Optimization Research On Anti-melting Ice Technology For Catenary Of Electrified Railway

In recent years,there have been frequent icing accidents on the catenary of electrified railways,causing problem such as train suspension,passenger and cargo detention.The current catenary deicing is still dominated by artificial deicing.Although there are many researches on anti-melting ice technology based on static var generator(SVG),its high cost limits its application in actual projects.How to reduce the capacity and cost of the device on the basis of ensuring the performance of the device and the effect of anti-melting ice needs further research.At present,there are few researches on the application of reactive power compensation devices combining active equipment and passive equipment to the field of antimelting ice in electrified railway catenary,and there is no deicing method that combines online anti-icing with efficient ice melting.Firstly,the ice-coating mechanism of the contact wire was studied and the anti-icing mathematical model of contact wire was established.The meteorological conditions which the contact wire needs to be anti-icing are given in terms of wind speed,humidity and temperature.On this basis,the contact wire anti-icing model was established,and the calculation formula of the critical anti-icing current was solved.At the same time,the ice melting process and temperature distribution of the contact wire were studied,the ice melting model of the contact wire was established,the calculation formula of the critical ice melting current was obtained,and the relationship between the ice melting current and the ice melting time was analyzed.Secondly,a combined online anti-icing and low voltage ice-melting scheme for catenary deicing was proposed,and an online anti-icing current decision-making method based on the all-parallel autotransformer(AT)power supply system was determined.The anti-melting ice equipment in the traction power substation adopts SVG+ thyristor switched capacitor(TSC),and the anti-melting ice equipment in the sectioning post adopts SVG+ thyristor switched reactor(TSR).On this basis,a three-level coordinated control strategy for the anti-melting ice device was given.The coordination layer completes reactive power detection and distribution,the control layer completes TSC/TSR switching control and SVG direct current control,and the executive layer controls TSC/TSR and SVG circuit action to generate corresponding reactive currents.The combined online anti-icing scheme can achieve the effect of low cost and large capacity while ensuring that the performance of the device is equivalent to SVG.The low voltage ice-melting scheme can further reduce the device capacity required for ice melting.Finally,the structure of the anti-melting ice device based on the all-parallel AT power supply system was designed,and the principle of determining the working voltage level of the device was proposed.A comprehensive simulation model of the full-parallel AT power supply system and the anti-icing system was built on Matlab/Simulink.The simulation results show that the couple of anti-melting ice equipment can cooperate with each other to accurately provide the anti-melting ice current required by the contact wire and ensure the power factor meets the standard.The correctness of the combined online anti-icing and low voltage icemelting scheme and the effectiveness of the coordinated control strategy were verified.