Ampacity Determination And Correction For Overhead Line Considering Meteorological Dynamics

With the continuous development of social economy,China’s demand for electric energy is increasing.In more developed areas,due to the difficulty of erecting new transmission lines and the constraints of various conditions,the electricity consumption situation has become increasingly severe.However,the ampacity of overhead line is not only related to the nature of wire itself,but also closely related to meteorological conditions.At the same time,artificial intelligence algorithms have great advantages in statistical analysis of meteorological data.Therefore,how to use the relevant algorithms of artificial intelligence to effectively mine the current-carrying capacity of overhead lines to meet people’s increasing demand for electricity has become an urgent problem to be studied and solved in the field of overhead lines operation and maintenance.In view of the increasingly severe situation of grid electricity consumption,this thesis focuses on a method for calculating and checking the ampacity of overhead lines that takes into account the dynamic changes of meteorology.At the same time in the algorithm of building model,on the basis of design and develop a set of based on B/S architecture both before and after the end of the separation of overhead line,load flow calculation and checking software system can give the grid operations staff to provide the reference in the process of power grid scheduling and operational and decision aid,and more targeted to improve the carrying capacity of overhead lines and effectively guarantee the safe operation of transmission lines.This thesis makes the following contributions to the research and application of overhead line ampacity calculation and checking model:（1）Based on the existing calculation model of rated ampacity,the boundary conditions of calculation of overhead line ampacity are analyzed.Considering the changes of regional historical meteorological data,statistical learning theory was introduced to model the historical meteorological data,and the annual meteorological data was divided into time periods based on k-means clustering algorithm.The calculation model of the rated ampacity of overhead line is constructed with cluster center as boundary condition.Finally,the validity of the proposed calculation model is verified with actual line data.（2）Based on the actual overhead line ampacity data set,the combined prediction model of working condition ampacity based on XGBoost algorithm and GRU algorithm is constructed.The error evaluation and comprehensive comparative analysis with different models show that the proposed method has higher prediction accuracy of the load capacity of overhead lines in working conditions,and effectively improves the safety and accuracy of the calculation of the load capacity of overhead lines in working conditions.（3）Based on the calculation model of safety limit,considering the influence of crossing point on the maximum allowable sag of overhead line,the relationship model between sag and ampacity of overhead line is established,and the overall design of ampacity checking and evaluation process is carried out.Finally,an actual line is used to verify that the proposed method can effectively check the overhead line ampacity,which further ensures the safety of overhead line operation.（4）According to the calculation model of overhead line ampacity,a set of overhead line ampacity calculation and checking software based on B/S architecture is designed and developed,which mainly includes three functional modules: rated ampacity calculation,operating ampacity calculation and ampacity checking and evaluating.Through this software system,it is more convenient to calculate and check and evaluate the ampacity of overhead line,and effectively improve the efficiency of overhead line operation and maintenance.