应用于高压直流换流站近区机组的次同步振荡阻尼控制器研究

Study on Sub-synchronous Oscillation Damping Controller for Near-area Unit of HVDC Converter Station

在交直流混联系统中,高压直流输电系统可能引发送端交流系统发生次同步振荡现象,造成换流站近区机组的轴系扭振,使得发电机组大轴及周围设备损坏,同时对升压变压器一次侧造成冲击。针对该问题,文中首先分析了高压直流换流站近区机组次同步振荡的产生机理,然后提出了一种基于附加次同步振荡阻尼控制器的抑制方法。最后在PSCAD电磁暂态仿真环境下计算表明,附加次同步振荡阻尼控制器能够快速响应次同步振荡扰动,抑制次同步振荡幅值,平抑次同步振荡引起的过电压和过电流,避免其对机组轴系和升压变压器一次侧的冲击。

In the AC/DC hybrid system, the HVDC transmission system may lead to the sub-synchronous oscillation of the AC system, this will cause the torsional vibration of the shaft of near-field unit of converter station and causes damage to the generator shaft and surrounding equipment,meanwhile, will impact on the primary side of the step-up transformer. In response to this problem, in this paper,the generation mechanism of sub-synchronous oscillation in near- area units of a HVDC converter station is analyzed, and then a suppression method based on an additional sub- synchronous oscillation damping controller is proposed. Finally, the simulation results under PSCAD/EMTDC show that the additional sub-synchronous oscillation damping controller can respond to sub-synchronous oscillation disturbance quickly. The amplitude of sub-synchronous oscillation are suppressed, the overvoltage and overcurrent caused by sub- synchronous oscillation are stabilized. So,the impaction on the primary side of the unit shafting and step-up transformer are avoided.