考虑源荷不确定性的电力系统薄弱环节辨识方法

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

【目的】随着我国新型电力系统的不断发展,新能源大规模并网极大增加了电网承受潮流冲击的可能性,系统线路的载流能力迎来严峻考验;同时,源荷不确定性的增加使得电网运行状态愈发复杂多变,基于确定性潮流的传统薄弱环节辨识技术难以达到要求,增加了电网运行控制的难度。【方法】针对以上问题,结合概率潮流算法提出基于改进熵理论的电力系统薄弱节点综合评估指标,以指标区间概率分布对节点薄弱程度进行分析。首先,基于模拟法概率潮流构建大量运行方式样本;其次,将熵理论与电网运行参数相结合,以指标区间概率密度对系统关键节点的潮流冲击分布均衡性以及电压稳定性进行有效评估。【结论】最后,在IEEE39节点系统进行仿真校验后得出结论,所提评估指标更加贴合电力系统实际运行状态,能有效降低因新型电力系统中新能源发电波动性以及负荷侧用户用电量不确定性增加对薄弱环节辨识带来的误差。

【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 en-tropy 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 effec-tively reduce the error of weak link identification caused by the fluctuation of new energy genera-tion in the new power system and the increase of the uncertainty of the load side user's electricity consumption.