最临近功率极限点的概率计算

Probabilistic Calculation of the Nearest Power Critical Point

功率极限(或电压稳定裕度)是衡量电力系统静态电压稳定性的一个重要指标,然而传统的最临近功率极限(或最小电压稳定裕度)计算是基于单一的系统运行方式,计算结果偏于乐观.文中从概率环境出发,考虑一段时期内系统的多种运行方式,在潮流方程中计入节点功率和节点电压的概率特性(均值和方差)的相互影响,从而计算了多运行方式下系统的最小电压稳定裕度;并在正态分布的假设下,计算了多运行方式下最小电压稳定裕度的分布范围.

The power limit （or voltage stability margin） serves as an important index to describe the static voltage stability of power system. As the conventional method to calculate the nearest power critical point （ or the minimum voltage stability margin） is based on a single system-operating state, the obtained results tend to be optimistic. In this paper, multiple system-operating conditions in a system period in the probabilistic environment are considered by inserting the probabilistic characteristics （ the mean values and the covariance） of nodal voltages and nodal powers into power flow equations. The minimum voltage stability margin of the system in multiple operating conditions is computed accordingly, and the corresponding margin distribution with a normal probability is finally calculated.