考虑分布式电源的静态电压稳定概率评估

Probabilistic Evaluation of Static Voltage Stability Taking Account of Distributed Generation

分布式电源的接入对电力系统的影响是智能电网发展的一个重要课题。针对分布式电源、负荷的不确定性,基于点估计法和柯尼斯–费希尔(Cornish-Fisher)级数提出含分布式电源的电力系统静态电压稳定概率评估方法。点估计法将概率问题转化为确定性问题,然后采用内点法求解各随机变量估计点的电压稳定临界点非线性规划模型,从而得到目标函数统计特征值,并由Cornish-Fisher级数获得其概率分布。IEEE118和300节点算例系统的计算结果表明,该方法计算精度较高,与蒙特卡罗(Monte Carlo)方法相比具有较小的计算量。

The impact of grid-connected distributed generation on power systems is very important subjects in smart grid. Accounting for uncertainties on the distributed generation and load, a probabilistic evaluation method was presented for static voltage stability based on point estimate method and Cornish-Fisher expansion. By the point estimate method the probabilistic problems could be handled as those corresponding to deterministic problems. The interior point method was employed to solve nonlinear programming problems for voltage stability critical point on the estimate points of random variables, and the statistical properties of objective function were obtained. According to Cornish-Fisher expansion, the probabilistic distribution functions were calculated. The numerical results of IEEE 118-bus and 300-bus test system shows that the proposed method maintains a high degree of accuracy and reduces the computational burden when compared with the Monte Carlo method.