Capacity configuration and energy management method for energy storage system in power distribution network

Abstract

The invention belongs to the technical field of energy storage, and particularly relates to a capacity configuration and energy management method for an energy storage system in a power distribution network, which comprises the following steps: a first objective function is constructed based on the investment cost of the energy storage system, and the investment cost of the energy storage system at least comprises the investment cost of a hydrogen energy storage device and the investment cost of an electric energy storage device. And a second objective function is constructed based on the operation cost of the power distribution network, and the operation cost of the power distribution network at least comprises the power grid electricity purchasing cost, the part maintenance cost, the energy loss cost and the renewable energy source reduction cost. And analyzing the first objective function and the second objective function based on a convex optimization method, and optimizing capacity configuration and energy management of the hydrogen energy storage device and the electric energy storage device according to the investment cost of the energy storage system and the operation cost of the power distribution network. According to the method, the energy loss of the energy storage component and the power transmission line is considered, and the capacity configuration and energy management of the energy storage system in the power distribution network are cooperatively optimized through the convex optimization method, so that the economic benefit of the power distribution network is improved.

Description

Technical Field

[0001] The present invention belongs to the field of energy storage technology, and in particular relates to a capacity configuration and energy management method for an energy storage system in a distribution network. Background Art

[0002] With the growing development of renewable energy, energy storage has become an important component of the power system. Furthermore, energy storage is widely used as one of the best solutions to adapt to the intermittent and uncertain nature of renewable energy, thereby improving the stability and economy of the power system. Electric energy storage is suitable for short-term (i.e., a few hours to a few days) and small- to medium-sized energy storage applications. Supercapacitors and / or batteries are typically used as short-term energy storage devices to store energy. Supercapacitors mainly include double-layer capacitors, lithium-ion capacitors, and sodium-ion capacitors. Batteries mainly include lithium-ion batteries, sodium-ion batteries, lithium metal batteries, semi-solid batteries, and solid-state batteries. Other energy storage devices, such as batteries and supercapacitors, have significant advantages in power density. For long-term (i.e., weekly, monthly, and seasonal) and large-scale applications, hydrogen energy storage may be a better choice. Hydrogen energy storage devices typically include components such as electrolyzers, fuel cells, and hydrogen storage tanks to convert electrical energy into hydrogen energy storage and hydrogen energy into electrical energy for utilization. Consequently, hydrogen energy storage devices have significant advantages in energy density. Considering the differences between electric energy storage and hydrogen energy storage technologies in physical properties such as energy density, power density, cycle life and energy efficiency, hybrid energy storage systems combining the two technologies are under research.

[0003] To improve the economic efficiency of energy storage systems, it is necessary to appropriately configure the capacity of energy storage components. However, capacity configuration and energy management of energy storage systems are actually two closely coupled issues that are interdependent and can be collaboratively optimized to achieve global optimality in system economics. For collaborative optimization of capacity configuration and energy management, convex optimization algorithms can guarantee a global optimal solution under convex models. However, despite significant progress in capacity configuration and energy management of energy storage systems, most research has focused on applications in microgrids and DC systems, without comprehensively considering the energy losses of transmission lines and energy storage components in distribution network applications. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to propose a collaborative optimization method based on convex optimization, which comprehensively considers the energy losses of energy storage components and transmission lines, aiming to minimize the total investment cost of the energy storage system in the distribution network and the operating cost of the distribution network, so as to optimize the capacity configuration and energy management of the energy storage system.

[0005] To achieve the above-mentioned objectives and other related objectives, the present invention provides a method for capacity configuration and energy management of an energy storage system in a distribution network, comprising: constructing a first objective function based on the investment cost of the energy storage system, wherein the investment cost of the energy storage system includes at least the investment cost of a hydrogen energy storage device and the investment cost of an electric energy storage device. Constructing a second objective function based on the operating cost of the distribution network, wherein the operating cost of the distribution network includes at least the grid electricity purchase cost, component maintenance cost, energy loss cost, and renewable energy reduction cost. Analyzing the first objective function and the second objective function based on a convex optimization method, optimizing the capacity configuration and energy management of the hydrogen energy storage device and the electric energy storage device according to the investment cost of the energy storage system and the operating cost of the distribution network.

[0006] According to a specific embodiment of the present invention, the investment cost of the hydrogen energy storage device includes at least: the investment cost of the fuel cell, the investment cost of the electrolyzer, and the investment cost of the hydrogen storage tank, and the calculation formula is as follows:

[0007] Fuel cell investment costs:

[0008] Investment cost of electrolyzer:

[0009] Investment cost of hydrogen storage tank:

[0010] Among them, C fc represents the investment cost of the fuel cell, C el represents the investment cost of the electrolytic cell, C tank represents the investment cost of the hydrogen storage tank, s fc Indicates the number of fuel cell cells, s el Indicates the number of cells in the electrolytic cell, s tank Indicates the number of hydrogen storage tanks, β fc represents the unit cost of the fuel cell, β el represents the unit cost of the electrolytic cell, β tank represents the unit cost of hydrogen storage tank, P fcb,max Represents the single cell capacity of the fuel cell, P elb,max Indicates the single cell capacity of the electrolytic cell, V tank Indicates the single capacity of the hydrogen storage tank, CF fc Represents the cost factor of the fuel cell and is related to its annual interest rate, component service life and the number of component replacements. CF el represents the cost factor of the electrolyzer and is related to its annual interest rate, component service life and the number of component replacements, CF tank represents the cost factor of the hydrogen storage tank, which is related to its annual interest rate, component service life and the number of component replacements, n dayIndicates the number of operating days per year, y sev Indicates the service life in one year.

[0011] According to a specific embodiment of the present invention, the investment cost of the electric energy storage device includes the investment cost of the supercapacitor and / or the battery, and is calculated as follows:

[0012]

[0013] Among them, C b represents the investment cost of supercapacitor / battery, s b Indicates the number of cells in the supercapacitor / battery, β b Indicates the unit cost of supercapacitor / battery, Q b Indicates the single capacity of supercapacitor / battery, CF b represents the cost factor of the supercapacitor / battery, and is related to its annual interest rate, component service life and the number of component replacements, n day Indicates the number of operating days per year, y sev Indicates the service life in one year.

[0014] According to a specific embodiment of the present invention, the calculation formula of the power grid purchase cost is as follows:

[0015]

[0016] Among them, C ele represents the cost of purchasing electricity from the power grid, β ele represents the electricity price, n day Indicates the number of operating days per year, P gd represents the power generation of the grid, β peak represents the peak electricity price, Indicates the peak power generation capacity of the power grid in a day.

[0017] According to a specific embodiment of the present invention, the hydrogen energy storage device includes a fuel cell, an electrolyzer, and a hydrogen storage tank, the electrical energy storage device includes a supercapacitor or a battery, and the calculation formula for the maintenance cost of the components is as follows:

[0018]

[0019] Among them, C m represents the component maintenance cost, n day Indicates the number of operating days per year, y sev represents the service life per year, β fc represents the unit cost of the fuel cell, β el represents the unit cost of the electrolytic cell, β H2tank represents the unit cost of hydrogen storage tank, β b Indicates the unit cost of supercapacitor / battery, sfc Indicates the number of fuel cell cells, s el Indicates the number of cells in the electrolytic cell, s tank Indicates the number of hydrogen storage tanks, P fcb,max Represents the single cell capacity of the fuel cell, P elb,max Indicates the single cell capacity of the electrolytic cell, V tank Indicates the single capacity of the hydrogen storage tank, Q b Indicates the single cell capacity of the supercapacitor / battery.

[0020] According to a specific embodiment of the present invention, the hydrogen energy storage device includes at least a fuel cell and an electrolyzer, the electrical energy storage device includes a supercapacitor or a battery, and the energy loss cost is calculated as follows:

[0021]

[0022] Among them, C loss represents the energy loss cost, β ele represents the electricity price, n day Indicates the number of operating days per year, I ij r ij Indicates line loss, P b,loss represents the power loss of the supercapacitor / battery, β H2 Indicates the selling price of hydrogen, LHV indicates the lower heating value of hydrogen, represents the power loss of the fuel cell, Indicates the power loss of the electrolytic cell.

[0023] According to a specific embodiment of the present invention, the power loss calculation formula of the fuel cell is as follows:

[0024]

[0025] Among them, b0, b1, b2 represent the non-negative first fitting coefficients, P fc represents the output power of the fuel cell, x fc Represents the scaling factor of the fuel cell.

[0026] According to a specific embodiment of the present invention, the power loss calculation formula of the electrolytic cell is as follows:

[0027]

[0028] Among them, c0, c1, c2 represent the non-negative second fitting coefficients, P el represents the input power of the electrolyzer, x el Indicates the scaling factor of the electrolytic cell.

[0029] According to a specific embodiment of the present invention, the energy storage system utilizes photovoltaic power generation, and the calculation formula for the renewable energy cost reduction is as follows:

[0030]

[0031] Among them, C pv,curt represents the cost of curtailing solar power, i.e. the cost of reducing renewable energy, β pv,curt Indicates the unit price of abandoned light, n day Indicates the number of operating days per year, P pv,curt,j Indicates the abandoned optical power of the energy storage system.

[0032] According to a specific embodiment of the present invention, the first objective function and the second objective function are analyzed based on a convex optimization method, and the steps of optimizing the capacity configuration and energy management of the hydrogen energy storage device and the electric energy storage device according to the investment cost of the energy storage system and the operating cost of the distribution network include: minimizing the first objective function and the second objective function to minimize the investment cost of the energy storage system and the operating cost of the distribution network, and calculating the capacity of the hydrogen energy storage device and the electric energy storage device, as well as the input / output power of the hydrogen energy storage device and the electric energy storage device. Optimizing the original capacity configuration of the hydrogen energy storage device and the electric energy storage device in the energy storage system according to the capacity of the hydrogen energy storage device and the electric energy storage device. Optimizing the energy management between the hydrogen energy storage device and the electric energy storage device in the energy storage system according to the input / output power of the hydrogen energy storage device and the electric energy storage device.

[0033] The present invention provides a capacity configuration and energy management method for an energy storage system in a distribution network. The method takes into account the energy losses of energy storage components and transmission lines in the distribution network, and collaboratively optimizes the capacity configuration and energy management of the energy storage system in the distribution network through a convex optimization method to improve the economic benefits of the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A flow chart of a specific embodiment of a method for capacity configuration and energy management of an energy storage system in a distribution network provided by the present invention;

[0035] Figure 2 This is a topological diagram of the two distribution network structures provided by the present invention. DETAILED DESCRIPTION

[0036] The following describes the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the various details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0037] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0038] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, publicly known structures and devices are shown in block diagram form rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0039] See Figure 1 A method for capacity configuration and energy management of an energy storage system in a distribution network is shown, comprising:

[0040] Step S100: constructing a first objective function based on the investment cost of the energy storage system, wherein the investment cost of the energy storage system includes at least the investment cost of the hydrogen energy storage device and the investment cost of the electric energy storage device.

[0041] Step S200: constructing a second objective function based on the operating cost of the distribution network, wherein the operating cost of the distribution network includes at least grid electricity purchase cost, component maintenance cost, energy loss cost, and renewable energy reduction cost.

[0042] Step S300: Analyze the first objective function and the second objective function based on a convex optimization method, and optimize the capacity configuration and energy management of the hydrogen energy storage device and the electric energy storage device according to the investment cost of the energy storage system and the operating cost of the distribution network.

[0043] It can be understood that the energy storage system is composed of electric energy storage devices and hydrogen energy storage devices, so that it can better cope with the instability of renewable energy. That is, when the electric power converted by renewable energy can meet the power supply needs of the distribution network and there is a surplus, the excess electric power can be converted into electric energy and hydrogen energy for storage; and when the electric power converted by renewable energy cannot meet the power supply needs of the distribution network, the stored electric energy and / or hydrogen energy can be released to maintain the power supply needs of the distribution network.

[0044] In addition, in order to achieve economical and efficient operation of the entire distribution network, it is necessary to balance the interests of all parties, including the main grid, renewable energy, and energy storage systems. This involves maximizing the energy efficiency and economic benefits of the distribution network, which requires coordinated operation between the electrical energy storage devices and hydrogen energy storage devices in the energy storage system. To this end, the primary goal is to reduce the investment cost of the energy storage system and the operating cost of the distribution network. Moreover, since the hydrogen energy storage device is composed of at least a fuel cell, an electrolyzer, and a hydrogen storage tank, the electrical energy storage device is composed of supercapacitors and / or batteries. Accordingly, the investment cost of the energy storage system includes the related costs of the fuel cell, electrolyzer, hydrogen storage tank, and supercapacitor / battery configuration. The operating cost of the distribution network includes the grid power purchase cost, component maintenance cost, energy loss cost, and curtailment cost. Furthermore, in this embodiment, a convex optimization method is used to reduce the investment cost of the above-mentioned energy storage system and the operating cost of the distribution network to achieve the optimal economic benefit of the distribution network.

[0045] It should be noted that in this embodiment, the energy storage system adopts photovoltaic power generation as an example, and the corresponding renewable energy cost reduction is the cost of curtailing light. However, this does not limit the application scope of the energy storage system. For example, when wind power generation is adopted, the renewable energy cost reduction corresponds to the cost of curtailing wind power, and so on. Without making too many restrictions on this, modifications and embellishments made to the embodiments of the present invention by those skilled in the art without departing from the spirit of the present invention still fall within the scope of the invention application of the present invention.

[0046] Specifically, since the first objective function is used to characterize the total investment cost of the energy storage system, it can be expressed as:

[0047] C inv =C fc +C el +C tank +C b ,

[0048] Among them, C inv represents the investment cost of the energy storage system, C fc represents the investment cost of the fuel cell, C el represents the investment cost of the electrolytic cell, C tank represents the investment cost of the hydrogen storage tank, Cb Represents the investment cost of the battery (taking the battery as an example, it can also be a supercapacitor, or a battery and a supercapacitor).

[0049] Furthermore, the investment cost of fuel cells can be referenced as follows:

[0050]

[0051] The investment cost of the electrolyzer can be referenced as follows:

[0052]

[0053] The investment cost of hydrogen storage tanks can be referenced as follows:

[0054]

[0055] Among them, C fc represents the investment cost of the fuel cell, C el represents the investment cost of the electrolytic cell, C tank represents the investment cost of the hydrogen storage tank, s fc Indicates the number of fuel cell cells, s el Indicates the number of cells in the electrolytic cell, s tank Indicates the number of hydrogen storage tanks, β fc represents the unit cost of the fuel cell, β el represents the unit cost of the electrolytic cell, β tank represents the unit cost of hydrogen storage tank, P fcb,max Represents the single cell capacity of the fuel cell, P elb,max Indicates the single cell capacity of the electrolytic cell, V tank Indicates the single capacity of the hydrogen storage tank, CF fc Represents the cost factor of the fuel cell and is related to its annual interest rate, component service life and the number of component replacements. CF el represents the cost factor of the electrolyzer and is related to its annual interest rate, component service life and the number of component replacements, CF tank represents the cost factor of the hydrogen storage tank, which is related to its annual interest rate, component service life and the number of component replacements, n day Indicates the number of operating days per year, y sev Indicates the service life in one year.

[0056] In addition, the investment cost of the battery can be referenced as follows:

[0057]

[0058] Among them, C b represents the investment cost of the battery, s b Indicates the number of battery cells, β brepresents the unit cost of the battery, Q b Indicates the single cell capacity of the battery, CF b represents the cost factor of the battery and is related to its annual interest rate, component service life and the number of component replacements, n day Indicates the number of operating days per year, y sev Indicates the service life in one year.

[0059] It can be seen that minimizing the first objective function can minimize the investment cost of the energy storage system.

[0060] Secondly, since the second objective function is used to characterize the total operating cost of the distribution network, it can be expressed as:

[0061] C ope =C ele +C m +C loss +C pv,curt ,

[0062] Among them, C ope represents the operating cost of the distribution network, C ele represents the cost of purchasing electricity from the power grid, C m represents the component maintenance cost, C loss represents the energy loss cost, C pv,curt Indicates the cost of abandoned light.

[0063] Correspondingly, the cost of purchasing electricity from the power grid can be referenced as follows:

[0064]

[0065] Among them, C ele represents the cost of purchasing electricity from the power grid, β ele Indicates the electricity price (unit price of electricity), n day Indicates the number of operating days per year, P gd represents the power generation of the grid, β peak represents the peak electricity price, Indicates the peak power generation capacity of the power grid in a day.

[0066] The maintenance cost of components can be referenced as follows:

[0067]

[0068] Among them, C m represents the component maintenance cost, n day Indicates the number of operating days per year, y sev represents the service life per year, β fc represents the unit cost of the fuel cell, β el represents the unit cost of the electrolytic cell, β H2tankrepresents the unit cost of hydrogen storage tank, β b Indicates the unit cost of the battery, s fc Indicates the number of fuel cell cells, s el Indicates the number of cells in the electrolytic cell, s tank Indicates the number of hydrogen storage tanks, P fcb,max Represents the single cell capacity of the fuel cell, P elb,max Indicates the single cell capacity of the electrolytic cell, V tank Indicates the single capacity of the hydrogen storage tank, Q b Indicates the single cell capacity of the battery.

[0069] The energy loss cost can be referred to as follows:

[0070]

[0071] Among them, C loss represents the energy loss cost, β ele represents the electricity price, n day Indicates the number of operating days per year, I ij r ij Indicates line loss, P b,loss Represents the power loss of the battery, β H2 Indicates the selling price of hydrogen, LHV indicates the lower heating value of hydrogen, represents the power loss of the fuel cell, Indicates the power loss of the electrolytic cell.

[0072] It should be noted here that fuel cells will produce energy conversion losses during operation, that is, losses will occur when hydrogen energy is converted into electrical energy, which can be expressed as:

[0073]

[0074] Among them, b0, b1, b2 represent the non-negative first fitting coefficients, P fc represents the output power of the fuel cell, s fc Indicates the scaling factor of the fuel cell, i.e. the number of cells.

[0075] Similarly, electrolyzers are similar to fuel cells and also produce energy conversion losses during operation. That is, the conversion of electrical energy into hydrogen energy will produce losses, which can be expressed as:

[0076]

[0077] Among them, c0, c1, c2 represent the non-negative second fitting coefficients, P el represents the input power of the electrolyzer, s el Indicates the scaling factor of the electrolytic cell, that is, the number of monomers.

[0078] Furthermore, the cost of abandoned light can be referred to as follows:

[0079]

[0080] Among them, C pv,curt represents the cost of abandoned light, β pv,curt Indicates the unit price of abandoned light, n day Indicates the number of operating days per year, P pv,curt,j Indicates the abandoned optical power of the energy storage system.

[0081] It can be seen that minimizing the second objective function can minimize the operating cost of the distribution network.

[0082] Therefore, minimizing the first and second objective functions can minimize investment and operating costs, and based on these, optimize the capacity configuration and energy management of the energy storage system, thereby achieving economical and sustainable operation of the distribution network. To this end, the capacity configuration of the energy storage system is optimized by calculating the optimized capacity of the hydrogen energy storage device and the electric energy storage device, and the energy management of the energy storage system is optimized by calculating the optimized input / output power of the hydrogen energy storage device and the electric energy storage device, thereby achieving the above goals. By adjusting the capacity configuration and energy management of the energy storage system, the efficient and economic operation of the distribution network is maintained.

[0083] In a specific embodiment, reference may be made to Figure 2 The two distribution network structures shown in the figure are used, and the capacity configuration and energy management method of the energy storage system provided in this embodiment can be applied to the distribution network structure. Among them, MVAC (Medium Voltage Alternating Current) represents medium voltage alternating current, LVAC (Low Voltage Alternating Current) represents low voltage alternating current, MVDC (Medium Voltage Direct Current) represents medium voltage direct current, LVDC (Low Voltage Direct Current) represents low voltage direct current, SST (Solid-State Transformer) represents solid-state transformer, DC / AC represents direct current / alternating current converter, DC / DC represents direct current / direct current converter, AC / DC represents alternating current / direct current converter, and LFT (Low Frequency Transformer) represents low frequency transformer. Figure 2The radial and grid structures of a distribution network are shown, respectively. In the traditional radial structure, LFTs are typically used to facilitate voltage conversion and electrical isolation between MVAC and LVAC, allowing LVAC to be distributed across the network to power various AC and DC loads. At a typical node in a radial network, multiple power conversion and isolation stages are required to integrate photovoltaic (PV) power sources, energy storage systems, and DC loads into the LVAC bus. Alternatively, SSTs can be used to perform the same function, corresponding to the grid structure. Among various configurations, a three-stage SST consisting of an AC / DC converter, an isolated DC / DC converter, and a DC / AC converter is the optimal solution. MVDC and LVDC connections can be integrated into the system. Hybrid grids with LVDC distribution offer an attractive solution for combining PV generation, energy storage systems, and DC loads, achieved by adding DC transmission lines between the LVDC bus and the distribution nodes.

[0084] It should be noted that the step division of the various methods above is only for the purpose of clear description. During implementation, they can be combined into one step or some steps can be split and decomposed into multiple steps. As long as they contain the same logical relationship, they are all within the scope of protection of this patent; adding insignificant modifications to the algorithm or process or introducing insignificant designs without changing the core design of the algorithm and process are all within the scope of protection of this patent.

[0085] In summary, the present invention provides a capacity configuration and energy management method for an energy storage system in a distribution network, which takes into account the energy losses of energy storage components and transmission lines in the distribution network, and collaboratively optimizes the capacity configuration and energy management of the energy storage system in the distribution network through a convex optimization method to improve the economic benefits of the distribution network.

[0086] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, any equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A capacity configuration and energy management method for an energy storage system in a distribution network, characterized in that: include: Constructing a first objective function based on the investment cost of the energy storage system, wherein the investment cost of the energy storage system includes at least the investment cost of the hydrogen energy storage device and the investment cost of the electric energy storage device; constructing a second objective function based on the operating cost of the distribution network, wherein the operating cost of the distribution network includes at least a grid power purchase cost, a component maintenance cost, an energy loss cost, and a renewable energy curtailment cost; The first objective function and the second objective function are analyzed based on a convex optimization method, and the capacity configuration and energy management of the hydrogen energy storage device and the electric energy storage device are optimized according to the investment cost of the energy storage system and the operating cost of the distribution network.

2. The method for capacity configuration and energy management of an energy storage system in a distribution network according to claim 1, characterized in that: The investment cost of the hydrogen energy storage device includes at least: the investment cost of the fuel cell, the investment cost of the electrolyzer, and the investment cost of the hydrogen storage tank, and the calculation formula is as follows: Fuel cell investment costs: Investment cost of electrolyzer: Investment cost of hydrogen storage tank: Among them, C fc represents the investment cost of the fuel cell, C el represents the investment cost of the electrolytic cell, C tank represents the investment cost of the hydrogen storage tank, s fc Indicates the number of fuel cell cells, s el Indicates the number of cells in the electrolytic cell, s tank Indicates the number of hydrogen storage tanks, β fc represents the unit cost of the fuel cell, β el represents the unit cost of the electrolytic cell, β tank represents the unit cost of hydrogen storage tank, P fcb,max Represents the single cell capacity of the fuel cell, P elb,max Indicates the single cell capacity of the electrolytic cell, V tank Indicates the single capacity of the hydrogen storage tank, CF fc Represents the cost factor of the fuel cell and is related to its annual interest rate, component service life and the number of component replacements. CF el represents the cost factor of the electrolyzer and is related to its annual interest rate, component service life and the number of component replacements, CF tank represents the cost factor of the hydrogen storage tank, which is related to its annual interest rate, component service life and the number of component replacements, n day Indicates the number of operating days per year, y sev Indicates the service life in one year.

3. The capacity configuration and energy management method of the energy storage system in the distribution network according to claim 1, characterized in that: The investment cost of the electric energy storage device includes the investment cost of the supercapacitor and / or battery, and is calculated as follows: Among them, C b represents the investment cost of supercapacitor / battery, s b Indicates the number of cells in the supercapacitor / battery, β b Indicates the unit cost of supercapacitor / battery, Q b Indicates the single capacity of supercapacitor / battery, CF b represents the cost factor of the supercapacitor / battery, and is related to its annual interest rate, component service life and the number of component replacements, n day Indicates the number of operating days per year, y sev Indicates the service life in one year.

4. The method for capacity configuration and energy management of an energy storage system in a distribution network according to claim 1, wherein: The calculation formula of the power grid purchase cost is as follows: Among them, C ele represents the cost of purchasing electricity from the power grid, β ele represents the electricity price, n day Indicates the number of operating days per year, P gd represents the power generation of the grid, β peak represents the peak electricity price, Indicates the peak power generation capacity of the power grid in a day.

5. The capacity configuration and energy management method of the energy storage system in the distribution network according to claim 1, characterized in that: The hydrogen energy storage device includes a fuel cell, an electrolyzer, and a hydrogen storage tank, and the electrical energy storage device includes a supercapacitor or a battery. The calculation formula for the maintenance cost of the components is as follows: Among them, C m represents the component maintenance cost, n day Indicates the number of operating days per year, y sev represents the service life per year, β fc represents the unit cost of the fuel cell, β el represents the unit cost of the electrolytic cell, β H2tank represents the unit cost of hydrogen storage tank, β b Indicates the unit cost of supercapacitor / battery, s fc Indicates the number of fuel cell cells, s el Indicates the number of cells in the electrolytic cell, s tank Indicates the number of hydrogen storage tanks, P fcb,max Represents the single cell capacity of the fuel cell, P elb,max Indicates the single cell capacity of the electrolytic cell, V tank Indicates the single capacity of the hydrogen storage tank, Q b Indicates the single cell capacity of the supercapacitor / battery.

6. The method for capacity configuration and energy management of an energy storage system in a distribution network according to claim 1, wherein: The hydrogen energy storage device includes at least a fuel cell and an electrolyzer, the electrical energy storage device includes a supercapacitor or a battery, and the energy loss cost is calculated as follows: Among them, C loss represents the energy loss cost, β ele represents the electricity price, n day Indicates the number of operating days per year, I ij r ij Indicates line loss, P b,loss represents the power loss of the supercapacitor / battery, β H2 Indicates the selling price of hydrogen, LHV indicates the lower heating value of hydrogen, represents the power loss of the fuel cell, Indicates the power loss of the electrolytic cell.

7. The method for capacity configuration and energy management of an energy storage system in a distribution network according to claim 6, characterized in that: The power loss calculation formula of the fuel cell is as follows: Among them, b0, b1, b2 represent the non-negative first fitting coefficients, P fc represents the output power of the fuel cell, s fc Indicates the number of cells in a fuel cell.

8. The method for capacity configuration and energy management of an energy storage system in a distribution network according to claim 6, characterized in that: The power loss calculation formula of the electrolytic cell is as follows: Among them, c0, c1, c2 represent the non-negative second fitting coefficients, P el represents the input power of the electrolyzer, s el Indicates the number of cells in the electrolytic cell.

9. The capacity configuration and energy management method of the energy storage system in the distribution network according to claim 1, characterized in that: The energy storage system utilizes photovoltaic power generation, and the calculation formula for the renewable energy cost reduction is as follows: Among them, C pv,curt represents the cost of curtailing solar power, i.e. the cost of reducing renewable energy, β pv,curt Indicates the unit price of abandoned light, n day Indicates the number of operating days per year, P pv,curt,j Indicates the abandoned optical power of the energy storage system.

10. The capacity configuration and energy management method of the energy storage system in the distribution network according to claim 1, characterized in that: The steps of analyzing the first objective function and the second objective function based on a convex optimization method and optimizing the capacity configuration and energy management of the hydrogen energy storage device and the electric energy storage device according to the investment cost of the energy storage system and the operating cost of the distribution network include: Minimizing the first objective function and the second objective function to minimize the investment cost of the energy storage system and the operating cost of the distribution network, and calculating the capacity of the hydrogen energy storage device and the electric energy storage device, as well as the input / output power of the hydrogen energy storage device and the electric energy storage device; Optimizing the original capacity configuration of the hydrogen energy storage device and the electric energy storage device in the energy storage system according to the capacities of the hydrogen energy storage device and the electric energy storage device; Energy management between the hydrogen energy storage device and the electric energy storage device in the energy storage system is optimized according to the input / output power of the hydrogen energy storage device and the electric energy storage device.

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