Research On The Solution Of Simulation For Urban Traction Power Including Regenerative Braking

Utilizing ground braking resistor in absorbing the excess regeneration energy can not only avoid the disabled of regenerative braking, but also decrease the vehicle weight and the temperature of the tunnels. The ground braking resistors always set on the ground and become a very important part of the traction power system. Therefore, when the traction power system is simulated, the influence of regeneration energy on traction net is considered, and the ground braking resistors which absorb the excess regeneration energy are analyzed. Thus, it is necessary to establish precise model and research urban traction power system including ground braking resistors.The structure and models of traction power system are analyzed in this paper, then the principle of regeneration braking and the management of excess energy are studied. Based on the analysis of existing simulations and their short comings, an algorithm of DC traction power which concerns ground braking resistors is proposed. Through the modeling of substation with ground braking resistors in the DC bus, the absorbing process of excess energy is studied, and the effect of different start voltage on regenerative energy effective ratio and voltage of traction net are discussed.On basis of above algorithm, the AC side of traction net is modeled in MATLAB/ SIMULINK, and then the model is interacted with the algorithm of DC side which compiles by M document to carry out calculating AC-DC power flow of urban traction power system. Finally, the factors effecting on bus voltage between AC side and DC side are analyzed.The results of simulation and check show as follow. Firstly, going up start-voltage will reduce the total energy of substations output, raise both the utilization of the regeneration energy and voltage of net. Whereas, lower start-voltage can limit the voltage of net, but make more regeneration energy be absorbed by ground braking resistors. Secondly, when analyzing urban traction power system, both DC side and AC side should be considered because of the interaction between AC-DC. Finally, the algorithm proposed in this paper could not only calculate power flow of normal DC traction power system, but effectively simulate power flow when ground brake resistors are included.