网故障下无Crowbar双馈风电机组的暂态稳定性分析与优化控制研究

Nowadays, the safe and stable operation of power systems is seriously threatened by the stability problems of the wind power generation equipment in weak grid. However, the research on the transient stability of DFIG-based wind turbines in weak grid is still at an early stage, and some issues such as the unclear stability mechanism and the lack of stability improvement method are needed to be solved urgently. As a consequence, this proposal intends to investigate the transient stability of crowbarless DFIG-based wind turbine under weak and faulty grid, and aims to reveal its transient stability mechanism and propose the stability improvement method. Firstly, an order-reduced and simplified model of DFIG-based wind turbine is established by using the singular perturbation multi-time scale method, which considers the weak grid, current loop, phase-locked loop and fault ride-through (FRT) control method. Based on the proposed model, the transient stability mechanism of DFIG-based wind turbine in weak grid and its key influencing factors are analyzed by the Lyapunov method. Afterward, the system transient stability is improved from two aspects, i.e., the optimized design of the current loop/phase-locked loop control parameters and improved design of FRT control method. Finally, the simulation model and experiment platform are constructed to validate the above analysis and optimized control method. The outcomes of this proposal will provide certain theoretical basis and key technology support to the safe and stable operation of power systems with high penetration of wind power.

目前风电装备在弱电网下的稳定性问题严重威胁着电力系统的安全稳定运行。然而，针对双馈风电机组在弱电网故障下暂态稳定性的研究尚处于起步阶段，存在稳定机理不清晰和稳定提高方法缺失等问题亟待解决。为此，本项目拟开展弱电网故障下无Crowbar双馈风电机组的暂态稳定性研究，旨在揭示其暂态稳定机理和提出稳定提高方法。首先，基于奇异摄动多时间尺度方法，建立计及弱电网、电流环、锁相环和故障穿越控制方法的双馈风电机组降阶简化模型；在此模型的基础上，采用李雅普诺夫方法分析双馈风电机组在弱电网故障下的暂态稳定机理及其关键影响因素；然后，分别从优化电流环/锁相环控制参数和改进故障穿越控制方法这两个方面来提高系统的暂态稳定性；最后，搭建仿真和实验平台对以上分析结果和优化控制方法进行验证。本项目的研究成果可为高比例风电接入电力系统的安全稳定运行提供一定的理论参考和技术支撑。

弱电网下风电并网稳定性问题严重威胁电力系统的安全稳定运行。然而，现有研究大多针对正常运行工况下的小扰动失稳问题，却较少研究弱电网故障下的暂态(大扰动)失稳问题，面临失稳机理不清和稳控方法缺失等关键挑战。为此，本项目围绕弱电网故障下双馈风电机组失稳机理与优化控制开展了深入的研究工作，并取得了如下创新成果：.1)建立了故障穿越控制算法的端口阻抗模型，实现了多样化暂态控制算法的统一表征，为暂态稳定性研究提供了模型基础；.2)建立了计及锁相环和电流环动态的双馈风机奇异摄动模型，解决了故障下全阶暂态模型高阶、非线性、求解困难的难题；.3)建立了双馈风机Lyapunov暂态稳定判据，揭示了故障深度、电网强度和多环路参数等多重因素对暂态稳定性的影响规律；.4)提出了基于可行域理念的锁相控制参数优化设计方法，增强了双馈风电机组在极弱电网(SCR=2)下的稳定运行能力；.5)提出了基于线路有功损耗补偿的暂态稳定控制方法，解决了弱电网故障下双馈风机因平衡点缺失而诱发的暂态失稳问题。.结合本项目研究，已发表SCI论文5篇(含IEEE期刊论文4篇、ESI高被引论文1篇)、EI论文4篇、中文核心论文1篇，申请国家发明专利3项，并培养出站博士后1名、学会优博1名、毕业硕士1名、在读博士生2名和在读硕士生5名。项目负责人入选中国能源研究会优秀青年能源科技工作者、国家博士后创新人才支持计划，并受邀担任IEEE Transactions on Industry Applications、IET Renewable Power Generation、Protection and Control of Modern Power Systems等国际期刊编委(Associate Editor)。研究成果获中国电源学会科学技术奖(基础研究类)特等奖、中国电源学会第一届优秀博士学位论文奖、第一届高校电气电子工程创新大赛全国一等奖和中国电源学会第二十五届学术年会优秀论文奖等奖励。