An electric-hybrid hydrogen-natural gas urban integrated energy system

Abstract

The present invention discloses an electric - hybrid hydrogen natural gas urban integrated energy system, comprising: a source side, which includes photovoltaic power, wind power generation, urban distribution network and hybrid hydrogen natural gas network; a load side, which includes four types of loads: electricity, gas, cooling and heating; an electric - hybrid hydrogen natural gas coupling point, which is composed of a hydrogen mixed - combustion engine and an electric - to - gas device; and an urban energy management system for scheduling and controlling the source side, the load side and the electric - hybrid hydrogen natural gas coupling point. The present invention schedules and controls the source side, the load side and the electric - hybrid hydrogen natural gas coupling point through the urban energy management system to achieve reasonable, stable and safe management of the urban integrated energy system, and realize energy cleaning and high - efficiency.

Description

Technical Field

[0001] The present invention relates to energy technologies, and particularly to an electric - hybrid hydrogen natural gas urban integrated energy system. Background Art

[0002] With the gradual development of hybrid hydrogen natural gas technology, hydrogen - fueled engines have become the key implementation nodes of future electric - hybrid hydrogen natural gas urban integrated energy systems. In recent years, gas turbines have been widely applied in various integrated energy systems due to their stable power output, fast response, and low pollutant emission levels, etc., and are a key link in realizing the coupling of electricity and gas. With the implementation of new policies globally, the use of gas turbines powered by traditional natural gas is restricted by the carbon trading market. Currently, the global energy structure is accelerating its transformation towards low - carbon and clean energy. However, gas turbines consuming traditional natural gas will produce more carbon dioxide, causing the greenhouse effect and many other climate problems. In view of the deficiencies of existing gas turbines and the dual - carbon goal, China has carried out many explorations on cutting - edge technologies for clean energy substitution: New energy represented by hydrogen energy is an ideal interconnection medium for realizing the clean and efficient utilization of energy and supporting the large - scale development of renewable energy, and is the best choice for deep decarbonization in various industrial fields. Due to the many difficulties such as high costs and difficult maintenance that may exist in hydrogen transportation pipelines and local storage, and considering the large - scale natural gas pipelines and relatively perfect operation and management technologies in China, a hybrid hydrogen natural gas network can be formed under the condition of ensuring safety, mixing hydrogen into natural gas pipelines for long - distance transportation, providing a new idea for realizing energy cleaning and high - efficiency, and at the same time, the gas turbine for electricity - gas coupling is developed into a hydrogen - fueled engine, using hybrid hydrogen natural gas as the supply fuel, which has the characteristics of low - carbon combustion, strong power performance, and high power generation efficiency, boosting the clean - up of gas - electricity, and its operating characteristics will have a greater impact on the dynamic dispatching plan of urban integrated energy systems. Therefore, establishing an electric - hybrid hydrogen natural gas urban integrated energy system considering the operating characteristics of hydrogen - fueled engines has important practical significance for ensuring the reasonable, stable, safe, and low - carbon energy use of urban integrated energy systems. Summary of the Invention

[0003] In order to solve at least one of the technical problems in the above - mentioned background art, the present invention provides an electric - hybrid hydrogen natural gas urban integrated energy system

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] An electric - hybrid hydrogen natural gas urban integrated energy system, comprising:

[0006] The source side, which includes photovoltaic power generation, wind power generation, urban distribution network, and hybrid hydrogen natural gas network;

[0007] The load side, which includes four types of loads: electricity, gas, cold, and heat;

[0008] The electricity - hybrid hydrogen natural gas coupling point is composed of a hydrogen - fueled engine and an electricity - to - gas device;

[0009] The urban energy management system is used to schedule and control the source side, the load side, and the electricity - hybrid hydrogen natural gas coupling point.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0011] The present invention schedules and controls the source side, the load side, and the electricity - hybrid hydrogen natural gas coupling point through the urban energy management system to achieve reasonable, stable, and safe management of the urban integrated energy system, and realize energy cleaning and high - efficiency. Brief Description of the Drawings

[0012] Figure 1 It is a schematic diagram of the composition of the electricity - hybrid hydrogen natural gas urban integrated energy system provided by the embodiment of the present invention;

[0013] Figure 2 It is a schematic diagram of the composition of the urban energy management system provided by the embodiment of the present invention;

[0014] Figure 3 It is a coupling architecture diagram of the hydrogen - mixed natural gas network and the hydrogen - fueled engine considering the multi - component tracking of hydrogen - mixed natural gas;

[0015] Figure 4 It is a working flow chart of the urban energy management system. Detailed Embodiments

[0016] Embodiment:

[0017] The technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0018] Refer to Figure 1 As shown, the basic structure of the electricity - hybrid hydrogen natural gas urban integrated energy system is as follows. Taking the urban energy management system as the multi - energy regulation center, the source side includes photovoltaic, wind power generation, urban distribution network, and hydrogen - mixed natural gas network, the load side includes four types of loads: electricity, gas, cold, and heat, and the electricity - hybrid hydrogen natural gas coupling point is composed of a hydrogen - fueled engine and an electricity - to - gas device. The source side, the load side, and the electricity - hybrid hydrogen natural gas coupling point are scheduled and controlled through the urban energy management system to achieve reasonable, stable, and safe management of the urban integrated energy system, and realize energy cleaning and high - efficiency.

[0019] In a specific embodiment, as Figure 2 shown, the above - mentioned urban energy management system includes:

[0020] An input module for inputting the operating parameters of the hydrogen - fueled engine;

[0021] The refined model module of the hydrogen hybrid engine constructs a refined model of the hydrogen hybrid engine considering carbon emissions and hybrid combustion characteristics based on the input operating parameters of the hydrogen hybrid engine;

[0022] The optimized scheduling objective function module stores the optimized scheduling objective function of the electric - hybrid hydrogen - natural gas urban integrated energy system;

[0023] The constraint module stores the constraints of the urban distribution network, the hybrid hydrogen - natural gas network, the user unit, and the coupled operation;

[0024] The optimized scheduling model module establishes an optimized scheduling model of the electric - hybrid hydrogen - natural gas urban integrated energy system considering the operating characteristics of the hydrogen hybrid engine based on the refined model module of the hydrogen hybrid engine, the optimized scheduling objective function module, and the constraint module;

[0025] The solver is used to solve the optimized scheduling model of the electric - hybrid hydrogen - natural gas urban integrated energy system to obtain the scheduling control instructions;

[0026] The output module is used to output the scheduling control instructions.

[0027] Specifically, the optimized scheduling objective function aims to minimize the total operating cost of the electric - hybrid hydrogen - natural gas urban integrated energy system including the urban distribution network, the hybrid hydrogen - natural gas network, and various user units, that is

[0028]

[0029] In the formula: f PG is the operating cost of the thermal power unit; f P2G is the operating cost of the power - to - gas equipment; f WT is the cost of curtailed wind power; is the environmental treatment cost brought by the carbon emissions of the hydrogen hybrid engine; f GS is the gas purchase cost at the gas source of the hybrid hydrogen - natural gas network; f HG is the gas consumption cost of the hydrogen hybrid engine inside the user unit; is the electricity purchase cost of the user unit; f DP is the maintenance cost of the internal operating equipment of the user unit.

[0030] Considering maximizing the consumption of renewable energy represented by wind power, the operation of other controllable equipment is optimized. Among them, the operating cost of the thermal power unit is expressed as follows:

[0031]

[0032] In the formula: NT is the scheduling period; G is the number of thermal power units; a g , b g , c g are the cost coefficients of the thermal power unit.

[0033] Taking into account the corresponding operating costs in the power-to-gas process and considering the curtailment costs in the process of wind power accommodation.

[0034]

[0035]

[0036] In the formula: N is the number of power-to-gas devices; W is the number of wind turbines; ζ P2G is the power-to-gas operating cost coefficient; P P2G,n,t is the power consumption of the nth power-to-gas device at time t; δ WT is the curtailment cost coefficient.

[0037] Due to the problem of CO2 emissions still existing in the hybrid combustion of the hydrogen-fired engine, the environmental cost brought by the carbon emissions of the hydrogen-fired engine is established as follows:

[0038]

[0039] In the formula: M is the number of hydrogen-fired engines; is the environmental cost price per unit of CO2 emissions.

[0040] The hydrogen-blended natural gas network and the user unit belong to different types of entities. Within a reasonable technical range, traditional natural gas is purchased at the gas source of the hydrogen-blended natural gas network, and a certain proportion of hydrogen is mixed with it in the gas network to obtain hydrogen-blended natural gas. Then, the hydrogen-blended natural gas is transported from the gas network node to the pressure regulating station for pressure regulation, and the natural gas energy company sells gas to the user unit. Here, it mainly considers the combustion output of the hydrogen-fired engine inside the user unit by the hydrogen-blended natural gas supply. Therefore, the gas purchase cost at the gas source of the hydrogen-blended natural gas network and the gas consumption cost of the hydrogen-fired engine inside the user unit are expressed as

[0041]

[0042]

[0043] In the formula: S is the number of gas sources; γ cg is the unit natural gas price; γ hg,t is the unit hydrogen-blended natural gas price at time t; Δt is the scheduling period interval; q s,t is the natural gas supply flow at the sth gas source at time t.

[0044] A part of the power supply of the user unit comes from the output of the hydrogen-fired engine, and the other part comes from purchasing electricity from the urban distribution network. Therefore, the electricity purchase cost of the user unit is shown in the following formula:

[0045]

[0046] In the formula: L is the number of user units; It represents the price at which the user unit purchases electricity from the urban distribution network at time t.

[0047] Considering the maintenance cost of the internal operating equipment of the user unit, it consists of Figure 1 It can be seen that it mainly includes the maintenance of equipment such as electric energy storage, hydrogen hybrid engine, electric chiller, adsorption chiller, electric boiler, and waste heat recovery boiler.

[0048]

[0049] In the formula: U is the quantity of electric energy storage; They are respectively the maintenance cost coefficients of the electric boiler, electric chiller, waste heat recovery boiler, adsorption chiller, hydrogen hybrid engine, and electric energy storage; P ht,m,t is the output of the m-th hydrogen hybrid engine at time t; P eh,t is the power consumption of the electric boiler at time t; P ec,t is the power consumption of the electric chiller at time t; H rh,in,t is the heat collection power on the input side of the waste heat recovery boiler at time t; H ac,in,t is the heat collection power on the input side of the adsorption chiller at time t.

[0050] Specifically, the above-mentioned operation constraints of the urban distribution network include: The controllable power sources such as thermal power units and renewable energy represented by wind power need to meet the output limit conditions during operation:

[0051] P g,min ≤P g,t ≤P g,max (10)

[0052]

[0053] Taking into account the power consumption of the power-to-gas equipment, the output of the thermal power unit, the actual output of renewable energy, the electricity purchase of the user unit, and the electrical load of the urban distribution network, the urban distribution network needs to meet the electrical power balance during operation, that is

[0054]

[0055] The above-mentioned constraints of the hydrogen-blended natural gas network include:

[0056] Assuming that the temperature of the hydrogen-blended natural gas pipeline does not change with the flow, and the initial combustion temperature at the inlet of the hydrogen hybrid engine is obtained by regulating the pressure at the pressure regulating station (converted according to the gas state equation using the node pressure of the gas network), then the hydrogen-blended natural gas network needs to meet the following constraint conditions:

[0057] 1) Constraint on the relationship between pipeline flow and gas network node pressure

[0058] Considering the flow rate of the hydrogen - blended natural gas pipeline with directionality, there is a certain relationship between the gas network node pressure and the pipeline flow rate, and it is also affected by the gas network structure. The hydrogen - blended natural gas needs to satisfy the pipeline flow rate and gas network node pressure limitations during the flow, that is

[0059]

[0060] -q ij,max ≤q ij,t ≤q ij,max (14)

[0061] p i,min ≤p i,t ≤p i,max (15)

[0062] In the formula: q ij,t is the pipeline flow rate between gas network node i and gas network node j at time t; p i,t is the pressure of gas network node i at time t; T st is the temperature of the hydrogen - blended natural gas under standard conditions; p st is the pressure of the hydrogen - blended natural gas under standard conditions; D ij 、L ij 、f ij are the inner diameter, pipeline length, and friction coefficient between gas network node i and gas network node j; T hg is the temperature of the hydrogen - blended natural gas pipeline, regarded as the temperature of the hydrogen - blended natural gas pipeline under safe standard conditions; Z ij is the compressibility factor (volume correction factor) between gas network node i and gas network node j; q ij,max is the upper limit of the pipeline flow rate between gas network node i and gas network node j at time t; p i,max 、p i,min are the upper and lower limits of the pressure of gas network node i at time t; R is the ideal gas constant.

[0063] 2) Energy balance constraint of gas network nodes

[0064] Since each gas network node is balanced in the form of energy flow, related to the gas source point, hydrogen - blending point, and other gas network nodes, and the flow has directionality. It is stipulated that the pipeline flow rate of the hydrogen - blended natural gas flowing into gas network node i is positive. At the same time, it is also necessary to establish a reference direction for the pipeline flow rate of the hydrogen - blended natural gas in the hydrogen - blended natural gas network. Let L q (j,i) represent the set of all pipelines with the reference direction from gas network node j to i, and L q (i,j) represent the set of all pipelines with the reference direction from gas network node i to j.

[0065]

[0066] E HT,i,t= GCV i,t ·V hg,i,t (17)

[0067]

[0068] where: χ h2,i and χ i,s are the hydrogen injection at gas network node i and the gas supply status of the s-th gas source respectively, taking 0 or 1; GCV s represents the higher heating value of the natural gas supplied by the s-th gas source; ε ij,t is the actual flow direction of the hydrogen-blended natural gas pipeline between gas network node i and gas network node j at time t, taking -1, 0, 1; u ij,t and δ ij,t are the positive direction identifier and the reverse direction identifier of the actual flow of the hydrogen-blended natural gas pipeline between gas network node i and gas network node j at time t; sgn(·) is the sign function; E D,i,t and E HT,i,t are the conventional user gas load and the hydrogen-fueled engine gas load at gas network node i at time t; GCV i,t is the calorific value of the hydrogen-blended natural gas at gas network node i at time t.

[0069] Taking into account the limitation of the gas supply flow of the gas source, and the gas supply flow satisfies

[0070] q s,min ≤ q s,t ≤ q s,max (19)

[0071] where: q s,max and q s,min are the upper and lower limits of the gas supply flow at the gas source respectively.

[0072] 3) Average pressure constraint of hydrogen-blended natural gas pipeline

[0073] Based on the Soave-Redlich-Kwong equation of state, its form is further improved to describe the average pressure of the hydrogen-blended natural gas pipeline at equilibrium.

[0074]

[0075] where: p av,ij,t is the average pipeline pressure between gas network node i and gas network node j at time t; T c,z and p c,z are the critical temperature and critical pressure of gas component z; ω z is the acentric factor of gas component z; Z ij is the pipeline compressibility factor between gas network node i and gas network node j; A ij,t and B ij,tis the state parameter of the hydrogen - mixed natural gas between gas network node i and gas network node j at time t; φ z is the conversion parameter of the acentric factor of gas component z.

[0076] 4) Calculation of the density, calorific value, and mole fraction of hydrogen - mixed natural gas

[0077] According to the mole fractions of each gas component in the hydrogen - mixed natural gas, the calculation methods of its density and calorific value are defined, and according to the flow balance relationship of the gas network nodes, the mole fraction calculation of gas component z in the hydrogen - mixed natural gas is obtained. Wherein, M z is the molar mass of gas component z; M air is the molar mass of air, generally taken as 29 g / mol; N h2,z,i,t is the mole fraction of gas component z in the hydrogen of the hydrogen - added electrolyzed water at gas network node i at time t, considering z ∈ Z(H2); N cg,z,i,t is the mole fraction of gas component z in the natural gas supplied by the gas source at gas network node i at time t, considering

[0078]

[0079]

[0080]

[0081] Among them, according to the current safety hydrogen - addition standard, hydrogen addition at gas network nodes needs to meet

[0082] 0 ≤ N z,i,t ≤ N h2,i,max , z ∈ Z(H2) (24)

[0083] In the formula: N h2,i,max is the upper limit of the hydrogen mole fraction at gas network node i.

[0084] 5) Constraints on compressors and pressure - regulating stations

[0085] In the hydrogen - mixed natural gas network, the hydrogen - mixed natural gas realizes safe and stable flow through the operation of the compressor, and the hydrogen - mixed natural gas on the outlet side of the gas network node is regulated by the pressure - regulating station to be suitable for the mixed combustion of the hydrogen - mixed engine. Therefore, relevant constraints are set for the compressor and the pressure - regulating station, that is

[0086]

[0087] In the formula: r ij,t is the compression ratio between gas network node i and gas network node j at time t; is the pressure conversion coefficient; k i,t is the pressure - regulating ratio on the outlet side of gas network node i at time t; r ij,max , rij,min are the upper and lower limits of the compression ratio between gas network node i and gas network node j at time t; k i,max , k i,min are the upper and lower limits of the pressure regulation ratio on the outlet side of gas network node i at time t.

[0088] The internal equipment operation constraints of the above user units include:

[0089] For the types of user units, they are mainly divided into three different types: residential communities, university towns, and industrial parks. In residential communities and university towns, the electric power balance is mainly achieved by hydrogen hybrid engines, photovoltaic units, and electric energy storage. Industrial parks include equipment such as hydrogen hybrid engines, photovoltaic units, electric boilers, electric refrigerators, waste heat recovery boilers, adsorption refrigerators, and electric energy storage. Define Q(l1), Q(l2), and Q(l3) as the numbering set of user units in residential communities, university towns, and industrial parks respectively; Q1(l1), Q1(l2), and Q1(l3) as the numbering set of hydrogen hybrid engines in user units in residential communities, university towns, and industrial parks respectively; Q2(l1), Q2(l2), and Q2(l3) as the numbering set of electric energy storage in user units in residential communities, university towns, and industrial parks respectively. Set the power supply of a single hydrogen hybrid engine and the charging and discharging regulation of a single electric energy storage within each user unit, that is, the number of hydrogen hybrid engines and the number of electric energy storage are consistent with the number of user units. Then the internal equipment operation satisfies the corresponding energy balance constraints as follows

[0090]

[0091]

[0092] H rh,t +H eh,t =H us,t (28)

[0093] C ec,t +C ac,t =C us,t (29)

[0094] In the formula: L us,l,t is the electric load of the l-th user unit at time t; H us,t is the heat load of the industrial park at time t; C us,t is the cooling load of the industrial park at time t; P v,l,t is the output power of the photovoltaic unit in the l-th user unit at time t; H rh,t is the heat release power on the output side of the waste heat recovery boiler at time t; H eh,t is the heat release power on the output side of the electric boiler at time t; C ec,t is the cooling supply power on the output side of the electric refrigerator at time t; C ac,tis the cooling power output from the adsorption chiller at time t.

[0095] 1) Electrical energy storage: Taking the battery as an example, establish a suitable flexible energy storage regulation method and energy storage capacity to promote the local consumption of renewable energy and improve the utilization rate of electrical energy. Therefore, the electrical energy storage constraints mainly include operation constraints and charge-discharge limit constraints.

[0096] 0 ≤ E st,u,t ≤ E st,u,max (30)

[0097] U dis,u,t + U ch,u,t ≤ 1 (31)

[0098] E st,u,t = E st,u,t-1 +(P ch,u,t - P dis,u,t )Δt (32)

[0099]

[0100] In the formula: E st,u,max is the upper limit of the energy storage capacity; E st,u,t is the capacity of the u-th electrical energy storage at time t; U ch,u,t and U dis,u,t are the charge and discharge states of the u-th electrical energy storage at time t respectively; P ch,u,max , P dis,u,max are the upper limits of the charge and discharge power of the u-th electrical energy storage; N bat,u is the charge-discharge conversion times of the u-th electrical energy storage.

[0101] 2) Waste heat recovery boiler and adsorption chiller: In the actual application of the hydrogen hybrid engine, the thermal energy input to the waste heat recovery boiler and the adsorption chiller both come from the waste heat generated by the hydrogen hybrid engine. The corresponding operation constraints and the balance conditions between the waste heat output by the hydrogen hybrid engine and the heat collection power of the absorption chiller and the waste heat recovery boiler are as follows

[0102]

[0103] H ht,m,t = η re P ht,m,t , m ∈ Q1(l3) (35)

[0104] H rh,in,t + H ac,in,t = H ht,m,t , m ∈ Q1(l3) (36)

[0105] In the formula: η rb,h 、η ar,cThey are the heat collection efficiency of the waste heat recovery boiler and the refrigeration efficiency of the adsorption refrigeration machine; β rb,h 、β ar,c are the heating coefficient and the refrigeration coefficient; η re is the waste heat recovery efficiency; H ht,m,t is the waste heat actually output by the hydrogen hybrid combustion engine in the industrial park at time t, that is, the waste heat output by the hydrogen hybrid combustion engine per unit time; H rh,in,max is the upper limit of the heat collection power on the input side of the waste heat recovery boiler; H ac,in,max is the upper limit of the heat collection power on the input side of the adsorption refrigeration machine.

[0106] 3) Electric boiler and electric refrigeration machine: The electric boiler and the electric refrigeration machine both use electric energy as the energy form on the input side, and are respectively converted into heat energy and cold energy through their respective working methods. Their corresponding operation constraints are expressed as

[0107]

[0108] In the formula: η eh is the heating efficiency of the electric boiler; η ec is the refrigeration efficiency of the electric refrigeration machine; P eh,max 、P ec,max are the upper limits of the power consumption of the electric boiler and the electric refrigeration machine.

[0109] The above-mentioned coupling operation constraints include:

[0110] The electric-hydrogen hybrid natural gas integrated energy system realizes the two-way coupling between the urban distribution network and the hydrogen hybrid natural gas network through the hydrogen hybrid combustion engine and the power-to-gas equipment.

[0111] 1) Hydrogen hybrid combustion engine: The carbon emission and mixed combustion output model of the hydrogen hybrid combustion engine are expressed as follows. The specific modeling method is as described below, and the boundary conditions of the electric-hydrogen hybrid natural gas coupling are set. The same variable modeled on the hydrogen hybrid combustion engine side has the same meaning and will not be described later. Restrictions are imposed on the actual gas consumption of the hydrogen hybrid combustion engine in all user units, then

[0112]

[0113]

[0114]

[0115]

[0116] 0 ≤ V hg,m,t ≤ V hg,m,max (42)

[0117] In the formula: η c is the power generation conversion efficiency; Q cab,m,tis the carbon emission of the m-th hydrogen hybrid engine at time t; λ wh,z,m,t is the stoichiometric number of the actual combustion reaction products of gas component z of the m-th hydrogen hybrid engine at time t; λ z,m,t is the stoichiometric number of the actual combustion reaction products of gas component z of the m-th hydrogen hybrid engine before the reaction reaches a steady state. When z = 1, 2, 3, 4, they correspond to the numbers of methane, ethane, propane, and hydrogen respectively. In the carbon emission model, it refers to the actual CO2 generation stoichiometric number; λ com,z is the stoichiometric number of the actual combustion reaction products of gas component z when the reaction reaches a steady state; Z1 is the number of alkane gas components in the hydrogen-blended natural gas; α nv,z is the volume conversion coefficient; T com,z is the steady-state combustion temperature of gas component z; T in,m,t is the initial combustion temperature at the intake port of the m-th hydrogen hybrid engine at time t; i z is the degree of freedom of gas component z; M in,m,t is the molar mass of the hydrogen-blended natural gas in the m-th hydrogen hybrid engine at time t; ψ z is the molar fraction unit conversion coefficient; V hg,m,t is the gas consumption of the m-th hydrogen hybrid engine at time t; V hg,m,max is the upper limit of the gas consumption of the m-th hydrogen hybrid engine; N z,i,t is the molar fraction of gas component z in gas network node i at time t; ρ i,t is the density of the hydrogen-blended natural gas in gas network node i at time t; T in,i,t is the temperature of the hydrogen-blended natural gas that meets the combustion conditions of the hydrogen hybrid engine after being adjusted by the pressure regulating station at gas network node i at time t; V hg,i,t is the gas consumption of the hydrogen hybrid engine at gas network node i at time t.

[0118] 2) Power-to-gas: Integrate the power-to-gas technology mainly based on the electrolysis of water reaction. Within a reasonable and safe technical range, mix the produced hydrogen with traditional natural gas and inject it into the network to further improve the renewable energy consumption rate. Considering the flow rate of hydrogen incorporated into the gas network node, establish the relationship between the power consumption of the power-to-gas equipment and the flow rate of hydrogen injected into the gas network node according to the high calorific value of hydrogen. And the power consumption of the power-to-gas equipment needs to meet the upper and lower limit constraints of the formula. Considering that the number, connection position of the power-to-gas equipment are related to the gas network node number, set the boundary conditions of the flow rate of hydrogen injected into the gas network node in the power-to-gas equipment - hydrogen-blended natural gas network node path, that is, the flow rate of hydrogen output by the power-to-gas equipment is equal to the flow rate of hydrogen injected into the gas network node.

[0119]

[0120] 0 ≤ P P2G,n,t ≤ P P2G,n,max (44)

[0121] qh2,i,t = q h2,n,t (45)

[0122] Where: P P2G,n,max is the upper limit of the power consumption of the nth power-to-gas device; q h2,n,t , q h2,i,t are the hydrogen flow rate output by the nth power-to-gas device at time t and the hydrogen flow rate injected into the gas network node i; η P2G,H is the conversion efficiency of electrolytic water hydrogen production.

[0123] In a specific embodiment, the modeling method of the refined model of the hydrogen co-firing engine considering carbon emissions and mixed combustion characteristics is as follows:

[0124] When considering the multi-component tracking of hydrogen-blended natural gas, the combustion of hydrogen-blended natural gas in a hydrogen co-firing engine can be refined into four links of methane, ethane, propane, and hydrogen combustion reactions as follows

[0125]

[0126] Starting from the perspectives of chemical reaction equilibrium and energy conversion, the influence of multi-component combustion on carbon emissions and mixed combustion is carefully considered to describe the key operating characteristics of the hydrogen co-firing engine. Based on the multi-disciplinary information fusion mainly composed of chemical reaction kinetics and system thermodynamics, the refined modeling of carbon emissions and mixed combustion output of the hydrogen co-firing engine is carried out respectively (ignoring the corresponding variables related to the number m of hydrogen co-firing engines, the scheduling period t, and the gas network node number i, etc.).

[0127] Basic assumptions of the model:

[0128] Since the combustion reaction of the hydrogen co-firing engine itself involves many influencing factors, in order to carry out reasonable refined modeling subsequently, the influence of its non-main factors is not considered, and the corresponding basic assumptions are made: 1) Since the reaction rate and reaction equilibrium are affected by the change of gaseous substances, the state of water in the chemical reaction equation is distinguished. It is assumed that the state of water in the combustion reaction of alkane gases is liquid water, ignoring the influence of its concentration on the reaction equilibrium, and in order to reflect the reaction rate of hydrogen, the state of water in its products is regarded as gaseous, so it is included in the reaction equilibrium expression; 2) It is assumed that the oxygen supply is sufficient and the concentration can be kept constant, which is 1 mol / m 3 ; 3) The temperature and pressure at each point in the cylinder of the hydrogen co-firing engine are equal, the hydrogen-blended natural gas is completely mixed and homogeneously distributed, and its mixed molar mass is distributed according to the molar fraction ratio of each gas component. Since the constructed model is applied to the scheduling of the urban integrated energy system, considering that the scheduling time is much longer than the time required for the combustion reaction to reach the steady-state equilibrium, it is assumed that the reaction change can depend on the steady-state combustion temperature and the initial combustion temperature at the intake port; 4) It is assumed that there is no gas leakage loss at the valves, piston rings, etc. in the cylinder of the hydrogen co-firing engine, and the whole process is approximately a closed combustion (adiabatic process) without heat dissipation to the outside.

[0129] Carbon Emission Model of Hydrogen Hybrid Combustion Engine Based on Arrhenius Equation

[0130] The establishment of the carbon emission model of the hydrogen hybrid combustion engine depends on the capture of the amount of CO2 generated by the actual combustion reaction. By introducing the chemical reaction kinetics mechanism and using the reversible reaction approximation equivalent method, the reaction equilibrium is related to the reaction rate. In chemical reaction kinetics, the Arrhenius equation reflects the variation of the gas reaction rate constant with the combustion temperature, showing a negative exponential distribution characteristic. Therefore, based on this equation, the relationship between the combustion reaction equilibrium and the combustion temperature of methane, ethane, propane, and hydrogen can be established. Taking the methane gas combustion reaction as an example, ignoring the influence of the concentration of water in the product, before reaching the steady state, its combustion reaction rate is divided into the forward reaction rate and the reverse reaction rate, which are expressed as follows:

[0131]

[0132]

[0133] In the formula: is the forward reaction rate of methane combustion; is the reverse reaction rate of methane combustion; is the forward rate constant of methane combustion; is the reverse rate constant of methane combustion; represents the concentration of methane; represents the concentration of oxygen; is the concentration of carbon dioxide.

[0134] When reaching the steady-state equilibrium, Establish the relationship between the reaction equilibrium constant and the rate constant based on the Arrhenius equation. Since the concentration of oxygen remains constant, let It is expressed as the ratio of the amount of substance of carbon dioxide generated to the amount of substance of methane consumed in the reaction, that is, the actual CO2 generation stoichiometric number. According to the gas concentration conversion formula c gs =n gs / V gs and the ideal gas state equation P gs V gs =m gs RT e / M gs , after sorting out, we can get

[0135]

[0136]

[0137] In the formula: c gs , n gs , V gs , P gs、m gs 、M gs are the concentration, amount of substance, volume, pressure, mass and molar mass of the ideal gas respectively; T e is the thermodynamic temperature; K CH4 is the equilibrium constant of methane combustion reaction; E CH4 is the activation energy of the methane combustion reaction, which is independent of temperature and depends on the nature of the reaction; A is the frequency factor; T in is the initial combustion temperature at the inlet of the hydrogen hybrid engine; T com,1 is the steady-state combustion temperature of methane.

[0138] λ1 describes the effect of combustion temperature on the amount of substance conversion in the methane combustion reaction, and can be regarded as the calculation of the carbon emission factor of the mixed hydrogen natural gas considering the combustion temperature. Therefore, the actual combustion reaction product stoichiometric numbers of other gas components are derived by the above method. For the combustion reactions of ethane, propane and hydrogen, the ratio of the amount of substance of the product to the amount of substance of the reactant is defined as the reaction product stoichiometric number. The reaction equilibrium of the combustion process satisfies the Arrhenius equation, and the relationship between the reaction product stoichiometric number and the reaction equilibrium constant is obtained by combining them. In the concentration conversion process, it is considered that the mixed hydrogen natural gas is transmitted to the hydrogen hybrid engine for combustion in a mixed state, and the molar mass and density of the mixed hydrogen natural gas are taken into account. In addition, there is a time lag problem in the system scheduling relative to the combustion reaction equilibrium. In order to optimize the amount of substance conversion efficiency at steady-state reaction equilibrium as much as possible to adapt to the subsequent scheduling model, the steady-state reaction conversion coefficients need to be respectively calculated when calculating the stoichiometric numbers of ethane and propane reaction products. , Approximately fixed according to the molar mass and density limit of the hydrogen-mixed natural gas.

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146] Where: λ2, λ3, λ4 are the actual CO2 generation numbers of ethane and propane combustion and the actual H2O generation numbers of hydrogen combustion respectively; represents the amount of substance of ethane; The amount of substance expressing propane; represents the amount of substance of hydrogen; represents the amount of substance of water vapor; represents the concentration of ethane; represents the concentration of propane; represents the concentration of hydrogen; represents the concentration of water vapor; are the equilibrium constants of the combustion reactions of ethane, propane, and hydrogen respectively; are the forward rate constants of the combustion of ethane, propane, and hydrogen respectively; are the reverse rate constants of the combustion of ethane, propane, and hydrogen respectively; are the activation energies of the combustion reactions of ethane, propane, and hydrogen respectively, depending on the nature of the reaction; T com,2 、T com,3 、T com,4 are the steady-state combustion temperatures of ethane, propane, and hydrogen respectively; ρ in,min is the lower limit of the density of hydrogen-blended natural gas; are the upper limits of the molar masses of ethane and propane in hydrogen-blended natural gas respectively, and depend on the upper limits of the mole fractions of the gas components.

[0147] In summary, ignoring the mutual influence between the gas components in hydrogen-blended natural gas, when the gas combustion reaches or exceeds the temperature condition of steady-state combustion, the combustion reaction can be regarded as having reached a steady state, and the stoichiometric coefficients of its reaction products remain constant. In order to reduce the occurrence of non-linear problems between components, the stoichiometric coefficients of the actual combustion of various alkane gases to produce CO2 are processed by linear weighted sum, and the relationship between the CO2 emissions and gas consumption of the hydrogen-blended combustion engine is established, so as to obtain the carbon emission model of the hydrogen-blended combustion engine based on the Arrhenius equation.

[0148]

[0149]

[0150] Hydrogen-blended combustion output model of hydrogen-blended combustion engine based on system thermodynamics

[0151] It is assumed that the hydrogen-blended combustion of the hydrogen-blended combustion engine is carried out in an adiabatic closed container with a regular shape, and the mass change rate of gas component z in the cylinder is considered during the combustion reaction process.

[0152]

[0153] In the formula: t cr is the combustion reaction time; m z is the mass of gas component z; w z is the molar amount change rate of component z in the mixed gas per unit volume during the combustion reaction, and w z=dn z / dt cr =Δn z / Δt cr According to the difference method principle, the product of the actual reaction stoichiometry and the initial conditions of the air inlet can be used to approximately calculate the amount of substance change in the combustion reaction, that is, Δn z / Δt cr =λ wh,z n in,z Among them, n in,z is the initial amount of substance of gas component z.

[0154] According to the law of conservation of mass, the total mass of the mixed substances in the cylinder of the hydrogen-fuel mixture engine before and after combustion remains unchanged, and the total internal energy of the combustion reaction of the mixed hydrogen and natural gas is obtained by the weighted sum of the internal energy of the gas components multiplied by their mass fractions.

[0155]

[0156]

[0157] Where: E hg is the total internal energy of the combustion reaction of mixed hydrogen and natural gas; m mix is the total mass of the mixture in the cylinder; e z is the internal energy of gas component z; Y z is the mass fraction of gas component z; Z is the number of gas components in hydrogen-mixed natural gas.

[0158] For the construction of the hydrogen hybrid combustion engine mixed combustion output model, the energy conversion link of the model is refined, and based on the basic working principle of the hydrogen hybrid engine, the conversion process of internal energy-mechanical energy-electrical energy is established. Based on the law of conservation of energy in system thermodynamics, the heat transferred by the hydrogen hybrid engine to the outside is ignored, that is, Q h =0, so the total internal energy change of the hydrogen-mixed natural gas combustion reaction in the cylinder is ΔE hg Equal to the mechanical energy W generated by the cylinder piston mec , thereby driving the generator rotor to work and convert it into electrical energy. Therefore, to build a hydrogen hybrid combustion engine mixed combustion output model, the key is to establish an expression for the total internal energy change produced by the combustion reaction of mixed hydrogen and natural gas. During the entire energy conversion process, since the combustion reaction will cause the mass fraction of each gas component in the mixed hydrogen and natural gas to change, define v = V hg / m mix is the specific volume of hydrogen-mixed natural gas, and the mass fraction change rate of each gas component in the hydrogen-mixed natural gas is obtained jointly.

[0159]

[0160] Where: n z The amount of substance of the gas component.

[0161] For the expression of the total internal energy change generated by the combustion reaction of hydrogen-blended natural gas, considering the influence of the internal energy and mass fraction of each gas component, the total internal energy change before and after the reaction can be approximated as the differential form of the total internal energy.

[0162]

[0163] Among them, the physical meaning of the above formula is that the first term reflects the change in internal energy caused by the inherent temperature rise of hydrogen-blended natural gas in the cylinder chamber. Considering parameters such as specific heat capacity and related to the physical properties of hydrogen-blended natural gas, it is a physical change, then Y z Basically remains constant and can depend on the initial conditions of hydrogen-blended natural gas at the cylinder intake port; the latter term considers the change in internal energy caused by the change in the mass fraction of each gas component during the actual combustion reaction of hydrogen-blended natural gas, which is the main source of the internal energy of the hydrogen hybrid engine and is a chemical change. During the combustion reaction process, due to the relatively complex expression form of the latter term, e z Involves multiple related variables, and m z and T e Will change simultaneously with Y z The calculation difficulty is relatively high and it is difficult to apply to the problem of integrated energy system scheduling. In order to reasonably construct the model and reduce the repeated occurrence of nonlinear problems and irrelevant terms, the calculation method of the latter term e z Is different. Within the allowable error range, according to the mass fraction change rate equation of each gas component in hydrogen-blended natural gas, the change in the mass fraction of the latter term is converted into the change in the amount of substance view. Given the initial combustion temperature and steady-state combustion temperature at the intake port, the standard molar combustion reaction internal energy e sc,z Of gas component z is introduced, and let e sc,z =i z RT in / 2. Since the volume, mass, and molar mass of hydrogen-blended natural gas can be regarded as fixed coefficients during a scheduling period, the latter term can be specifically expressed as the product of the standard molar combustion reaction internal energy at the initial state of the reaction and the change in the amount of reaction substance, which can be approximated as the total internal energy increased by the combustion reaction of the mixed gas.

[0164]

[0165] Since dE = ΔE, and the relevant variables of the first term mainly depend on the initial state of the intake port and the change in the amount of substance of the combustion reaction satisfy the conditions of the difference method, after reducing the order of the above formula, we can get:

[0166]

[0167] In the formula: Y in,z Is the initial mass fraction of gas component z at the intake port, and Yin,z = ψ z N in,z ; m in,z is the initial mass of gas component z.

[0168] Substitute the specific volume of hydrogen - mixed natural gas, gas concentration conversion, and mole fraction unit conversion formulas into the above formula, that is

[0169]

[0170] In the formula: M in is the molar mass of hydrogen - mixed natural gas, and

[0171] In the process of mechanical - electrical energy conversion, comprehensively considering the influence of friction loss and energy conversion loss, that is, taking into account the power generation conversion efficiency, the mixed combustion output model of the hydrogen - mixed combustion engine is expressed as

[0172]

[0173] In the formula: η c is the power generation conversion efficiency; P ht is the power generation power of the hydrogen - mixed combustion engine.

[0174] In summary, the above formula is established based on the relevant mechanisms of system thermodynamics. Starting from the essence of energy conversion, multiple energy conversion links are carefully considered, and finally, a mixed combustion output model of the hydrogen - mixed combustion engine related to the mole fraction, molar mass, gas consumption, and steady - state and initial combustion temperature of hydrogen - mixed natural gas is formed.

[0175] Implementation architecture of the coupling of the hydrogen - mixed natural gas network and the hydrogen - mixed combustion engine considering multi - component tracking of hydrogen - mixed natural gas

[0176] As a conversion device for the coupling of electricity - hydrogen - mixed natural gas, the way of constructing its model will have a great impact on the dispatching on both sides. Considering the deficiencies of the traditional gas turbine model, and hydrogen - mixed natural gas is a mixture of multiple gas components such as methane, ethane, propane, and hydrogen, so it is necessary to realize multi - component tracking of hydrogen - mixed natural gas in the hydrogen - mixed natural gas network model. The corresponding modeling of the hydrogen - mixed combustion engine also incorporates this point into the relevant characteristic modeling to achieve the coupling of the hydrogen - mixed natural gas network and the hydrogen - mixed combustion engine. The implementation architecture of the coupling of the hydrogen - mixed natural gas network and the hydrogen - mixed combustion engine corresponding to the present invention is as follows Figure 3As shown. It can be seen that when the hydrogen - blended natural gas network is coupled with the hydrogen - mixed combustion engine, the hydrogen - blended natural gas network supplies the hydrogen - mixed combustion engine with hydrogen - blended natural gas containing multiple gas components after pressure regulation at the pressure regulation station. Therefore, the combustion output of the hydrogen - mixed combustion engine realizes power supply to end - users. In this implementation process, due to the complex physical structure of the hydrogen - mixed combustion engine, it needs to be simplified into a physical calculation model of a cylindrical container with a diameter of d. The reciprocating motion of its piston can change relevant variables such as mass and volume. Since the carbon emissions and mixed - combustion characteristics of the hydrogen - mixed combustion engine are greatly affected by the hydrogen - blended natural gas, a refined model for carbon emissions and mixed - combustion output of the HMGT considering multi - component tracking of HCNG is constructed to realize two - way coupling modeling of electricity - hydrogen - blended natural gas and further improve the model correlation.

[0177] The implementation process of the entire urban energy management system is as Figure 4 shown.

[0178] In summary, compared with the prior art, the present invention has the following technical advantages:

[0179] (1) An optimized dispatching model for the urban integrated energy system of electricity - hydrogen - blended natural gas considering the operating characteristics of the hydrogen - mixed combustion engine is established, providing a novel means of controlling the hydrogen energy flow path. Within the scope of safety technology, hydrogen is produced by the power - to - gas equipment and incorporated into the existing natural gas pipeline network to realize the mixed transportation of hydrogen and natural gas. Compared with the local hydrogen storage method (i.e., power - to - gas is directly transported to the hydrogen storage tank for storage), there are significant differences in the hydrogen energy flow path, effectively solving the problems existing in local hydrogen storage and meeting the actual low - carbon production needs; it is of great significance for ensuring the reasonable, stable, safe, and low - carbon energy use of the urban integrated energy system.

[0180] (2) The representation method considering multi - component tracking of hydrogen - blended natural gas is taken into account, which not only increases the accuracy of the hydrogen - mixed combustion engine model but also carefully considers the influence of multiple gas components in the hydrogen - blended natural gas on the optimized dispatching. The combustion of hydrogen - blended natural gas is divided into four links: methane combustion, ethane combustion, propane combustion, and hydrogen combustion. On the gas network side, the mixed - flow characteristics are presented in the form of mixed density and mixed calorific value and meet the relevant constraints of the gas network structure. On the hydrogen - mixed combustion engine side, the influence of the combustion links of multiple gas components on carbon emissions and mixed - combustion output is considered to realize two - way coupling modeling considering multi - component tracking of hydrogen - blended natural gas.

[0181] (3) Starting from the perspective of energy conversion, based on the energy realization path of the hydrogen - mixed combustion engine of "thermal energy - mechanical energy - electrical energy", the single - zone combustion model of the hydrogen - mixed combustion engine is reduced - order processed by using the first law of thermodynamics, and the relationship between the mixed - combustion output of the hydrogen - mixed combustion engine and the consumption of hydrogen - blended natural gas is constructed, effectively avoiding the problem of homogenization of the combustion engine model.

[0182] (4) Establish the stoichiometric number expressions for the actual combustion of various alkane gases to produce CO2 through the Arrhenius equation, and further perform linear weighted sum processing, so as to construct the relationship between the carbon emissions of the hydrogen hybrid engine and the consumption of hydrogen-blended natural gas, which can reduce the occurrence of non-linear problems and improve the solution efficiency of the model to a certain extent.

[0183] The above embodiments are only used to illustrate the technical concept and characteristics of the present invention, and the purpose is to enable those ordinary skilled in the art to understand the content of the present invention and implement it accordingly, and it should not be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the essence of the content of the present invention should be covered within the protection scope of the present invention.

Claims

1. An electric-hybrid hydrogen natural gas urban integrated energy system, characterized in that Including: The source side, which includes photovoltaic power generation, wind power generation, urban distribution network and hydrogen-blended natural gas network; The load side, which includes four types of loads: electricity, gas, cold and heat; The electricity-hydrogen-blended natural gas coupling point, which is composed of a hydrogen combustion engine and an electricity-to-gas device; The urban energy management system, which is used to schedule and control the source side, load side and electricity-hydrogen-blended natural gas coupling point; The urban energy management system includes: An input module, which is used to input the operating parameters of the hydrogen combustion engine; A refined model module of the hydrogen combustion engine, which constructs a refined model of the hydrogen combustion engine considering carbon emissions and mixed combustion characteristics based on the input operating parameters of the hydrogen combustion engine; An optimized scheduling objective function module, which stores the optimized scheduling objective function of the electricity-hydrogen-blended natural gas urban integrated energy system; A constraint module, which stores the operating constraints of the urban distribution network, hydrogen-blended natural gas network, user unit and coupled operation; An optimized scheduling model module, which establishes an optimized scheduling model of the electricity-hydrogen-blended natural gas urban integrated energy system considering the operating characteristics of the hydrogen combustion engine based on the refined model module of the hydrogen combustion engine, the optimized scheduling objective function module and the constraint module; A solver, which is used to solve the optimized scheduling model of the electricity-hydrogen-blended natural gas urban integrated energy system to obtain scheduling control instructions; An output module, which is used to output the scheduling control instructions; The coupled operation constraints include: 1) Hydrogen combustion engine: Set the boundary conditions of electricity-hydrogen-blended natural gas coupling for the refined model of the hydrogen combustion engine considering carbon emissions and mixed combustion characteristics, and put forward restrictive requirements for the actual gas consumption of the hydrogen combustion engine in all user units, then 0 ≤ V hg,m,t ≤ V hg,m,max Where: η c is the power generation conversion efficiency; Q cab,m,t is the carbon emission of the m-th hydrogen hybrid combustor at time t; λ wh,z,m,t is the stoichiometric number of the actual combustion reaction products of gas component z of the m-th hydrogen hybrid combustor at time t; λ z,m,t is the stoichiometric number of the actual combustion reaction products of gas component z of the m-th hydrogen hybrid combustor before the reaction reaches a steady state. When z = 1, 2, 3, 4, they correspond to the numbers of methane, ethane, propane, and hydrogen respectively. In the carbon emission model, it refers to the actual CO2 generation stoichiometric number; λ com,z is the stoichiometric number of the actual combustion reaction products of gas component z when the reaction reaches a steady state; Z1 is the number of components of alkane gases in the hydrogen-blended natural gas; α nv,z is the volume conversion coefficient; T com,z is the steady-state combustion temperature of gas component z; T in,m,t is the initial combustion temperature at the intake port of the m-th hydrogen hybrid combustor at time t; i z is the degree of freedom of gas component z; M in,m,t is the molar mass of the hydrogen-blended natural gas in the m-th hydrogen hybrid combustor at time t; ψ z is the molar fraction unit conversion coefficient; V hg,m,t is the gas consumption of the m-th hydrogen hybrid combustor at time t; V hg,m,max is the upper limit of the gas consumption of the m-th hydrogen hybrid combustor; N z,i,t is the molar fraction of gas component z in gas network node i at time t; ρ i,t is the density of the hydrogen-blended natural gas in gas network node i at time t; T in,i,t is the temperature of the hydrogen-blended natural gas that meets the combustion conditions of the hydrogen hybrid combustor after being adjusted by the pressure regulating station at gas network node i at time t; V hg,i,t is the gas consumption of the hydrogen hybrid combustor at gas network node i at time t; 2) Electricity-to-gas: Considering the flow rate of hydrogen incorporated into the gas network node, establish the relationship between the power consumption of the electricity-to-gas device and the flow rate of hydrogen injected into the gas network node according to the high calorific value of hydrogen, and the power consumption of the electricity-to-gas device needs to meet the upper and lower limit constraints of the formula; Considering that the number, connection position of the electricity-to-gas device are related to the gas network node number, set the boundary conditions of the flow rate of hydrogen injected into the gas network node in the path of the electricity-to-gas device-hydrogen-blended natural gas network node, that is, the flow rate of hydrogen output by the electricity-to-gas device is equal to the flow rate of hydrogen injected into the gas network node; 0 ≤ P P2G,n,t ≤ P P2G,n,max q h2,i,t = q h2,n,t where: HHV z is the higher heating value of gas component z, and Z(H2) is the set of hydrogen numbers; P P2G,n,max is the upper limit of the power consumption of the nth power-to-gas device; q h2,n,t , q h2,i,t are the hydrogen flow rates output by the nth power-to-gas device at time t and the hydrogen flow rate injected into gas network node i; η P2G,H is the conversion efficiency of hydrogen production by electrolyzing water.

2. The electric-hybrid hydrogen natural gas urban integrated energy system according to claim 1, characterized in that The optimized scheduling objective function of the electricity-hydrogen-blended natural gas urban integrated energy system is: Where: f PG is the operating cost of the thermal power unit; f P2G is the operating cost of the power-to-gas equipment; f WT is the cost of wind curtailment; is the environmental treatment cost brought about by the carbon emissions of the hydrogen hybrid engine; f GS is the gas purchase cost at the gas source of the hydrogen-blended natural gas network; f HG is the gas consumption cost of the hydrogen hybrid engine inside the user unit; is the electricity purchase cost of the user unit; f DP is the maintenance cost of the operating equipment inside the user unit.

3. The electric-mixed hydrogen natural gas urban integrated energy system according to claim 1, wherein The operating constraints of the urban distribution network include: The controllable power sources of thermal power units and renewable energy represented by wind power need to meet the output limit conditions during operation: P g,min ≤P g,t ≤P g,max Wherein: P g,max and P g,min are the upper and lower limits of the output of the g-th thermal power unit at time t; P g,t is the output of the g-th thermal power unit at time t; P w,t is the actual output of the w-th wind power unit at time t; is the predicted output of the w-th wind power unit at time t; Considering the power consumption of the power-to-gas equipment, the output of the thermal power unit, the actual output of the renewable energy, the power purchase of the user unit, and the electrical load of the urban distribution network, the power balance needs to be satisfied during the operation of the urban distribution network, that is Wherein: P uv,t is the photovoltaic output of the urban distribution network at time t; is the power purchase of the l-th user unit at time t; P P2G,n,t is the power consumption of the n-th P2G device at time t; L ud,t is the electrical load of the urban distribution network at time t.

4. The electric-hybrid hydrogen-natural gas urban integrated energy system according to claim 1, wherein The operating constraints of the hydrogen-blended natural gas network include the relationship constraints between pipeline flow and gas network node pressure, gas network node energy balance constraints, average pressure constraints of hydrogen-blended natural gas pipelines, constraints on hydrogen-blended natural gas density, calorific value and molar fraction, and constraints on compressors and pressure regulating stations.

5. The electric-hybrid hydrogen natural gas urban integrated energy system according to claim 1, characterized in that, The operating constraints of the user unit include: setting single hydrogen-fired combined heat and power (CHP) unit power supply and single electric energy storage charge and discharge regulation within each user unit, that is, the number of hydrogen-fired CHP units, the number of electric energy storages is the same as the number of user units. Then, the operation of internal equipment satisfies the corresponding energy balance constraints as follows l ∈ {Q(l1), Q(l2)}, m ∈ {Q1(l1), Q1(l2)}, u ∈ {Q2(l1), Q2(l2)} l ∈ Q(l3), m ∈ Q1(l3), u ∈ Q2(l3)H rh,t +H eh,t =H us,t C ec,t +C ac,t =C us,t In the formula: P ht,m,t is the power generation power of the m-th hydrogen-fired CHP unit at time t; L us,l,t is the electrical load of the l-th user unit at time t; H us,t is the heat load of the industrial park at time t; C us,t is the cooling load of the industrial park at time t; P v,l,t is the output power of the photovoltaic unit in the l-th user unit at time t; H rh,t is the heat release power on the output side of the waste heat recovery boiler at time t; H eh,t is the heat release power on the output side of the electric boiler at time t; C ec,t is the cooling power supplied on the output side of the electric chiller at time t; C ac,t is the cooling power supplied on the output side of the adsorption chiller at time t; P ch,u,t and P dis,u,t are the charging and discharging powers of the u-th electric energy storage at time t, respectively.

6. The electric-mixed hydrogen natural gas urban integrated energy system according to claim 1, characterized in that, The refined model of the hydrogen combustion engine considering carbon emissions and mixed combustion characteristics is constructed in the following way: When considering the multi-component tracking of hydrogen-blended natural gas, the combustion of hydrogen-blended natural gas by the hydrogen combustion engine is refined into four links: the combustion reactions of methane, ethane, propane and hydrogen; Perform linear weighted sum processing on the actual combustion CO2 stoichiometric numbers of various alkane gases, establish the relationship between the CO2 emissions and gas consumption of the hydrogen combustion engine, and obtain the carbon emission model of the hydrogen combustion engine based on the Arrhenius equation; Based on the basic working principle of the hydrogen hybrid engine, according to the conversion process of internal energy - mechanical energy - electrical energy, a hybrid combustion output model of the hydrogen hybrid engine based on system thermodynamics is established.

7. The electric-mixed hydrogen natural gas urban integrated energy system according to claim 1, characterized in that, The solvers include CPLEX and CONOPT.

8. The electric-hybrid hydrogen natural gas urban integrated energy system according to claim 1, wherein The urban energy management system's dispatching control of the source side, load side, and the electricity - hybrid hydrogen - natural gas coupling point includes: Within the scope of safety technology, hydrogen is produced by an electric - to - gas device and incorporated into the natural gas network to achieve the mixed transportation of hydrogen and natural gas.

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