Study On The Wire Selection Methods Of OCS For Electric Railway Considering Geographical And Climatic Conditions

The rapid development of electric railway has enormous advantages in transportation capacity,operating costs,energy conservation and environmental protection.Currently,as an indispensable means of transportation in China,its development potential is still enormous and further research is needed.At present,in the design of traction power supply,the design of OCS is still advancing.In the context of social environmental protection and energy conservation,considering the operating cost and construction investment of OCS is an issue that cannot be ignored in engineering.The length of OCS along the line,spanning different regions,and the varying environments in which it operates pose certain difficulties for the design of OCS.As the part of power transmission in traction power supply,the catenary plays an important role in ensuring the stable operation of electric locomotive.The ability of power transmission can be determined by the reasonable selection of catenary conductors.China is already at the forefront of the world in the design of overhead contact line conductors.However,due to its huge land area and significant climate differences,China only determines the current carrying capacity of overhead contact line conductors under fixed meteorological conditions.Although it ensures the safety of transmission lines,it does not conform to the concept of energy conservation.Therefore,in practice,it is necessary to make reasonable selections based on the characteristics of each region.This thesis conducts relevant research based on this drawback.This thesis takes the electric railway catenary wires as the research object.By calculating the current carrying capacity of the contact wires and stranded conductors in different regions and meteorological conditions,various wires are combined and matched to obtain the current carrying capacity of OCS,and then analyze the reasonable selection of wires.The specific content is as follows:(1)This thesis introduces the basic characteristics of the wire,model,and other types of Overhead lines in the new standard,provides impedance calculation methods for each conductor of overhead contact line under different suspension methods,and briefly introduces the simulation software used in the current selection of overhead contact line conductors.It analyzes the climatic conditions based on which the current selection is based,and explains the determination of the continuous current carrying capacity of overhead contact line conductors,The continuous current carrying value indicates the shortcomings of the current selection of wires.(2)In response to the impact of geographical and climatic factors on the changes in the carrying capacity of overhead contact line conductors,specific meteorological parameters were analyzed.Through the description of thermal load in the IEEE-738 standard,transient and steady-state thermal balance were established,and the functional relationship between heat absorption and heat dissipation was listed.The method of controlling variables was used to analyze specific meteorological parameters in different regions,with the overhead contact line as the research object,It is concluded that wind speed has the greatest impact on the current carrying capacity of overhead contact line conductors,while altitude has the smallest impact on the current carrying capacity of overhead contact line conductors.(3)Based on the impedance calculation results of the Overhead lines wires,the current distribution coefficients under different wire combinations were obtained.Different climatic parameters are adopted in different regions to calculate the current carrying capacity of each conductor in OCS at the highest allowable working temperature,thereby determining the comprehensive current carrying capacity of OCS.By using historical meteorological data,different meteorological boundary values are selected for different regions,and the current carrying capacity of the overhead contact line conductor is calculated.The selected conductor takes into account the characteristics of the region,ensuring the safe and stable operation of the train while improving the capacity utilization rate of the transmission line.(4)After determining the spatial distribution position and geographical and climatic conditions of the wires,corresponding calculation examples are designed and analyzed.Two types of contact wires and two types of stranded conductors are used as research objects to calculate the unit self impedance and unit mutual impedance of each wire,as well as the heat absorption,heat dissipation,and current carrying capacity of each wire.Finally,through historical data records,the meteorological conditions with regional characteristics are selected,and the current carrying capacity of the catenary is calculated using the current partition coefficient.The current carrying capacity of each conductor is analyzed through the capacity utilization ratio.