渝鄂背靠背柔性直流附加阻尼控制策略研究

Damping control based on back to back VSC-HVDC connecting Chongqing and Hubei Power Grid

针对渝鄂异步互联北通道及三峡近区大机组与常规直流和柔性直流强耦合动态问题,建立了包含三峡左一电厂、渝鄂背靠背柔性直流以及龙政直流外送通道的简化等值系统及其详细电磁暂态数学模型。仿真研究了暂态扰动下换流站近区机组的动态稳定特性。提出采用柔性直流有功无功解耦控制回路附加阻尼控制的方法平抑扰动后机组持续缓慢衰减的功率振荡问题,分别设计了基于有功调制和无功调制的阻尼控制控制器,比较研究了两者的作用效果。研究表明,采用有功和无功协同调制的阻尼控制策略可同时快速平抑功率振荡和电压波动,提高系统的动态稳定性,可为工程应用提供参考。

With the scheduled back to back VSC-HVDC based unsynchronized interconnection between Chongqing and Hubei power grid, the dynamic of such hybrid AC-DC power system consist of large capacity hydro-generator units and both LCC and VSC based HVDC is of serious concern. An equivalent system and the detailed time domain model are established including Three Gorge Power Plant No. 1 located at left bank, the back to back VSC-HVDC and the Long-Zheng LCC-HVDC. Transient simulation is undertaken which demonstrates post fault power oscillation of the hydro-generator units with poor damping. It is proposed that damping controllers can be added to either the active or reactive control loop of VSC-HVDC to improve the damping of the power oscillation. These two ways of damping control design are studied and validated. Results show that combination of both design, i.e., damping controls based on active control and reactive control, could fast decrease power oscillation as well as stabilize voltage variation.