大规模海上风电场经HVDC并网引发轴系扭振分析与抑制

Analysis and Damping of Subsynchronous Torsional Interaction in Large Scale Offshore Wind Farm Supply Power by HVDC

针对大规模海上风电场经HVDC引起的风机轴系振荡问题,提出基于复转矩法的思想进行分析研究,并设计相应的阻尼控制器,以实现抑制风机轴系振荡的目的。首先,分析风机轴系扭振产生机理,通过复转矩系数法得到系统的电气阻尼系数,以判断固有扭振频率下的系统稳定性;然后,计算出待补偿的电磁转矩和风机转子转速的相角差;最后,通过设计附加阻尼控制器抑制风机轴系扭振。所设计的阻尼控制器具有较好的阻尼效果,且控制器阶数较低,便于实际工程实现。在PSCAD程序中搭建风电场经HVDC并网模型进行仿真分析,分析结果表明,系统加入阻尼控制器后,风机轴系扭振迅速衰减,控制器的加入有效增大了系统阻尼比。此研究为大规模海上风电场通过HVDC并网提供了理论基础。

In order to prevent the wind shaft system oscillation caused by HVDC,a damping controller was designed based on the complex torque coefficient approach. The electrical damping coefficient curve was got firstly based on complex torque coefficient approach,and the phase lag between the electromagnetic torque and the rotate speed at nature frequency of the shaft was calculated. Then a supplementary subsynchronous damping controller was designed to damping the oscillation between shaft masses. The effectiveness of the controller can be verified through time domain simulation and eigenvalue analysis. The simulation results showed that the oscillation amplitude could decreases quickly when the controller is added to the system,which provides a theoretical basis when the offshore wind farms are connected to the onshore grid through a HVDC transmission line.