一种恒速风力发电机低电压穿越改进方案的研究

Study on an Improved Low Voltage Ride Through Scheme for Constant-speed Wind Turbines

提出了一种全新的恒速恒频风力机低电压穿越方案,在故障期间投入背靠背换流器并配合反并联晶闸管,使风力机组与电网通过背靠背换流器间接连接。同时通过合理的无功功率补偿与有功功率吸收,可维持机端电压幅值与频率为额定值,从而使风力机平稳度过低电压暂态。文章首先建立了风力机系统各个部分的数学模型,随后详细描述并分析了换流器的控制策略,并最终在PSCAD/EMTDC平台中建立了风力机与低电压穿越装置的精确仿真模型。在仿真中施加了包括25%、50%、80%电压跌落的3种不同故障。仿真结果证明了本文所提出的低电压穿越改进方案的可行性与可靠性。

Due to the higher and higher requirement of operation characteristics of wind turbine,a kind of novel low voltage ride-through scheme for constant-speed and constant-frequency（CSCF） wind turbine is proposed.The back-to-back converter with anti-parallel thyristors are put into use during fault occur,through which wind turbine connects with power grid.At the same time,the generator terminal voltage amplitude and frequency can maintain rated value through proper reactive power compensation and active power absorption,which make wind turbine work stably under transient low voltage.In this paper,the mathematical models of each part of wind turbine system are built firstly,and the control strategies of converter are described and analyzed.In the end,the precise simulation model of wind turbine and low voltage ride through equipment are built on PSCAD/EMTDC platform.Three kinds of different faults that include 25%,50% and 80% voltage sags are simulated,and the results verify the feasibility and reliability of proposed improved low voltage ride through scheme.