The Optimal Scheduling Strategy Of Highway Microgrid System Based On Mobile Energy Storage

With the continuous renovation in energy system,the development of energy-transportation fusion has been emerged as a new prospective direction.As a major sector in transportation,highway transportation is moving to “green,flexible,self-consistent,and sustainable”.As a key transportation line through our whole country,middle-west regions have an increasing transportation load demand.Highways in the remote areas of middle-west regions are mostly out of the range of national power grids.The lack of infrastructure is a main reason that restricts the development of highway,while the distributed energy supply is another factor that restricts the development of infrastructure.This thesis studied the energy scheduling and optimization of a typical mid-west highway microgrid power system with distributed energy sources.This thesis aims to find a suitable energy scheduling and optimization plan for a highway microgrid system.The main contributions are summarized as follows.1.Considering long-distance,large regional span and strip distributed features of highways,the mobile energy storage system was introduced into the proposed energy scheduling structure.A new topology and energy scheduling architecture of highway microgrid system is established.Based on these,the mathematical model of highway micro-grid and mobile energy storage system model are constructed.The model includes renewable energy,local energy storage units,loads,mobile energy storage system,and other mathematical models.The cost-price mechanism has been improved to for subsequent collaborative optimization research of multi-microgrid system.2.A dual-layer scheduling strategy is designed to deal with the load demand versus the uncertainty of renewable energy output in highway microgrid systems.The dispatching loss of mobile energy storage is introduced into a cost-tariff mechanism,and the operation mode of each microgrid is determined by the principle of economic benefits.The upper DNO determines the set value of energy dispatching by collecting the energy supply and demand information uploaded by each microgrid.The lower local controller tracks the optimal setting of DNO to ensure the amount of charge and discharge in local energy storage and the reduction of controllable load.Finally,simulation results confirm the effectiveness and economy of the proposed optimization strategy.3.In order to solve communication burden,privacy protection and failure risk induced by multiple microgrids and complex highway power system structure,a distributed real-time energy optimization scheduling strategy is designed for adjacent microgrids using alternating direction multiplier.Setting the minimum total operation cost of highway microgrid system as the coupling variable,and Lagrange penalty function as the relaxation augment,the original optimization problem is decoupled into independent sub-optimization problems in each subsystem,and the global optimal solution is obtained through a two-layer cyclic method.Each microgrid only needs to exchange energy demand information with its neighboring microgrids,which reduces communication burden and energy dispatching costs.The simulation results verify the effectiveness of this proposed strategy.