高比例风电接入电力系统机电振荡阻尼特性精细化分析与调控策略研究

Damping is the key factor for the electromechanical oscillations of power systems. With high proportion of wind power penetrating into the grid, wind generators are commonly required to participate in system frequency/voltage ancillary control according to the connection requirements, which makes the damping property of electromechanical oscillations more complex. In addition, the demand for the damping contribution of components including the wind generation is more urgent. Nowadays, the global modal damping, which just works around the stable equilibrium point, is usually adopted in the analysis and control of electromechanical oscillations in multi-machine power systems. However, the concept of local link or subsystems damping is absent. It restricts the thoughtful analysis of damping property in theory. Moreover, it cannot provide inadequate support for the control strategy of oscillation accidents, the division of responsibilities and the improvement measures after the accidents. In this project, the energy principle of oscillation analysis in mechanics is introduced to deal with the local link or subsystems damping property, which is the core of the project. Firstly, the energy functions of double fed induction wind turbines is built and analyzed. On the basis of the applicant’s previous research, the energy structure of powers system with wind generation is proposed. Then, the energy representing method and the coupling relationship of different local link or subsystems damping property is investigated. Finally, the optimal re-dispatching of power systems for wide area damping and the coordinating design for multi-type wide area damping controllers are studied. The project will provide the theoretical guidance and technical measures for improving the security defense capability of the power system.

阻尼是影响电力系统机电振荡的核心因素。高比例风电接入后，并网导则要求风电参与系统调频调压拓宽了风机与电网间动态交互的通道，使得系统机电振荡的阻尼特性更加复杂，对风机等局部元件对系统阻尼贡献信息的需求也更为迫切。目前，多机系统的机电振荡分析和控制依赖仅在平衡点附近有效的模态全局阻尼，缺乏局部环节/子系统的阻尼概念，理论上限制了系统阻尼特性的深层次分析，工程上也无法为振荡事故的控制决策、事故后的责任划分与整改提供有效支撑。本项目引入力学中振荡分析的能量原理，围绕含风电电力系统机电振荡局部环节/子系统的阻尼特性，从双馈风机能量函数构建和解析出发，结合已有研究基础，建立含风电电力系统能量结构，研究不同局部环节/子系统阻尼特性的能量表征方法和关联关系，在此基础上，研究基于局部阻尼评估的广域阻尼动态潮流优化调整策略和多类型广域阻尼控制器的协调设计方法，为提升电力系统安全防御能力提供理论参考和技术措施。

在高比例风电并网条件下，系统机电振荡的阻尼特性将发生深刻变化，精细认识进而高效调控系统阻尼成为系统机电振荡抑制的关键问题。项目构建了含风电电力系统的暂态能量函数，通过建立时域下阻尼贡献因子贡献指标，以及双馈风机机组守恒下频域阻尼贡献因子指标，提出了含风电电力系统机电振荡阻尼特性精细化评估方法；为了应对DFIG引入虚拟惯量控制所带来的扭振阻尼恶化现象，研究了含虚拟惯量的双馈风电机组扭振分析与抑制方法为了对系统不同模式下的振荡区域进行识别；研究了基于支路模式振荡能量的低频振荡区域定位方法，定义了从网络角度研究系统振荡规律的支路振荡能量，解析发现支路振荡能量由多个支路模式振荡能量构成，并依据支路模式振荡能量及其分担度提供了一种在线的低频振荡区域定位方法；为了消除系统的弱阻尼模式，提出了基于机组有功调制和基于信息物理融合架构下的电力系统广域阻尼优化调控策略；以发电机端口耗散能量流辨识的发电机阻尼结果来计算发电机的局部有功灵敏度，提出基于机组有功调制的阻尼优化调控策略。