Optimal Allocation Of Comprehensive Energy System Capacity Based On Hybrid Energy Storage

With the rapid development of new energy power generation,China’s energy structure is still dominated by thermal power.As a big energy consuming country,China’s total energy is in the forefront of the world,but the per capita energy is extremely scarce.The adjustment of the energy system is imminent.With the increasing power consumption,traditional thermal power can no longer meet the demand,and its pollution to the environment has been paid more and more attention.Therefore,the development of new energy has been paid attention by the state.With the strong support of the country,the proportion of new energy in China is getting higher and higher,among which wind power generation accounts for a large part.As a clean energy,scenery resources are inexhaustible,but its output is greatly influenced by the environment,which is characterized by strong randomness and great fluctuation.If large-scale grid connection will have a great negative impact on the stability of the power grid,it is often necessary to abandon the wind and light for the stable operation of the power grid,which has caused great waste of resources.Therefore,other means are needed to adjust the fluctuation of scenery output.Relying solely on thermal power units will adversely affect the safe operation of thermal power units,so the role of energy storage is reflected,and the allocation of energy storage consistent with the wind and light output can effectively absorb the fluctuation of wind and light output.Energy storage is often divided into power storage and energy storage,and a single energy storage mode can not adapt to the required application scenarios in many cases.Therefore,in some scenarios,a variety of energy storage methods will be combined.At present,the battery-supercapacitor scheme is widely used.The traditional electrochemical battery has a short life,and its energy storage capacity will gradually decrease with the number of charge and discharge.With the development of battery technology,the emergence of new flow batteries has greatly made up for the shortcomings of traditional chemical batteries.Compared with the traditional storage battery,the storage capacity and service life have been greatly improved,and the use environment is also wider.The all-vanadium flow battery used in this paper can not affect the battery life under the condition of deep charge and discharge.The vanadium ion in the battery has the characteristics of high electrochemical reversibility and small polarization,which can also be satisfied for fast charging with large current.In the aspect of power energy storage,the flywheel energy storage system used in this paper is a physical energy storage method compared with supercapacitors,which is more friendly to the environment and has no influence on the life of charging and discharging times.In this paper,these two energy storage methods are combined to stabilize the volatility of the comprehensive energy system with high wind-solar ratio.In order to better alleviate the problem of wind and light output fluctuation,this paper proposes a wind and light fire storage capacity allocation model based on hybrid energy storage,and analyzes the output characteristics of all-vanadium flow battery and flywheel energy storage by combining them.Considering the investment cost and operation cost,the capacity of each unit of wind and light fire storage is simulated and calculated,and the corresponding output curve is obtained.It is found that the addition of hybrid energy storage effectively reduces the regulation pressure of thermal power units.In the distributed wind-solar power generation system,a capacity allocation model considering the loss cost is constructed,and the power flow of the power grid is analyzed by using multiple objective functions.By comparing the voltage amplitudes of different nodes with different arrangement capacities,the influence of arrangement nodes and capacities on node voltages is analyzed.On this basis,the ratio of wind and solar capacity is calculated,and the corresponding placement nodes are obtained,which effectively reduces the node voltage loss and branch power loss.The validity of this model is verified,which provides a reference for the application of large-scale energy storage in wind,light and fire comprehensive energy system.