Energy Management Strategies For Traction Power Systems With Photovoltaic And Energy Storage Interation

In recent years,with the rapid development of electrified railroads,railroad carbon emissions are increasing day by day.In order to achieve the goal of "double carbon" of electrified railroads,a number of railroad energy optimization initiatives have been put into practice and have achieved certain results,however,the optimization of energy consumption alone does not cure the symptoms.In order to cure the carbon emission problem of electrified railroad,new energy is introduced into the traction power supply system,starting from the source of power consumption of traction power supply system,to enrich the system power supply and thus reduce carbon emission.At the same time,based on the concept of smart grid,the energy management strategy of traction power supply system is formulated in the context of power market,and the complexity of control system is reduced based on the established functions through hierarchical and graded optimization scheduling to achieve a win-win situation in terms of system operation performance and economic benefits.Therefore,this paper carries out the following work.(1)Build a traction power system that takes into account photovoltaic and energy storage interation.Based on the traditional traction power supply system structure,the topology structure of the traction power supply system with PV and energy storage interation is designed,considering the special characteristics of traction load and grid-connected operation of new energy devices.The interaction mechanism of each power supply source is analyzed and the corresponding energy management strategy aims to break the barrier of relative independence and fragmentation of each "source" end of the system through hierarchical and graded optimization,so as to realize multi-energy complementation.(2)Reduce the operating cost of the traction power supply system with PV and energy storage interation.The system is based on the power purchase criteria in the context of the electricity market,and the system will supply energy to the low bidder through competitive bidding among the supply sources,and the energy storage device will arbitrage through low storage and high generation and braking energy reuse.At the same time,the energy storage device uses the concept of sharing,combining the photovoltaic side and traction side energy storage device into one,building a shared energy storage device to improve the economic efficiency of the system.(3)Ensure the operational safety of the traction power supply system.Photovoltaic and energy storage in the traction power supply system will significantly reduce the system carbon emissions and improve the environmental protection of the system operation,but the high PV penetration rate will also affect the system operation performance,respectively,to study the relationship between PV penetration rate and the system three-phase voltage unbalance and reactive power reserve,set energy storage device between the system stability base value,to ensure the safety of the traction power supply system operation with high PV penetration rate.(4)Balance the operational performance and economic benefits of the traction power supply system.The concept of comprehensive performance of the traction power supply system is proposed,and the proportion of operational performance and economic benefits in the comprehensive performance of the system is assigned.A two-tier optimization strategy is designed,with the objective of local optimization being aimed at improving the operational performance of the system and selecting the optimal one by comparing the performance of three dispatching methods.The global optimization objective is to select the one with the lowest carbon emission among the dispatching solutions with the best system performance,so as to realize a win-win situation for both the operational performance and economic benefits of the traction power supply system.