Two-stage optimization method for island microgrid considering hydrogen energy cascade utilization

Abstract

The present application relates to a kind of island micro energy network two-stage optimization method considering hydrogen energy cascade utilization, belong to integrated energy field, including the island micro energy network of integrated hydrogen energy cascade utilization device is constructed;Based on wind power, photovoltaic and historical data of photo-thermal power station, and the output of energy supply equipment, storage device, gas turbine and hydrogen fuel cell of island micro energy network, the day-ahead stage objective function with day-ahead market net profit maximum as target is constructed;Day-ahead target function is solved based on day-ahead supply-demand balance constraint, unit constraint and demand response constraint, and the electric, heat and gas transaction volume of day-ahead market is obtained;The real-time stage objective function with the minimum adjustment cost of island micro energy network real-time market deviation as target is constructed;Real-time target function is solved based on real-time supply-demand balance constraint, unit constraint, demand response constraint, the uncertainty of supply-demand cooperation and the electric, heat and gas transaction volume of day-ahead market, and the optimal solution of each unit output and the reduction amount of demand side reducible load are obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of comprehensive energy, in particular to a two-stage optimization method for island micro energy network considering hydrogen energy cascade utilization. BACKGROUND

[0002] As a large country with vast sea areas, China cannot ignore the large amount of exploitable energy resources in the sea. However, due to the geographical location of most islands far away from the mainland and the imbalance between energy types and demand loads on the islands, the traditional energy supply on the islands relies on ship transportation, which is difficult to meet the growing demand for multiple types of energy on the islands. With the continuous development of island development and the increasing demand for electricity, heat and gas loads on the islands, the self-sufficient energy supply mode on the islands cannot meet the growing demand for multiple loads, so it is inevitable to build a large-scale island multi-energy micro-grid cluster energy supply network for the sustainable development of islands.

[0003] Island areas have abundant renewable energy such as wind and solar energy, but these energy sources are intermittent and unstable. The current structure of micro energy networks mainly focuses on micro energy network utilization scenarios in rural areas, cities, industrial parks, etc., and the devices involved mainly include wind power, photovoltaic, energy storage and demand response (a phenomenon on the user side, such as reducing load demand when increasing electricity price, or increasing load demand when reducing electricity price, to participate in grid regulation in this way), etc. Due to the abundance of seawater resources and adequate light resources on islands, the optimization of existing island micro energy networks is the key to improving energy utilization efficiency.

[0004] At the same time, the uncertainty of internal devices in the island micro energy network will affect the final scheduling result. How to characterize this fluctuation factor is an important prerequisite for ensuring the safe and stable operation of the system. Most current researches only focus on the impact of output uncertainty of supply-side resources such as wind and light or demand-side resource load uncertainty on the scheduling results of micro energy networks, and do not maximize the mobilization of internal supply and demand resources to form a supply and demand interconnection and cooperation mode to improve the energy supply reliability of island micro energy networks. Therefore, it is urgent to propose an optimization strategy for supply and demand cooperation operation.

[0005] The existing island micro energy network does not consider the hydrogen load demand of the micro energy network and the abundant seawater resources, does not realize the recycling of carbon elements to reduce carbon dioxide emissions, and does not maximize the mobilization of internal supply and demand resources to form a supply and demand interconnection and cooperation mode to improve the energy supply reliability of island micro energy networks and meet the growing demand for multiple loads. SUMMARY

[0006] In view of the above analysis, the embodiment of the present application aims to provide a two-stage optimization method for island micro energy network considering hydrogen energy cascade utilization, to solve the technical problems that the existing method does not consider the cascade utilization of island hydrogen energy and the richness of seawater resources, and fails to maximize the mobilization of internal supply and demand resources, forming an effective supply and demand interconnection collaboration mode, to improve the energy supply reliability of island micro energy network and meet the demand of various loads.

[0007] The present application provides a two-stage optimization method for island micro energy network considering hydrogen energy cascade utilization, comprising the following steps:

[0008] Constructing an island micro energy network integrated with a new hydrogen energy cascade utilization device;

[0009] Based on the obtained historical data of wind power, photovoltaic and photothermal power stations, and the output of energy supply equipment, energy storage equipment, gas turbine and hydrogen fuel cell of the island micro energy network, a day-ahead stage objective function is constructed with the goal of maximizing the net profit of the day-ahead market;

[0010] Solving the day-ahead stage objective function based on day-ahead supply and demand balance constraints, day-ahead unit constraints and demand response constraints, to obtain the electricity, heat and gas transaction volume of the day-ahead market;

[0011] Constructing a real-time stage objective function with the goal of minimizing the real-time market deviation adjustment cost of the island micro energy network;

[0012] Solving the real-time stage objective function based on real-time supply and demand balance constraints, real-time unit constraints, real-time demand response constraints, the uncertainty of supply and demand cooperation and the electricity, heat and gas transaction volume of the day-ahead market as constraints, to obtain the optimal solution of the output of each unit on the supply side of the island micro energy network, and the reduction amount of the reducible load on the demand side of the user.

[0013] Further, the new hydrogen energy cascade utilization device comprises an electrolyzer, a hydrogen storage device, a hydrogen fuel cell and a methane reactor;

[0014] The electrolyzer is used to electrolyze seawater using the remaining clean energy generated during the large-scale generation of wind energy and photovoltaic energy units in the island micro energy network, to obtain hydrogen and oxygen, and to convert electrical energy into hydrogen energy;

[0015] The hydrogen storage device is used to store the hydrogen obtained by conversion through the electrolyzer;

[0016] The hydrogen fuel cell is used to obtain hydrogen converted by the electrolyzer or hydrogen stored in the hydrogen storage device when the demand for island electricity increases, and to convert hydrogen and oxygen into electrical energy and thermal energy through reaction;

[0017] The methane generator is used for reacting hydrogen gas converted by the electrolytic cell or hydrogen gas stored in the hydrogen storage device with carbon dioxide generated by a gas turbine in a combined heat and power unit in the island micro energy network to generate easy-to-store and transport methane natural gas, thereby realizing carbon cycle.

[0018] The heat energy generated by the hydrogen fuel cell is collected by a waste heat recovery device in the combined heat and power unit for heat energy utilization.

[0019] Further, the energy supply equipment output includes wind power, photovoltaic, photo-thermal power station, combined heat and power unit and ground source heat pump output.

[0020] The energy storage equipment output includes storage of electricity, heat and hydrogen devices.

[0021] Further, the day-ahead stage objective function is as follows:

[0022]

[0023] Wherein, F r is the day-ahead market island micro energy network net income, α1 is the probability of exceeding the expected income, represents the supply side net income F r is greater than the expected net income The probability is greater than or equal to α1. And are the electricity, heat and gas trading volumes at t period respectively; And are the electricity, heat and gas prices at t period respectively; And are the operation and maintenance cost and depreciation cost of unit n at t time respectively; T is the dispatching period; N is the number of units, is the unit output of equipment n in the island micro energy network at t period; is the unit operation and maintenance cost of equipment n; are the outputs of wind power, photovoltaic, photo-thermal power station, combined heat and power unit, ground source heat pump, electricity storage device, heat storage device, hydrogen storage device, gas turbine and hydrogen fuel cell unit at t period respectively.

[0024] The unit n is wind power, photovoltaic, new hydrogen energy cascade utilization device, combined heat and power unit, electricity storage device, ground source heat pump, photo-thermal power station unit in the island micro energy network.

[0025] When the island micro energy net income is maximum, the utilization rate of electricity, heat and gas load is maximum.

[0026] Further, the day-ahead supply and demand balance constraint is as follows:

[0027]

[0028]

[0029] wherein β1, β2 and β3 are the electricity, heat and gas supply-demand balance confidence respectively, and are the electricity, heat and gas demand of the island micro-energy network user in the time period t at time t; and are the output of the wind power, photovoltaic, gas turbine, photo-thermal power station and hydrogen fuel cell at time t; and are the heat output of the hydrogen storage device, hydrogen fuel cell and power heat pump respectively; are the gas load demand satisfied by the methane reactor and external natural gas network at time t respectively;

[0030] The day-ahead unit constraints include wind power, photovoltaic, photo-thermal power station, electricity storage device and new hydrogen energy cascade utilization device unit output constraints.

[0031] Further, the real-time stage objective function is as follows:

[0032]

[0033] wherein F c is the real-time market island micro-energy network deviation adjustment cost, α2 is the probability of exceeding the expected deviation adjustment cost, represents the probability that the island micro-energy network deviation adjustment cost is less than the expected deviation adjustment cost is greater than or equal to α2, is the incentive demand response cost of the kth type of load at time t; is the unit reduction penalty cost of the kth type of load at time t; is the type of load shedding at time t, are the electricity, heat and gas load shedding types at time t respectively, is the compensation price of the kth type of load in the time period t interruption or transfer, are the real-time stage electricity, heat and gas load transfer amounts respectively, l is the step size of the kth type of load, and v is the step price of the kth type of load;

[0034] wherein the kth type of load is the electricity, heat and gas three types of load.

[0035] Further, the real-time supply-demand balance constraint is as follows:

[0036]

[0037] Wherein, β6, β7 and β8 are respectively the real-time stage electric, thermal and gas supply and demand balance confidence, which are preset values, and are respectively the real-time electric, thermal and gas cut load at time t; and are respectively the real-time electric, thermal and gas transfer load at time t; and are respectively the electric, thermal and gas load uncertainty factors; are respectively the electric load satisfied by the real-time market wind power, photovoltaic, gas turbine, solar-thermal power station and hydrogen fuel cell at time t; are respectively the thermal load satisfied by the real-time market electricity storage device, hydrogen storage device, hydrogen fuel cell and heat pump at time t; is the gas load satisfied by the real-time market methane reactor at time t.

[0038] Further, the real-time demand response constraint is as follows:

[0039]

[0040] Wherein, and are respectively the upper and lower limits of the user participation demand response electric load interruption and transfer at time t; and are respectively the upper and lower limits of the user participation demand response thermal load interruption and transfer at time t; and are respectively the upper and lower limits of the user participation demand response gas load interruption and transfer at time t; β9, β 10 and β 11 are respectively the real-time stage electric, thermal and gas demand response confidence.

[0041] Further, the real-time unit constraint includes real-time wind turbine constraint, photovoltaic unit constraint, new hydrogen energy cascade utilization device unit constraint, solar-thermal power station unit constraint, gas turbine unit constraint, hydrogen fuel cell unit constraint, electricity storage device unit constraint, hydrogen storage device unit constraint and ground source heat pump unit constraint.

[0042] Further, in addition to integrating the new hydrogen energy cascade utilization device, the island micro energy network also includes wind power, photovoltaic, combined heat and power unit, solar-thermal power station, electricity storage device, ground source heat pump, external gas network and load;

[0043] The combined heat and power unit includes a gas turbine, a waste heat recovery device and a heat exchange device;

[0044] The solar-thermal power station includes a generator, a heat collection field and a heat storage device;

[0045] The load includes electricity, heat and gas load;

[0046] Among them, wind power, photovoltaic, photothermal power station, combined heat and power unit, ground source heat pump are energy supply equipment; electricity storage device, heat storage device and hydrogen storage device are energy storage equipment.

[0047] Compared with the prior art, the present application can at least realize one of the following beneficial effects:

[0048] 1、The present application constructs an island micro energy network structure integrated with a new hydrogen energy cascade utilization device, considers the uncertainty of the supply and demand sides and the cooperation strategy of the supply and demand sides, adds a ladder type demand response price mechanism, constructs a two-stage stochastic optimization model of supply and demand cooperation, wherein the total planned output in the day-ahead stage is obtained as an objective function to maximize the system net profit; the objective of minimizing the operation cost is constructed in the real-time stage to carry out optimization, the incremental output of the unit and the demand response of the user are called to suppress the deviation, and finally the real-time optimal output scheme in the day is obtained to meet the total planned output in the day-ahead stage. The present application aggregates the distributed resources, more optimally considers the multi-type energy load demand of the micro energy network, and better promotes the consumption of wind power and photovoltaic, and promotes the transformation of the power system in China;

[0049] 2、The present application constructs a large-scale island multi-energy micro grid cluster energy supply network, enhances the energy self-sufficiency of the island area, reduces the dependence on external energy supply, especially for the islands far from the mainland, which is particularly important. The abundant wind power and photovoltaic renewable energy of the island is utilized, the effective conversion and cascade utilization between electricity, heat and gas energy are realized through the hydrogen energy cascade utilization device, and the comprehensive utilization efficiency of energy is improved;

[0050] 3、The present application realizes the accurate matching and interconnection cooperation of the supply and demand sides through the two-stage optimization method of the day-ahead market and the real-time market, improves the energy supply reliability of the island micro energy network, and meets the increasing demand of various loads. Through the objective functions of maximizing the net profit in the day-ahead market and minimizing the deviation adjustment cost in the real-time market, the operation cost of the island micro energy network is reduced;

[0051] 4、The present application considers the uncertainty of the supply and demand sides, effectively deals with the volatility and uncertainty of wind power and photovoltaic new energy output, enhances the flexibility and reliability of the system. And the hydrogen and carbon dioxide are reacted to generate methane natural gas through the methane reactor, realizes the recycling of carbon elements, reduces the emission of carbon dioxide, and reduces environmental pollution. By maximizing the mobilization of internal supply and demand resources, an effective supply and demand interconnection cooperation mode is formed, and the energy supply security of the island micro energy network in the face of emergencies and extreme weather is improved;

[0052] 5、The hydrogen energy cascade utilization device maximizes the use of wind energy and photovoltaic energy, reduces the problem of abandoned wind and light, and promotes the consumption of renewable energy.

[0053] The above technical solutions can be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by those skilled in the art. The purpose and other advantages of the present application can be achieved and obtained from the contents specifically pointed out in the specification and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0054] The accompanying drawings are included to provide a further understanding of the embodiments, and are incorporated in and constitute a part of this application, illustrate embodiments of the application, and together with the description serve to explain the principles of the application.

[0055] Figure 1 It is a kind of island micro energy network optimization method flow chart considering hydrogen energy cascade utilization;

[0056] Figure 2 It is an island micro energy network structure schematic diagram;

[0057] Figure 3 It is a hydrogen energy cascade utilization device structure schematic diagram;

[0058] Figure 4 It is an incentive demand response ladder type cost schematic diagram;

[0059] Figure 5 It is an extreme scenario schematic diagram;

[0060] Figure 6 It is a demand side uncertainty schematic diagram. DETAILED DESCRIPTION

[0061] The preferred embodiments of the present application will be specifically described below in combination with the drawings, wherein the drawings constitute a part of this application, and are used to illustrate the principles of the embodiments of the present application, and are not used to limit the scope of the present application.

[0062] The present application aims to propose a two-stage optimization method of island micro energy network considering hydrogen energy cascade utilization, a new type of hydrogen energy cascade utilization device is integrated on the basis of traditional island micro energy network, a new type of hydrogen energy cascade utilization device is introduced, and a new type of island micro energy network system structure is formed;

[0063] A two-stage operation optimization model of island micro energy network supply-demand cooperation considering uncertainty is constructed by taking day-ahead stage profit maximization and intraday implementation stage cost minimization as objective functions, so as to maximize the mobilization of supply and demand resources, improve the reliability of island micro energy network power supply and meet the demand of various loads.

[0064] On the basis of the traditional island micro energy network structure, hydrogen energy and heat energy are reasonably transformed and utilized through devices such as hydrogen production by electrolysis and photo-thermal power station, electric energy conversion is realized, and the demand side of island users for electric, heat and gas load demand is met.

[0065] As shown in Figure 1 One specific embodiment of the present application discloses a two-stage (day-ahead stage and real-time stage) optimization method of island micro energy network considering hydrogen energy cascade utilization, comprising the following steps:

[0066] Step S1, constructing an island micro energy network integrated with new hydrogen energy cascade utilization devices;

[0067] Step S2, based on the obtained historical data of wind power, photovoltaic and photo-thermal power station, and the output of energy supply equipment, energy storage equipment, gas turbine and hydrogen fuel cell of the island micro energy network, a day-ahead stage objective function taking the maximum day-ahead market net profit as the target is constructed;

[0068] Step S3, solving the day-ahead stage objective function based on day-ahead supply-demand balance constraints, day-ahead unit constraints and demand response constraints to obtain the electric, heat and gas transaction volume of the day-ahead market;

[0069] Step S4, constructing a real-time stage objective function taking the minimum real-time market deviation adjustment cost of the island micro energy network as the target;

[0070] Step S5, solving the real-time stage objective function based on real-time supply-demand balance constraints, real-time unit constraints, real-time demand response constraints, uncertainty of supply-demand cooperation and the electric, heat and gas transaction volume of the day-ahead market as constraints to obtain the optimal solution of each unit output of the supply side of the island micro energy network and the reduction amount of the reducible load of the demand side of the user.

[0071] Step S1 includes steps S11-S12.

[0072] S11, constructing an island micro energy network integrated with new hydrogen energy cascade utilization devices.

[0073] On the basis of the traditional micro energy network, the island micro energy network breaks through the original device barriers, considers the integration of new hydrogen energy cascade utilization devices, and proposes an island micro energy network integrating electric energy, natural gas and hydrogen energy.

[0074] In order to practically solve the energy demand of various energy categories in island scenarios, such as Figure 2As shown, the present application integrates an electrolysis cell EC, a methane reactor MR, a hydrogen storage device HSD, and a hydrogen fuel cell HFC to form a new cascade hydrogen utilization device CHUD.

[0075] In addition to the new cascade hydrogen utilization device, the island micro-energy network also includes a wind power plant WPP, a photovoltaic power plant PV, a coupled-heating-power unit CHP, a solar thermal power plant STPP, a power storage device PSD, a ground source heat pump unit GSHP, an external gas network, and a load.

[0076] The coupled-heating-power unit includes a gas turbine GT, a waste heat recovery device WHD, and a change heat device CH.

[0077] The solar thermal power plant includes a power generator PG, a heating central field HCF, and a heating storage system HSS.

[0078] The load includes an electricity load EL, a hydrogen load HL, and a gas load GL.

[0079] The wind power plant, the photovoltaic power plant, the solar thermal power plant, the coupled-heating-power unit, and the ground source heat pump unit are energy supply devices.

[0080] The load includes an electricity load EL, a hydrogen load HL, and a gas load GL.

[0081] When the island micro energy network system is running, wind power, photovoltaic and photo-thermal power station are used to meet the system's electricity and heat load demand. Through heat collection in the heat collection field, electricity is directly generated by the generator to meet the electricity load EL demand, and through the heat storage device, heat charging and heat releasing are carried out to meet the electricity and heat load demand, realizing energy multi-energy collaborative.

[0082] By using the natural gas resources on the island, using the cogeneration unit in the mode of "electricity determines heat", the gas turbine is used to preferentially meet the electricity load demand of the user, and the waste heat boiler is used to absorb the waste heat through the waste heat recovery device to meet the heat load demand; considering the incomplete matching characteristics of the wind and light energy supply units and the user load, the electricity storage device, the ground source heat pump and the hydrogen energy cascade utilization device are used to realize electricity conversion and meet the electricity, heat and gas load demand.

[0083] S12, construct a new hydrogen energy cascade utilization device structure.

[0084] The new hydrogen energy cascade utilization device includes an electrolytic cell, a hydrogen storage device, a hydrogen fuel cell and a methane reactor; the energy flow relationship is as shown in Figure 3 .

[0085] The electrolytic cell is used to electrolyze seawater using the remaining clean energy generated by the wind energy and photovoltaic energy unit in the island micro energy network, to obtain hydrogen and oxygen, and to convert electricity into hydrogen energy;

[0086] The hydrogen storage device is used to store the hydrogen obtained by the electrolytic cell;

[0087] The hydrogen fuel cell is used to obtain hydrogen converted by the electrolytic cell or hydrogen stored in the hydrogen storage device when the island electricity demand increases, and to convert hydrogen and oxygen into electricity and heat energy;

[0088] The methane generator is used to react the hydrogen converted by the electrolytic cell or the hydrogen stored in the hydrogen storage device with the carbon dioxide generated by the gas turbine in the cogeneration unit in the island micro energy network to generate easy-to-store and transport methane natural gas, realizing carbon cycle;

[0089] Wherein, the heat energy generated by the hydrogen fuel cell is collected by the waste heat recovery device in the cogeneration unit for heat energy utilization.

[0090] When wind and photovoltaic clean energy units are generating a large amount of electricity, the electrolytic cell absorbs the remaining clean energy to electrolyze seawater H2O to generate hydrogen H2 and oxygen O2, and the hydrogen is stored by a hydrogen storage device. In order to reduce the energy loss caused by hydrogen methanation, a hydrogen fuel cell is configured to store a part of hydrogen energy. When the electricity is insufficient, the hydrogen fuel cell is used to convert hydrogen energy into electricity to meet the electricity demand. A part of hydrogen energy is converted into methane by a methane reactor and injected into the external gas network natural gas system to meet the gas demand. The waste heat recovery device in the combined heat and power unit is used to recover the heat generated by the methane chemical reaction to meet the heat demand.

[0091] The electrolytic cell is the starting point of the hydrogen energy cascade utilization device.

[0092] The hydrogen H2 stored in the hydrogen storage device is stored in the form of compressed hydrogen or liquefied hydrogen;

[0093] The hydrogen fuel cell converts the chemical energy in hydrogen into electrical energy and generates heat energy at the same time;

[0094] The methane reactor: a part of hydrogen obtained by electrolyzing water in the electrolytic cell is used for power generation, and a part of hydrogen reacts with carbon dioxide CO2 in the methane reactor to generate methane CH4, which is called methanation, and the hydrogen is converted into natural gas form which is easy to store and transport;

[0095] The waste heat recovery device in the combined heat and power unit collects the heat energy generated in the hydrogen fuel cell HFC and the methane reactor MR, and the heat energy is used for heating, hot water or industry to meet the heat demand of the island demand side and improve the energy utilization efficiency.

[0096] The design goal of the new hydrogen energy cascade utilization device is:

[0097] (1) Maximize the utilization efficiency of clean energy (photovoltaic and wind power) and reduce the waste of abandoned wind and light energy;

[0098] (2) Provide flexible energy supply and utilization methods to cope with the intermittency and instability of renewable energy;

[0099] (3) Convert hydrogen into natural gas energy form which is easy to store and transport through the methanation process;

[0100] (4) Improve the comprehensive utilization efficiency of energy and reduce the overall energy consumption of the system through the waste heat recovery device.

[0101] The hydrogen energy cascade utilization device is introduced in the hydrogen production link, hydrogen to electricity and heat link and hydrogen to methane link, as follows:

[0102] (1) Hydrogen production link

[0103] The electrolyzer is the first link in the new hydrogen energy cascade utilization device. Through the conversion of electrical energy (provided by photovoltaic and wind power) into hydrogen energy, the electricity-hydrogen conversion is realized, and the input-output model is as follows:

[0104]

[0105] Among them, and are the hydrogen power output by the electrolyzer and the electrical power input into the electrolyzer, respectively, EC , b EC and c EC are the quadratic term coefficient, the linear term coefficient and the constant term coefficient of the electrolysis efficiency function, respectively, and these coefficients affect the electrolysis efficiency and the energy conversion process; is the rated power of the electrolyzer, and η EC is the water electrolysis efficiency of the electrolyzer.

[0106] The input of the electrolyzer is the electrical energy provided by photovoltaic and wind power, and seawater, and the output of the electrolysis is hydrogen and oxygen.

[0107] The hydrogen electrolyzed by the electrolyzer is transported to the hydrogen storage device for storage, and to the methane reactor for methanation.

[0108] The hydrogen production link realizes efficient and reliable hydrogen energy production and storage, and methanation to generate methane, providing a basis for subsequent hydrogen utilization links (such as the hydrogen-to-electricity-heat link and the hydrogen-to-methane link).

[0109] (2) Hydrogen-to-electricity-heat link

[0110] When the island's power demand increases, the hydrogen in the hydrogen storage device is sent to the hydrogen fuel cell HFC, and the hydrogen fuel cell reacts hydrogen with oxygen to convert into electrical energy and thermal energy.

[0111] The hydrogen fuel cell realizes the conversion between hydrogen energy and electrical energy and thermal energy, realizes hydrogen-electricity conversion and hydrogen-heat conversion, and the conversion efficiency is approximately regarded as a constant, and the input-output model is as follows:

[0112]

[0113] Among them, P t HFC is the total power of the hydrogen fuel cell at time t, is the hydrogen power input into the hydrogen fuel cell by the hydrogen storage device HSD at time t, and are the electrical and thermal power output by the hydrogen fuel cell HFC at time t, respectively; and are the electrical and thermal power conversion efficiencies of the hydrogen fuel cell HFC, respectively; is the maximum value of the total thermal and electrical efficiency; and aHFC , b HFC , c HFC , d HFC , e HFC and f HFC are the first, second, third, fourth and fifth electric power efficiency function coefficients, respectively; is the hydrogen fuel cell HFC rated electric output power.

[0114] (3) Hydrogen to methane link

[0115] The methane reactor uses part of the hydrogen converted by the electrolyzer EC to react with CO2, realizes hydrogen methanation, realizes hydrogen-natural gas conversion, and its input-output model is as follows:

[0116]

[0117] wherein, is the methane gas power output by the methane reactor MR at time t, is the hydrogen power input into the methane reactor at time t, η MR is the methanation efficiency of the methane reactor MR.

[0118] Step S2 includes steps S21-S24.

[0119] S21, obtain historical data of wind power, photovoltaic and photo-thermal power stations, and model the output of energy function equipment and the output of energy storage equipment of the island micro-energy network.

[0120] The energy supply equipment output includes wind power, photovoltaic, photo-thermal power station, combined heat and power unit and ground source heat pump output.

[0121] The energy supply equipment mainly includes wind turbine, photovoltaic turbine, photo-thermal power station turbine and combined heat and power unit, and its output modeling is as follows:

[0122] (1) Wind turbine output model

[0123] The wind speed affects the output of the wind turbine. Since the wind speed is affected by natural conditions and has volatility, the output of the wind turbine has uncertainty. The linkage relationship between the wind turbine output and the wind speed is shown in formula (4):

[0124]

[0125] wherein, represents the power of wind power generation at time t; v t represents the wind speed at time t, unit: m / s; v in and v out represent the cut-in wind speed and cut-out wind speed of the wind turbine; v cFor the rated wind speed, the wind turbine set reaches the rated wind speed and the wind turbine set runs safely, the wind turbine set is g c The rated power is generated.

[0126] The wind speed is represented by a Weibull distribution function, as shown in equation (5):

[0127]

[0128] The wind speed is represented by a Weibull distribution function, as shown in equation (5): t The wind speed at time t; c and k are the scale parameter and state parameter of the Weibull distribution, respectively.

[0129] (2) Photovoltaic power plant output model

[0130] Solar radiation intensity affects the output of photovoltaic power plants. Since solar radiation intensity is affected by natural conditions and is volatile, the output of photovoltaic power plants is uncertain.

[0131] The relationship between photovoltaic power plant output and solar radiation intensity is shown in equation (6):

[0132]

[0133] The relationship between photovoltaic power plant output and solar radiation intensity is shown in equation (6): The output of the photovoltaic power plant at time t; η PV The power conversion efficiency of the photovoltaic power plant; S PV The solar radiation area; θ t The solar radiation intensity at time t.

[0134] The solar radiation intensity is described by a beta distribution function, as shown in equation (7):

[0135]

[0136] The solar radiation intensity is described by a beta distribution function, as shown in equation (7): t The solar radiation intensity at time t; r and r max The solar radiation intensity at time t; r and r

[0137] (3) Output model of solar thermal power station

[0138] Solar thermal power stations absorb solar radiation energy through a solar heat collection field (HCF) and convert it into heat energy, which is then used for power generation or storage.

[0139] This part of the heat energy can be generated by a generator, or it can be stored through a heat storage device; when needed, heat is released for power generation.

[0140] The power supply of the solar thermal power plant is similar to that of the photovoltaic unit, both of which are affected by the randomness of solar radiation and have uncertain output. The solar radiation beta distribution model is referenced by formula (7), and the heat collection field heat collection power model is further obtained, as shown in formula (8):

[0141]

[0142] wherein, is the heat collection amount of the solar thermal power plant STPP at time t; η STPP is the light-heat conversion efficiency of the solar heat collection field HCF; S STPP is the area of the solar heat collection field.

[0143] Based on the heat collection amount, the power supply and heat storage amount models of the solar thermal power plant are obtained.

[0144] The power supply amount model of the generator set is shown in formula (9):

[0145]

[0146] wherein, is the power supply amount of the solar thermal power plant STPP at time t; is the power generation efficiency of the generator set of the solar thermal power plant STPP; is the heat amount used for power generation of the solar thermal power plant STPP at time t.

[0147] The heat amount can be provided by the solar heat collection field or the heat storage device;

[0148] The heat storage amount model of the heat storage device is shown in formula (10):

[0149]

[0150] wherein, and are the heat storage amounts of the energy storage device HSS at times t and t-1, respectively; is the heat storage loss rate; ζ is a state variable, which is in the heat release state when equal to 1; and are the charging and discharging power of the heat storage equipment at time t, respectively; and are the charging and discharging efficiencies of the heat storage equipment, respectively.

[0151] (4) Heat and power cogeneration unit CHP output model

[0152] The heat and power cogeneration unit includes a gas turbine, a waste heat recovery device, and a heat exchange device, and the output model thereof is shown in formula (11):

[0153]

[0154] wherein, is the power supply of the combined heat and power unit CHP at the t th moment; V t CHP,g is the amount of natural gas consumed at the t th moment; η CHP is the power generation efficiency of the combined heat and power unit CHP; is the waste heat power generated by the combined heat and power unit CHP at the t th moment; γ GT is the heat-to-power ratio; is the amount of waste heat entering the heat exchange device CH; η WHB,t is the percentage of heat entering the heat exchange device CH from the waste heat recovery device WHD at the t th moment to the total heat of WHD at the t th moment; η h is the heat transfer efficiency of the heat exchange device CH.

[0155] (5) Ground source heat pump output model

[0156] The ground source heat pump refers to using the earth as a cold and heat source, driven by high-quality energy, extracting heat from the ground or water in winter, transferring heat to the indoor of the building for heating, and releasing heat to the ground or surface water in summer for cooling.

[0157] wherein, high-quality energy is an energy form with high energy quality, high conversion efficiency, easy to control and use, and electric energy is a typical high-quality energy.

[0158] The air source heat pump for cooling refers to using the heat in the air as a low-temperature heat source, driven by high-quality energy (electric energy), exchanging heat through the air conditioner condenser or evaporator, and then through the circulating system to extract or release heat energy to meet the user's heat load demand. The ground source heat pump refers to using water (groundwater, surface rivers, lakes and oceans) as a cold and heat source, driven by high-quality energy (electric energy), realizing the transfer of low-temperature heat energy to high-temperature heat energy, realizing heating in winter and heating in summer. The ground source heat pump output model is shown in formula (12):

[0159]

[0160] wherein, is the power supply of the ground source heat pump unit at the t th moment; COP HP is the electric-thermal, electric-cooling conversion efficiency of the ground source heat pump unit; g GSHP,t is the amount of high-quality energy entering the ground source heat pump unit at the t th moment.

[0161] The energy storage device output includes power storage, heat storage and hydrogen storage device output.

[0162] The energy storage device stores energy during the peak output period of the unit and releases the stored energy during the peak energy consumption period, thereby reducing the abandoned energy during the peak output period and improving the energy demand on the load side during the peak energy consumption period.

[0163] The energy storage device includes an electricity storage device, a heat storage device and a hydrogen storage device, and the output general model is shown in formula (13).

[0164]

[0165] Among them, and are the energy storage of the energy storage device at the t time and the t-1 time respectively. t esc and P t esd are the charging and discharging power of the energy storage device at the t time respectively. esc and η esd are the charging and discharging efficiency of the energy storage device. is the energy storage loss rate of the energy storage device; ζ is the state variable of the energy storage device at the t time, which is 0 or 1, when ζ=1, it is the storage energy state, and when ζ=0, it is the discharging state.

[0166] The constraint condition of the output general model of the energy storage device is shown in formula (14)-(16).

[0167]

[0168] Among them, is the maximum energy storage of the energy storage device. and are the maximum storage and discharging power of the energy storage device respectively.

[0169] The island micro-energy network integrated with the hydrogen energy cascade utilization device utilizes new energy generation (wind power and photovoltaic), uses an electrolytic cell, electrolyzes seawater resources during the peak period, generates hydrogen, and reacts with carbon dioxide generated by a gas turbine GT to generate methane, realizes carbon recycling, reduces carbon dioxide emission, improves energy utilization rate, and reduces abandoned wind and light.

[0170] For the island micro-energy network, the internal coupling wind power, photovoltaic and other uncertain clean energy units are lack of backup of the main network, and there is a strong energy supply risk, how to maximize the mobilization of internal supply and demand resources, form a supply and demand interconnection cooperation mode, to improve the reliability of the island micro-energy network energy supply.

[0171] The application designs a supply and demand interconnection cooperation mode based on the demand side response mode, and the specific implementation is as follows:

[0172] (1) In the day-ahead market, based on the demand-side electricity load data, the supply-side makes a day-ahead prediction of the supply capacity of its new energy generators, considers the user load demand elasticity coefficient, introduces price-type demand response, guides users to reasonably shift energy demand, determines the total supply with the demand side, arranges the generator dispatching plan with maximum revenue to meet the demand-side energy demand the next day.

[0173] Among them, the price-type energy demand response model in the day-ahead market is shown in formula (17):

[0174]

[0175] Among them, is the kth load transfer amount affected by the price-type demand response in the tth period, is the original kth load amount in the tth period, is the elasticity coefficient of the kth load at the ith moment to the jth moment price, which is used to measure the sensitivity of the load to the price change, is the selling price of the kth load after price-type demand response in the tth period, is the original selling price of the kth load in the tth period.

[0176] For the island micro-energy network structure, the kth load is the electricity, heat, and gas three types of load.

[0177] (2) In the real-time market, the supply side determines the total demand with the demand side based on the real-time prediction of the supply capacity of its new energy generators, takes the minimum load shedding cost as the target, considers the maximum and minimum load reduction amount of the demand side, introduces incentive-type energy demand response, and guides the demand side to make load interruption strategy. Among them, the incentive-type energy demand response model in the real-time market is shown in formula (18):

[0178]

[0179] Among them, is the total amount of the kth load after reduction affected by the incentive-type demand response in the tth period, is the reducible amount of the kth load in the tth period.

[0180] The "take the minimum load shedding cost as the target" mentioned in the real-time market refers to the supply side striving to reduce the cost of load reduction measures as much as possible while meeting the supply and demand balance when responding to power supply shortage or demand surplus.

[0181] Load reduction cost: When the power supply cannot meet the demand, the supply side needs to take measures to reduce part of the demand, such as reducing the electricity consumption of certain types of load on the demand side through demand response. This load reduction may incur costs, especially during peak demand periods when quick response is required.

[0182] Optimization goal: The goal of the supply side is to minimize the cost of energy supply while ensuring the stable and reliable operation of the island micro-energy network.

[0183] Supply-demand balance: The supply side needs to monitor the supply-demand situation in real time and take measures such as adjusting power generation, starting backup power or implementing demand response to maintain supply-demand balance when necessary.

[0184] Incentive demand response: The supply side can introduce incentives to encourage the demand side to voluntarily reduce electricity consumption when power supply is tight, which can reduce the cost of load shedding.

[0185] System stability: The ultimate goal is to minimize cost without sacrificing stability and reliability, ensuring that all users on the island micro-energy demand side can obtain the required power.

[0186] Classify demand response into day-ahead and real-time stages, consider the transferable load of price-type demand response in the day-ahead stage, and consider the interruptible load of incentive-type demand response in the real-time stage, so as to fully tap the adjustable potential of demand response and ensure the flexible, safe and stable operation of the power system.

[0187] Step S22, constructing a day-ahead stage target function with the goal of maximizing day-ahead market net profit.

[0188] The two-stage supply-demand cooperation optimization is divided into a day-ahead supply-demand cooperation pre-dispatching stage and a real-time supply-demand cooperation emergency balancing stage. According to the operation optimization strategy, the supply and demand sides match in the day-ahead market to form a supply-demand curve.

[0189] The present application optimizes the output of internal resources of the island micro-energy network from the supply side, maximizes the revenue in the day-ahead market as the day-ahead stage target function, and aims to maximize the net revenue of the island micro-energy network.

[0190] The day-ahead stage target function is shown in formula (19):

[0191]

[0192] Where F r is the net revenue of the island micro-energy network in the day-ahead market, α1 is the probability of exceeding the expected revenue, represents the net revenue F r of the supply side, the probability of being greater than the expected net revenue is greater than or equal to α1; and are the electricity, heat and gas trading volumes at time t, respectively; and respectively, are the operation and maintenance cost and the depreciation cost of unit n at time t; T is the scheduling period; N is the number of units, is the unit output of device n in the island micro energy network at time t; is the unit operation and maintenance cost of device n; respectively, are the outputs of wind power, photovoltaic, solar-thermal power station, combined heat and power unit, ground source heat pump, electricity storage device, heat storage device, hydrogen storage device, gas turbine and hydrogen fuel cell unit at time t;

[0193] The unit n is a wind power, photovoltaic, new hydrogen energy cascade utilization device, combined heat and power unit, electricity storage device, ground source heat pump, solar-thermal power station device in the island micro energy network;

[0194] When the island micro energy net income is maximum, the utilization rate of electricity, heat and gas load is maximum.

[0195] T is the scheduling period, if one day is taken as the scheduling period and 1h is taken as the scheduling interval, then T = 24.

[0196] The depreciation cost of unit n at time t is shown as formula (20):

[0197]

[0198] Wherein, C ii-n , C re-n and D n are the investment cost, residual value and service life of device n respectively.

[0199] The operation and maintenance cost of unit n at time t is shown as formula (21):

[0200]

[0201] Wherein, P t n is the unit output of unit n at time t; is the unit operation and maintenance cost of unit n.

[0202] Step S3 includes steps S31-S32.

[0203] Step S31, constructing day-ahead supply and demand balance constraints, day-ahead unit constraints and day-ahead demand response constraints.

[0204] (1) Constructing day-ahead supply and demand balance constraints.

[0205] The day-ahead supply and demand balance constraints are shown as formulas (22)-(24):

[0206]

[0207] wherein β1, β2 and β3 are the electric, thermal and gas supply-demand balance confidence levels, respectively, and are the electric, thermal and gas demands of the island micro-energy network users at time t in the time period t; and are the outputs of the wind power, photovoltaic, gas turbine, solar-thermal power station and hydrogen fuel cell at time t; and are the thermal outputs of the hydrogen storage device, hydrogen fuel cell and power source heat pump; are the gas load demands met by the methane reactor and external natural gas network at time t.

[0208] (2) constructing a day-ahead unit constraint condition.

[0209] The day-ahead unit constraint includes wind power, photovoltaic, solar-thermal power station, electricity storage device and new hydrogen energy cascade utilization device unit output constraint.

[0210] Wind and light output constraint: based on the modeling of wind power generator set and photovoltaic set, the constraint is as shown in formulas (25)-(26):

[0211]

[0212] wherein, and are the maximum operating powers of wind power WPP and photovoltaic PV; β4 and β5 represent the confidence levels of formula (25) and formula (26), respectively.

[0213] Solar-thermal power station STPP constraint: the present application assumes that the STPP thermal energy collection is only provided by the heat collection field HCF, and the heat storage device model is as shown in formula (27):

[0214]

[0215] wherein, and are the heat storage amounts at times t and t-1; is the heat storage loss rate; ζ is a state variable, which is a heat release state when equal to 1; and are the charging and discharging powers of the heat storage device at time t; and are the charging and discharging efficiencies of the heat storage device.

[0216] Based on the solar-thermal power station STPP model, the unit constraint condition is obtained, as shown in formula (28):

[0217]

[0218] wherein, and Pmax,STPP, Pmax,GT, Pmax,HFC, Pmax,PSD, Pmax,HSD, and Pmax,GSHP represent the maximum charging / discharging power of STPP, GT, HFC, PSD, HSD, and GSHP, respectively.

[0219] Electrolyzer unit constraints, as shown in equation (29):

[0220]

[0221] where, and Pmin,ECand Pmax,ECrepresent the lower and upper bounds of the input power of electrolyzer EC, respectively.

[0222] Maximum storage capacity, maximum charging power, and discharging power constraints of the solar-thermal power plant STPP, as shown in equation (30):

[0223]

[0224] where, β8is the confidence level of equation (30); and Pmax,STPP, Pmax,GT, Pmax,HFC, Pmax,PSD, Pmax,HSD, and Pmax,GSHP represent the maximum charging / discharging power of STPP, GT, HFC, PSD, HSD, and GSHP, respectively.

[0225] The output and constraints of the storage unit are referred to model (27) and (30), respectively.

[0226] Hydrogen energy cascade utilization device unit constraints: based on the modeling of the hydrogen energy cascade utilization device, its constraints are shown in equation (31):

[0227]

[0228] where, Pmin,HFC(t) represents the lower bound of the input hydrogen of hydrogen fuel cell HFC at time t; Pmin,MR(t) represents the lower bound of the input hydrogen of methane reactor MR at time t; Pmin,EC(t) represents the lower bound of the input hydrogen of electrolyzer EC at time t; and Pmin,ECand Pmax,ECrepresent the lower and upper bounds of the input power of electrolyzer EC, respectively. and Pmin,HFCand Pmax,HFCrepresent the lower and upper bounds of the input hydrogen of hydrogen fuel cell HFC, respectively. and Pmin,MRand Pmax,MRrepresent the lower and upper bounds of the input hydrogen of methane reactor MR, respectively.

[0229] (3) Construct the day-ahead market demand response constraints.

[0230]

[0231] where, and respectively, are the energy cost of the user before and after the user participates in the price-type demand response in the day-ahead market at time t.

[0232] The peak-valley price inversion constraint is shown in formula (34):

[0233]

[0234] wherein, and respectively, are the high peak and low valley energy selling prices of the kth load after the price-type demand response is implemented in the day-ahead market.

[0235] Step S32, the day-ahead stage target function is solved.

[0236] Based on the day-ahead supply-demand balance constraint, the day-ahead unit constraint and the demand response constraint, the day-ahead stage target function is solved by using the solver CPLEX to obtain the electricity, heat and gas trading volume in the day-ahead market;

[0237] Based on the historical data of wind power, photovoltaic, and photothermal power stations, a typical day scenario of the island micro energy network is generated by using the scenario generation method, and the typical day scenario and the parameter data of each unit are input as original data to solve the day-ahead stage target function.

[0238] Step S4, specifically.

[0239] Since there is a certain uncertainty on both the supply side and the demand side, in order to reduce the influence of the bias between the supply side and the demand side on the dispatching strategy in the implementation stage, a real-time stage target function is constructed in the real-time market, with the objective of minimizing the bias adjustment cost.

[0240] The real-time stage target function is shown in formula (35):

[0241]

[0242] wherein, F c is the bias adjustment cost of the island micro energy network in the real-time market, alpha2 is the probability of exceeding the expected bias adjustment cost, represents the probability that the bias adjustment cost of the island micro energy network is less than the expected bias adjustment cost is greater than or equal to alpha2, is the incentive-type demand response cost of the kth load at time t; is the unit reduction penalty cost of the kth load at time t; is the type of load shedding at time t, respectively, are the types of electricity, heat and gas load shedding at time t, is the compensation price of the kth load interruption or transfer in the t period, respectively are the real-time phase electric, thermal, and gas load transfer amount, l is the step size of the kth load, and v is the step price of the kth load;

[0243] The kth load is electric, thermal, and gas.

[0244] As shown in Figure 4 The step price is expressed as an interval step type charge, indicating the relationship between load reduction and incentive price. When in the [0, l] segment, the incentive price at this time is The incentive price in the [l, 2l] interval is The larger the load participating in the response, the higher the unit cost.

[0245]

[0246] wherein, is the electric load demand of the user after supply-demand cooperation in the real-time market at time t; is the contracted amount in the day-ahead market at time t; is the real-time reducible electric load at time t; is an uncertainty factor; is the real-time electric load shedding amount at time t; the superscript r is the electric load amount satisfied by the real-time market at time t; respectively are the actual output of wind power WPP, photovoltaic PV, and solar-thermal power station STPP in the real-time phase; respectively are the electric output of gas turbine GT and hydrogen fuel cell HFC at time t in the real-time phase.

[0247] Step S5 includes steps S51-S53.

[0248] Step S51, constructing real-time supply-demand balance constraints, real-time unit constraints, and real-time demand response constraints.

[0249] (1) Constructing real-time supply-demand balance constraints.

[0250] The real-time supply-demand balance constraints are shown in formulas (37)-(39):

[0251]

[0252] wherein β6, β7, and β8 are respectively the real-time phase electric, thermal, and gas supply-demand balance confidence, which are preset values, and respectively are the real-time electric, thermal, and gas load shedding amount at time t; and respectively are the real-time electric, thermal, and gas transfer load amount at time t; and respectively are the electric, thermal, and gas load uncertainty factors; respectively represent the upper and lower limits of the interruptible and transferable electric load of the user at time t; respectively represent the upper and lower limits of the interruptible and transferable thermal load of the user at time t; respectively represent the upper and lower limits of the interruptible and transferable gas load of the user at time t.

[0253] (2) Construct real-time demand response constraints.

[0254] The real-time demand response constraints are shown in formula (40):

[0255]

[0256] wherein, and respectively represent the upper and lower limits of the interruptible and transferable electric load of the user at time t; and respectively represent the upper and lower limits of the interruptible and transferable thermal load of the user at time t; and respectively represent the upper and lower limits of the interruptible and transferable gas load of the user at time t. 10 and 11 respectively represent the upper and lower limits of the interruptible and transferable gas load of the user at time t.

[0257] (3) Construct real-time unit constraints

[0258] The real-time unit constraints include real-time wind turbine constraints, photovoltaic unit constraints, new hydrogen energy cascade utilization device unit constraints, solar thermal power station unit constraints, gas turbine unit constraints, hydrogen fuel cell unit constraints, electricity storage device unit constraints, hydrogen storage device unit constraints, and ground source heat pump unit constraints.

[0259] Wind and solar power output constraints: based on the modeling of wind turbine units and photovoltaic units, the constraints are shown in formulas (41)-(42):

[0260]

[0261] wherein, 12 and 13 respectively represent the confidence of formula (41) and formula (42).

[0262] In addition, the output of the remaining units of the island micro energy network should be less than the maximum output constraint, which is shown in formula (42):

[0263]

[0264] wherein, and The maximum output upper limit of STPP, GT, HFC, PSD, HSD, and GSHP, respectively.

[0265] The electrolytic cell output constraint of the hydrogen energy cascade utilization device unit, as shown in equation (43):

[0266]

[0267] Step S52, uncertainty modeling of both supply and demand sides.

[0268] In the present application, the uncertainty comes from the supply side and the demand side, and the uncertainty of the supply side and the demand side will be modeled respectively as follows.

[0269] (1) Uncertainty modeling of the supply side.

[0270] Wind power, photovoltaic and photo-thermal power stations are affected by the natural environment, and their output has a certain degree of uncertainty, which is represented by extreme scenarios, as shown in equation (44): Figure 5

[0271] The extreme scenario refers to the maximum or minimum output scenario of wind power, photovoltaic and photo-thermal power stations, which can be calculated from historical data. The predicted output of wind power, photovoltaic and photo-thermal power stations needs to be between the maximum and minimum output scenarios, so the uncertainty of the output of wind power, photovoltaic and photo-thermal power stations is modeled as shown in equations (44)-(46):

[0272]

[0273] wherein, and are the actual output of wind power, photovoltaic and photo-thermal power stations at time t; and represent the minimum and maximum output of wind power at time t; and represent the minimum and maximum output of photovoltaic at time t; and represent the minimum and maximum output of photo-thermal power station at time t.

[0274] Then, the uncertainty set of the output scenario is converted into the following form as shown in equations (47)-(49):

[0275]

[0276] wherein, and are the output fluctuation rates of wind power, photovoltaic and photo-thermal power stations; and ​These are the projected output values ​​for wind power, photovoltaic, and solar thermal power plants, respectively. and These are the output errors for wind power, photovoltaic, and solar thermal power plants, respectively, and these output errors can be obtained through extreme scenarios.

[0277] Extreme scenarios refer to uncertainties on the supply side, where the output of clean energy units such as wind, solar, and concentrated solar power (CSP) plants may be affected by the natural environment. Extreme scenarios represent the maximum or minimum possible output of these energy units, which can be calculated using historical data. Specifically, the predicted output of wind, solar, and CSP plants needs to fall between their respective maximum and minimum output scenarios.

[0278] (2) Demand-side uncertainty modeling.

[0279] Demand is influenced by various factors, including the natural environment. When cooperating with the supply side in energy transfer response, there are two scenarios: over-response and under-response. Essentially, this involves using price signals or incentives to encourage users to increase or decrease their electricity load, thereby achieving a regulatory effect. However, in actual grid operation, only basic predictions of adjustable load can be made. The specific adjustable load is determined by factors such as the natural environment and users' energy consumption intentions. Therefore, this invention incorporates [the following] into the modeling of demand-side uncertainties. and like Figure 6 As shown, this is to quantify the uncertainty on the demand side.

[0280] Demand-side uncertainty is shown in formulas (50)-(51):

[0281]

[0282] in, and These represent the load demand after time t, which is the implementation time of the k-th type of load demand response in the day-ahead market and the real-time market, respectively. and These represent the original load amounts of the k-th type of load demand response at time t, respectively, in the day-ahead market and the real-time market. This represents the deviation of the price-based demand response at time t. This represents the deviation of the incentive-driven demand response at time t.

[0283] The purpose of this step is to model the uncertainties of wind power, photovoltaic, and solar thermal power plants on the supply side and the demand response on the demand side, so as to reduce the impact of uncertainties on both the supply and demand sides on the two-stage scheduling strategy for supply and demand cooperation in the subsequent stochastic optimization model.

[0284] Step S53, solving the real-time stage target function to obtain the optimal solution of the output of each unit on the supply side of the island micro energy network and the reduction amount of the reducible load on the demand side of the user.

[0285] Based on the real-time supply-demand balance constraint, the real-time unit constraint, the real-time demand response constraint, the uncertainty of supply-demand cooperation and the transaction amount of electricity, heat and gas in the day-ahead market as constraints, the CPLEX solver is used to solve the real-time stage target function.

[0286] The typical day scene with the maximum fluctuation value is selected as the uncertainty factor for processing the uncertainty of the opportunity constraint, and based on the extreme scene, the uncertainty set is constructed to determine the data of the real-time stage wind power, photovoltaic and photo-thermal power station and the demand side load for solving the real-time stage target function.

[0287] Finally, the optimal operation strategy of the real-time stage island micro energy network and the reducible load amount of the real-time stage are solved.

[0288] In summary, the two-stage optimization method of the island micro energy network considering hydrogen energy cascade utilization of the embodiment has the following beneficial effects:

[0289] 1、The application constructs an island micro energy network structure integrated with a new hydrogen energy cascade utilization device, considers the uncertainty of the supply-demand two sides and the cooperation strategy of the supply-demand two sides, adds a ladder type demand response price mechanism, and constructs a supply-demand cooperation two-stage stochastic optimization model, wherein the day-ahead stage takes the maximum system net profit as a target function to obtain a total planned output; the real-time stage constructs a target of minimum operation cost for optimization, calls incremental output of units and user demand response to suppress deviation, and finally obtains an intra-day real-time optimal output scheme for meeting the total planned output in the day-ahead stage. The application aggregates distributed resources, more optimally considers multiple types of energy load demand of the micro energy network, better promotes the consumption of wind power and photovoltaic power, and promotes the transformation of the power system in China.

[0290] 2、The application constructs a large-scale island multi-energy micro grid cluster energy supply network, enhances the energy self-sufficiency ability of the island area, reduces the dependence on external energy supply, and is particularly important for islands far from the mainland. The abundant wind power and photovoltaic renewable energy of the island is used to realize effective conversion and cascade utilization among electricity, heat and gas energy through the hydrogen energy cascade utilization device, and improve the comprehensive utilization efficiency of energy.

[0291] 3、The application realizes accurate matching and interconnection cooperation of the supply and demand sides by the two-stage optimization method of the day-ahead market and the real-time market through the cooperation of the supply and demand sides, improves the energy supply reliability of the island micro energy network, and meets the growing demand of various loads, reduces the operation cost of the island micro energy network through the objective function of maximizing the net profit of the day-ahead market and minimizing the deviation adjustment cost of the real-time market;

[0292] 4、The application considers the uncertainty of the supply and demand sides, effectively deals with the volatility and uncertainty of wind power and photovoltaic new energy output, enhances the flexibility and reliability of the system, realizes the recycling of carbon elements by reacting hydrogen and carbon dioxide in the methane reactor to generate methane natural gas, reduces the emission of carbon dioxide, and reduces environmental pollution, maximizes the mobilization of internal supply and demand side resources to form an effective supply and demand interconnection cooperation mode, and improves the energy supply security of the island micro energy network in the face of emergencies and extreme weather;

[0293] 5、The application maximizes the use of wind energy and photovoltaic energy through the hydrogen energy cascade utilization device, reduces the problem of abandoned wind and light, and promotes the consumption of renewable energy, stably and reliably meets the electricity, heat and gas load demand of island residents, and improves the life quality and comfort of island residents.

[0294] The above is only the preferred specific embodiment of the application, but the protection scope of the application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered within the protection scope of the application.

Claims

1. A two-stage optimization method for island microgrid considering hydrogen energy cascade utilization, characterized in that, The method comprises the following steps: constructing an island micro energy network integrated with a hydrogen energy cascade utilization device; based on the obtained historical data of wind power, photovoltaic and photo-thermal power stations, and the output of energy supply equipment, energy storage equipment, gas turbine and hydrogen fuel cell of the island micro energy network, constructing a day-ahead stage target function with the maximum day-ahead market net profit as the target; solving the day-ahead stage target function based on day-ahead supply-demand balance constraints, day-ahead unit constraints and demand response constraints to obtain the electricity, heat and gas transaction volume of the day-ahead market; constructing a real-time stage target function with the minimum real-time market deviation adjustment cost of the island micro energy network as the target; solving the real-time stage target function based on real-time supply-demand balance constraints, real-time unit constraints, real-time demand response constraints, the uncertainty of supply-demand cooperation and the electricity, heat and gas transaction volume of the day-ahead market to obtain the optimal solution of the output of each unit on the supply side of the island micro energy network and the reduction amount of the reducible load on the demand side of the user; the hydrogen energy cascade utilization device comprises an electrolytic cell, a hydrogen storage device, a hydrogen fuel cell and a methane reactor; the electrolytic cell is used for electrolyzing seawater by using the remaining clean energy generated by the wind energy and photovoltaic energy unit in the island micro energy network to obtain hydrogen and oxygen and convert electrical energy into hydrogen energy; the hydrogen storage device is used for storing the hydrogen obtained by the electrolytic cell; the hydrogen fuel cell is used for directly obtaining the hydrogen converted by the electrolytic cell or obtaining the hydrogen stored in the hydrogen storage device when the island power demand increases, and converting the hydrogen and oxygen into electrical energy and thermal energy; the methane reactor is used for reacting the hydrogen converted by the electrolytic cell or the hydrogen stored in the hydrogen storage device with the carbon dioxide generated by the gas turbine in the combined heat and power unit in the island micro energy network to generate easy-to-store and transport methane natural gas, thereby realizing carbon recycling; wherein the thermal energy generated by the hydrogen fuel cell is collected by a waste heat recovery device in the combined heat and power unit for thermal energy utilization; the energy supply equipment output comprises wind power, photovoltaic, photo-thermal power station, combined heat and power unit and ground source heat pump output; the energy storage equipment output comprises electric storage, heat storage and hydrogen storage device output; the day-ahead stage target function is as follows: Wherein, F r is the net income of the island micro energy grid in the day-ahead market, α1 is the probability of exceeding the expected income, represents the supply side net income F r is greater than the expected net income The probability is greater than or equal to α1. and are the electricity, heat and gas trading volumes in the t period respectively; and are the electricity, heat and gas prices in the t period respectively; are the operation and maintenance costs and depreciation costs of unit n at time t respectively; T is the dispatching period; N is the number of units, is the unit output of device n in the island micro energy grid in the t period; is the unit operation and maintenance cost of device n. Pwind(t), Ppv(t), Pth(t), Pchp(t), Pghp(t), Pst(t), Phs(t), Phs(t), Pgh2(t), Ph2(t) are the output of wind power, photovoltaic power, solar thermal power station, combined heat and power unit, ground source heat pump, electricity storage device, heat storage device, hydrogen storage device, gas turbine and hydrogen fuel cell unit at time t, respectively. the unit n is the wind power, photovoltaic, hydrogen energy cascade utilization device, combined heat and power unit, electric storage device, ground source heat pump and photo-thermal power station unit in the island micro energy network; when the island micro energy net profit is maximum, the electricity, heat and gas load utilization rate is maximum; the real-time stage target function is as follows: wherein F c is the real-time market island micro energy network deviation adjustment cost, α2 is the probability of exceeding the expected deviation adjustment cost, represents the probability that the island micro energy network deviation adjustment cost is less than the expected deviation adjustment cost is greater than or equal to α2, is the incentive demand response cost of the kth type of load at time t; is the unit reduction penalty cost of the kth type of load at time t; is the type of load shedding at time t, is the type of load shedding of electricity, heat and gas at time t, respectively, is the compensation price of the kth type of load interruption or transfer in the t period, is the load transfer amount of electricity, heat and gas in the real-time stage, respectively, l is the step size of the kth type of load, and v is the step price of the kth type of load. wherein the k type load is the electricity, heat and gas three types of load.

2. The method of claim 1, wherein, the day-ahead supply-demand balance constraint is as follows: wherein β1, β2 and β3 are the electricity, heat and gas supply-demand balance confidence levels, respectively, and are the electricity, heat and gas demand of the island microgrid users at time t in the t time interval, respectively; and are the output of the wind power, photovoltaic, gas turbine, photo-thermal power station and hydrogen fuel cell at time t, respectively; and are the heat output of the hydrogen storage device, hydrogen fuel cell and power heat pump, respectively; are the gas load demand satisfied by the methane reactor and external natural gas network at time t, respectively. the day-ahead unit constraint comprises wind power, photovoltaic, photo-thermal power station, electric storage device and hydrogen energy cascade utilization device unit output constraint.

3. The method of claim 1, wherein, the real-time supply-demand balance constraint is as follows: Wherein, β6, β7 and β8 are respectively real-time stage electric, thermal and gas supply and demand balance confidence, which are preset values, and respectively real-time electric, thermal and gas cut load at time t; and respectively real-time electric, thermal and gas transfer load at time t; and respectively electric, thermal and gas load uncertainty factor; respectively electric load satisfied by real-time market wind power, photovoltaic, gas turbine, photo-thermal power station and hydrogen fuel cell at time t; respectively thermal load satisfied by real-time market electric storage device, hydrogen storage device, hydrogen fuel cell and power heat pump at time t; respectively gas load satisfied by real-time market methane reactor at time t.

4. The method of claim 3, wherein, the real-time demand response constraint is as follows: wherein, and are the upper and lower limits of the amount of load curtailment and shifting of the user participating in the demand response of electricity at time t, respectively; and are the upper and lower limits of the amount of load curtailment and shifting of the user participating in the demand response of heat at time t, respectively; and are the upper and lower limits of the amount of load curtailment and shifting of the user participating in the demand response of gas at time t, respectively; β 10 and β 11 are the confidence levels of the demand response of electricity, heat and gas in the real-time stage, respectively.

5. The method of claim 4, wherein, The real-time unit constraint includes real-time wind turbine constraint, photovoltaic unit constraint, hydrogen energy cascade utilization device unit constraint, solar thermal power station unit constraint, gas turbine unit constraint, hydrogen fuel cell unit constraint, electricity storage device unit constraint, hydrogen storage device unit constraint and ground source heat pump unit constraint.

6. The method according to any one of claims 1 to 5, characterized in that, In addition to integrating the hydrogen energy cascade utilization device, the island micro energy network also includes wind power, photovoltaic, combined heat and power unit, solar thermal power station, electricity storage device, ground source heat pump, external gas network and load. The combined heat and power unit includes a gas turbine, a waste heat recovery device and a heat exchange device. The solar thermal power station includes a generator, a heat collection field and a heat storage device. The load includes electricity, heat and gas load. Among them, wind power, photovoltaic, solar thermal power station, combined heat and power unit, ground source heat pump are energy supply equipment; electricity storage device, heat storage device and hydrogen storage device are energy storage equipment.

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