基于动态电压恢复器的低电压穿越控制技术研究

大规模海上风电接入电网给电网安全运行和管理带来了较大的挑战，新的电网导则要求风电机组应保证具备低电压穿越(Low voltage ride through，LVRT)能力。考虑到动态电压恢复器(dynamic voltage restorer，DVR) 具有能在短时间内快速准确进行电压补偿的优势，本文提出了基于动态电压恢复器的双馈风电机组故障穿越方案。针对风电机组特点进行系统建模，根据DVR的控制特性，提出一种基于坐标变换的双Q-P理论的DVR控制算法，该算法可以补偿瞬时电压扰动，并且能有效改善动态电压恢复器的补偿性能。利用PSCAD/EMTDC仿真软件建立仿真平台，仿真结果表明，在海上风电场传输电能至电网过程中出现严重短路故障时，DVR能快速检测电压变化并且准确补偿所需电压，获得理想的瞬态特性，进而改善了风电机组的低电压穿越性能。

Research on low voltage ride through control technology based on DVR

Large-scale wind power connection to the power grid brings great challenges to the safe operation and management of the power grid. Considering that dynamic voltage restorer (DVR) has the advantage of fast and accurate voltage compensation in a short time, this paper proposes a fault crossing scheme for doubly-fed wind turbine based on dynamic voltage restorer. According to the control characteristics of DVR, a DVR control algorithm based on double q-p theory based on coordinate transformation is proposed, which can compensate instantaneous and long-term voltage disturbances, and can effectively improve the compensation performance of dynamic voltage restorer with sufficient versatility. Electromagnetic transient simulation software PSCAD/EMTDC is used to establish the simulation platform, the simulation results show that the power transmission in the offshore wind farm to grid in serious failure, DVR can detect voltage change fast and accurate compensation voltage required, obtain ideal transient characteristics, thus improved the Low voltage of wind turbines through (Low voltage ride through of LVRT) performance.