The Analysis Of The Electrical Characteristics Of Locomotive And Traction Network Inclusive Of The Contact Resistance Between Pantograph And Catenary

Heavy load and high speed are the two main trends of the development of the Chinese railway. As the development of the high-speed railways and the increase of virtual armature trains, the problem of matching the parameters between electric vehicle and traction network has been more and more serious. In the past studies, the motor trains were mostly simplified as current source models, which cannot describe the electrical characteristics with sufficient details. And the contact resistance between the pantograph and catenary was not taken into account either. In order to solve these problems, three parts of work are done in this paper. Firstly, the AT power supply system and CRH2 motor train unit are adopted as the research objectives to construct the vehicle-network model. The harmonic distribution and the resonance law of the motor train unit are studied. Secondly, through introducing the contact resistance, the influence of the contact force, vehicle speed and current on the contact resistance is analyzed. Thirdly, through the combination of the previous two parts, the contact resistance is introduced into the vehicle-network model. The influence of contact resistance the caused by different vehicle speed and contact force on the voltage and current of vehicle and traction network is analyzed.Firstly, the construction characteristics of the traction network of AT are analyzed. Then the multi-conductor transmission lines(MTLS) "π" model of the traction network is established based on traditional Carson theory and MTLS theory. According to the operating principle and the harmonic generation principle of the traction converter of the virtual armature train, the distribution of the harmonic current is analyzed and the CRH2 model is established based on MATLAB/Simulink.Secondly, the resonances of the traction network under two conditions(in which the train model is considered as a current source or the real vehicle model) are analyzed. The simulation result shows that the harmonic amplification factor in the previous condition is evaluated more conservative. Then the harmonic distortion is analyzed under different working conditions. The results show that total harmonic distortion values of the harmonic voltage and current in the head of the traction network decrease with the increase of the length of the traction network, as well as with the increase of the distance from the traction substation. The harmonic distortion values of the harmonic current decrease with the increase of the number of the operating vehicles and the vehicle power. However, the harmonic distortion values of the harmonic voltage increase with that.Thirdly, the proper calculation model of the contact resistance is adopted. The influence of the current value, contact force and vehicle speed on the contact resistance is analyzed. The results show that the resistance increases with the vehicle speed’s increasing and declines with the increase of the current value. The change of the contact resistance is more sensitive when the current is relatively small. Then the static contact resistance is introduced into the motor train unit and traction network model to undertake simulation. The electrical characteristics of the current and voltage inclusive of the contact resistance are analyzed. It is found that the introduction of the contact resistance only leads to small change of the voltage and current of the vehicle and traction network.Last, in order to take the non-smooth of the contact force, the pantograph-catenary model is established. The time-varying contact force is obtained. The influence of the vehicle speed and the current value on the dynamic contact resistance is analyzed. Then, through inserting the application development module into the Simulink model, the’vehicle-contact resistance-traction network’ model is established. Then the influence of the contact resistance on the vehicle current, vehicle voltage, current and voltage in the head of the traction network is analyzed. It is found that the influence is too small. The contact resistance can be neglected in real projecti.