Identification Method of Weak Link in Power System Considering Uncertainty of Power Supply and Load

Abstract

Purposes With the continuous development of new electric power system in our country, large-scale new energy connected to the grid has greatly increased the possibility of bearing the impact of power flow, the current carrying capacity of the system line has been on a serious test. At the same time, the increase of source load uncertainty makes the operation state of power grid more complex and changeable, and the traditional weak link identification technology based on deterministic power flow is difficult to meet the requirements, which increases the difficulty of power grid operation control. Methods In view of the above problems, a comprehensive evaluation index of weak nodes of power system based on the improved entropy theory was proposed by combining probabilistic power flow algorithm, and the weakness degree of nodes was analyzed by the probability distribution of index interval. First, a large number of operating mode samples were constructed by probabilistic power flow simulation method. Second, the entropy theory was combined with the operating parameters of the power grid, and the probability density of the index interval was used to effectively evaluate the power flow impact distribution equilibrium and voltage stability of the key nodes of the system. Conclusions Finally, after the IEEE39-node system was simulated and verified, the conclusion was drawn that the proposed evaluation index is more suitable for the actual running state of the power system, and can effectively reduce the error of weak link identification caused by the fluctuation of new energy generation in the new power system and the increase of the uncertainty of the load side user's electricity consumption.

Keywords

• uncertainty of power supply and load
• entropy theory
• a weak link
• probabilistic power flow