The Study On Economic Optimization Scheme Of Regenerative Energy Storage System Of Electrified Railway

With the rapid development of China’s economy,the past situation of resource-for-development has long gone.The country takes sustainable development as the development goal and vigorously advocates energy conservation and consumption reduction.The regenerative braking energy of high-speed railway in China is rich.In addition to being absorbed and utilized by the train under the traction condition of the same power supply arm,it can only be consumed by the braking resistance in the form of heat or reversely sent to the power grid side,and the regenerative braking energy cannot be effectively recovered and utilized.For the railway system,the regenerative braking energy treatment is not only not economical,but also has the problem of raising the network pressure and aggravating the power quality such as negative sequence.As the largest single load in China,high-speed railway has important value and significance in improving its operation economy.The development of high-speed railway with energy storage technology will be an effective way to improve the operation economy of China’s high-speed railway system.To this end,the thesis focuses on the topological structure,control strategy and capacity optimization configuration of Hybrid Energy Storage System(HESS)in high-speed railway.The main contents are as follows:(1)Formulated a hybrid energy storage scheme using Railway Static Power Conditioner(RPC)as an energy transfer station.Firstly,the load characteristics of traction power supply system are analyzed.Then,the modeling analysis and the economic index study of supercapacitor and accumulator are carried out respectively.Finally,according to the characteristics of load,regenerative braking energy and energy storage components,the topological structure of the hybrid energy storage scheme is presented.(2)Developed the control strategy of high-speed railway hybrid energy storage system with RPC as the energy transfer station.First,the Direct axis-quadrature axis(dq)current decoupling algorithm is used to control the system.The outer ring controls the power flow and realizes the voltage stabilization of RPC dc side,while the inner ring controls RPC to realize the power quality compensation.Then the first-order low-pass algorithm is used as the hybrid energy storage power distribution scheme to coordinate and control the energy storage system.Finally,the simulation model is built on MATLAB/Simulink platform,and the simulation results are analyzed to verify the feasibility of the scheme and the correctness of the control strategy.(3)An optimization model of hybrid energy storage system based on the whole life cycle was established and solved.Firstly,the method of electric charge pricing of electrified railway is analyzed,and the energy management strategy of coordinated control of hybrid energy storage system based on low-pass filtering algorithm is established.A two-layer optimization model based on the whole life cycle hybrid energy storage system is established Then,the optimization model of hybrid energy storage system is solved by improved particle swarm optimization algorithm.Finally,the model optimization results and the operation of the hybrid energy storage system are simulated and analyzed based on the actual data.Finally,the work of this paper is summarized and the shortcomings of this paper are prospected.