Study On Calculation Of Electrical Parameters Of Traction Network Considering Geographical And Climatic Conditions

As a major national livelihood project,the railway has developed rapidly under the support and encouragement of relevant national policies.As the backbone of the transportation interconnection system,its importance is increasingly prominent.Traction power supply system is an important part of the electrified railway,which undertakes the important task of providing electric energy for the electric locomotive.To achieve more accurate power flow calculation and other analyses of the traction power supply system,it is very important to get accurate electrical parameters of traction network lines.Therefore,it is necessary to study the influence of different geographical and climatic conditions on the electrical parameters of the traction network.To obtain accurate electrical parameters of the traction network,on the one hand,it can clearly understand the operation of the traction network,on the other hand,it has a positive significance for the real-time dynamic analysis of the traction power supply system.This thesis takes the electrified railway traction network as the research object,mainly introduces the basic theory of electrical parameter calculation,and studies the calculation and correction of traction network impedance and admittance parameters under the influence of different climatic conditions,as well as the traction network model of the sectional structure.(1)It introduces the traction power supply system and the power supply mode of the traction network of electrified railway,studies the calculation method of electrical parameters based on Carson’s theory,analyzes the solution method of impedance matrix of the multi-conductor transmission line,and combines and simplifies the lines in traction network.Taking the direct power supply mode of a single line back to streamline as an example,the equivalent impedance of the single line traction network is obtained.(2)In view of the influence of climate and environmental factors on the conductor resistance of traction network,firstly,this thesis analyzes the changes of the conductor of traction network under the influence of different conductor temperature,which indicates that the resistance of traction network will change with the actual temperature of the conductor when it is running and analyzes that the conductor temperature is related to the surrounding external environment temperature and other factors,and the conductor temperature is affected by the external meteorological environment.Secondly,referring to the research idea of power system transmission line,the heat balance equation is introduced into the analysis and calculation of impedance parameters of traction network,and the relationship between the resistance,the current carrying capacity of conductor and the meteorological parameters such as ambient temperature,wind speed,altitude,the sunshine intensity of conductor is obtained through the electrothermal coupling.With the idea of control variables,several different meteorological parameters involved in the heat balance equation are analyzed The influence of environmental factors on the current carrying capacity of the catenary is analyzed.Then,the fourth-order Runge Kutta method is used to discuss the solution of the transient heat balance equation,and the transient change process of traction network resistance under different ambient temperatures and current-carrying conditions is analyzed.Finally,under the condition of a given line current,the change of contact wire resistance affected by environmental factors such as ambient temperature,wind speed,and wind direction angle is analyzed.(3)In view of the influence of climate and environment on the admittance parameters of traction network,the physical quantities that may be affected by climate and environment in the calculation formula of admittance parameters are analyzed,and the relationship between dielectric coefficient and environment temperature,atmospheric pressure and relative humidity of air is analyzed by using dielectric theory.Starting from the ice covering the structure of the traction network,the calculation and correction formula of the potential coefficient under the condition of the line icing is derived by using the equivalent ice covering thickness analysis.The capacitance parameters of the traction network line affected by the meteorological conditions and ice covering in different areas and different times are quantitatively studied and analyzed.(4)Based on the temporal and spatial differences of the traction network along with the climate conditions,the calculation model of the electrical parameters of the traction network along the line is proposed.In the modeling,the nonuniformity of wind speed and line length is added to make the difference of space environment into account in parameter calculation.The electric parameter calculation results in the previous chapter are used to carry out the power flow calculation of electrothermal coupling,and the climatic environment conditions and traction network parameters are coupled to make the power flow calculation results in more practical.