惯量控制下双馈风电场的双层阻尼控制

Two-Level Damping Control for DFIG-based Wind Farm Providing Synthetic Inertial Service

随着电网中风电比重的不断升高,各国电网运营商逐渐开始要求风电场提供类似同步发电机的惯量响应以减小电力系统等效惯量下降的趋势。本文研究发现弱电网条件下风电场惯量控制不仅恶化风电机组的轴系扭振,而且实施惯量控制的风电场会参与到电力系统低频振荡当中并引入新的弱阻尼振荡。上述振荡威胁风电机组及电力系统的小干扰稳定性,限制风电场满足风电并网导则的要求。为解决此问题,本文提出基于风机层扭振阻尼控制和风电场层低频振荡阻尼控制的双层阻尼控制体系来增强风电场的阻尼特性。仿真结果表明提出的双层阻尼控制能够在多工况下协同改善多种低频振荡模式。

Equivalent inertia of the power system is reducing with the increasing wind power penetration. To alleviate this issue, more and more countries have put forward grid codes which require wind farms （WFs） to provide inertial response as traditional synchronous generation does. It is found in this paper that the synthetic inertial control of the WF in a weak grid deteriorates drive-train torsional oscillation of wind turbine generators （WTGs）. Furthermore, the WF emulating inertial response is involved in power system oscillations and induces a new critical low frequency oscillation. The above oscillations threaten small-signal stability of the WF and the power system, which restricts the WF to fulflll grid code requirements. To overcome this problem, this paper proposes a two-level damping control scheme consisting of a WTG level torsional oscillation damping control and a WF level low frequency oscillation adaptive damping control to enhance damping characteristic of the WF. Simulation results show that the two-level damping control can simultaneously counteract these concerned multiple oscillations under various operating conditions, which facilitates the WF to meet grid code requirements and improves dynamic stability of the WF and the power system.