A long-term energy storage optimization configuration method in power distribution network considering bidirectional energy conversion

Abstract

The present application relates to the field of gas-electric integrated comprehensive energy system, especially to a long-term energy storage optimization configuration method in distribution network considering energy two-way conversion, which utilizes proton exchange membrane electrolytic cell, electrolytic hydrogen production, hydrogen storage device and hydrogen fuel cell to realize the two-way conversion of electric energy and hydrogen energy, the electrolytic cell produces hydrogen and stores when the power grid load is low, and the hydrogen fuel cell generates power when the load is high. The present application establishes a capacity configuration model of hydrogen energy storage system, takes the economic cost optimization as the target, comprehensively considers the construction cost and operation and maintenance cost of the system, maximizes the utilization rate of renewable energy, reduces the phenomenon of abandoned wind and light, and enhances the flexibility and stability of the distribution network.

Description

Technical Field

[0001] This invention relates to the field of integrated gas-electric energy systems, and more particularly to a method for optimizing the configuration of medium- and long-term energy storage in a distribution network that considers bidirectional energy conversion. Background Technology

[0002] Under the "dual carbon" target, the energy structure transformation of the power distribution network is imminent, especially with the increasing proportion of renewable energy generation. The power system faces numerous challenges, including efficient absorption and stable operation. While renewable energy sources such as wind and solar power are environmentally friendly, their volatility and randomness lead to instability in the operation of the power distribution network. To address the volatility issues brought about by renewable energy integration, existing technologies typically employ battery energy storage or load regulation to balance supply and demand. However, battery energy storage suffers from high costs, limited storage time, and energy loss, making it insufficient to meet large-scale, long-term energy storage needs. Therefore, existing power distribution network energy storage technologies face the problem of being unable to store energy on a large scale and efficiently, resulting in severe wind and solar power curtailment. Summary of the Invention

[0003] To address the numerous problems existing in the prior art, this invention provides a method for optimizing the configuration of medium- and long-term energy storage in power distribution networks, considering bidirectional energy conversion. This invention utilizes a hydrogen energy storage system to achieve bidirectional conversion between electrical and hydrogen energy. During periods of low grid load, electrical energy is converted into hydrogen energy and stored via a proton exchange membrane electrolyzer. During periods of high grid load, hydrogen energy is converted into electrical energy via a hydrogen fuel cell to supply the grid, ensuring a stable power supply. Simultaneously, this invention minimizes construction and operation / maintenance costs through an optimization model, improving energy utilization efficiency and reducing renewable energy waste.

[0004] A method for optimizing the allocation of medium- and long-term energy storage in a distribution network considering bidirectional energy conversion includes the following steps:

[0005] Hydrogen is produced by electrolysis using a proton exchange membrane electrolyzer. The proton exchange membrane electrolyzer model is based on reversible voltage, electrode overvoltage, and ohmic overvoltage, and uses electrical energy to produce hydrogen.

[0006] A hydrogen storage device is modeled, and the model is configured with hydrogen storage balance constraints, upper and lower limits of hydrogen storage capacity constraints, and input and output power constraints of the hydrogen storage tank.

[0007] A hydrogen fuel cell model is constructed based on a proton exchange membrane fuel cell. The proton exchange membrane fuel cell model converts hydrogen energy into electrical energy through the electrochemical reaction of hydrogen, and takes into account operating temperature, conversion efficiency and power regulation flexibility to output electrical energy.

[0008] To ensure that the active power output and input of each node in the distribution network remain in balance, the power flow balance model comprehensively considers the power of local generation, renewable energy access and bidirectional energy conversion.

[0009] With the goal of achieving optimal economic cost, the capacity configuration of the energy storage system is optimized by combining the construction costs and annual operation and maintenance costs of the proton exchange membrane electrolyzer, hydrogen storage device, and proton exchange membrane fuel cell.

[0010] Preferably, the voltage across the proton exchange membrane electrolyzer is calculated using the following formula:

[0011]

[0012] in, This refers to the voltage across a single electrolytic cell. It is a reversible voltage; This is an electrode overvoltage; This is an ohmic overvoltage.

[0013] Preferably, the reversible voltage of the proton exchange membrane electrolyzer is calculated using the following formula:

[0014]

[0015] in, This refers to the operating temperature of the proton exchange membrane electrolyzer, which ranges from 60 to 80 degrees Celsius. Let be the ideal gas constant, taken as 8.314. ; Let be the Faraday constant, taken as 96485. ; This represents the partial pressure of hydrogen at the cathode of the electrolyzer, taken as 6.9. ; This represents the partial pressure of oxygen at the anode of the electrolytic cell, taken as 1.3. .

[0016] Preferably, the hydrogen storage capacity balance constraint of the hydrogen storage device model is calculated using the following formula:

[0017]

[0018] in, Let t be the amount of hydrogen stored in the hydrogen storage tank at time t; and These represent the input and output hydrogen power of the hydrogen storage tank at time t, respectively. and These represent the hydrogen storage and release efficiencies of the hydrogen storage tank, respectively.

[0019] Preferably, the electrical output power of the proton exchange membrane fuel cell model is calculated using the following formula:

[0020]

[0021] In the formula, It is the open-circuit voltage of a proton exchange membrane fuel cell; It is the activation loss voltage, which is related to the activation loss at low current density and is used to drive electrochemical reactions. It is the ohmic loss voltage of a proton exchange membrane fuel cell, which is related to voltage loss on contact resistance, etc. This is the concentration loss voltage, which is related to the uneven concentration that occurs when reactants are rapidly consumed.

[0022] Preferably, the energy conversion efficiency of the proton exchange membrane fuel cell is calculated using the following formula:

[0023]

[0024] in, It is the rate at which a proton exchange membrane fuel cell consumes hydrogen. Indicates that there is A proton exchange membrane fuel cell operates in series, generating a total electrical power; It is the total power generated by the chemical reaction in a proton exchange membrane fuel cell.

[0025] Preferably, the economic cost objective function of the optimized configuration model is calculated using the following formula:

[0026]

[0027] in, , , and These are the comprehensive equivalent annual cost, investment cost, maintenance cost, and operating cost, respectively. This refers to the operating cost of hydrogen energy storage.

[0028] Preferably, the economic cost objective function also includes the penalty cost of curtailing wind and solar power.

[0029] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0030] This invention achieves bidirectional conversion between electrical energy and hydrogen energy by introducing a hydrogen energy storage system. It utilizes surplus electricity to produce hydrogen during off-peak hours and generates electricity through hydrogen fuel cells during peak hours, thus solving the problems of small battery energy storage capacity, high cost, and large energy loss in existing technologies.

[0031] This invention achieves long-term and efficient energy storage through proton exchange membrane electrolyzers, electrolytic hydrogen production, hydrogen storage devices, and hydrogen fuel cells. Furthermore, by optimizing the model, it minimizes construction and operation and maintenance costs, further reducing wind and solar curtailment rates and improving the utilization rate of new energy sources. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the process of the present invention;

[0033] Figure 2 This is a flowchart of the electrolytic cell process in this invention;

[0034] Figure 3 This is a flowchart of the hydrogen storage device model in this invention;

[0035] Figure 4 This is a schematic diagram of the hydrogen fuel cell power generation process in this invention. Detailed Implementation

[0036] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0037] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0038] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0039] like Figure 1 As shown, this invention provides a method for optimizing the configuration of medium- and long-term energy storage in a distribution network that considers bidirectional energy conversion, for integrated energy systems.

[0040] This invention establishes a hydrogen energy storage system comprising an electrolyzer for hydrogen production, a hydrogen storage device, and a hydrogen fuel cell, serving as a medium- to long-term energy storage solution for power distribution networks. This system enables bidirectional energy conversion between electricity and hydrogen, utilizing surplus electricity to produce hydrogen during periods of low grid load and storing the hydrogen. During periods of high grid load, the hydrogen is used to generate electricity, thereby improving the grid's power supply capacity. Based on this, an optimized configuration method for medium- to long-term energy storage in power distribution networks is established, with the economic cost of network construction, operation, and maintenance as the objective function. The specific steps are as follows:

[0041] like Figure 2 As shown, step one: Establish an electrolyzer model that can realize the electrolytic hydrogen production process, wherein the electrolyzer is a proton exchange membrane electrolysis device with high efficiency, moderate cost, fast response speed, and good flexibility. The model is as follows:

[0042] When an electric current is applied between the cathode and the anode, the reaction that occurs at the anode is as follows:

[0043]

[0044] The anode reaction produces hydrogen ions, which then pass through the proton exchange membrane and participate in the reaction at the cathode of the electrolyzer.

[0045] The reaction formula at the cathode of the electrolytic cell is:

[0046]

[0047] The overall chemical reaction formula for proton exchange membrane electrolysis is:

[0048]

[0049] A proton exchange membrane electrolyzer electrolyzes water, producing oxygen at the anode and hydrogen at the cathode.

[0050] The electrolysis equipment of this invention is used to absorb excess electricity when the power grid load is low, and requires multiple proton exchange membrane electrolyzers to operate in series. The voltage across a single proton exchange membrane electrolyzer is:

[0051] (1)

[0052] in, This represents the voltage across a single electrolytic cell. In proton exchange membrane electrolysis, the electrolysis reaction is not spontaneous. It is the minimum starting voltage (i.e., reversible voltage) of the reaction. This is an electrode overvoltage. The concentration overvoltage is ohmic. In this model, the concentration overvoltage is neglected because in a proton exchange membrane electrolyzer, the concentration overvoltage is much smaller than that of an ohmic overvoltage. and sum.

[0053] The formula for calculating the reversible voltage of a proton exchange membrane electrolyzer is:

[0054] (2)

[0055] In the formula, This refers to the operating temperature of the proton exchange membrane electrolyzer, which is typically between 60 and 80 degrees Celsius. Let be the ideal gas constant, taken as 8.314. ; Let be the Faraday constant, taken as 96485. ; This represents the partial pressure of hydrogen at the cathode of the electrolyzer, taken as 6.9. ; This represents the partial pressure of oxygen at the anode of the electrolytic cell, taken as 1.3. .

[0056] The formula for calculating electrode overvoltage is:

[0057] (3)

[0058] In the formula, It is the anode current density, taken as ; It is the cathode current density, taken as ; It is the current density of the proton exchange membrane electrolyzer, which is the ratio of the current flowing through the proton exchange membrane electrolyzer to the effective area of ​​the electrolyzer.

[0059] (4)

[0060] in, It is the current value flowing through the proton exchange membrane electrolyzer. This is the effective area of ​​a single electrolytic cell, taken as 212.5. .

[0061] The formula for calculating the ohmic overvoltage of a proton exchange membrane electrolyzer is:

[0062] (5)

[0063] In the formula, The thickness of the proton exchange membrane is taken as 0.0178. ; The membrane conductivity is 0.14. .

[0064] Electric power that can be used for hydrogen electrolysis Input into the proton exchange membrane electrolyzer, satisfy:

[0065] (6)

[0066] The proton exchange membrane electrolyzer produces hydrogen gas during operation. The hydrogen production per unit time is... (unit: )for:

[0067] (7)

[0068] After hydrogen is produced by electrolysis, electrical energy is converted into chemical energy, and the power that produces chemical energy is... :

[0069] (8)

[0070] In the formula, The combustion enthalpy of hydrogen gas burning to form liquid water, i.e., the standard enthalpy of formation of liquid water, is taken as -285.83. .

[0071] Therefore, the energy conversion efficiency of the proton exchange membrane electrolysis module is

[0072] (9)

[0073] Step Two: As Figure 3 As shown, a hydrogen storage device model is established, including hydrogen storage balance constraints, upper and lower limits of hydrogen storage capacity constraints, and upper and lower limits of hydrogen tank input and output constraints. The hydrogen storage tank model is represented as follows:

[0074] (10)

[0075] (11)

[0076] (12)

[0077] (13)

[0078] In the formula: Let t be the amount of hydrogen stored in the hydrogen storage tank at time t; and These represent the input and output hydrogen power of the hydrogen storage tank at time t, respectively. and These are the hydrogen storage and discharging efficiencies of the hydrogen storage tank, respectively. and These are the minimum and maximum capacities of the hydrogen storage tank, respectively. , These represent the minimum and maximum hydrogen storage capacity of the hydrogen storage tank, respectively. , These represent the minimum and maximum hydrogen release power of the hydrogen storage tank, respectively. The 0-1 variable is used to characterize the hydrogen storage and release states of hydrogen storage tanks.

[0079] Step 3: Establish a hydrogen fuel cell model capable of converting hydrogen energy into electrical energy. Taking into account factors such as the fuel cell's operating temperature, conversion efficiency, and power regulation flexibility, a proton exchange membrane fuel cell (PEMFC) is chosen here, and its model is as follows:

[0080] Hydrogen gas undergoes an oxidation reaction at the negative electrode of the PEMFC:

[0081]

[0082] Oxygen undergoes a reduction reaction at the positive electrode of a proton exchange membrane fuel cell:

[0083]

[0084] The overall chemical reaction formula for a fuel cell is:

[0085]

[0086] A fuel cell can be viewed as a direct current power source; the voltage provided by a single fuel cell is... The formula for its calculation is:

[0087] (14)

[0088] In the formula, It is the open-circuit voltage of a proton exchange membrane fuel cell. It is the activation loss voltage, which is related to the activation loss at low current densities and is used to drive electrochemical reactions. This is the ohmic loss voltage of PEMFC, which is related to voltage losses due to contact resistance, etc. This is the concentration loss voltage, which is related to the concentration unevenness that occurs when reactants are rapidly consumed. The calculation formulas are as follows:

[0089] (15)

[0090] (16)

[0091] (17)

[0092] (18)

[0093] In the formula, This refers to the operating temperature of the fuel cell; PEMFCs typically operate between room temperature and 100 degrees Celsius. This is the nominal operating temperature, taken as 296K; and Set the partial pressures of oxygen and hydrogen, each at 1 atm. It is the current density, which satisfies:

[0094] (19)

[0095] In the formula, It is the current flowing through the fuel cell. It is the effective membrane area of ​​a single fuel cell, taken as 61. .

[0096] have When fuel cells are connected in series, the total electrical power they generate is:

[0097] (20)

[0098] The rate at which PEMFC consumes hydrogen is:

[0099] (twenty one)

[0100] PEMFC occurs The total power produced by a chemical reaction:

[0101] (twenty two)

[0102] like Figure 4 As shown, of the total energy released by this chemical reaction, part is converted into electrical energy via a fuel cell, and some is converted into heat and other forms during the reaction. Let the proportion of the chemical energy released by the reaction that can be used to generate electricity from the fuel cell be %. .

[0103] The energy conversion efficiency of a fuel cell is:

[0104] (twenty three)

[0105] Step 4: Establish power flow balance constraints for the power grid. The active power balance constraints for the distribution network can be expressed as:

[0106] (twenty four)

[0107] (25)

[0108] In the formula, For the power generation load of various types of generator sets (including power supplied from the upper grid, local traditional generator sets, and local renewable energy generator sets). For grid load; , Representing distribution network nodes The upper and lower limits of the generating capacity of the unit.

[0109] Step 5: Construct an optimal allocation model with the objective of achieving the best economic cost, which includes construction costs and annual operation and maintenance costs. The model is as follows:

[0110] The objective function includes the equivalent annual investment cost and the operation and maintenance cost:

[0111] (26)

[0112] (27)

[0113] (28)

[0114] (29)

[0115] In the formula: , , and These are the comprehensive equivalent annual cost, investment cost, maintenance cost, and operating cost, respectively. A collection of photovoltaic, wind power, and other generator sets; This is the capital recovery coefficient; The discount rate; For equipment Operating lifespan; , , and These are the unit capacity investment costs for equipment k, the electrolyzer, the hydrogen storage tank, and the hydrogen fuel cell, respectively. , , and The annual maintenance costs per unit capacity for equipment k, the electrolyzer, the hydrogen storage tank, and the hydrogen fuel cell are respectively. , , and These are the planned capacities for equipment k, the electrolyzer, the hydrogen storage tank, and the hydrogen fuel cell, respectively.

[0116] Annual operating costs The costs of fuel, electricity purchase and sale, and wind and solar power curtailment can be represented as follows:

[0117] (30)

[0118] In the formula: , and These are annual fuel costs, electricity purchase and sale costs, and annual penalties for wind and solar power curtailment.

[0119] The operating costs of hydrogen energy storage include the operating costs of the electrolyzer, hydrogen storage tank, and hydrogen fuel cell:

[0120] (31)

[0121] (32)

[0122] (33)

[0123] (34)

[0124] In the formula: , and These are the operating costs of the electrolyzer, hydrogen storage tank, and hydrogen fuel cell, respectively. , and These are the unit operating cost coefficients for hydrogen production by electricity, hydrogen storage tanks, and hydrogen fuel cell power generation, respectively.

[0125] Furthermore, in step one, an electrolyzer model for the hydrogen production process was established. A proton exchange membrane electrolysis (PEMEC) device, characterized by high efficiency, moderate cost, fast response, and good flexibility, was selected as the modeling object. Parameters such as reversible voltage, electrode overvoltage, and ohmic overvoltage were considered during the modeling process.

[0126] Furthermore, in step two, a model of the hydrogen storage device is established. Constraints such as hydrogen storage balance constraints, upper and lower limits of hydrogen storage capacity, and upper and lower limits of hydrogen tank input and output are considered, and the hydrogen storage tank performs hydrogen storage or release operations at a certain time period.

[0127] Furthermore, in step three, a hydrogen fuel cell model capable of converting hydrogen energy into electrical energy is established. Based on a comprehensive consideration of factors such as the fuel cell's operating temperature, conversion efficiency, and power regulation flexibility, a proton exchange membrane fuel cell (PEMFC) is selected as the modeling object.

[0128] Furthermore, step four establishes power flow balance constraints for the power distribution network. The active power of the distribution network nodes should satisfy the input-output balance, taking into account the power of various generator sets, power flow, loads, and bidirectional energy conversion.

[0129] Furthermore, step five establishes an optimal allocation model with the objective of achieving the best economic cost. This model considers the construction costs and annual operation and maintenance costs of electrolyzers, hydrogen storage tanks, hydrogen fuel cells, and other devices. The construction costs are converted to equivalent annual investment costs, while the operation and maintenance costs include annual equipment maintenance costs, fuel costs, electricity purchase and sale costs, and annual wind and solar curtailment penalties.

[0130] The present invention will be further illustrated below through a specific embodiment.

[0131] 1. Establish an electrolyzer model capable of realizing the electrolytic hydrogen production process, using a proton exchange membrane electrolysis (PEMEC) device as the modeling object. The model is as follows:

[0132] (35)

[0133] in: This refers to the voltage across a single electrolytic cell. The electrolysis reaction in PEMEC is not spontaneous. It is the minimum starting voltage (i.e., reversible voltage) of the reaction. This is an electrode overvoltage. For ohmic overvoltage; This refers to the operating temperature of the proton exchange membrane electrolyzer, which is typically between 60 and 80 degrees Celsius. Let be the ideal gas constant, taken as 8.314. ; Let be the Faraday constant, taken as 96485. ; This represents the partial pressure of hydrogen at the cathode of the electrolyzer, taken as 6.9. ; This represents the partial pressure of oxygen at the anode of the electrolytic cell, taken as 1.3. ; It is the anode current density, taken as ; It is the cathode current density, taken as ; It is the current density of the proton exchange membrane electrolyzer, which is the ratio of the current flowing through the proton exchange membrane electrolyzer to the effective area of ​​the electrolyzer. It is the current value flowing through the proton exchange membrane electrolyzer. This is the effective area of ​​a single electrolytic cell, taken as 212.5. ; The thickness of the proton exchange membrane is taken as 0.0178. ; The membrane conductivity is 0.14. ; The electrical power that can be used for hydrogen production by electrolysis; Hydrogen production per unit time (unit: ); The power that generates chemical energy in the electrolytic cell; The enthalpy of combustion for the production of liquid water from the combustion of hydrogen; This refers to the energy conversion efficiency of the proton exchange membrane electrolysis module.

[0134] 2. Establish a model for the hydrogen storage device, including constraints on hydrogen storage balance, upper and lower limits of hydrogen storage capacity, and upper and lower limits of input and output constraints for the hydrogen storage tank. The model is as follows:

[0135] (36)

[0136] in: Let t be the amount of hydrogen stored in the hydrogen storage tank at time t; and These represent the input and output hydrogen power of the hydrogen storage tank at time t, respectively. and These are the hydrogen storage and release efficiencies of the hydrogen storage tank, respectively. and These are the minimum and maximum capacities of the hydrogen storage tank, respectively. , These represent the minimum and maximum hydrogen storage power of the hydrogen storage tank, respectively. , These represent the minimum and maximum hydrogen release power of the hydrogen storage tank, respectively. The 0-1 variable is used to characterize the hydrogen storage and release states of hydrogen storage tanks.

[0137] 3. Establish a hydrogen fuel cell model capable of converting hydrogen energy into electrical energy, with the proton exchange membrane fuel cell (PEMFC) as the modeling object. The model is as follows:

[0138] (37)

[0139] In the formula: It is the open-circuit voltage of a proton exchange membrane fuel cell; It is the activation loss voltage, which is related to the activation loss at low current density and is used to drive electrochemical reactions. It is the ohmic loss voltage of PEMFC, which is related to the voltage loss on contact resistance, etc. This is the concentration loss voltage, which is related to the uneven concentration generated when reactants are rapidly consumed. This refers to the operating temperature of the fuel cell; PEMFCs typically operate between room temperature and 100 degrees Celsius. This is the nominal operating temperature, taken as 296K; and Set the partial pressures of oxygen and hydrogen, each at 1 atm. It is the current density; It is the current flowing through the fuel cell; It is the effective membrane area of ​​a single fuel cell, taken as 61. ; It refers to the number of fuel cells connected in parallel; It is the total electrical power generated; This refers to the energy conversion efficiency of a fuel cell.

[0140] 4. Establish active power balance constraints for the distribution network. The model is as follows:

[0141] (38)

[0142] In the formula, For the power generation load of various types of generator sets (including power supplied from the upper grid, local traditional generator sets, and local renewable energy generator sets); For grid load; , Representing distribution network nodes The upper and lower limits of the generating capacity of the unit; This indicates the power flow of power grid 1.

[0143] 5. Construct an optimal allocation model with the objective of achieving the best economic cost. Economic cost includes construction cost and annual operation and maintenance cost. Construction cost is converted to an equivalent annual investment cost, while operation and maintenance cost includes annual equipment maintenance cost, fuel cost, electricity purchase and sale cost, and annual wind and solar curtailment penalty cost. The objective function is as follows:

[0144] (39)

[0145] In the formula: , , and These are the comprehensive equivalent annual cost, investment cost, maintenance cost, and operating cost, respectively. A collection of photovoltaic, wind power, and other generator sets; This is the capital recovery coefficient; The discount rate; For equipment Operating lifespan; , , and These are the unit capacity investment costs for equipment k, the electrolyzer, the hydrogen storage tank, and the hydrogen fuel cell, respectively. , , and The annual maintenance costs per unit capacity for equipment k, the electrolyzer, the hydrogen storage tank, and the hydrogen fuel cell are respectively. , , and These are the planned capacities for equipment k, the electrolyzer, the hydrogen storage tank, and the hydrogen fuel cell, respectively. , and These are annual fuel costs, electricity purchase and sale costs, and annual penalties for wind and solar power curtailment; , and These are the operating costs of the electrolyzer, hydrogen storage tank, and hydrogen fuel cell, respectively. , and These are the unit operating cost coefficients for hydrogen production by electricity, hydrogen storage tanks, and hydrogen fuel cell power generation, respectively.

[0146] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects.

[0147] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for optimizing the allocation of medium- and long-term energy storage in a distribution network considering bidirectional energy conversion, characterized in that, Includes the following steps: Hydrogen is produced by electrolysis using a proton exchange membrane electrolyzer. The proton exchange membrane electrolyzer model is based on reversible voltage, electrode overvoltage, and ohmic overvoltage, and uses electrical energy to produce hydrogen. The calculation expression is as follows: in: This refers to the voltage across a single electrolytic cell. The electrolysis reaction in PEMEC is not spontaneous. It is the minimum starting voltage (i.e., reversible voltage) of the reaction. This is an electrode overvoltage. For ohmic overvoltage; This refers to the operating temperature of the proton exchange membrane electrolyzer, which is 60-80 degrees Celsius. Let be the ideal gas constant, taken as 8.

314. ; Let be the Faraday constant, taken as 96485. ; This represents the partial pressure of hydrogen at the cathode of the electrolyzer, taken as 6.

9. ; This represents the partial pressure of oxygen at the anode of the electrolytic cell, taken as 1.

3. ; It is the anode current density, taken as ; It is the cathode current density, taken as ; It is the current density of the proton exchange membrane electrolyzer, which is the ratio of the current flowing through the proton exchange membrane electrolyzer to the effective area of ​​the electrolyzer. It refers to the number of proton exchange membrane electrolyzers; It is the current value flowing through the proton exchange membrane electrolyzer. This is the effective area of ​​a single electrolytic cell, taken as 212.

5. ; The thickness of the proton exchange membrane is taken as 0.0178. ; The membrane conductivity is 0.

14. ; The electrical power that can be used for hydrogen production by electrolysis; Hydrogen production per unit time (unit: ); The power that generates chemical energy in the electrolytic cell; The enthalpy of combustion for the production of liquid water from the combustion of hydrogen; The energy conversion efficiency of the proton exchange membrane electrolysis module; A hydrogen storage device is modeled, and the model is configured with hydrogen storage balance constraints, upper and lower limits of hydrogen storage capacity constraints, and input and output power constraints of the hydrogen storage tank. A hydrogen fuel cell model is constructed based on a proton exchange membrane fuel cell. The proton exchange membrane fuel cell model converts hydrogen energy into electrical energy through the electrochemical reaction of hydrogen, and takes into account operating temperature, conversion efficiency and power regulation flexibility to output electrical energy. To ensure that the active power output and input of each node in the distribution network remain in balance, the power flow balance model comprehensively considers the power of local generation, renewable energy access and bidirectional energy conversion. With the goal of optimizing economic cost, and considering the construction costs and annual operation and maintenance costs of proton exchange membrane electrolyzers, hydrogen storage devices, and proton exchange membrane fuel cells, the capacity configuration of the energy storage system is optimized. The objective function is as follows: In the formula: , , and These are the comprehensive equivalent annual cost, investment cost, maintenance cost, and operating cost, respectively. A collection of photovoltaic, wind power, and other generator sets; This is the capital recovery coefficient; The discount rate; For equipment Operating lifespan; , , and These are the unit capacity investment costs for equipment k, the electrolyzer, the hydrogen storage tank, and the hydrogen fuel cell, respectively. , , and The annual maintenance costs per unit capacity for equipment k, the electrolyzer, the hydrogen storage tank, and the hydrogen fuel cell are respectively. , , and These are the planned capacities for equipment k, the electrolyzer, the hydrogen storage tank, and the hydrogen fuel cell, respectively. , and These are annual fuel costs, electricity purchase and sale costs, and annual penalties for wind and solar power curtailment; , and These are the operating costs of the electrolyzer, hydrogen storage tank, and hydrogen fuel cell, respectively. , and These are the unit operating cost coefficients for hydrogen production by electricity, hydrogen storage tanks, and hydrogen fuel cell power generation, respectively. For the electrolytic cell in Input power during a given time period; , The hydrogen storage tanks are respectively Input and output power during a given time period; For hydrogen fuel cells Output power during the time period; A 0-1 variable representing the input and output states of the hydrogen storage tank. A value of 0 indicates input, while a value of 0 indicates output.

2. The method for optimizing the configuration of medium- and long-term energy storage in a distribution network considering bidirectional energy conversion as described in claim 1, characterized in that, The hydrogen storage capacity balance constraint of the hydrogen storage device model is calculated using the following formula: in, Let t be the amount of hydrogen stored in the hydrogen storage tank at time t; and These represent the input and output hydrogen power of the hydrogen storage tank at time t, respectively. and These represent the hydrogen storage and release efficiencies of the hydrogen storage tank, respectively.

3. The method for optimizing the configuration of medium- and long-term energy storage in a distribution network considering bidirectional energy conversion as described in claim 1, characterized in that, The output voltage of the proton exchange membrane fuel cell model is calculated using the following formula: In the formula, It is the open-circuit voltage of a proton exchange membrane fuel cell; It is the activation loss voltage, which is related to the activation loss at low current density and is used to drive electrochemical reactions. It is the ohmic loss voltage of a proton exchange membrane fuel cell, which is related to voltage loss on contact resistance, etc. This is the concentration loss voltage, which is related to the uneven concentration that occurs when reactants are rapidly consumed.

4. The method for optimizing the configuration of medium- and long-term energy storage in a distribution network considering bidirectional energy conversion as described in claim 1, characterized in that, The energy conversion efficiency of the proton exchange membrane fuel cell is calculated using the following formula: in, It refers to the energy conversion efficiency of a proton exchange membrane fuel cell; Indicates that there is A proton exchange membrane fuel cell operates in series, generating a total electrical power. It is the total power generated by the chemical reaction in a proton exchange membrane fuel cell.

5. The method for optimizing the configuration of medium- and long-term energy storage in a distribution network considering bidirectional energy conversion as described in claim 1, characterized in that, The economic cost objective function also includes the penalty cost of curtailing wind and solar power.

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