Rural hydrogen micro-grid planning method with optimal leveling cost per kilowatt-hour

Abstract

The invention relates to a rural hydrogen micro-grid planning method with optimal leveling cost per kilowatt-hour. The method comprises the following steps: step 1, establishing a rural micro-grid model considering an electricity-hydrogen deep coupling advantage; 2, establishing a rural micro-grid operation method considering hydrogen product transaction, and considering a load curve of a hydrogen fuel automobile in a rural hydrogen load application scene; 3, establishing a grid-connected rural hydrogen micro-grid collaborative planning method with the aim of leveling the optimal kilowatt-hour cost; the system has the advantages that distributed hydrogen production is achieved, the absorption rate is effectively increased, stable hydrogen load supply is formed, and the operation economical efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the field of electrical engineering technology, and in particular relates to a rural hydrogen microgrid planning method with optimal levelized cost of electricity. Background Art

[0002] In order to achieve the "dual carbon" goal, the power industry has a particularly heavy responsibility. According to China's rural energy consumption structure, it can be seen that the proportion of coal in rural energy consumption is still high. At the same time, biomass resources such as straw and firewood are renewable resources unique to rural areas. They have abundant reserves, but their utilization efficiency is relatively low. Relying on the power grid platform, vigorously developing renewable energy and improving the level of rural electrification are the keys to solving rural energy problems. Electricity is a clean, efficient and convenient secondary energy with high terminal utilization efficiency of more than 90%. Electrification is an inevitable trend in rural energy construction. We should coordinate the construction of rural microgrids, make full use of local renewable energy in rural areas with conditions, and coordinate the use of abundant biomass and other energy sources, which will help ensure rural energy supply and reduce carbon emissions, and help achieve the "dual carbon" goal. However, there are still many problems in rural microgrids, the main one being that rural power grid facilities are relatively weak. On the power generation side, the main technical difficulty faced by intermittent renewable energy power access such as photovoltaic power generation and wind power generation is that their output is highly random and has a large fluctuation range, which will bring severe tests to the fluctuation capacity of smart microgrids; especially under extreme weather conditions, it is not uncommon for renewable energy power generation to surge or plummet. If a sound fluctuation capacity smoothing operation mechanism cannot be established, it is easy to cause microgrid tripping or collapse. The current energy storage facilities cannot fully meet the operation requirements of rural microgrids; therefore, it is very necessary to provide a rural hydrogen microgrid planning method with the optimal levelized electricity cost, which can provide distributed hydrogen production, effectively improve the absorption rate, form a stable hydrogen load supply, and improve the operation economy. Summary of the invention

[0003] 1. Technical issues

[0004] In view of the above-mentioned existing technical status, this application mainly addresses the following technical problems:

[0005] 1. Rural power grid facilities are relatively weak. On the power generation side, the main technical difficulties faced by intermittent renewable energy power access such as photovoltaic power generation and wind power generation are that their output is highly random and has a large fluctuation range, which will bring severe tests to the fluctuation capacity of smart microgrids;

[0006] 2. Especially under extreme weather conditions, it is not uncommon for renewable energy generation to surge or plummet. If a sound mechanism for smoothing fluctuations in capacity is not established, it can easily lead to microgrid tripping or collapse. Current energy storage facilities cannot fully meet the operating requirements of rural microgrids.

[0007] 2. When hydrogen energy is added to the rural microgrid system, how to configure the capacity of each part of the system and improve the reliability and economy of microgrid operation has become a current problem.

[0008] (II) Technical solution

[0009] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a rural hydrogen microgrid planning method with the best levelized cost of electricity, which can produce distributed hydrogen, effectively improve the consumption rate, form a stable hydrogen load supply, and improve the operating economy.

[0010] The object of the present invention is achieved by: a rural hydrogen microgrid planning method with optimal levelized cost of electricity, the method comprising the following steps:

[0011] Step 1: Establish a rural microgrid model that takes into account the advantages of deep coupling of electricity and hydrogen;

[0012] Step 2: Establish a rural microgrid operation method that takes into account hydrogen product trading, considering the load curve of hydrogen fuel cell vehicles in rural hydrogen load application scenarios;

[0013] Step 3: Establish a collaborative planning method for grid-connected rural hydrogen microgrids with the goal of optimizing the levelized cost of electricity. Consider the initial investment cost, operation and maintenance cost, and residual value of equipment at the end of the operation period of the rural microgrid project, plan the installed capacity of each equipment under the optimal levelized cost of electricity, and set the wind and solar power abandonment rate and self-balancing rate as evaluation indicators.

[0014] Furthermore, the rural microgrid model constructed in step 1 taking into account the advantages of deep coupling of electricity and hydrogen is a source-grid-load-storage synergy model taking into account the complementary advantages of hybrid energy storage of electricity and hydrogen, including: new energy operation constraints, electrochemical energy storage operation energy storage constraints, hydrogen energy storage constraints, power balance constraints, and hydrogen supply and demand balance constraints; wherein, the new energy operation constraints are: In the formula, They represent the wind power and photovoltaic output in time period t respectively; They respectively represent the maximum power that can be generated by wind power and photovoltaic power in time period t, that is, the construction capacity.

[0015] Furthermore, the electrochemical energy storage operation energy storage constraint is: Among them, P t bat,c and P t bat,d is the electrochemical energy storage charging and discharging power at time t; P bat,c,max and P bat,d,max It is the upper limit of the charging and discharging power of electrochemical energy storage; is the charge and discharge state of electrochemical energy storage at time t; Represents the amount of electrochemical energy stored at time t; η bat,c and η bat,d E is the charge and discharge efficiency of electrochemical energy storage; bat,min and E bat,max The lower and upper limits of the storage capacity of electrochemical energy storage; and are the initial capacity and final capacity of electrochemical energy storage, respectively.

[0016] Furthermore, the hydrogen energy storage constraint is: λP H,c,max ≤P t H,c ≤P H,c,max (8), Where, λ is the minimum load rate of the electrolytic cell; P t H,c P is the hydrogen production power of the hydrogen energy storage electrolyzer at time t; t H,s is the equivalent electric power supplied by the rural microgrid to the hydrogen load at time t; P t H,c,max is the maximum hydrogen production power that the electrolyzer can achieve at time t; P H,c,max is the installed capacity of the electrolyzer; Δt is the duration of a single dispatch; η H,c The power efficiency of hydrogen production for hydrogen energy storage; represents the storage capacity of hydrogen energy at time t; E H,min and E H,max The lower and upper limits of hydrogen energy storage; and They are the initial capacity and final capacity of hydrogen energy storage respectively.

[0017] Furthermore, the power balance constraint is: Among them, P t load is the microgrid load power at time t; P t Pur Represents the purchased power at time t.

[0018] Furthermore, the hydrogen supply and demand balance constraint is: in, is the amount of hydrogen supplied by the microgrid at time t; is the hydrogen demand of hydrogen load at time t; H HV is the calorific value of hydrogen.

[0019] Furthermore, the method for establishing a rural microgrid operation method taking into account hydrogen product trading in step 2 is specifically as follows: the coordinated operation cost of the rural microgrid taking into account hydrogen product trading is as follows: In the formula, represents the total operation and maintenance cost of the rural microgrid project in year y; represents the equipment operation and maintenance cost in year y; represents the electricity purchase cost in year y; Represents the hydrogen product trading revenue in year y.

[0020] Furthermore, the step 3 of establishing a grid-connected rural hydrogen microgrid collaborative planning method with the goal of optimizing the levelized cost of electricity is specifically: establishing a source-grid-load-storage collaborative planning model for fixed load demand and with the goal of optimizing the levelized cost of electricity, to guide the planning of installed capacity of various types of equipment, and the calculation formula is as follows: in, In the formula, λ i , S i They represent the initial investment cost per unit capacity and installed capacity of equipment i respectively; represents the residual value rate of equipment i; P l,t Represents the load power at time t; N L Indicates the number of time periods into which a year is divided during the planning process.

[0021] Furthermore, the wind and solar power abandonment rate microgrid evaluation index in step 3 is: the wind and solar power abandonment rate is usually expressed as a percentage, and the calculation formula is as follows: Where, L PV , L WT They represent the rates of curtailed solar power and wind power, respectively.

[0022] Furthermore, the self-balancing rate microgrid evaluation index in step 3 is: when the grid-connected microgrid cannot meet the load demand within its internal output, the microgrid purchases electricity from the large power grid to meet the remaining load demand. The self-balancing rate represents the ratio of the power provided to the load within the microgrid to the total power demand of the load, and the expression is: Where R represents the self-balancing rate; E self The amount of electricity provided to the load within the microgrid; E total is the total load demand.

[0023] (III) Beneficial effects

[0024] 1. Establish a rural grid-connected electric-hydrogen microgrid coordination model that takes into account the advantages of hydrogen energy storage, and fully consider the regulation capacity of hydrogen energy storage in rural microgrids;

[0025] 2. Using the hydrogen consumption curve of hydrogen fuel cell vehicles as the rural hydrogen load curve, by adjusting the coordinated operation of various devices in the microgrid, it can not only meet the supply of rural electricity load and hydrogen load, but also reduce the system operation cost;

[0026] 3. Taking into account the initial investment cost, operation and maintenance cost, and residual value of equipment at the end of the operation period of rural microgrid projects, the installed capacity of each equipment under the optimal levelized cost of electricity is planned, and the wind and solar power abandonment rate and self-balancing rate are set as evaluation indicators;

[0027] 4. A hydrogen energy storage model is added to the rural grid-connected microgrid model. Hydrogen is produced by electrolyzing water during periods of surplus renewable energy, which improves the level of new energy consumption. Hydrogen is stored in hydrogen storage tanks, which can achieve a stable supply of rural hydrogen loads. Compared with the microgrid model without hydrogen energy, it can improve the power supply reliability and economy of the rural microgrid. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of the present invention.

[0029] Figure 2 This is the rural wind power, photovoltaic and electric load power per unit curve diagram of the present invention.

[0030] Figure 3 This is a hydrogen load output per unit curve diagram of the present invention.

[0031] Figure 4 It is a graph of electric energy conservation in the grid-connected hydrogen microgrid dispatching result of the present invention.

[0032] Figure 5 It is a hydrogen conservation curve diagram in the grid-connected hydrogen microgrid scheduling result of the present invention.

[0033] Figure 6 It is a curve diagram of the change of electrochemical energy storage quantity in the grid-connected hydrogen microgrid scheduling result of the present invention.

[0034] Figure 7 It is a curve diagram of the change of hydrogen storage energy of the hydrogen storage tank in the grid-connected hydrogen microgrid scheduling result of the present invention. DETAILED DESCRIPTION

[0035] In view of the above defects or improvement needs of the prior art, the present invention provides an operation planning method for a grid-connected rural microgrid with optimal cost per kilowatt-hour, thereby solving the technical problems of how to configure the capacity of various parts in the system when hydrogen energy is added to the rural microgrid system and improve the reliability and economy of the microgrid operation. To achieve the above purpose, the present invention provides an operation planning method for a grid-connected rural microgrid taking into account hydrogen product trading.

[0036] The present invention is further described below in conjunction with embodiments and / or drawings.

[0037] Example 1

[0038] like Figure 1-7As shown, a method for planning a rural hydrogen microgrid with optimal levelized cost of electricity is provided, the method comprising the following steps:

[0039] Step 1: Establish a rural microgrid model that takes into account the advantages of deep coupling of electricity and hydrogen;

[0040] In the present invention, the rural microgrid model constructed taking into account the advantages of deep coupling of electricity and hydrogen is a source-grid-load-storage synergy model taking into account the complementary advantages of electricity-hydrogen hybrid energy storage, including: new energy operation constraints, electrochemical energy storage operation energy storage constraints, hydrogen energy storage constraints, power balance constraints, hydrogen supply and demand balance constraints; wherein ① new energy operation constraints: In the formula, They represent the wind power and photovoltaic output in time period t respectively; They respectively represent the maximum power that can be generated by wind power and photovoltaic power in time period t, that is, the construction capacity.

[0041] ②Electrochemical energy storage operation energy storage constraints:

[0042] Formula (3) is the upper and lower limit constraints of the charge and discharge power of electrochemical energy storage; Formula (4) is the charge and discharge state constraint of electrochemical energy storage; Formula (5) is the charge state balance constraint of electrochemical energy storage; Formula (6) is the upper and lower limit constraints of the energy storage capacity of electrochemical energy storage; Formula (7) indicates that the initial capacity and final capacity of electrochemical energy storage must be consistent; where P t bat,c and P t bat,d is the electrochemical energy storage charging and discharging power at time t; P bat,c,max and P bat,d,max It is the upper limit of the charging and discharging power of electrochemical energy storage; is the charge and discharge state of the electrochemical energy storage at time t; constraint (4) avoids the situation where the electrochemical energy storage / hydrogen energy storage is charged and discharged at the same time; SOC t bat Represents the amount of electrochemical energy stored at time t; η bat,c and η bat,d E is the charge and discharge efficiency of electrochemical energy storage; bat,min and E bat,max The lower and upper limits of the storage capacity of electrochemical energy storage; and are the initial capacity and final capacity of electrochemical energy storage, respectively.

[0043] ③ Hydrogen energy storage constraint: λP H,c,max ≤P t H,c ≤P H,c,max (8), Since hydrogen fuel cells have low efficiency and high cost, no planning is made here. The hydrogen produced by the electrolyzer is only supplied to rural hydrogen loads and stored in hydrogen storage tanks. Formula (8) is the upper and lower limit constraints of the hydrogen production power of the hydrogen energy storage electrolyzer; Formula (9) is the maximum power limit of the electrolyzer; Formula (10) is the charge state balance constraint of the hydrogen energy storage; Formula (11) is the upper and lower limit constraints of the energy storage capacity of the hydrogen energy storage; Formula (12) indicates that the initial capacity and final capacity of the hydrogen energy storage must be consistent; where λ is the minimum load rate of the electrolyzer; P t H,c P is the hydrogen production power of the hydrogen energy storage electrolyzer at time t; t H,s is the equivalent electric power supplied by the rural microgrid to the hydrogen load at time t; P t H,c,max is the maximum hydrogen production power that the electrolyzer can achieve at time t; P H,c,max is the installed capacity of the electrolyzer; Δt is the duration of a single dispatch; η H,c The power efficiency of hydrogen production for hydrogen energy storage; represents the storage capacity of hydrogen energy at time t; E H,min and E H,max The lower and upper limits of hydrogen energy storage; and They are the initial capacity and final capacity of hydrogen energy storage respectively.

[0044] ④Power balance constraints: Among them, P t load is the microgrid load power at time t; P t Pur Represents the purchased power at time t.

[0045] ⑤ Hydrogen supply and demand balance constraints: Formula (14) indicates that the hydrogen supplied by the microgrid at time t should meet a certain proportion of the hydrogen load demand to achieve stable hydrogen supply. The missing part of the hydrogen supply is purchased at the hydrogen market price and included in the total cost; Formula (15) shows the corresponding relationship between the amount of hydrogen produced and the electric power of the electrolyzer; where, is the amount of hydrogen supplied by the microgrid at time t; is the hydrogen demand of hydrogen load at time t; H HV is the calorific value of hydrogen, which is taken as 33kWhkg.

[0046] Step 2: Establish a rural microgrid operation method that takes into account hydrogen product trading, considering the load curve of hydrogen fuel cell vehicles in rural hydrogen load application scenarios;

[0047] In the present invention, specifically: the coordinated operation cost of rural microgrids taking into account hydrogen product trading is as follows: In the formula, represents the total operation and maintenance cost of the rural microgrid project in year y; represents the equipment operation and maintenance cost in year y; represents the electricity purchase cost in year y; represents the trading income of hydrogen products in year y;

[0048] The specific formula is as follows: Where I represents the total number of equipment types considered for the overall project, i=1,2,...,4 represents wind power, photovoltaic, electrochemical energy storage, and hydrogen energy storage respectively; represents the operation and maintenance cost of device i;

[0049] The specific formula is as follows: In the formula, represents the operation and maintenance rate of equipment i; Represents the initial investment cost of equipment i.

[0050] Rural microgrid projects can purchase electricity at a time-of-use price. The specific calculation formula is as follows: In the formula, c Pur represents the electricity price at time t.

[0051] The grid-connected rural microgrid project obtains revenue by supplying hydrogen produced by the electrolyzer as a hydrogen product to rural hydrogen loads. The specific calculation formula is as follows: In the formula, c H Indicates the selling price of hydrogen.

[0052] Step 3: Establish a collaborative planning method for grid-connected rural hydrogen microgrids with the goal of optimizing the levelized cost of electricity. Consider the initial investment cost, operation and maintenance cost, and residual value of equipment at the end of the operation period of the rural microgrid project, plan the installed capacity of each equipment under the optimal levelized cost of electricity, and set the wind and solar power abandonment rate and self-balancing rate as evaluation indicators.

[0053] In the present invention, a source-grid-load-storage collaborative planning method with the goal of optimizing the levelized cost per kilowatt-hour is established. Specifically, the traditional levelized cost per kilowatt-hour calculation formula is as follows: In the formula, represents the initial investment cost of equipment i; V i R represents the residual value of fixed assets at the end of the operation period of equipment i; r represents the discount rate of the overall source, grid, load and storage project; n is the project life cycle; E y Represents the power generation of the project in the yth year; since the numerator and denominator of formula (21) are variables, the planning model with formula (21) as the objective function is nonlinear and difficult to solve.

[0054] Based on this, a source-grid-load-storage collaborative planning model is established for fixed load demand and with the goal of optimizing the levelized cost of electricity to guide the planning of installed capacity of various types of equipment. The calculation formula is as follows: in, In the formula, λ i , S i They represent the initial investment cost per unit capacity and installed capacity of equipment i respectively; represents the residual value rate of equipment i; P l,t Represents the load power at time t; N L Indicates the number of time periods into which a year is divided during the planning process.

[0055] Consider the following equipment planning constraints: α min (S WT +S PV )≤(P bat ,c ,max +P H,c,max )≤α max (S WT +S PV )(24), E bat,max =T bat P bat,c,max (25), where α max , α min Indicates the upper and lower limits of the new energy storage ratio of the project; T bat Indicates the charge and discharge time of electrochemical energy storage; S WT , S PV For the construction capacity of wind and photovoltaic units.

[0056] Microgrid evaluation indicators:

[0057] ① Wind and solar power abandonment rate: The wind and solar power abandonment rate measures the proportion of renewable energy (such as wind and solar energy) that is not utilized in the power generation process. Due to various technical, economic and policy factors, the power generation capacity of some renewable energy may not be absorbed by the power grid, resulting in wind or solar power abandonment. The wind and solar power abandonment rate is usually expressed as a percentage, and the calculation formula is as follows: Where, L PV , L WT They represent the rates of curtailed solar power and wind power, respectively.

[0058] ② Self-balancing rate: The proportion of load that can be met by the grid-connected microgrid through its own distributed power supply reflects the power supply capacity of the microgrid and its dependence on the large power grid. When the internal output of the grid-connected microgrid cannot meet the load demand, the microgrid purchases electricity from the large power grid to meet the remaining load demand. The self-balancing rate represents the ratio of the power provided to the load by the microgrid to the total power demand of the load, and the expression is: Where R represents the self-balancing rate; E selfThe amount of electricity provided to the load within the microgrid; E total is the total load demand.

[0059] The present invention provides a rural hydrogen microgrid planning method with the best levelized cost of electricity. The method is characterized in that distributed hydrogen production is carried out in rural areas, and hydrogen is produced by electrolysis of water to absorb excess new energy power generation. The produced hydrogen can be stored in hydrogen storage tanks and released when needed, and can also be sold as a hydrogen product, which can also improve the economic efficiency of rural microgrid operation; the daily hydrogen demand curve of hydrogen load around rural areas is added as a boundary condition to the rural hydrogen microgrid planning model; the present invention aims at the phenomenon that more and more new energy power generation is wasted with the large-scale construction of wind and solar units in rural areas. Distributed hydrogen production in rural microgrids can effectively improve the absorption rate of new energy, and can form a stable supply of hydrogen load around rural areas. The income from the sale of hydrogen products can also improve the operating economy of rural hydrogen microgrids; the present invention has the advantages of distributed hydrogen production, effectively improving the absorption rate, forming a stable hydrogen load supply, and improving operating economy.

[0060] Example 2

[0061] like Figure 1-7 As shown, a method for planning a rural hydrogen microgrid with optimal levelized cost of electricity is provided, the method comprising the following steps:

[0062] Step 1: Establish a rural grid-connected electric-hydrogen microgrid coordination model that takes into account the advantages of hydrogen energy storage. The model fully considers the regulation capacity of hydrogen energy storage in rural microgrids.

[0063] Step 2: Establish a microgrid operation method that takes rural hydrogen load into account, using the hydrogen consumption curve of hydrogen fuel cell vehicles as the rural hydrogen load curve, and by adjusting the coordinated operation of various microgrid devices, it can not only meet the supply of rural electricity load and hydrogen load, but also reduce the system operation cost;

[0064] Step 1: Establish a source-grid-load-storage collaborative planning method with the goal of optimizing the levelized cost of electricity. Consider the initial investment cost, operation and maintenance cost, and residual value of equipment at the end of the operation period of the rural microgrid project, plan the installed capacity of each equipment under the optimal levelized cost of electricity, and set the wind and solar power abandonment rate and self-balancing rate as evaluation indicators.

[0065] In the present invention, 1. Example analysis: Wind power and photovoltaic power are the energy sources of this system. Their output curves refer to the historical wind power and photovoltaic power output per unit data of a village in Lankao, Henan Province. The load data refer to the actual annual load output per unit curve of the village. A typical day is selected as the wind power, photovoltaic and load daily power curves, where the sampling time is 1h interval, that is, in each interval, it is considered that the power does not change, and the value is equivalent to the value at the beginning of the interval. The power curve is as follows Figure 2 shown.

[0066] The hydrogen load curve selects the daily hydrogen demand per unit curve of hydrogen fuel cell vehicles, such as Figure 3 As shown, the hydrogen load of this system selects 5 hydrogen fuel vehicles. Assuming that the hydrogen fuel vehicles travel 200km per day and consume 5.5kg of hydrogen per 100km, this system can supply 55kg of hydrogen per day.

[0067] The electrolyzer in this system uses PEM electrolyzer. Although PEM is currently more expensive, it has the advantages of high efficiency, large load-reducing operation range, and fast response speed. It is more suitable for rural distributed hydrogen production scenarios, and there is a lot of room for cost reduction in the future. In the future, PEM hydrogen production will have broader development space and potential in rural microgrids.

[0068] Table 1 shows the main parameters of the grid-connected hydrogen microgrid model.

[0069] Table 1 Main parameters of the grid-connected hydrogen microgrid model

[0070]

[0071] 2. Simulation Results

[0072] The above grid-connected hydrogen microgrid model was solved using Gurobi10.0.3 and the following results were obtained: Figure 3 The energy conservation curve in the grid-connected hydrogen microgrid dispatch results is displayed. The microgrid can maintain energy conservation in every time period. Electrochemical energy storage and hydrogen energy storage play an important role in smoothing wind and solar fluctuations and ensuring the supply of electricity load. When there is a surplus of new energy, the battery is charged and more hydrogen is produced. When the supply of new energy is insufficient, the battery discharge is used to ensure rural electricity consumption. Only during the period of 15:00-16:00, it is necessary to purchase electricity from the grid to ensure energy conservation, indicating that the hydrogen microgrid has a strong self-balancing ability. Figure 4 The hydrogen conservation curve in the grid-connected hydrogen microgrid dispatch results is shown. In the time periods of 0:00-3:00 and 20:00-24:00, wind power output is in surplus and hydrogen load demand is small. More hydrogen produced by the electrolyzer is stored in the hydrogen storage tank. In the time period of 3:00-20:00, the hydrogen produced by the electrolyzer cannot meet the demand for hydrogen load in most of the time periods, and the hydrogen storage device needs to release hydrogen to meet the conservation of hydrogen load. Figure 5 , Figure 6 The electrochemical energy storage capacity change curve and the hydrogen storage capacity change curve in the grid-connected hydrogen microgrid scheduling results are shown respectively.

[0073] Table 2 below is a table of simulation results parameters for grid-connected microgrids with hydrogen and without hydrogen.

[0074] Table 2 Parameters of simulation results of grid-connected hydrogen microgrid model

[0075]

[0076] As can be seen from Table 2, the volatility of hydrogen load is increased in the hydrogen microgrid model, and the wind curtailment rate, solar curtailment rate and self-balancing rate are reduced by 1.24%, 0.77% and 0.26% respectively compared with the microgrid without hydrogen. However, by selling hydrogen products, the LCOE is significantly reduced, which is 0.0433 lower than that of the microgrid without hydrogen, thereby improving the operating efficiency of the microgrid.

[0077] The grid-connected hydrogen microgrid operation model proposed in the present invention can form a stable hydrogen supply in rural areas, and increase the unit electricity cost of the microgrid by selling hydrogen, thereby improving the economic benefits of the microgrid operation.

[0078] The present invention provides a rural hydrogen microgrid planning method with the best levelized cost of electricity. The method is characterized in that distributed hydrogen production is carried out in rural areas, and hydrogen is produced by electrolysis of water to absorb excess new energy power generation. The produced hydrogen can be stored in hydrogen storage tanks and released when needed, and can also be sold as a hydrogen product, which can also improve the economic efficiency of rural microgrid operation; the daily hydrogen demand curve of hydrogen load around rural areas is added as a boundary condition to the rural hydrogen microgrid planning model; the present invention aims at the phenomenon that more and more new energy power generation is wasted with the large-scale construction of wind and solar units in rural areas. Distributed hydrogen production in rural microgrids can effectively improve the absorption rate of new energy, and can form a stable supply of hydrogen load around rural areas. The income from the sale of hydrogen products can also improve the operating economy of rural hydrogen microgrids; the present invention has the advantages of distributed hydrogen production, effectively improving the absorption rate, forming a stable hydrogen load supply, and improving operating economy.

Claims

1. A rural hydrogen microgrid planning method with optimal levelized cost of electricity, characterized by: The method comprises the following steps: Step 1: Establish a rural microgrid model that takes into account the advantages of deep coupling of electricity and hydrogen; Step 2: Establish a rural microgrid operation method that takes into account hydrogen product trading, considering the load curve of hydrogen fuel cell vehicles in rural hydrogen load application scenarios; Step 3: Establish a collaborative planning method for grid-connected rural hydrogen microgrids with the goal of optimizing the levelized cost of electricity. Consider the initial investment cost, operation and maintenance cost, and residual value of equipment at the end of the operation period of the rural microgrid project, plan the installed capacity of each equipment under the optimal levelized cost of electricity, and set the wind and solar power abandonment rate and self-balancing rate as evaluation indicators.

2. A method for planning a rural hydrogen microgrid with optimal levelized cost of electricity as claimed in claim 1, characterized in that: The rural microgrid model constructed in step 1 taking into account the advantages of deep coupling of electricity and hydrogen is a source-grid-load-storage synergy model taking into account the complementary advantages of electricity-hydrogen hybrid energy storage, including: new energy operation constraints, electrochemical energy storage operation energy storage constraints, hydrogen energy storage constraints, power balance constraints, and hydrogen supply and demand balance constraints; wherein, the new energy operation constraints are: In the formula, They represent the wind power and photovoltaic output in time period t respectively; They respectively represent the maximum power that can be generated by wind power and photovoltaic power in time period t, that is, the construction capacity.

3. A method for planning a rural hydrogen microgrid with optimal levelized cost of electricity as claimed in claim 2, characterized in that: The electrochemical energy storage operation energy storage constraints are: Among them, P t bat,c and P t bat,d is the electrochemical energy storage charging and discharging power at time t; P bat,c,max and P bat,d,max It is the upper limit of the charging and discharging power of electrochemical energy storage; is the charge and discharge state of electrochemical energy storage at time t; Represents the storage capacity of electrochemical energy storage at time t; η bat,c and η bat,d E is the charge and discharge efficiency of electrochemical energy storage; bat,min and E bat,max The lower and upper limits of the storage capacity of electrochemical energy storage; and are the initial capacity and final capacity of electrochemical energy storage, respectively.

4. A method for planning a rural hydrogen microgrid with optimal levelized cost of electricity as claimed in claim 2, characterized in that: The hydrogen energy storage constraint is: λP H,c,max ≤P t H,c ≤P H,c,max (8), Where, λ is the minimum load rate of the electrolytic cell; P t H,c P is the hydrogen production power of the hydrogen energy storage electrolyzer at time t; t H,s is the equivalent electric power supplied by the rural microgrid to the hydrogen load at time t; P t H,c,max is the maximum hydrogen production power that the electrolyzer can achieve at time t; P H,c,max is the installed capacity of the electrolyzer; Δt is the duration of a single dispatch; η H,c The power efficiency of hydrogen production for hydrogen energy storage; represents the storage capacity of hydrogen energy at time t; E H,min and E H,max The lower and upper limits of hydrogen energy storage; and They are the initial capacity and final capacity of hydrogen energy storage respectively.

5. A method for planning a rural hydrogen microgrid with optimal levelized cost of electricity as claimed in claim 2, characterized in that: The power balance constraint is: Among them, P t load is the microgrid load power at time t; P t Pur Represents the purchased power at time t.

6. A method for planning a rural hydrogen microgrid with optimal levelized cost of electricity as claimed in claim 2, characterized in that: The hydrogen supply and demand balance constraint is: in, is the amount of hydrogen supplied by the microgrid at time t; is the hydrogen demand of hydrogen load at time t; H HV is the calorific value of hydrogen.

7. A rural hydrogen microgrid planning method with optimal levelized cost of electricity as claimed in claim 1, characterized in that: The method for establishing a rural microgrid operation method taking into account hydrogen product transactions in step 2 is specifically as follows: the coordinated operation cost of the rural microgrid taking into account hydrogen product transactions is as follows: In the formula, represents the total operation and maintenance cost of the rural microgrid project in year y; represents the equipment operation and maintenance cost in year y; represents the electricity purchase cost in year y; Represents the hydrogen product trading revenue in year y.

8. A method for planning a rural hydrogen microgrid with optimal levelized cost of electricity as claimed in claim 1, characterized in that: The method for establishing a grid-connected rural hydrogen microgrid collaborative planning with the goal of optimizing the levelized cost of electricity in step 3 is specifically: establishing a source-grid-load-storage collaborative planning model for fixed load demand and with the goal of optimizing the levelized cost of electricity to guide the planning of installed capacity of various types of equipment. The calculation formula is as follows: in, In the formula, λ i , S i They represent the initial investment cost per unit capacity and installed capacity of equipment i respectively; represents the residual value rate of equipment i; P l,t Represents the load power at time t; N L Indicates the number of time periods into which a year is divided during the planning process.

9. A method for planning a rural hydrogen microgrid with optimal levelized cost of electricity as claimed in claim 8, characterized in that: The wind and solar power abandonment rate microgrid evaluation index in step 3 is: the wind and solar power abandonment rate is usually expressed as a percentage, and the calculation formula is as follows: Where, L PV , L WT They represent the rates of curtailed solar power and wind power, respectively.

10. A method for planning a rural hydrogen microgrid with optimal levelized cost of electricity as claimed in claim 9, characterized in that: The self-balancing rate microgrid evaluation index in step 3 is: when the internal output of the grid-connected microgrid cannot meet the load demand, the microgrid purchases electricity from the large grid to meet the remaining load demand. The self-balancing rate represents the ratio of the power provided to the load by the microgrid to the total power demand of the load, and the expression is: Where R represents the self-balancing rate; E self The amount of electricity provided to the load within the microgrid; E total is the total load demand.

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