考虑风电随机性的静态电压稳定概率评估

Probabilistic Steady-State Voltage Stability Assessment Considering Stochastic Wind Power

提出了一种考虑风电随机性的静态电压稳定概率评估方法。选用L指标评估各节点的电压稳定性,推导了L指标对节点注入功率的灵敏度。根据风电功率的概率密度函数计算其半不变量,再根据L指标和节点注入功率的近似线性关系计算L指标的半不变量。然后按Gram-Charlier级数展开计算L指标的概率密度函数,结合静态电压失稳严重度计算各节点的静态电压失稳风险,评估系统静态电压稳定性并识别薄弱节点。仿真结果验证了方法的有效性,可用于风电并网情况下的静态电压稳定概率评估。

A probabilistic steady-state voltage stability assessment method considering stochastic wind power was proposed. The L index was adopted to assess the voltage stability of buses, and the sensitivity of L index to bus injection power was firstly derived. From the probability density function of wind power, the cumulants were computed, and then the cumulants of L index were computed from the approximate linear relationship of L index and bus injection power. Finally the probability density function of L index was reconstructed using the Gram-Charlier series expansion and used to compute the risk of voltage instability, which could be used to assess the voltage stability of the system and identify weak buses. The method is validated by simulation results and can be used for probabilistic steady-state voltage stability assessment of power systems with wind power integration.