Research On The Judging Method Of Key Transmission Section Considering The Integration Of Renewable Evergy Sources Into Grid

With the development of the energy Internet,the grid of large-scale renewable energy,and the grid structure of power system is more and more complex,and its scale is bigger and bigger.The interconnection of power grids in different regions is becoming increasingly tighter,the operation status and operation mode of the power grid is also becoming more diverse.In this background,the safe and stable operation of the power grid has been faced with severe challenges.In recent years,there have been many blackouts in many parts of the world,which makes it urgent to solve the problem of safe and stable operation of power grids.Through the analysis of a large blackout accident,the key to solve this problem is to accurately determine the vulnerable lines and key transmission sections that can cause cascading outages in the power grid.In this paper,a complete set of methods for accurately determining critical transmission sections is developed,the research work is carried out from three aspects: bad data identification,vulnerable line identification and critical transmission section determination.Based on GSA’s elbow criterion theory,we apply it to the analysis of bad data identification in power system,a new identification method of GSA bad data based on region density statistics is proposed.The algorithm calculates the area density of data objects,select the k points in the high density area and the longest distance from each other as the initial cluster centers,to make the initial clustering center of the clustering algorithm is stable.Experiments show that the optimized GSA algorithm of bad data identification greatly improves the accuracy and efficiency of bad data identification.This method is based on the set of power transmission paths between "power generation-load node pairs" and proposes a "power generation-load node pair" impact factor of distributed power source.At the same time,combining the complex network theory and the topology model of the power grid,this paper proposes the line self-impact factors.Integrating these two influencing factors,the integrated trend of the line is used as the identification index of the vulnerable line.Finally,the power transmission efficiency index is proposed to indicate the impact of the disconnection of the vulnerable line on the integrity of the power grid system.The simulation experiment is combined with the IEEE-39 system.The results verify the accuracy and effectiveness of this method in the identification of vulnerable lines.This paper proposes a key transmission section determination method based on vulnerable circuits.Based on the effective identification of vulnerable lines,this method searches the power transmission paths of power-load nodes at both ends of vulnerable lines to determine the parallel transmission sections of vulnerable lines.By calculating the power transmission factor of each transmission line in the parallel transmission section,the difference coefficient of the power transmission factor with the vulnerable line is obtained,and the critical transmission section of the vulnerable line is finally determined according to the set difference threshold.Combining with the IEEE-39 system simulation experiment,the key transmission sections are analyzed from two aspects: the traditional grid structure and the grid structure with distributed renewable energy.The results verify the accuracy of the proposed method in this paper.In summary,the proposed method can accurately determine the critical transmission sections in a complex power grid,which can effectively prevent the occurrence of cascading failures,to ensure the safe and stable operation of the power grid.