基于临界惯量和预想故障的含风电电力系统暂态功角稳定在线预警

大规模风电接入使得电力系统惯量水平降低，暂态功角失稳风险加剧，开展含风电电力系统故障前的暂态功角稳定在线预警对保障其安全稳定至关重要。提出了基于临界惯量和预想故障的含风电电力系统暂态功角稳定在线预警方法。首先，通过理论分析得到风电场在故障清除后短时间的功率恢复过程不能忽略的推论，并建立等效外特性模型，进而基于扩展等面积定则构建了计及风电场多阶段外特性的暂稳数学模型。其次，定义了含风电系统暂态功角稳定的临界等效惯量，并通过匀加速分段等效提出了实用化的求解方法，进一步提出了暂态临界惯量指数，实现稳定裕度量化分析并给出风险等级。最后，以含风电接入的四机两区域系统和IEEE39节点系统为例，仿真验证了所提方法的有效性和适用性。

Online warning of transient power angle stability of power systems with wind power based on critical inertia and anticipated faults

Large-scale wind power access reduces the inertia level of a power system and increases the risk of transient power angle instability. Carrying out online warning of transient power angle stability before faults in power systems with wind power is essential to ensure their safety and stability. An online early warning method for the transient power angle stability of power systems with wind power based on critical inertia and anticipated faults is proposed. First, a theoretical analysis is used to obtain the inference that the power recovery process of a wind farm cannot be neglected for a short period of time after fault clearance, and an equivalent external characteristic model is established. A mathematical model is constructed based on the extended equal area rule to take into account the multi-stage characteristics of wind farms. Second, the critical equivalent inertia of the transient power angle stability of power systems with wind power is defined, and a practical solution is proposed by means of uniformly accelerated segmental equivalence. A transient critical-inertia index is then proposed to quantify the stability margin analysis and give a risk rating. Finally, the validity and applicability of the proposed method is verified by simulation using a four-machine two-area system with wind power access and an IEEE39 system as examples.