关键词: 电压稳定性, 功率极限, 鞍节分岔点, 概率潮流, 连续潮流

Abstract:

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.

Key words: voltage stability, power limit, saddle node bifurcation, probabilistic power flow, continuous power flow