Coordinated Optimal Scheduling Method Of Rail Transit Train Load And Energy Storage System Considering Speed Constraint

According to the current development plan of China’s rail transit,the energy consumption of rail transit will reach a considerable scale in the next few decades.Therefore,the State Grid has taken transportation as one of the main areas to promote the substitution of electricity for fossil fuels,and is trying to innovate and build a green,low-carbon,clean and efficient transportation energy Internet to promote the significant increase of the proportion of electric energy in the transportation terminal consumption.A large number of trains and traction substations become the coupling nodes of rail transit and power system,which interact and associate with the two systems.According to the different working conditions of rail train,there are two states between train and traction system:using electric energy(power flows from traction network to train)and feedback electric energy(power flows from train to traction network).By controlling the track of the train,the load power obtained by the train from the traction substation is adjusted.In this way,the rail train load will become a controllable load to participate in the peak clipping and valley filling of the power system and accurate load shedding control of power grid in emergency.Then,the power system and the rail transit system will realize cooperative operation and improve their comprehensive operation efficiency.At the same time,the rail transit system is connected to the power system as a large industrial load.At the same time,the rail transit system is connected to the power system as a large industrial load,and the energy consumption fee is charged according to the two-part and time-of-use prices.The energy storage batteries charge at the valley of the system load and discharge at the peak of the system load,that is,the energy storage batteries absorb electrical energy from the power grid at the valley of the system load and it discharges at the peak of the system load,thereby reducing the cost of purchasing electricity for rail transit trains.Firstly,in order to reduce the energy consumption cost of rail train operation,improve passenger driving comfort,and realize peak clipping and valley filling of train traction power supply system,a coordinated optimal scheduling method of rail transit train load and energy storage system considering speed constraint is proposed.Under the condition of meeting the multi train running diagram and considering the requirements of train driving comfort,the energy consumption cost of rail transit system can be reduced and the peak clipping and valley filling of train traction power supply system can be realized,by controlling the charging/discharging power of energy storage system and adjusting the train traveling speed under traction,cruise and braking conditions.Finally,the model is solved by genetic algorithm,and the results show that the proposed model can effectively reduce the energy consumption and realize peak clipping and valley filling of train traction power supply system.Secondly,when the active power loss fault occurs in the power system,in case of a major fault,in order to re balance the power of the power grid,the precise load shedding control system of the power grid requires rail transit users to reduce a certain amount of traction load power,A rail transit user precise load shedding control method considering multi-stage speed limit operation of trains in emergency is proposed.First of all,a control framework for rail transit users to participate in accurate load shedding in emergency is proposed,by determining the running time between stations,optimizing the train speed trajectory,and controlling the running state of energy storage system.On this basis,considering the constraints of train running time,running speed,motor power and so on,the objective of maximum the load shedding of train traction power supply system is proposed,and the accurate load shedding control model of rail transit users considering multi-stage speed limit operation of trains in emergency is constructed to realize the accurate load shedding control of rail transit users.In the end,the genetic algorithm is used to solve the model,and the results show that the proposed model can effectively realize the accurate load shedding control of rail transit users and cooperate with power precise load shedding system to realize load control.To sum up,the coordinated optimal scheduling method of rail transit train load and energy storage system considering speed constraint can effectively reduce the operation energy consumption cost of rail transit system and realize peak clipping and valley filling of power system while ensuring passengers’ driving comfort.The accurate load shedding control model considering the multi-stage speed limit operation of trains in emergency of rail transit users can realize the accurate load shedding control of rail transit system in emergency.