Static Margin Assessment Method And Adjustment Measure Considering Sequential Characteristic Of Power System

As one of the most basic security constraints,static security constraints have always been the focus of grid dispatchers and researchers;Ample security margins can ensure that the grid operates safely under various uncertainties,so it is of great significance to accurately assess and improve the static security margin of the grid.The security distance method has the advantages of small amount of calculation,fixed dimension,and quantitative assessment of security margin when analyzing the static security problem of the power grid,but the traditional method takes the shortest distance as the evaluation index,ignores the timing and tendency of power grid operation,and only analyzes the power flow under each independent section.The evaluation result is relatively conservative,and it is unable to describe the power grid operation behavior scientifically and accurately.In view of the above problems,this paper proposes a static security margin assessment method and adjustment measures that take into account the sequential characteristic of the power grid.The main contents are as follows:(1)Based on the AC power flow model,the reasons for the conservativeness of the traditional static security distance method evaluation results are analyzed,and the key factors and specific methods for solving the problem are proposed.(2)The physical meaning of the sequential characteristic of the grid operation is analyzed,the definition of the timing evolution direction is given and specific mathematical model is established.The LSTM is used to predict and identify the timing evolution direction of the power grid,which provides a theoretical basis for the direction selection of the static security distance analysis method.(3)The static security margin assessment method that takes into account the sequential evolution characteristics of the power grid is established : In the static security distance analysis method,the sequential evolution direction of the power grid is incorporated,the static security margin of the grid is evaluated by using the Euclidean distance between the static security domain boundary point and the operating point in this direction.In the evaluation,not only the state information of the current operating point but also the influence of the historical operating conditions are considered,the connection between the power flow sections is effectively established,and the conservative problem of static security margin evaluation with the shortest security distance is avoided.(4)Based on the static security margin assessment,the basic principle of rationally distributing power generation to improve static security margin is revealed.Taking the maximumstatic security margin as the objective function,the optimal power generation mode is found by particle swarm optimization algorithm,the static security margin of the grid operation is improved scientifically,and the practical application scenario of the static security margin assessment is extended.In this paper,IEEE 9 standard calculation example and actual power grid simulation example are used to verify the effectiveness of the above method.The method proposed in this paper can assess the static security margin considering the time sequential characteristics of the power grid,reasonably optimize the power generation mode to improve the static security margin,and provide accurate and effective security information and adjustment measures for the dispatcher,which has certain practical application value.