含可控惯量发电系统的功角暂态稳定分析与惯性控制策略

Power Angle Transient Stability Analysis and Inertial Control Strategy for Power Generation System with Controlled Inertia

具备虚拟惯性的变速风电机组可改善系统频率稳定性,但发电系统的功角暂态稳定也会因可控惯性的改变而发生显著改变。该文首先推导两端接入风电的互联两区域电网的数学模型,并分析在两区域电网中,风电机组的惯性调节对互联系统暂态能量的影响,以评估系统功角暂态稳定性。之后,为改善风电惯性控制对系统功角暂态稳定的不利影响,提出基于暂态能量的双馈风电机组(doubly-fed induction generator,DFIG)变虚拟惯量控制策略,通过快速调节两端区域电网内风电机组的虚拟惯性,不仅可避免故障后快速的惯性响应导致功角失稳,还能够提高系统暂态稳定性。最后,建立高风电渗透率的两区域互联系统仿真模型,验证了所提出的控制策略的有效性。

The variable speed wind turbines with virtual inertia can improve the system frequency stability, and the power angle transient stability of the power generation system will undergo significant changes due to the change of controllable inertia. Firstly, this paper derives the mathematical model of the interconnected two-regional power grid with wind power at both ends. By theoretically analyzing the influence of wind turbines inertial adjustment on the interconnected system transient energy in two- regional power grid, the system power angle transient stability level is evaluated. Then, for improving the adverse effects of the wind power inertial control on the system power angle transient stability, this paper proposes a variable virtual inertia control strategy of doubly fed induction generator （DFIG） based on transient energy. By rapidly adjusting the inertias at both sides of two-regional power grid, it not only can avoid the power angle instability caused by fast inertial response after failure, but also improve the transient stability of the system. Finally, a simulation model of two-regional interconnected system with high wind power penetration is established to verify the effectiveness of the proposed control strategy.