Research On Ice-melting Technology Of Urban Rail Transit Catenary Based On Energy Cycle

With the change of global climate,the outbreak of natural disasters such as ice disasters is on the rise.Urban rail transit is an important infrastructure related to the national economy and the people's livelihood.The catenary of urban rail transit on the ground is very easily covered by ice,when it is in a climate of low temperature,freezing rain,wet snow and so on.When the catenary is covered with ice,there will be arcs between the contact wire and the pantograph.The arcs will cause the train to be powered abnormally,and even cause serious accidents such as catenary breaks and pantograph damage,which will affect the train operation and bring serious economic loss and social influence.This thesis proposes an ice-melting scheme of urban rail transit catenary based on energy-cycle,which makes full use of the medium-voltage energy-fed device with four-quadrant converter capability to form an energy circulation path between medium-voltage AC grid and ice-covered catenary.The catenary current is controlled over the ice-melting current,which produces Joule heat to achieve the purpose of melting ice.Firstly,this thesis calculates the anti-icing current,the minimum ice-melting current,the maximum ice-melting current and the ice-melting current under certain weather conditions and ice-melting time.According to the ice-melting calculation results,the voltage level of the catenary and the capacity of the medium-voltage energy-fed device,the selection method of ice-melting current is analyzed.Secondly,this thesis divides four typical energy circulation paths according to the different combinations of rectifier unit and medium-voltage energy-fed device of each traction substation in the ice-melting section.This thesis studies the control strategy of the medium-voltage energy-fed device under different operating conditions and the cooperative control strategy when the medium-voltage energy-fed device and the rectifier unit work together as ice-melting power source.The effectiveness of the control strategies is verified by simulation,and the expected energy cycle is realized.Thirdly,according to the working process of the ice-melting system,this thesis adopts the Lab VIEW software to program the ice-melting monitoring platform.This thesis sets up a communications test platform to realize the functions of start-stop control,operation status monitoring,parameter setting,and ice-melting calculation.Finally,this thesis sets up a ice-melting simulation test platform,and carries out the test based on the 2MW medium-voltage energy-fed device.Through analyzing and summarizing the test data,this thesis verifies the function of the ice-melting monitoring platform and the feasibility of the dual energy-fed devices energy cycle ice-melting scheme.