Fast Search Algorithm For Transmission Sections Based On Topology Converging Of Adjacency Matrix And Power Flow Control Strategy Considering Units Adjustment Delay

With the continuous expansion of power grid scale and the increase of renewable energy consumption proportion,the operation state of the system becomes more complex,and the difficulty of system monitoring is increasing.In recent years,the frequent blackouts in the world has always threatened the safe and reliable operation of power systems in all of the world.These accidents indicate that the traditional loose power system management model is no longer applicable,and it is necessary to develop more reasonable power system monitoring and protection measures.In order to reduce the difficulty of system monitoring and improve the level of system protection,this paper deeply studies the methods of transmission section search and section power flow control: reducing the monitoring difficulty of the power system by searching the transmission section and focusing on it;at the same time,a more reasonable section power flow control strategies can effectively inhibit the occurrence of cascading disasters in power grid.Firstly,this paper systematically untangle and analyzes the current research literature on transmission section search and section power flow control,and summarizes two definitions of transmission section and four popular transmission section search algorithms,as well as two main cross-section power flow control algorithms.For each section search and power flow control method,detailed principle and main operation steps are introduced,and the shortcomings of each method are pointed out.The aim is to establish a complete research route for transmission section search and section power flow control.Secondly,to solve the problems of line omission and long time in the transmission section search method mentioned in the current literature,a new algorithm for fast search of key transmission sections based on topology aggregation of adjacency matrix is proposed in this paper.The algorithm is based on graph theory,and transforms the adjacency matrix of the power grid topology graph into a topological aggregation adjacency matrix through simple matrix exchange rules,thereby rearranging the buses in the power grid according to the topological distance.Moreover,based on the topology aggregation adjacency matrix,a simple addition operation is used to search for the initial section that satisfying the definition of the transmission section,and then the distribution factor is used to determine the key transmission section of the system.Simulations have been carried out in multiple IEEE systems,and the calculation resultsverify that the algorithm not only avoids the cumbersome calculation burden,but also realizes the accurate search of the transmission section.Finally,in view of the fact that current transmission section power flow control algorithms generally ignore the characteristics of the unit’s output time delay,resulting in the adjustment scheme not conforming to the actual operation of the power grid.After analyzes the influence of the time delay characteristics of the unit’s output adjustment on the unit output plan and the thermal limit stability time of the line in detail,a hybrid power flow control algorithm is proposed.The algorithm selects the units participating in the output adjustment task by the reverse difference matching method,and determines the output adjustment quantity by the optimal power flow method.The rapidity of sensitivity method and the accuracy of the optimized power flow method are integrated.By simulating in the modified IEEE-30 buses system,it is verified that considering the unit output adjustment time delay characteristics is more conform to the actual operation of the power grid,the proposed hybrid power flow control algorithm is also more advantageous.