Park integrated energy system optimization scheduling method based on electric hydrogen coupling characteristics

Abstract

The invention relates to a park integrated energy system optimization scheduling method based on an electricity-hydrogen coupling characteristic. The method comprises the following steps: constructing a park integrated energy system overall structure considering the electricity-hydrogen-gas coupling characteristic; establishing an electricity-hydrogen-gas coupled park comprehensive energy system operation optimization scheduling model objective function considering seasonal and fault factors; putting forward constraint conditions of the optimized dispatching model of the integrated energy system of the electricity-hydrogen-gas coupled park considering the temperature influence factor; solving the park integrated energy system optimization operation model considering the electricity-hydrogen-gas coupling characteristic by using an improved dragonfly algorithm; according to the method, the impact of the randomness and volatility of renewable energy power generation on the power distribution network is relieved, the equipment scheduling of the comprehensive energy system is optimized, meanwhile, the peak load shifting effect is achieved, and the economical efficiency and stability of the comprehensive energy system are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system optimization operation, and in particular relates to a method for optimizing the dispatching of a park integrated energy system based on the electric-hydrogen-gas coupling characteristics. Background Art

[0002] In order to improve the utilization rate of renewable energy, hydrogen energy, which has great potential, is taken into account in the context of the integrated energy system (IES). As an efficient and clean secondary energy source, hydrogen energy has the characteristics of high calorific value and convenient storage and transportation. The hydrogen produced by the electrolyzer through water electrolysis technology can react with carbon dioxide in the methane reactor to produce natural gas for use in the integrated energy system. On the one hand, it can reduce CO2 emissions. On the other hand, by producing natural gas, the system is self-sufficient and reduces the purchase cost of natural gas. In addition, the hydrogen produced by the electrolyzer can also react chemically with oxygen in the hydrogen fuel cell to directly convert chemical energy into electrical energy for use in the integrated energy system. Introducing hydrogen energy into the integrated energy system and combining it with the integrated energy system to build a hydrogen-containing integrated energy system. The coupling of multiple energy sources within the system is of great significance to improving the consumption of renewable energy and achieving the "dual carbon" goal.

[0003] Therefore, how to introduce a hydrogen storage system into the original integrated energy system to overcome the randomness and volatility of new energy power generation, which leads to the inability to fully absorb new energy, resulting in the abandonment of wind and solar power and the waste of energy resources, has become a technical problem that this field has always been eager to solve. Summary of the invention

[0004] In view of the shortcomings of the above-mentioned existing technologies, a method for optimizing the dispatching of a park integrated energy system based on the coupling characteristics of electricity, hydrogen and gas is proposed. The purpose is to alleviate the impact of the randomness and volatility of renewable energy generation on the distribution network and optimize the equipment dispatching of the integrated energy system.

[0005] The technical solution adopted by the present invention is:

[0006] A method for optimizing and dispatching a comprehensive energy system in a park based on the coupling characteristics of electricity, hydrogen and gas, comprising the following steps:

[0007] S1: Construct the overall structure of the park's integrated energy system considering the coupling characteristics of electricity, hydrogen and gas;

[0008] S2: Establish the objective function of the operation optimization scheduling model of the electric-hydrogen-gas coupled park integrated energy system considering seasonality and fault factors;

[0009] S3: Propose the constraint conditions of the optimal scheduling model of the electricity-hydrogen-gas coupled park integrated energy system considering the temperature influence factor;

[0010] S4: Use the improved dragonfly algorithm to solve the optimal operation model of the park's integrated energy system considering the electricity-hydrogen-gas coupling characteristics.

[0011] Furthermore, in step S1, the overall structure of the park integrated energy system includes an energy input layer, an energy conversion layer, an energy storage layer and a load side;

[0012] The energy input layer includes wind energy, photovoltaic power, external power grid and external gas grid; when wind power and photovoltaic power supply are insufficient to meet demand, external power grid purchases are relied upon to ensure user energy demand;

[0013] The energy conversion layer includes a combined heat and power (CHP) unit, an electrolyzer, a methane reactor, and a gas boiler;

[0014] The energy storage layer includes: heat storage tanks, energy storage batteries, electrolyzers, hydrogen storage tanks, and hydrogen fuel cells;

[0015] The load side includes: electrical load, thermal load, and gas load.

[0016] Furthermore, the CHP unit utilizes natural gas to generate electricity and heat through a methane reactor, and the shortfall is supplemented from the external gas grid; abandoned wind power is used to produce hydrogen in an electrolyzer after rectification and stored in a hydrogen storage tank to meet hydrogen demand; if there is excess hydrogen, it is used in a methane reactor to produce methane to provide fuel for the CHP unit and the gas boiler.

[0017] Furthermore, in step S2,

[0018] The total cost f of the integrated energy system containing electricity, hydrogen and gas is the sum of equipment investment cost F1, operation and maintenance cost F2, polluted gas treatment cost F3, energy purchase cost F4 and system depreciation cost F5. The minimum total cost f is the objective function;

[0019] Therefore, the objective function is expressed as:

[0020] minf=F1+F2+F3+F4+F5;

[0021] (1) Equipment investment cost F1:

[0022] The mathematical expression of the investment cost of the installed equipment in the integrated energy system considering the coupling characteristics of electricity, hydrogen and gas is:

[0023]

[0024] Where i represents different equipment types in the system; I represents the total number of equipment types that require investment in the system; n i The number of each type of equipment that needs to be installed; C i Rated capacity of each equipment type; M iThe investment cost per unit capacity of each equipment type; δ i Indicates whether device i is selected. If δ i＝1 Indicates the selection of device i, δ i＝0 Indicates that device i is not selected; μ(r,Y i ) is a function of the discount rate r and the useful life Y of equipment i i Related functions for calculating equal impairment charges;

[0025] (2) Operation and maintenance cost F2:

[0026]

[0027] Where: T d is the scheduling period; λ is the equipment failure coefficient; is the power generation of the wind turbine at time t; is the power generation of the photovoltaic device at time t; is the charging and discharging power of the hydrogen energy storage system at time t; is the charging and discharging power of the electric energy storage system at time t; is the heat generated by the electric boiler at time t; is the heat generated by the gas boiler at time t; Thermal energy stored in the heat storage tank at time t; C WT is the unit operation and maintenance cost of the wind turbine; C PV is the unit operation and maintenance cost of photovoltaics; C eb is the unit operation and maintenance cost of the hydrogen energy storage system; C gb is the unit operation and maintenance cost of the battery; C tst Unit operation and maintenance cost of the heat storage tank, in (yuan / kW·h);

[0028] (3) Polluted gas treatment cost F3:

[0029] In the park's integrated energy system, F3 represents the environmental governance cost of polluted gases. This cost mainly covers the treatment costs of SO2, NO2, and CO2 gases generated by the combustion of gas boilers. The specific expression of F3 is:

[0030]

[0031] Where: T d is the scheduling period; is the emission of SO2, in tons / hour, is the unit price of SO2, in (yuan / ton), is the emission coefficient of SO2; is the emission of NO2, in tons / hour, is the unit price of NO2, in (yuan / ton), is the emission coefficient of NO2; is the CO2 emission, in tons / hour, is the unit price of CO2, in (yuan / ton), is the emission coefficient of CO2;

[0032] (4) Energy purchase cost F4:

[0033] F4 is the total cost involved in purchasing electricity, heat energy and gas for the integrated energy system considering the coupling characteristics of the electricity-hydrogen-gas park; the specific expression is:

[0034]

[0035] Where: T d is the scheduling period; g e is the unit cost of electricity purchased, g h is the unit cost of purchased heat, g gb is the unit cost of gas purchase; P t BUY For electricity purchase, Purchase heat, is the gas purchase volume; α is the seasonal weight factor. The cost of purchasing electricity, heat and gas in the electricity-hydrogen-gas integrated energy system will be affected by seasonal factors.

[0036] (5) Depreciation cost of the integrated energy system considering the coupling characteristics of electricity, hydrogen and gas F5:

[0037] F5 is the depreciation cost of the electricity-hydrogen-gas integrated energy system, which refers to the part of the economic value of each device in the integrated energy system that gradually decreases during its expected service life due to daily use and natural wear and tear. The calculation formula is:

[0038] F5=C cap -C cap γ a

[0039] Where γ a Represents the residual value coefficient, C cap The investment cost of purchasing equipment for the system.

[0040] In step S3, the constraints described take into account the actual situation of both the power load supply and demand sides, and the optimization scheduling model should meet the hydrogen storage balance constraint, thermal system constraint, CHP unit constraint, and carbon capture constraint; their mathematical expressions are,

[0041] (1) Hydrogen fuel cell model and its constraints:

[0042] In the wind power hydrogen production device, the water electrolysis process absorbs power and produces hydrogen. The relationship between the absorbed power and the hydrogen output is:

[0043]

[0044] Where: is the power absorbed by the electrolyzer during the electrolysis of water during period t, including rectifier loss and hydrogen compression power consumption; p e is the power consumed to produce unit volume of hydrogen; θ e The temperature coefficient affected by temperature during the process of water electrolysis to produce hydrogen; is the volume of hydrogen produced by the electrolysis device during time t;

[0045] The relationship between hydrogen consumption and output power of a hydrogen fuel cell is:

[0046]

[0047] Where: The power released by consuming a unit volume of hydrogen; p H is the power consumed per unit volume of hydrogen; is the volume of hydrogen consumed by the hydrogen fuel cell during time period t; θ H The temperature coefficient of the hydrogen fuel cell power output affected by temperature;

[0048] The operation of electrolyser plants and hydrogen fuel cells is subject to the following constraints:

[0049]

[0050] Where: The maximum value of the power consumed by the electrolyzer device; is the maximum value of the fuel cell output power; θ e The temperature coefficient affected by temperature during the process of water electrolysis to produce hydrogen; is the maximum power consumption of the electrolysis device, is the minimum output power of the fuel cell; θ H The temperature coefficient of the hydrogen fuel cell power output affected by temperature;

[0051] The storage balance constraint of hydrogen is:

[0052]

[0053] Where: is the hydrogen capacity in the hydrogen storage device during period t; is the demand for hydrogen load during period t; is the power absorbed by the water electrolysis device during period t; P tis the power released by the fuel cell in period t; T is the temperature coefficient affected by temperature during hydrogen storage; p e is the power consumed to produce unit volume of hydrogen; p H The power released for the consumption of a unit volume of hydrogen;

[0054] The storage capacity of hydrogen and the power constraints of wind turbines and photovoltaic equipment are:

[0055]

[0056] Where: is the storable amount of hydrogen; is the maximum hydrogen storage capacity; P i w,t,max is the maximum output power of the i-th wind turbine; η WT is the power loss coefficient of the wind turbine; P i w,t,max is the maximum output power of the i-th photovoltaic device; η PV is the power loss coefficient of photovoltaic equipment;

[0057] (2) Thermal system constraints,

[0058] The total heat output balance constraint of the heating network is:

[0059]

[0060] Where: T d is a scheduling cycle; is the heat load of the integrated energy system of the electricity-hydrogen-gas park at time t; k is the heat energy utilization ratio of the heating network; is the pipeline thermal power in period t; is the pipeline heat power loss during period t; sea is the seasonal coefficient of heat power loss of heat load pipeline, sea = a, b, c, d, where a, b, c, d represent spring, summer, autumn and winter respectively;

[0061] Thermal power loss occurs in the thermal energy transmission process of the thermal system The mathematical expression is:

[0062]

[0063] Where: is the water supply temperature; is the ambient temperature at time t; k w is the heat transfer coefficient from the heat source to the heat exchange station; Q L is the mass of water flowing through the heat load; γ loss is the temperature influence coefficient;

[0064] The thermal system transfers heat through water, and the thermal power absorbed by the heat load node for:

[0065]

[0066] Where: C w is the specific heat capacity of water; Q L is the mass of water flowing through the heat load; is the water supply temperature; is the return water temperature; L is the temperature influence coefficient;

[0067] (3) Combined heat and power (CHP) unit constraints,

[0068] Considering the electricity-hydrogen-gas coupled integrated energy system, the CHP unit is included to meet the thermal energy supply of the system, and its ramp constraint is:

[0069]

[0070] Where: and They are the up and down ramp power limits of the CHP unit respectively; CHP is the stability factor of the system CHP unit system; It is the lower limit constraint of CHP unit output; is the upper limit constraint of CHP unit output; η CHP The efficiency of the CHP unit will affect the setting of the upper and lower limits of the output;

[0071] (4) Carbon capture and storage equipment models and constraints,

[0072] The carbon capture and storage device captures the carbon dioxide emitted by the system as the carbon source of the methane generator; the mathematical model of the carbon capture and storage device is:

[0073]

[0074] Where P CCS,t is the total energy consumption of the carbon capture system; k CCS is the operating energy consumption coefficient of the unit CO2 capture system; is the amount of stored CO2; C is the conversion coefficient between methane and CO2; is the volume of CO2; P F is the fixed energy consumption of the carbon capture system; δ T,P is the temperature and pressure influence coefficient of carbon capture system; Total amount of CO2 captured for the integrated energy system.

[0075] Furthermore, in step S4, a mutation operator and a disturbance factor are added to improve the dragonfly algorithm, specifically including:

[0076] First, input the parameter configuration of each device in the integrated energy system, such as the operating parameters of wind turbines, photovoltaic equipment, and hydrogen production equipment, update the parameters of the five behaviors of the dragonfly algorithm, and use the objective function of the total operating cost f of the integrated energy system as the fitness function. Use the dragonfly search process to solve the optimal equipment output when the integrated energy system is running, thereby obtaining the minimum operating cost of the electricity-hydrogen-gas integrated energy system.

[0077] The calculation expression of the selected dragonfly individual after adding the mutation factor is:

[0078]

[0079]

[0080] Where r is the number of iterations of the current era, α is a random number on [0,1], is the maximum variation value of the dragonfly individual in the d dimension, is the minimum variation value of the dragonfly individual in the d dimension; N(0,1) is a normally distributed random number with a mean of 0 and a variance of 1;

[0081] After adding the disturbance factor and mutation speed factor, the dragonfly position is updated:

[0082]

[0083] is the position of the individual before mutation; is the maximum value of an individual in the dth dimension, is the minimum value of the individual in the dth dimension, r is the number of iterations, R is the maximum number of iterations; s is the mutation rate factor, and ω is the disturbance factor.

[0084] The advantages and effects of the present invention are as follows:

[0085] The present invention discloses an integrated energy system with electric-hydrogen-gas coupling characteristics and a scheduling method, wherein the integrated energy system includes a power generation device, a carbon capture device, a carbon storage device, an electric-to-gas device, and a hydrogen production device; the present invention combines multiple energy supply modes with the integrated energy system, and uses an improved dragonfly algorithm to solve the problem of a single energy supply scheduling algorithm for the integrated energy system in the prior art, thereby improving energy scheduling efficiency. By adding a variation factor and a disturbance factor, the stability of the algorithm is increased, which helps the algorithm to jump out of the local optimum.

[0086] The present invention alleviates the impact of the randomness and volatility of renewable energy generation on the distribution network, optimizes the equipment scheduling of the integrated energy system, and in the low-valley electricity price stage, balances energy storage and electricity, while playing a role in peak shaving and valley filling, thereby improving energy utilization efficiency and enhancing the economy and stability of the integrated energy system. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 This is a framework diagram of a comprehensive energy system for a park that takes into account the electricity-hydrogen-gas coupling characteristics provided by the present invention;

[0088] Figure 2 It is a flow chart of a comprehensive energy system and a dispatching method considering the coupling characteristics of electricity, hydrogen and gas provided by the present invention;

[0089] Figure 3 It is a schematic diagram of the improved dragonfly algorithm provided by the present invention;

[0090] Figure 4 It is an optimized electric load output diagram of a park comprehensive energy system considering the electric-hydrogen-gas coupling characteristics provided by the present invention;

[0091] Figure 5 It is the gas load output diagram after optimization of the park comprehensive energy system taking into account the electricity-hydrogen-gas coupling characteristics provided by the present invention. DETAILED DESCRIPTION

[0092] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0093] The present invention discloses a method for optimizing and dispatching a comprehensive energy system of a park taking into account the coupling characteristics of electricity, hydrogen and gas.

[0094] The specific steps are as follows:

[0095] Step S1, constructing the overall structure of the park comprehensive energy system considering the electricity-hydrogen-gas coupling characteristics;

[0096] The energy input layer of the system covers wind power, photovoltaics, external power grids and external gas grids. When wind power and photovoltaic power supply are insufficient to meet demand, the system will rely on external power grids to purchase electricity to ensure user energy needs. The energy conversion layer includes combined heat and power (CHP) units, electrolyzers, methane reactors and gas boilers; the energy storage layer includes: heat storage tanks, energy storage batteries, electrolyzers, hydrogen storage tanks and hydrogen fuel cells; the load side includes: electrical load, thermal load, gas load;

[0097] The CHP unit uses natural gas to generate electricity and heat through a methane reactor, and the shortfall is supplemented by the external gas grid; for wind power that may be abandoned, it is used to produce hydrogen in an electrolyzer after rectification and stored in a hydrogen storage tank to meet hydrogen demand. If there is excess hydrogen, it can be used in a methane reactor to produce methane to provide fuel for the CHP unit and gas boiler. This process not only improves energy efficiency, but also reduces the risk of purchasing and transporting hydrogen, achieving a win-win effect in energy utilization.

[0098] Step S2: Establish an objective function of the operation optimization scheduling model of the electricity-hydrogen-gas coupled park integrated energy system taking into account seasonality and fault factors.

[0099] By rationally dispatching the energy supply equipment and energy storage equipment in the system, the operating costs of the integrated energy system can be reduced. The total cost f of the electricity-hydrogen-gas integrated energy system includes the equipment investment cost F1, operation and maintenance cost F2, polluted gas treatment cost F3, energy purchase cost F4 and system depreciation cost F5, and the minimum sum is the objective function.

[0100] Therefore, the objective function is expressed as:

[0101] minf=F1+F2+F3+F4+F5

[0102] (1) Cost of equipment investment F1:

[0103] The mathematical expression of the cost of investment in installed equipment in a comprehensive energy system considering the coupling characteristics of electricity, hydrogen and gas is:

[0104]

[0105] Where i represents different equipment types in the system; I represents the total number of equipment types that require investment in the system; n i The number of each type of equipment that needs to be installed; C i Rated capacity of each equipment type; M i The investment cost per unit capacity of each equipment type; δ i Indicates whether device i is selected. If δ i＝1 Indicates the selection of device i, δ i＝0 Indicates that device i is not selected; μ(r,Y i ) is a function of the discount rate r and the useful life Y of equipment i i Related functions are used to calculate equal impairment charges.

[0106] (2) Operation and maintenance costs F2:

[0107]

[0108] Where: T dis the scheduling period; λ is the equipment failure coefficient; is the power generation of the wind turbine at time t; is the power generation of the photovoltaic device at time t; is the charging and discharging power of the hydrogen energy storage system at time t; is the charging and discharging power of the electric energy storage system at time t; is the heat generated by the electric boiler at time t; is the heat generated by the gas boiler at time t; Thermal energy stored in the heat storage tank at time t; C WT is the unit operation and maintenance cost of the wind turbine; C PV is the unit operation and maintenance cost of photovoltaics; C eb is the unit operation and maintenance cost of the hydrogen energy storage system; C gb is the unit operation and maintenance cost of the battery; C tst Unit operation and maintenance cost of the heat storage tank, in (yuan / kW·h).

[0109] (3) Polluted gas treatment cost F3:

[0110] In the park's integrated energy system, F3 represents the environmental governance cost of polluted gases, which mainly covers the treatment costs of SO2, NO2, CO2 and other gases generated by the combustion of gas boilers. The specific expression of F3 is:

[0111]

[0112] Where: T d is the scheduling period; is the emission of SO2, in tons / hour, is the unit price of SO2, in (yuan / ton), is the emission coefficient of SO2; is the emission of NO2, in tons / hour, is the unit price of NO2, in (yuan / ton), is the emission coefficient of NO2; is the CO2 emission, in tons / hour, is the unit price of CO2, in yuan / ton, is the emission coefficient of CO2;

[0113] (4) Energy purchase cost F4:

[0114] F4 is the total cost involved in purchasing electricity, heat and gas for the integrated energy system considering the coupling characteristics of the electricity-hydrogen-gas park. The specific expression is:

[0115]

[0116] Where: T d is the scheduling period; g e is the unit cost of electricity purchased, g h is the unit cost of purchased heat, g gb is the unit cost of gas purchase; P t BUY For electricity purchase, Purchase heat, is the gas purchase volume; α is the seasonal weight factor. The cost of purchasing electricity, heat and gas in the electricity-hydrogen-gas integrated energy system will be affected by different seasonal factors.

[0117] (5) Depreciation cost of the integrated energy system considering the coupling characteristics of electricity, hydrogen and gas F5:

[0118] F5 is the depreciation cost of the electricity-hydrogen-gas integrated energy system, which mainly refers to the part of the economic value of each device in the integrated energy system that gradually decreases during its expected service life due to daily use and natural wear and tear. The calculation formula is:

[0119] F5=C cap -C cap γ a

[0120] Where γ a Represents the residual value coefficient, C cap The investment cost of purchasing equipment for the system.

[0121] Step S3: Propose constraint conditions for the optimization scheduling model of the electricity-hydrogen-gas coupled park integrated energy system considering the influence of temperature.

[0122] Taking into account some actual conditions of both the supply and demand sides of power load, the optimal scheduling model should meet the hydrogen storage balance constraints, thermal system constraints, CHP unit constraints, and carbon capture constraints. Their mathematical expressions are:

[0123] (1) Hydrogen fuel cell model and its constraints

[0124] In the wind power hydrogen production device, the water electrolysis process absorbs power and produces hydrogen. The relationship between the absorbed power and the hydrogen output is:

[0125]

[0126] Where: is the power absorbed by the electrolyzer during the electrolysis of water during period t, including rectifier loss and hydrogen compression power consumption; p e is the power consumed to produce unit volume of hydrogen; θ e The temperature coefficient affected by temperature during the process of water electrolysis to produce hydrogen; is the volume of hydrogen produced by the electrolysis device during time period t.

[0127] The relationship between hydrogen consumption and output power of a hydrogen fuel cell is:

[0128]

[0129] Where: The power released by consuming a unit volume of hydrogen; p H is the power consumed per unit volume of hydrogen; is the volume of hydrogen consumed by the hydrogen fuel cell during time period t; θ H It is the temperature coefficient affected by temperature during the power output of hydrogen fuel cells.

[0130] The operation of electrolyser plants and hydrogen fuel cells is subject to the following constraints:

[0131]

[0132] Where: The maximum value of the power consumed by the electrolyzer device; is the maximum value of the fuel cell output power; θ e The temperature coefficient affected by temperature during the process of water electrolysis to produce hydrogen; is the maximum power consumption of the electrolysis device, is the minimum output power of the fuel cell; θ H It is the temperature coefficient affected by temperature during the power output of hydrogen fuel cells.

[0133] The storage balance constraint of hydrogen is:

[0134]

[0135] Where: is the hydrogen capacity in the hydrogen storage device during period t; is the demand for hydrogen load during period t; is the power absorbed by the water electrolysis device during period t; P t is the power released by the fuel cell in period t; T is the temperature coefficient affected by temperature during hydrogen storage; p e is the power consumed to produce unit volume of hydrogen; p H The power released by consuming a unit volume of hydrogen.

[0136] The storable amount of hydrogen and the power constraints of wind turbines and photovoltaic equipment are:

[0137]

[0138] Where: is the storable amount of hydrogen; is the maximum hydrogen storage capacity; P i w,t,max is the maximum output power of the i-th wind turbine; η WT is the power loss coefficient of the wind turbine; P i w,t,max is the maximum output power of the i-th photovoltaic device; η PV is the power loss coefficient of photovoltaic equipment.

[0139] (2) Thermal system constraints

[0140] The total heat output balance constraint of the heating network is:

[0141]

[0142] Where: T d is a scheduling cycle; is the heat load of the integrated energy system of the electricity-hydrogen-gas park at time t; k is the heat energy utilization ratio of the heating network; is the pipeline thermal power in period t; is the pipeline heat power loss during period t; sea is the seasonal coefficient of heat power loss of heat load pipeline, sea = a, b, c, d, where a, b, c, d represent spring, summer, autumn and winter respectively.

[0143] Thermal power loss occurs in the thermal energy transmission process of the thermal system The mathematical expression is:

[0144]

[0145] Where: is the water supply temperature; is the ambient temperature at time t; k w is the heat transfer coefficient from the heat source to the heat exchange station; Q L is the mass of water flowing through the heat load; γ loss is the temperature influence coefficient.

[0146] The thermal system transfers heat through water, and the thermal power absorbed by the heat load node for:

[0147]

[0148] Where: C w is the specific heat capacity of water; Q L is the mass of water flowing through the heat load; is the water supply temperature; is the return water temperature; L is the temperature influence coefficient.

[0149] (4) Combined Heat and Power (CHP) Unit Constraints

[0150] Considering the electricity-hydrogen-gas coupled integrated energy system, the CHP unit is included to meet the thermal energy supply of the system, and its ramp constraint is:

[0151]

[0152] Where: and They are the up and down ramp power limits of the CHP unit respectively; CHP is the stability factor of the system CHP unit system; It is the lower limit constraint of CHP unit output; is the upper limit constraint of CHP unit output; η CHP The efficiency of the CHP unit will affect the setting of the upper and lower limits of the output.

[0153] (5) Carbon capture and storage equipment model and constraints

[0154] The carbon capture and storage equipment captures the carbon dioxide emitted by the system as the carbon source for the methane generator. The mathematical model of the carbon capture and storage equipment is:

[0155]

[0156] Where: P CCS,t is the total energy consumption of the carbon capture system; k CCS is the operating energy consumption coefficient of the unit CO2 capture system; is the amount of stored CO2; C is the conversion coefficient between methane and CO2; is the volume of CO2; P F is the fixed energy consumption of the carbon capture system; δ T,P is the temperature and pressure influence coefficient of carbon capture system; Total amount of CO2 captured for the integrated energy system.

[0157] Step S4: Use the improved dragonfly algorithm to solve the optimization operation model of the electricity-hydrogen-gas park integrated energy system.

[0158] The present invention solves the optimization objective function of the integrated energy system with electricity-hydrogen-gas coupling characteristics based on the improved dragonfly algorithm.

[0159] Dragonfly Algorithm is an algorithm proposed based on the natural characteristics of dragonflies. Dragonfly populations are divided into two types of population search, static search and dynamic search. The former refers to the global search behavior of a small group of dragonflies in the entire solution space, while the latter refers to the local optimization process of a large group of dragonflies in a small range.

[0160] The DA algorithm searches for the optimal solution by simulating the clustering behavior of dragonflies, including separation, alignment, cohesion, food search, and avoidance of natural enemies. The mathematical expressions of the five behaviors of the basic dragonfly algorithm during flight will not be described here. The existing dragonfly algorithm is improved for multi-objective optimization in integrated energy systems.

[0161] In order to improve the diversity of the dragonfly algorithm population and prevent the algorithm from falling into a local optimal solution, mutation operators and disturbance factors are added to the algorithm to prevent the algorithm from falling into the optimal solution too early. The present invention improves the algorithm by adding mutation operators and disturbance factors.

[0162] The calculation expression of the selected dragonfly individual after adding the mutation factor is:

[0163]

[0164] Where r is the number of iterations of the current era, α is a random number on [0,1], is the maximum variation value of the dragonfly individual in the d dimension, is the minimum variation value of the dragonfly individual in the d dimension; N(0,1) is a normally distributed random number with a mean of 0 and a variance of 1.

[0165]

[0166] is the position of the individual before mutation; is the maximum value of an individual in the dth dimension, is the minimum value of the individual in the dth dimension, r is the number of iterations, and R is the maximum number of iterations; s is the mutation rate factor, and ω is the disturbance factor. The disturbance factor introduces randomness, allowing the algorithm to jump out of the current local area during the search process, thereby exploring a wider search space.

[0167] By adding mutation factors and disturbance factors, the stability of the algorithm is increased, which helps the algorithm escape from the local optimum.

[0168] The improved dragonfly algorithm is used to solve the optimal operation model of the park integrated energy system considering the coupling characteristics of electricity, hydrogen and gas. First, the parameter configuration of each device in the integrated energy system, such as the operating parameters of wind turbines, photovoltaic equipment, and hydrogen production equipment, is input, and the parameters of the five behaviors of the dragonfly algorithm are updated. The objective function of the total operating cost f of the integrated energy system is used as the fitness function. The dragonfly search process is used to solve the optimal equipment output during the operation of the integrated energy system, thereby obtaining the minimum operating cost of the electricity-hydrogen-gas integrated energy system.

[0169] The optimization result analysis of the example shows that the present invention takes the minimization of the total operating cost of the electric-hydrogen-gas park integrated energy system as the optimization goal, inputs the parameters of each device into the optimization model of the total operating cost of the system, and performs simulation analysis on the embodiment of the present invention, with one hour as a step length and 24 hours a day as a cycle. Tables 1 and 2 are the economic parameters and technical parameter configurations of hydrogen energy storage equipment in the park integrated energy system. Figure 4 and Figure 5 They are the electricity load and gas load of a cycle of the integrated energy system taking winter as a typical day.

[0170] In summary, the method for optimizing the operation of the electric-hydrogen-gas coupled park integrated energy system of the present invention establishes an integrated energy system model of the park containing electric-hydrogen-gas and various equipment models in the system; considers the economic benefits of the integrated energy system, maintenance of primary energy consumption equipment and carbon dioxide emissions, and establishes an optimized scheduling model of the park integrated energy system containing electric-hydrogen-gas; and solves the objective function through the improved dragonfly algorithm. The present invention can guide the formulation of the integrated energy system scheduling plan, enhance the flexibility of the integrated energy system operation, improve the consumption of renewable energy, and significantly reduce the system's operating costs, primary energy consumption and carbon emissions.

[0171] It should be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprising a reference structure" do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0172] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0173] Table 1 Economic parameters of hydrogen energy storage equipment

[0174]

[0175] Table 2 Technical parameters of hydrogen energy storage equipment

[0176]

Claims

1. A method for optimizing the dispatching of a comprehensive energy system in a park based on the coupling characteristics of electricity, hydrogen and gas, characterized in that The following steps are involved: S1: Construct the overall structure of the park's integrated energy system considering the coupling characteristics of electricity, hydrogen and gas; S2: Establish the objective function of the operation optimization scheduling model of the electric-hydrogen-gas coupled park integrated energy system considering seasonality and fault factors; S3: Propose the constraint conditions of the optimal scheduling model of the electricity-hydrogen-gas coupled park integrated energy system considering the temperature influence factor; S4: Use the improved dragonfly algorithm to solve the optimal operation model of the park's integrated energy system considering the electricity-hydrogen-gas coupling characteristics.

2. The method for optimizing the dispatching of a comprehensive energy system in a park based on the coupling characteristics of electricity, hydrogen and gas according to claim 1 is characterized in that In the step S1, the overall structure of the park integrated energy system includes an energy input layer, an energy conversion layer, an energy storage layer and a load side; The energy input layer includes wind energy, photovoltaic power, external power grid and external gas grid; when wind power and photovoltaic power supply are insufficient to meet demand, external power grid purchases are relied upon to ensure user energy demand; The energy conversion layer includes a combined heat and power (CHP) unit, an electrolyzer, a methane reactor, and a gas boiler; The energy storage layer includes: heat storage tanks, energy storage batteries, electrolyzers, hydrogen storage tanks, and hydrogen fuel cells; The load side includes: electrical load, thermal load, and gas load.

3. The method for optimizing the dispatching of a comprehensive energy system in a park based on the coupling characteristics of electricity, hydrogen and gas according to claim 2 is characterized in that The CHP unit utilizes natural gas to generate electricity and provide heat through a methane reactor, and the shortfall is supplemented from the external gas grid. For abandoned wind power, it is used in an electrolyzer to produce hydrogen after rectification and stored in a hydrogen storage tank to meet hydrogen demand. If there is excess hydrogen, it is used in a methane reactor to produce methane to provide fuel for the CHP unit and the gas boiler.

4. The method for optimizing the dispatching of a comprehensive energy system in a park based on the coupling characteristics of electricity, hydrogen and gas according to claim 1 is characterized in that In the step S2, The total cost f of the integrated energy system containing electricity, hydrogen and gas is the sum of equipment investment cost F1, operation and maintenance cost F2, polluted gas treatment cost F3, energy purchase cost F4 and system depreciation cost F5. The minimum total cost f is the objective function; Therefore, the objective function is expressed as: minf=F1+F2+F3+F4+F5; (1) Equipment investment cost F1: The mathematical expression of the investment cost of the installed equipment in the integrated energy system considering the coupling characteristics of electricity, hydrogen and gas is: Where i represents different equipment types in the system; I represents the total number of equipment types that require investment in the system; n i The number of each type of equipment that needs to be installed; C i Rated capacity of each equipment type; M i The investment cost per unit capacity of each equipment type; δ i Indicates whether device i is selected. If δ i＝1 Indicates the selection of device i, δ i＝0 Indicates that device i is not selected; μ(r,Y i ) is a function of the discount rate r and the useful life Y of equipment i i Related functions for calculating equal impairment charges; (2) Operation and maintenance cost F2: Where: T d is the scheduling period; λ is the equipment failure coefficient; is the power generation of the wind turbine at time t; is the power generation of the photovoltaic device at time t; is the charging and discharging power of the hydrogen energy storage system at time t; is the charging and discharging power of the electric energy storage system at time t; is the heat generated by the electric boiler at time t; is the heat generated by the gas boiler at time t; Thermal energy stored in the heat storage tank at time t; C WT is the unit operation and maintenance cost of the wind turbine; C PV is the unit operation and maintenance cost of photovoltaics; C eb is the unit operation and maintenance cost of the hydrogen energy storage system; C gb is the unit operation and maintenance cost of the battery; C tst Unit operation and maintenance cost of the heat storage tank, in (yuan / kW·h); (3) Polluted gas treatment cost F3: In the park's integrated energy system, F3 represents the environmental governance cost of polluted gases. This cost mainly covers the treatment costs of SO2, NO2, and CO2 gases generated by the combustion of gas boilers. The specific expression of F3 is: Where: T d is the scheduling period; is the emission of SO2, in tons / hour, is the unit price of SO2, in yuan / ton, is the emission coefficient of SO2; is the emission of NO2, in tons / hour, is the unit price of NO2, in (yuan / ton), is the emission coefficient of NO2; is the CO2 emission, in tons / hour, is the unit price of CO2, in (yuan / ton), is the emission coefficient of CO2; (4) Energy purchase cost F4: F4 is the total cost involved in purchasing electricity, heat energy and gas for the integrated energy system considering the coupling characteristics of the electricity-hydrogen-gas park; the specific expression is: Where: T d is the scheduling period; g e is the unit cost of electricity purchased, g h is the unit cost of purchased heat, g gb is the unit cost of gas purchase; P t BUY For electricity purchase, Purchase heat, is the gas purchase volume; α is the seasonal weight factor. The cost of purchasing electricity, heat and gas in the electricity-hydrogen-gas integrated energy system will be affected by seasonal factors. (5) Depreciation cost of the integrated energy system considering the coupling characteristics of electricity, hydrogen and gas F5: F5 is the depreciation cost of the electricity-hydrogen-gas integrated energy system, which refers to the part of the economic value of each device in the integrated energy system that gradually decreases during its expected service life due to daily use and natural wear and tear. The calculation formula is: F5=C cap -C cap ·γ a Where γ a Represents the residual value coefficient, C cap The investment cost of purchasing equipment for the system.

5. The method for optimizing the dispatching of a comprehensive energy system in a park based on the coupling characteristics of electricity, hydrogen and gas according to claim 1 is characterized in that In step S3, the constraints described take into account the actual situation of both the power load supply and demand sides, and the optimization scheduling model should meet the hydrogen storage balance constraint, thermal system constraint, CHP unit constraint, and carbon capture constraint; their mathematical expressions are, (1) Hydrogen fuel cell model and its constraints: In the wind power hydrogen production device, the water electrolysis process absorbs power and produces hydrogen. The relationship between the absorbed power and the hydrogen output is: Where: is the power absorbed by the electrolyzer during the electrolysis of water during period t, including rectifier loss and hydrogen compression power consumption; p e is the power consumed to produce unit volume of hydrogen; θ e The temperature coefficient affected by temperature during the process of water electrolysis to produce hydrogen; is the volume of hydrogen produced by the electrolysis device during time t; The relationship between hydrogen consumption and output power of a hydrogen fuel cell is: Where: The power released by consuming a unit volume of hydrogen; p H is the power consumed per unit volume of hydrogen; is the volume of hydrogen consumed by the hydrogen fuel cell during time period t; θ H The temperature coefficient of the hydrogen fuel cell power output affected by temperature; The operation of electrolyser plants and hydrogen fuel cells is subject to the following constraints: Where: The maximum value of the power consumed by the electrolyzer device; is the maximum value of the fuel cell output power; θ e The temperature coefficient affected by temperature during the process of water electrolysis to produce hydrogen; is the maximum power consumption of the electrolysis device, is the minimum value of the fuel cell output power; θ H The temperature coefficient of the hydrogen fuel cell power output affected by temperature; The storage balance constraint of hydrogen is: Where: is the hydrogen capacity in the hydrogen storage device during period t; is the demand for hydrogen load during period t; is the power absorbed by the water electrolysis device during period t; P t is the power released by the fuel cell in period t; T is the temperature coefficient affected by temperature during hydrogen storage; p e is the power consumed to produce unit volume of hydrogen; p H The power released for the consumption of a unit volume of hydrogen; The storage capacity of hydrogen and the power constraints of wind turbines and photovoltaic equipment are: Where: is the storable amount of hydrogen; is the maximum hydrogen storage capacity; P i w,t,max is the maximum output power of the i-th wind turbine; η WT is the power loss coefficient of the wind turbine; P i w,t,max is the maximum output power of the i-th photovoltaic device; η PV is the power loss coefficient of photovoltaic equipment; (2) Thermal system constraints, The total heat output balance constraint of the heating network is: Where: T d is a scheduling cycle; is the heat load of the integrated energy system of the electricity-hydrogen-gas park at time t; k is the heat energy utilization ratio of the heating network; is the pipeline thermal power in period t; is the pipeline heat power loss during period t; sea is the seasonal coefficient of heat power loss of heat load pipeline, sea=a,b,c,d, where a,b,c,d represent spring, summer, autumn, Winter four seasons; Thermal power loss occurs in the thermal energy transmission process of the thermal system The mathematical expression is: Where: is the water supply temperature; is the ambient temperature at time t; k w is the heat transfer coefficient from the heat source to the heat exchange station; Q L is the mass of water flowing through the heat load; γ loss is the temperature influence coefficient; The thermal system transfers heat through water, and the thermal power absorbed by the heat load node for: Where: C w is the specific heat capacity of water; Q L is the mass of water flowing through the heat load; is the water supply temperature; is the return water temperature; L is the temperature influence coefficient; (3) Combined heat and power (CHP) unit constraints, Considering the electricity-hydrogen-gas coupled integrated energy system, the CHP unit is included to meet the thermal energy supply of the system, and its ramp constraint is: Where: and They are the up and down ramp power limits of the CHP unit respectively; CHP is the stability factor of the system CHP unit system; It is the lower limit constraint of CHP unit output; is the upper limit constraint of CHP unit output; η CHP The efficiency of the CHP unit will affect the setting of the upper and lower limits of the output; (4) Carbon capture and storage equipment models and constraints, The carbon capture and storage device captures the carbon dioxide emitted by the system as the carbon source of the methane generator; the mathematical model of the carbon capture and storage device is: Where P CCS,t is the total energy consumption of the carbon capture system; k CCS is the operating energy consumption coefficient of the unit CO2 capture system; is the amount of stored CO2; C is the conversion coefficient between methane and CO2; is the volume of CO2; P F is the fixed energy consumption of the carbon capture system; δ T,P is the temperature and pressure influence coefficient of carbon capture system; Total amount of CO2 captured for the integrated energy system.

6. The method for optimizing and dispatching a comprehensive energy system in a park based on the coupling characteristics of electricity, hydrogen and gas according to claim 1 is characterized in that In step S4, mutation operators and disturbance factors are added to improve the dragonfly algorithm, specifically including: First, input the parameter configuration of each device in the integrated energy system, such as the operating parameters of wind turbines, photovoltaic equipment, and hydrogen production equipment, update the parameters of the five behaviors of the dragonfly algorithm, and use the objective function of the total operating cost f of the integrated energy system as the fitness function. Use the dragonfly search process to solve the optimal equipment output when the integrated energy system is running, thereby obtaining the minimum operating cost of the electricity-hydrogen-gas integrated energy system. The calculation expression of the selected dragonfly individual after adding the mutation factor is: Where r is the number of iterations of the current era, α is a random number on [0,1], is the maximum variation value of the dragonfly individual in the d dimension, is the minimum variation value of the dragonfly individual in the d dimension; N(0,1) is a normally distributed random number with a mean of 0 and a variance of 1; After adding the disturbance factor and mutation speed factor, the dragonfly position is updated: is the position of the individual before mutation; is the maximum value of an individual in the dth dimension, is the minimum value of the individual in the dth dimension, r is the number of iterations, R is the maximum number of iterations; s is the mutation rate factor, and ω is the disturbance factor.

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