Research On Automatic Mapping For Single Line Diagram Of Distribution Network Based On CIM

Almost all the monitoring and management functions of the distribution network require the background support of the schematic single-line diagram of the distribution network.On the background of single-line diagrams,power operators can monitor the operating status of power equipment in distribution networks and make effective decisions for the safe and economic operation of distribution networks.The Common Information Model(CIM)is an abstract model.It provides a unified logical representation of all major objects in the power system,and can describe information such as grid device objects and their topological connection relationships in a standardized manner.Researching automatic mapping technology of single-line diagrams of distribution network based on CIM has important theoretical and practical significance for greatly reducing the workload of on-site personnel graphics maintenance and avoiding the inconsistency of graphics and data.For the radial or weak ring structure of distribution network,considering the drawing principle of single-line diagram and the reading habits of electric power personnel,in many automatic drawing algorithms,the trunk-branch algorithm can achieve the best single-line drawing effect.However,the current trunk-branch algorithm still has the problem of excessive stretching and translation,which results in the waste of the drawing space,and the process of cross-over and overlapping of graphics elements is too complicated.Based on extensive research of automatic drawing technology,aiming at the current problems,this paper presents a new algorithm for automatic drawing of single-line diagrams of distribution networks.The algorithm improves the trunk-branch algorithm,innovatively uses the branch as an unit for the overall layout,uses a polygonal boundary to describe the layout area of the branch,and subordinate branches only process overlapping with their superior branches.By the way of boundary merging,the layout area of the subordinate branch is recursively merged into the layout area of the upper branch to form a whole.For the combined elements such as RMU,the internal and external models are established respectively.The internal layout is based on the internal model,and then the overall layout is based on the external model.Compared with the previous algorithms,the improved algorithm can achieve a more compact layout without excessive extension and translation of the branches.At the same time,the calculation amount of crossover overlap determination is reduced,and all cross-over and overlapping between branches can be eliminated at once without introducing new ones.After completing the automatic layout of the elements,this paper uses the improved A*algorithm to search for the optimal routing path between the elements.An improved method of dynamic step is proposed.When expanding the child node of the current optimal node,a single step is used in the direction away from the target,and dynamic steps are used in the direction close to the target.The improved algorithm reduces the number of extended nodes,narrows the search range,and accelerates the optimization of the routing path.In this paper,the layout space is meshed and a reasonable evaluation function is established for the A*algorithm.In order to speed up the searching,insertion and deletion of the OPEN table,a binary heap is used to store the nodes in the OPEN table so that the operating efficiency of the algorithm is improved.An automatic drawing system is designed and implemented in Python language.The system is mainly composed of four functional modules:CIM file parsing:module,automatic layout module,automatic wiring module,and graphic generation module.Using the distribution network CIM file of a certain area in Nanjing,several groups of single-line diagrams of the distribution network were automatically generated.The results show that the proposed algorithm can draw compact and beautiful single line diagrams which have good readability and can meet the viewing habits of the site personnel.