双馈型风电集中接入对暂态功角稳定的影响分析

Impact of DFIG-Based Wind Power Integration on the Transient Stability of Power Systems

大规模双馈型风电集中接入对电网中传统同步机组暂态功角稳定有重要影响。以含双馈型风电集中接入的单机无穷大系统为对象,分析了风电对暂态功角稳定的影响。首先根据三相短路故障下具备低电压穿越能力的双馈风电机组暂态特性,得到了其阻抗等效模型。其次,推导了双馈型风电直接接入与等容量替换同步机时的系统同步机功角特性方程,并分析了风电接入比例与传输线电抗对功角特性方程的影响,以及两种风电接入方式对系统加减速面积、不稳定平衡点、稳定裕度的影响特性。然后,利用等面积准则分析了双馈风电接入对暂态功角稳定的影响。研究结果表明,双馈风电直接接入时,同步机暂态功角稳定性降低;等容量替换同步机时,同步机暂态功角稳定性提高。最后,通过仿真验证了理论分析的正确性。

With increasing penetration of doubly fed induction generator（DFIG） based wind power into power grid, its effects on transient stability of synchronous generators become extremely prominent. In this paper, transient stability of modified single machine infinite bus（SMIB） system with DFIG-based wind farm integrated was studied. Firstly, an equivalent model of DFIG with low voltage ride through capabilitywas proposed considering transient characteristics of DFIG during three-phase short-circuit fault. And then, power-angle characteristics of synchronous generator were analyzed with wind power additionally added to the system or replacing the same capacity of synchronous generator active power. In addition, effects of wind power penetration level and transmission line reactance on power-angle characteristics,and effects of wind power integration on acceleration area, deceleration area, UEP（unstable equilibrium point） and stability margin,were discussed. Finally, effect of wind power integration on transient stability was analyzed theoretically based on EAC（equal-area criterion）. The study shows that transient stability decreases when wind power integrating additionally and increases when wind power replacing the same capacity of synchronous generator active power.Effectiveness of the analysis was verified with time-domain simulation.