CN115907485A - Comprehensive energy system and optimal scheduling method thereof - Google Patents

Abstract

The invention belongs to the technical field of new energy and energy conservation, and discloses a comprehensive energy system considering two-stage operation of a cascade carbon trading mechanism and a power-to-gas (P2G) and an optimal scheduling method thereof in order to improve the energy efficiency level of the comprehensive energy system. Firstly, a Carbon Capture System (CCS) is introduced, so that the problems of carbon source required by P2G and carbon emission of a cogeneration unit are solved; meanwhile, a hydrogen fuel cell is introduced on the basis of the traditional P2G, and the multiple benefits of P2G two-stage operation are researched; finally, a step carbon trading mechanism is applied to limit carbon emission. On the basis, an optimized scheduling model with the aim of minimizing carbon transaction cost, system operation cost and wind and light abandoning cost is established, an IPOPT (intelligent power plant operation) commercial solver is used for solving, and the economy, low carbon and wind and light absorption capacity of the model are shown through comparison and analysis with other traditional models.

Description

Comprehensive energy system and optimal scheduling method thereof

Technical Field

The invention belongs to the technical field of new energy and energy conservation, and particularly relates to a comprehensive energy system considering two-stage operation of a cascade carbon trading mechanism and electricity-to-gas and an optimal scheduling method thereof.

Background

Combined Heat and Power (CHP) is one of the main forms of IES, and the generated heat energy is also utilized while generating electricity, thereby improving the economy of the system. But its "hot-fix" nature limits the consumption of renewable energy. To enhance the flexibility of the CHP, electrical power is converted to natural gas (P2G) as a connector between the power system and the natural gas system. However, most of the current researches on P2G only consider a single process of converting electricity into natural gas, and the energy conversion processes of an electrolytic cell and a methane reactor are not deeply researched in detail. Jiayanbing et al point out that the efficiency of electricity to produce hydrogen is 25% higher than that of electricity to produce natural gas, and that combustion hydrogen does not discharge carbon dioxide. Meanwhile, there is a clear literature considering the heat generation effect of the electrolyzer and the hydrogen fuel cell, and therefore it is necessary to intensively study the P2G two-stage operation.

In the above studies, energy conversion of P2G requires the purchase of carbon dioxide, which brings carbon source cost to P2G. Carbon capture technology is widely used in coal or gas fired power plants. The Carbon Capture System (CCS) consumes electric energy to capture carbon dioxide discharged from Combined Heat and Power (CHP), which is equivalent to increase the electrical load of the CHP, thereby improving the utilization efficiency of renewable energy while reducing carbon emission. However, most current carbon capture technologies store the captured carbon dioxide and transmit it to the P2G over long distances, requiring transmission and storage costs. Therefore, the introduction of CCS can be considered to capture the carbon dioxide discharged by CHP directly to P2G, avoid long-distance transmission and storage, and reduce the carbon emission of CHP while meeting the requirement of a P2G carbon source.

In view of the above studies, the prior art has the following problems, most of which do not mention the effect of CCS on P2G; when P2G is applied, the benefits generated by the two-stage operation of the P2G are not fully considered; most of the established models adopt fixed price for carbon transaction, and detailed research on the carbon emission model is not carried out. Meanwhile, the research on the coordination operation of the CCS and the P2G two-stage operation and the cascade carbon trading mechanism is less.

Disclosure of Invention

Aiming at the problems, the invention provides a comprehensive energy system considering a cascade carbon trading mechanism and electricity-to-gas two-stage operation and an optimization scheduling method thereof. The system is a comprehensive energy system considering two-stage operation of a cascade carbon trading mechanism and electricity-to-gas, is a low-carbon economic dispatching model, and is established by taking the comprehensive minimum of carbon trading cost, system operation cost and wind and light abandoning cost as an objective function. Compared with other traditional scenes, the positive influence of two-stage operation of CCS, P2G refinement and the cascade carbon transaction mechanism on IES optimization scheduling is verified, and the system and the method have high economical efficiency, low carbon and wind-light absorption capability.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a comprehensive energy system which is built under the consideration of a cascade carbon trading mechanism and P2G two-stage operation and comprises a wind power photovoltaic power generation unit, a carbon trading market unit, a CCS (central control system) and P2G two-stage operation related device, a CHP (choking process) unit, a micro gas turbine unit (MT), an Electric Refrigerator (ER) and various loads; wherein the P2G two-stage operation related devices comprise a Methane Reactor (MR), an electrolytic cell (EL) and a Hydrogen Fuel Cell (HFC); various loads include electrical loads, thermal loads, air loads, and cold loads; wind power and photovoltaic provide clean renewable energy for the comprehensive energy system; the CHP and HFC are important supply sources of electricity and heat in the system; the CCS collects carbon dioxide generated by the CHP unit to improve carbon emission reduction; the EL carries out heat and hydrogen co-production, and is an important element for realizing coupling of electric energy, hydrogen and heat energy; the MR converts the hydrogen energy into natural gas energy; MT burns natural gas to provide electric heating and cooling energy for the system, so that coupling between gas energy and cold, heat and electricity energy is realized; the air load is cooperatively provided by an air source and the MR; the ER and the MT provide cold energy required by providing cold load; and the carbon dioxide discharged by the coal-fired CHP unit is traded through the stepped carbon trading market when the MT link and the P2G link stop operating.

The invention also provides an optimized scheduling method of the comprehensive energy system based on the comprehensive energy system, which comprises the following steps:

step 1, constructing each unit model in the system, wherein the unit model comprises a carbon capture system and an electricity-to-gas two-stage coordinated operation model, a cascade carbon transaction mechanism model and operation models of other links;

step 2, comprehensively considering the carbon transaction cost, the system operation cost and the wind and light abandoning cost, and constructing an optimized operation objective function of the comprehensive energy system;

step 3, setting up power balance constraint conditions and operation constraint conditions of each link of the system;

and 4, solving by using an IPOPT commercial solver called by Yalmip.

Further, the carbon capture system and electricity-to-gas two-stage coordinated operation model in step 1 specifically includes a CHP cogeneration link and a P2G two-stage operation link, and the models of the links are as follows:

(1) CHP combined heat and power generation link:

CHP generates electricity by burning coal to supply power for CCS, EL and electric load, and simultaneously utilizes heat generated in the power generation process to supply heat load, and the expression of electric energy is

P _CHP,e (t)＝P _CHP,e1 (t)+P _CHP,e2 (t)+P _CHP,e3 (t) (1)

In the formula: p is _CHP,e (t) is the generated power of the CHP in the t period; p is _CHP,e1 (t)、P _CHP,e2 (t) and P _CHP,e3 (t) power supplied by the CHP to the grid, CCS and EL during time t, respectively;

(2) P2G two-stage operation link

According to the comprehensive energy system, the following steps are carried out: in the first stage of electric gas conversion, CCS consumes electric energy provided by CHP to capture carbon dioxide discharged by the CHP and transmits the carbon dioxide to MR, and EL is introduced into a heat recovery device to recycle heat generated during hydrogen production; in the second stage, the MR uses a part of hydrogen energy to synthesize methane; the HFC directly converts the residual hydrogen energy into the electric heat energy, and compared with the method of synthesizing methane and then burning for energy supply, the energy loss and the emission of carbon dioxide are reduced; therefore, after the P2G two-stage operation is considered, the refined utilization of energy can be realized, and the energy utilization efficiency is improved; the specific energy conversion relationship is as follows:

1) A CCS carbon dioxide capturing link: the CCS captures carbon dioxide discharged by the coal-fired CHP unit to supply power for gas conversion and reuse, so that the carbon emission is effectively reduced, and the economy of the system is improved; the carbon capture amount of which is expressed as

C _CC (t)＝λ _CC P _CHP,e2 (t) (2)

In the formula: c _CC (t) is the carbon dioxide capture amount of CCS during time t; lambda _CC Is the trapping coefficient of CCS;

2) An EL (electro-thermal) hydrogen co-production link: in the process, a heat recovery device is introduced to recover heat generated by the electrolytic cell, and electric energy in a wind and light high-power generation period is converted into heat energy and hydrogen energy; the energy conversion relationship is

P _EL,h (t)＝λ _EL,h P _CHP,e3 (t) (4)

In the formula:

and P _EL,h (t) hydrogen production and heat production power of the EL during time period t, respectively; lambda _EL,H2 And λ _EL,h The conversion coefficients of the EL for hydrogen production and heat production are respectively; />

3) A step of preparing methane by MR; the MR synthesizes methane by using the carbon dioxide captured by the CCS and the hydrogen generated by the EL on the spot, so that the cost and the risk caused by long-distance transmission and storage of the carbon dioxide are avoided; the energy conversion relationship is

P _MR,gs (t)＝λ _MR,gs P _MR,H2 (t) (5)

In the formula: p _MR,gs (t) is the gas generation power of the MR in the t period; p _MR,H2 (t) hydrogen power supplied to the MR by EL for a period t; lambda _MR,gs Hydrogen conversion coefficient for MR;

4) HFC combined heat and power generation link: when the oxidation-reduction reaction occurs in HFC, the electrons move directionally to generate direct current voltage, the direct current voltage is converted into alternating current voltage by an inverter, and then the alternating current voltage is boosted by a transformer to transmit electric energy to an electric load; the chemical reaction generates electricity and simultaneously generates heat, thereby reducing the thermal output of other equipment and finally realizing cogeneration; the energy conversion relationship is

P _HFC,e (t)＝λ _HFC,e P _HFC,H2 (t) (6)

P _HFC,h (t)＝λ _HFC,h P _HFC,H2 (t) (7)

λ _HFC,e +λ _HFC,h ＝λ _HFC,max (8)

In the formula: p _HFC,H2 (t) hydrogen power supplied by EL to HFC for time t; p _HFC,e (t) and P _HFC,h (t) the power generation and heat production power of HFC at the time t are respectively; lambda _HFC,e And λ _HFC,h Respectively the electrical and thermal efficiencies of HFC; lambda [ alpha ] _HFC,max The sum of the thermoelectric efficiencies of the HFCs is the maximum value.

Further, the operation models of other links in the step 1 include an MT cogeneration link and an ER operation model, wherein:

(1) The MT electric heating and cooling cogeneration link specifically comprises the following steps: the MT recovers the waste heat in the high-temperature flue gas discharged by methane combustion to provide cold, heat and electric energy; the energy conversion relationship of the energy conversion system is,

P _MT,e (t)＝λ _MT,e P _MT,gs (t) (9)

in the formula, P _MT,gs (t) gas consumption power for t period MT; p _MT,e (t) generated power for t period MT; p is _MT,h (t) and P _MT,c (t) the heat production and refrigeration power of the bromine cooler for time period t, respectively; lambda _MT,e The power generation coefficient of MT; lambda [ alpha ] _MT,h And λ _MT,c The heat production and refrigeration coefficients of the bromine cooler are respectively; eta _r Is the coefficient of heat loss; eta _l The recovery rate of the waste heat of the flue gas is the bromine cooler;

(2) The ER operation model is specifically

P _ER,c (t)＝λ _ER,c P _ER,e (t) (12)

In the formula, P _ER,e (t) is the electrical power consumed by ER during the t period; p is _ER,c (t) is the refrigeration power of ER during t period; lambda _ER,c The refrigeration coefficient is the ER.

Further, the cascade carbon transaction mechanism model in the step 1 specifically includes:

(1) Actual carbon emission of the system

The carbon emission sources in IES are mainly CHP, MT, furthermore CCS can capture part of the carbon to supply MR to synthesize methane; the actual carbon emission is expressed as

In the formula: e _CHP,CO2 And E _MT,CO2 Carbon emissions of CHP and MT, respectively; e _CO2,a The actual carbon emission of the system; p is _CHP,h (t) heat generation power of CHP over a period t; a is a _co2 、b _co2 And c _co2 Is the CHP carbon emission coefficient; d is a radical of _co2 Carbon emission coefficient of MT; c _ν1 The electric-thermal conversion coefficient is the minimum CHP power;

(2) Carbon emission quota for system

In the formula: e ₀ A carbon emission quota for the system; p _MT,e (t)、P _wind (t)、P _pv (t) t periods MT, wind, light generation power, respectively; a is a carbon emission quota per unit power;

(3) Cascaded carbon trading costs

Carbon emission trading amount E participating in carbon trading market _CO2 The difference between the actual carbon emission of the system and the carbon emission quota; the expression is

E _CO2 ＝E _CO2,a -E ₀ (17)

The step carbon trading mechanism divides the trading value of the carbon emission right into a plurality of sections, the corresponding trading price is higher after the sections are more, and the carbon trading cost m is higher ₁ Comprises the following steps:

in the formula: gamma is a carbon trading base price; alpha is the carbon transaction price growth rate; l is the length of the carbon emission interval.

Further, the carbon transaction cost, the system operation cost and the wind and light abandoning cost are comprehensively considered in the step 2, and a specific process of constructing the optimized operation objective function M of the comprehensive energy system is as follows:

min M＝m ₁ +m ₂ +m ₃ (19)

in the formula, carbon transaction cost m ₁ See formula (18);

system running cost m ₂ Including CHP, EL, MR, CCS, HFC, MT, ER operating costs,

m ₂ ＝C ₁ +C ₂ +C ₃ +C ₄ +C ₅ +C ₆ +C ₇ (27)

in the formula: c ₁ 、C ₂ 、C ₃ 、C ₄ 、C ₅ 、C ₆ 、C ₇ The running costs of the cogeneration, the electrolytic bath, the methane reactor, the carbon capture system, the hydrogen fuel cell, the micro gas turbine unit and the electric refrigerator are respectively calculated; a is a ₁ 、b ₁ The operating cost coefficient is the co-generation operating cost coefficient; c. C ₁ Is the running cost coefficient of the electrolytic cell; d is a radical of ₁ Is the methane reactor operating cost factor; e.g. of the type ₁ A carbon capture system operating cost factor; f. of ₁ Is a carbon dioxide sequestration cost factor; g ₁ The cost coefficients of cogeneration power generation and heat production are respectively; h is a total of ₁ Is the running cost coefficient of the micro gas turbine set; i.e. i ₁ Is the electrical refrigerator operating cost factor;

wind and light abandoning cost m ₃ Comprises the following steps:

in the formula: j is a function of ₁ And k ₁ Respectively, the cost coefficients of abandoned wind and abandoned light, P _cwind (t) and P _cpv And (t) respectively representing the abandoned wind power and the abandoned light power in the t period.

Further, the power balance constraint in the step 3 comprises an electric power constraint, a thermal power constraint, a cold power constraint, a gas power constraint and a hydrogen power constraint; wherein:

(1) Under the constraint condition of electric power, the generated energy at any moment is equal to the electricity consumption of the load;

in the formula: p _pl (t) electrical load power for a period of t;

(2) Thermal power constraints, since the inertia of the heat supply network can maintain the temperature, the imbalance between the heat supply and the demand can be in a limited range;

in the formula: p _hl (t) thermal load power for a period of t; delta _1,max And delta _1,min The upper limit proportion and the lower limit proportion of the thermal load adjustment are respectively;

(3) The cold power constraint condition is that the cold power is similar to the thermal power, and inertia also exists;

in the formula: p _cl (t) the cold load power for a period of t; delta _2,max And delta _2,min The upper limit proportion and the lower limit proportion of the cold load adjustment are respectively;

(4) Under the constraint condition of gas power, supplying MT and gas load together with gas source by MR synthetic methane;

P _gl (t)+P _MT,gs (t)＝P _s (t)+P _MR,gs (t) (32)

in the formula: p _gl (t) gas load power for time period t, respectively; p is _s (t) gas source power for a period of t;

(5) Hydrogen power constraint conditions, namely hydrogen energy requirements of supplying HFC and MR to EL hydrogen production;

P _HFC,H2 (t)+P _MR,H2 (t)＝P _EL,H2 (t) (33)。

further, the operation constraint conditions of each link of the system in the step 3 include CHP, CCS, EL, MR, HFC and other link operation constraints; wherein:

(1) CHP operating force constraints

In the formula:

and &>

The upper limit and the lower limit of the CHP generating power are respectively; />

And &>

The upper limit and the lower limit of CHP heat production power; c _ν1 And C _ν2 CHP power min andmaximum time electric-thermal conversion coefficient; c _m Linear supply slope for CHP thermoelectric power; p is _CHP,h0 The heat power when the CHP electric power is minimum;

(2) CCS, EL, MR, HFC operational constraints

In the formula:

and &>

Supplying upper and lower limits of electric power to the CCS for the cogeneration in the period t, respectively; />

And

upper and lower limits of electrical power supplied to the electrolyzer for the CHP; />

And &>

The upper and lower limits of the hydrogen power supplied to the methane reactor for EL, respectively; />

And &>

Upper and lower limits of power supplied to the HFC for the EL, respectively; />

And &>

The EL climbing constraint upper limit and the EL climbing constraint lower limit are respectively set; />

And &>

Respectively restricting the upper limit and the lower limit of the MR climbing; />

And &>

HFC climbing constraint upper and lower limits are respectively set;

(3) Other link operation constraints

In the formula:

and &>

The MT electric power upper and lower limits; />

And &>

The upper limit and the lower limit of ER power consumption are set;

the upper limit and the lower limit of the air source power are respectively; />

And &>

An MT climbing constraint upper limit and a MT climbing constraint lower limit are respectively set; />

And

respectively limiting the upper limit and the lower limit of ER climbing.

Compared with the prior art, the invention has the following advantages:

the invention provides the IES scheduling model considering the cascade carbon trading mechanism and the detailed P2G two-stage operation, introduces the cascade carbon trading mechanism, and jointly operates the CCS and the P2G two stages, thereby improving the wind and light absorption capability and the low-carbon economy. The method comprises the following specific steps:

1) The cascaded carbon trading mechanism can lead the IES to reduce carbon trading costs. Compared with the scenario one, the carbon trading cost is reduced by 0.44 ten thousand yuan in the scenario two considering the cascade carbon trading mechanism.

2) After CCS is introduced into IES, carbon dioxide generated by CHP can be captured to MR, carbon emission is reduced, and the wind and light utilization rate of the system is improved. Compared with a third scene without considering CCS, the four-carbon emission amount of the scene is reduced by 0.109t, and the wind and light utilization rate is respectively improved by 6.69% and 3.85%.

3) The P2G two-stage operation is considered, so that the wind and light efficiency can be improved, and the potential of high energy efficiency of hydrogen energy can be effectively explored; besides, the EL and HFC can bear part of the thermoelectric supply of CHP and MT, thereby reducing the carbon emission of CHP and MT and reducing the operation cost. Compared with the traditional scheduling model (scenario two) without considering P2G, the model provided by the invention has the advantages that the operation cost is reduced by 18.17 ten thousand yuan; compared with the scheduling model (scenario four) considering the traditional P2G, the scheduling model reduces by 3.88 ten thousand yuan.

Drawings

Fig. 1 is a block diagram of the operation of the integrated energy system of the present invention.

Fig. 2 is a P2G two-stage process.

FIG. 3 is a diagram of wind, light and various load prediction curves.

Fig. 4 shows the electric power optimization results.

FIG. 5 shows the thermal power optimization results.

Fig. 6 shows the results of the breathing power optimization.

Fig. 7 shows the cold power optimization results.

Fig. 8 shows the hydrogen power optimization results.

FIG. 9 shows wind power output conditions of each scene.

Fig. 10 shows the photovoltaic output of each scene.

Fig. 11 shows the carbon emission amount for each scene.

Detailed Description

The technical solution of the present invention will be specifically and specifically described below with reference to the embodiments of the present invention and the accompanying drawings. It should be noted that variations and modifications can be made by those skilled in the art without departing from the principle of the present invention, and these should also be construed as falling within the scope of the present invention.

The IES energy supply block diagram considering the two-stage operation of the cascade carbon trading mechanism and the P2G is shown in figure 1 and comprises a wind power photovoltaic power generation unit, a carbon trading market unit, CCS and P2G two-stage operation related devices, a CHP unit, a micro gas turbine unit (MT), an Electric Refrigerator (ER) and various loads; wherein the P2G two-stage operation related device comprises a Methane Reactor (MR), an electrolysis bath (EL) and a Hydrogen Fuel Cell (HFC); various loads include electrical loads, thermal loads, gas loads, and cold loads; wind power and photovoltaic provide clean renewable energy for the comprehensive energy system; CHP and HFC are important supply sources of electricity and heat in the system; the CCS captures carbon dioxide generated by the CHP unit so as to improve carbon emission reduction; the EL carries out heat and hydrogen co-production, and is an important element for realizing the coupling of electric energy, hydrogen and heat energy; the MR converts hydrogen energy into natural gas energy; MT burns natural gas to provide electric heating and cooling energy for the system, so that coupling between gas energy and cold, heat and electricity energy is realized; the air load is cooperatively provided by an air source and the MR; the ER and the MT provide cold energy required by cold load; and (4) the carbon dioxide discharged by the coal-fired CHP unit when the MT and P2G links stop operating is traded through a stepped carbon trading market.

The comprehensive energy system optimal scheduling method based on the comprehensive energy system comprises the following steps:

step 1, constructing each unit model in the system, wherein the unit model comprises a carbon capture system and an electricity-to-gas two-stage coordinated operation model, a cascade carbon transaction mechanism model and operation models of other links; wherein:

1.1, the carbon capture system and electricity-to-gas two-stage coordinated operation model specifically comprises a CHP cogeneration link and a P2G two-stage operation link, and the model of each link is as follows:

(1) CHP cogeneration link:

CHP generates electricity by burning coal to supply electricity to CCS, EL and electric load, and simultaneously utilizes heat generated in the electricity generation process to supply heat load, and the expression of electric energy is

P _CHP,e (t)＝P _CHP,e1 (t)+P _CHP,e2 (t)+P _CHP,e3 (t) (1)

In the formula: p _CHP,e (t) is the generated power of the CHP in the t period; p _CHP,e1 (t)、P _CHP,e2 (t) and P _CHP,e3 (t) power supplied by the CHP to the grid, CCS and EL during time t, respectively;

(2) A P2G two-stage operation link, and a P2G two-stage operation process is shown in fig. 2.

Therefore, the following steps are carried out: in the first stage of electric gas conversion, CCS consumes electric energy provided by CHP to capture carbon dioxide discharged by the CHP and transmits the carbon dioxide to MR, and EL is introduced into a heat recovery device to recycle heat generated during hydrogen production; in the second stage, MR uses part of hydrogen energy to synthesize methane; the HFC directly converts the residual hydrogen energy into the electric heat energy, and compared with the method of synthesizing methane and then burning for energy supply, the energy loss and the emission of carbon dioxide are reduced; therefore, after the P2G two-stage operation is considered, the refined utilization of energy can be realized, and the energy utilization efficiency is improved; the specific energy conversion relationship is as follows:

1) A CCS carbon dioxide capturing link: the CCS collects the carbon dioxide discharged by the coal-fired CHP unit to supply power, changes the power into gas and recycles the gas, effectively reduces the carbon emission and improves the economy of the system; the carbon capture amount of which is expressed as

C _CC (t)＝λ _CC P _CHP,e2 (t) (2)

In the formula: c _CC (t) is the carbon dioxide capture amount of CCS during time t; lambda [ alpha ] _CC Is the capture coefficient of CCS;

2) An EL (electro-thermal) hydrogen co-production link: in the process, a heat recovery device is introduced to recover heat generated by the electrolytic cell, and electric energy in a wind and light high-power generation period is converted into heat energy and hydrogen energy; the energy conversion relationship is

P _EL,h (t)＝λ _EL,h P _CHP,e3 (t) (4)

In the formula:

and P _EL,h (t) hydrogen production and heat production power of the EL during time period t, respectively; lambda _EL,H2 And λ _EL,h The conversion coefficients of the EL for hydrogen production and heat production are respectively;

3) A step of preparing methane by MR; the MR synthesizes methane by using the carbon dioxide captured by the CCS and the hydrogen generated by the EL on site, so that the cost and risk caused by long-distance transmission and storage of the carbon dioxide are avoided; the energy conversion relationship is

P _MR,gs (t)＝λ _MR,gs P _MR,H2 (t) (5)

In the formula: p _MR,gs (t) is the gas production power of the MR in the t period; p _MR,H2 (t) hydrogen power supplied to the MR by EL for a period t; lambda [ alpha ] _MR,gs Hydrogen conversion coefficient for MR;

4) HFC combined heat and power generation link: when oxidation-reduction reaction occurs in HFC, the electrons move directionally to generate direct current voltage, the direct current voltage is converted into alternating current voltage by an inverter, and then the alternating current voltage is boosted by a transformer to send electric energy to an electric load; the chemical reaction generates electricity and simultaneously generates heat, thereby reducing the thermal output of other equipment and finally realizing cogeneration; the energy conversion relationship is

P _HFC,e (t)＝λ _HFC,e P _HFC,H2 (t) (6)

P _HFC,h (t)＝λ _HFC,h P _HFC,H2 (t) (7)

λ _HFC,e +λ _HFC,h ＝λ _HFC,max (8)

In the formula: p _HFC,H2 (t) hydrogen power supplied by EL to HFC for time t; p _HFC,e (t) and P _HFC,h (t) the power generation and heat production power of HFC at the time t are respectively; lambda [ alpha ] _HFC,e And λ _HFC,h Respectively the electric and thermal efficiency of HFC; lambda [ alpha ] _HFC,max The sum of the thermoelectric efficiencies of the HFCs is the maximum value.

1.2, the operation models of other links comprise an MT (MT) electric heating and cooling cogeneration link and an ER (extreme machine) operation model, wherein:

(1) The MT electric heating and cooling cogeneration link specifically comprises the following steps: the MT recovers the waste heat in the high-temperature flue gas discharged by methane combustion to provide cold, heat and electric energy; the energy conversion relationship of the energy conversion system is,

P _MT,e (t)＝λ _MT,e P _MT,gs (t) (9)

in the formula, P _MT,gs (t) gas consumption power for t period MT; p _MT,e (t) generated power for t period MT; p _MT,h (t) and P _MT,c (t) the heat production and refrigeration power of the bromine cooler at time t, respectively; lambda [ alpha ] _MT,e The power generation coefficient of MT; lambda [ alpha ] _MT,h And λ _MT,c The heat production and refrigeration coefficients of the bromine cooler are respectively; eta _r Is the coefficient of heat loss; eta _l The recovery rate of the waste heat of the flue gas is the bromine cooler;

(2) The ER operation model is specifically

P _ER,c (t)＝λ _ER,c P _ER,e (t) (12)

In the formula, P _ER,e (t) is the electrical power consumed by ER during the t period; p is _ER,c (t) refrigeration power for ER during t period; lambda _ER,c The refrigeration coefficient is the ER.

1.3, the cascade carbon trading mechanism model specifically comprises the following steps:

(1) Actual carbon emission of system

The carbon emission sources in the IES are mainly CHP, MT, and furthermore CCS can capture part of the carbon to supply MR for methane synthesis; the actual carbon emission is expressed as

In the formula: e _CHP,CO2 And E _MT,CO2 Carbon emissions of CHP and MT, respectively; e _CO2,a The actual carbon emission of the system; p is _CHP,h (t) heat generation power of CHP over a period t; a is _co2 、b _co2 And c _co2 Is the CHP carbon emission coefficient; d _co2 Carbon emission coefficient of MT; c _ν1 The electric-thermal conversion coefficient is the minimum CHP power;

(2) Carbon emission quota for system

In the formula: e ₀ A carbon emission quota for the system; p is _MT,e (t)、P _wind (t)、P _pv (t) t periods MT, wind, light generation power, respectively; a is carbon emission quota per unit power;

(3) Cascaded carbon trading costs

Carbon emission right trading amount E participating in carbon trading market _CO2 The difference between the actual carbon emission amount of the system and the carbon emission quota; the expression is

E _CO2 ＝E _CO2,a -E ₀ (17)

The cascade carbon trading mechanism divides the trading value of the carbon emission right into a plurality of sections, and the sections are the later phaseThe higher the transaction price, the higher the carbon transaction cost m ₁ Comprises the following steps:

in the formula: gamma is a carbon trading base price; alpha is carbon transaction price growth rate; l is the length of the carbon emission interval.

Step 2, comprehensively considering the carbon transaction cost m ₁ System running cost m ₂ And wind and light abandoning cost m ₃ The specific process of constructing the optimal operation objective function M of the comprehensive energy system is as follows:

min M＝m ₁ +m ₂ +m ₃ (19)

in the formula, carbon transaction cost m ₁ See formula (18);

system running cost m ₂ Including CHP, EL, MR, CCS, HFC, MT, ER operating costs,

m ₂ ＝C ₁ +C ₂ +C ₃ +C ₄ +C ₅ +C ₆ +C ₇ (27)

in the formula: c ₁ 、C ₂ 、C ₃ 、C ₄ 、C ₅ 、C ₆ 、C ₇ The running costs of the cogeneration, the electrolytic cell, the methane reactor, the carbon capture system, the hydrogen fuel cell, the micro gas turbine unit and the electric refrigerator are respectively calculated; a is a ₁ 、b ₁ A co-generation operating cost factor; c. C ₁ Is the running cost coefficient of the electrolytic cell; d ₁ Is the methane reactor operating cost factor; e.g. of the type ₁ Is the carbon capture system operating cost factor; f. of ₁ Is a carbon dioxide sequestration cost factor; g ₁ The cost coefficients of cogeneration power generation and heat production are respectively; h is ₁ The running cost coefficient of the micro gas turbine set is obtained; i.e. i ₁ Is the electrical refrigerator operating cost factor;

wind and light abandoning cost m ₃ Comprises the following steps:

in the formula: j is a function of ₁ And k ₁ Respectively, the cost coefficients of abandoned wind and abandoned light, P _cwind (t) and P _cpv And (t) respectively representing the abandoned wind power and the abandoned light power in the t period.

Step 3, setting up power balance constraint conditions and operation constraint conditions of each link of the system;

3.1, power balance constraints comprise an electric power constraint, a thermal power constraint, a cold power constraint, a gas power constraint and a hydrogen power constraint; wherein:

(1) Under the constraint condition of electric power, the generated energy at any moment is equal to the electricity consumption of the load;

in the formula: p _pl (t) electrical load power for a period of t;

(2) Thermal power constraints, since the inertia of the heat supply network can maintain the temperature, the imbalance between the heat supply and the demand can be in a limited range;

in the formula: p _hl (t) thermal load power for a period of t; delta _1,max And delta _1,min The upper limit proportion and the lower limit proportion of the thermal load adjustment are respectively;

(3) The cold power constraint condition is that the cold power is similar to the thermal power, and inertia also exists;

in the formula: p _cl (t) the cold load power for a period of t; delta. For the preparation of a coating _2,max And delta _2,min The upper limit proportion and the lower limit proportion of the cold load adjustment are respectively;

(4) Under the constraint condition of gas power, supplying MT and gas load together with gas source by MR synthetic methane;

P _gl (t)+P _MT,gs (t)＝P _s (t)+P _MR,gs (t) (32)

in the formula: p _gl (t) gas load power for time period t, respectively; p _s (t) gas source power for a period of t;

(5) Hydrogen power constraint conditions, and hydrogen energy requirements of supplying HFC and MR by EL hydrogen production;

P _HFC,H2 (t)+P _MR,H2 (t)＝P _EL,H2 (t) (33)。

3.2, the operation constraint conditions of each link of the middle system comprise CHP, CCS, EL, MR, HFC and other link operation constraints; wherein:

(1) CHP operating force constraints

In the formula:

and &>

The upper limit and the lower limit of the CHP generating power are respectively; />

And &>

The upper limit and the lower limit of CHP heat production power; c _ν1 And C _ν2 The electric-thermal conversion coefficients are respectively the minimum and maximum CHP power; c _m Linear supply slope for CHP thermoelectric power; p is _CHP,h0 The heat power when the CHP electric power is minimum;

(2) CCS, EL, MR, HFC operational constraints

/>

In the formula:

and &>

Supplying power to the CCS for the cogeneration at the upper limit and the lower limit of the electric power respectively during the period t; />

And

upper and lower limits of electrical power supplied to the electrolyzer for the CHP; />

And &>

The upper and lower limits of the hydrogen power supplied to the methane reactor for EL, respectively; />

And &>

Upper and lower limits of power supplied to the HFC for the EL, respectively; />

And &>

Respectively restricting upper and lower limits for EL climbing; />

And &>

Respectively restricting the upper limit and the lower limit of the MR climbing; />

And &>

HFC climbing restriction upper and lower limits are respectively;

(3) Other links operating constraints

In the formula:

and &>

MT upper and lower electric power limits; />

And &>

The upper limit and the lower limit of ER power consumption are set;

the upper limit and the lower limit of the air source power are respectively; />

And &>

The MT climbing constraint upper limit and the MT climbing constraint lower limit are respectively set; />

And

respectively an ER climbing constraint upper limit and an ER climbing constraint lower limit.

And 4, solving by adopting an IPOPT commercial solver called by Yalmip.

And performing simulation verification by taking 24h as an optimized scheduling period. The wind, light and load prediction curves are shown in FIG. 3, and the references of the relevant parameters of each operation link are "Modeling and Optimization of Combined Heat and Power with Power-to-Gas and Carbon Capture System in Integrated Energy System" and "Integrated Energy System thermoelectric Optimization considering stepwise Carbon trading mechanism and electrohydrogen production". Taking gamma =108 yuan/t as a carbon transaction cost calculation parameter; α =25%; l =75t; a =0.798t/MWh. The IES low-carbon economic dispatching model established by the invention contains a mixed integer nonlinear model, so that the solving tool adopts an IPOPT (intelligent power over fiber) commercial solver called by Yalmip.

Five scenes are set for analyzing and comparing in order to verify the wind-light absorption capability and the low-carbon economy of the proposed model.

Scene one: regardless of CCS, P2G, and cascade carbon trading mechanisms;

scene two: regardless of CCS and P2G, consider a cascade carbon trading mechanism;

scene three: regardless of CCS, consider P2G and cascade carbon trading mechanisms;

scene four: consider CCS, P2G and cascade carbon trading mechanisms;

scene five: consider the CCS, P2G two-stage operation and the cascaded carbon trading mechanism (the optimization scheduling model mentioned here)

Analysis of optimization results

Scene five is the optimized scheduling method provided by the invention, and the electric heating gas cooling hydrogen optimization results are shown in fig. 4-8.

(1) Analysis of electrical and thermal optimization results

From fig. 4 and 5, it can be seen that wind power, photovoltaic, CHP, MT and HFC supply the electrical load and the electrical energy demand of ER, and MT, CHP, EL and HFC supply the thermal load demand. MT is an important gas-electricity-cooling-heat coupling link in the system and is in a working state for a long time so as to keep the system balanced.

During the high-wind power generation period (0-5, 10-00, 00-15, 22; the heat load demand is dominated by the CHP supply and the EL, HFC supply is dominated by the heat load demand.

In the wind-solar low-power generation period (5-10 00, 15-00).

(2) Analysis of gas, cold and hydrogen optimization results

From FIGS. 6-8, the gas supply, MR, supply MT and gas load natural gas demand, and MT, ER supply cooling load demand. The EL hydrogen production provides hydrogen energy of MR and HFC.

Specifically, in the wind and light high-power period, the EL, HFC and MR can be known to be in the working state according to the electric heating optimization result. EL is used for heat and hydrogen cogeneration, HFC is used for heat and power cogeneration, MR uses hydrogen and carbon dioxide to synthesize methane, so that the output of an air source is reduced, ER consumes electric energy to generate cold energy, part of cold load is supplied, and the rest of cold load is supplied by MT; in the low-power period of wind and light, the air load is supplied by the air source and the MT, the cold load is supplied by the MT and the ER, and hydrogen energy is not produced and consumed.

Different optimization scenario contrastive analysis

(1) Wind power output comparative analysis

The wind power output and the predicted wind power output under the five operation scenes are shown in fig. 9. As can be seen from the figure, the wind power consumption capability is gradually improved from scene one to scene five. Compared with the first scene, the introduction of the cascade carbon transaction does not affect the wind power consumption capability, and the first and second scenes do not contain CCS and P2G, so that the electric load is not enough to consume all wind power, and a larger wind abandon problem exists; in the third scene, P2G is introduced, and in the high-wind-power generation period, the surplus electric energy is converted into natural gas energy, so that the problem of wind abandonment is reduced; the CCS is introduced in the scene IV, the CCS consumes electric energy to capture carbon, and the wind power absorption capacity of the system is improved; and in the fifth scene, P2G is refined into two stages and HFC is added, so that the direct conversion of hydrogen energy to electric heat energy is realized, and the wind power consumption capability of the system is further improved.

(2) Photovoltaic output contrast analysis

The photovoltaic output and the photovoltaic predicted output under the five operating scenarios are shown in fig. 10. Similar to wind power output, the utilization rate of the first photovoltaic and the second photovoltaic in the scene is the same; the introduction of the scene three P2G requires electric energy consumption, so that the consumption capacity of photovoltaic power generation can be improved; compared with the scene three phase, the scene four is added with the CCS, so that the consumption capacity of photovoltaic power generation is further improved; compared with the scene four, the scene five introduces the refined utilization of hydrogen energy, but is limited by the upper and lower limits of the output power of the CHP unit, and the absorption capacity of photovoltaic power generation is not improved.

(3) Comparative analysis of carbon emissions

The carbon emissions for the five operating scenarios are shown in fig. 11. In the high wind and light generation period, the output of the CHP unit is reduced, so the carbon emission is reduced. The carbon emission is not influenced by the introduction of the first, second and third cascade carbon trading mechanisms and the P2G; in the fourth scenario, the CCS captures and transmits carbon dioxide to the P2G, so that carbon emission of the system is reduced; in scenario five, during cogeneration of heat and electricity by using hydrogen energy, the HFC does not generate carbon emission, and therefore, the carbon emission is lower than that of scenario four.

(4) Specific benefit comparison analysis

The benefits for the five operating scenarios are shown in table 1. As can be seen from the table, scene five has the best optimization effect compared with the other four scenes. Compared with the four-phase and three-phase scenes, the wind energy utilization rate is respectively improved by 3.5 percent and 10.19 percent, the carbon emission is respectively reduced by 0.064t and 0.173t, the corresponding carbon transaction cost is respectively reduced by 0.56 ten thousand yuan and 3.23 ten thousand yuan, and the total operation cost is respectively reduced by 3.88 ten thousand yuan and 8.74 ten thousand yuan; and each parameter of the scene five is obviously better than that of the scenes two and one, and the total operation cost is respectively reduced by 18.17 ten thousand yuan and 18.62 ten thousand yuan.

TABLE 1 comparison of specific benefits for various scenarios

By combining the concrete analysis of the table 1, compared with the scene one, after a step carbon trading mechanism is introduced into the scene two, the carbon trading cost is reduced by 0.44 ten thousand yuan; compared with the first scene and the second scene, after the third scene introduces P2G, the wind and light utilization rate is respectively improved by 19.25% and 8.65%, and meanwhile, due to the increase of carbon emission quota, the carbon transaction cost is respectively reduced by 2.58 ten thousand yuan and 2.14 ten thousand yuan; compared with the third scenario, after the CCS is considered in the fourth scenario, the carbon emission is reduced by 0.109t, and the operation cost is reduced by 18.7%; compared with the fourth scene, the fifth scene refines the P2G into a two-stage operation process of EL, HFC and MR combination, the wind energy utilization rate is improved by 3.5%, the carbon emission is reduced by 0.064t, and the operation cost is reduced by 3.88 ten thousand yuan. In summary, it can be seen that the IES considering two-stage operation of CCS and P2G has significant multifaceted benefits.

Comprehensively obtaining: the invention provides the IES scheduling model considering the two-stage operation of the cascade carbon transaction mechanism and the detailed P2G, introduces the cascade carbon transaction mechanism, and jointly operates the two stages of CCS and P2G, thereby improving the wind-light absorption capability and the low-carbon economy. The specific conclusions are as follows:

2) The cascaded carbon trading mechanism can lead the IES to reduce carbon trading costs. Compared with the scenario one, the carbon trading cost is reduced by 0.44 ten thousand yuan in the scenario two considering the cascade carbon trading mechanism.

2) After CCS is introduced into IES, carbon dioxide generated by CHP can be captured to MR, carbon emission is reduced, and the wind and light utilization rate of the system is improved. Compared with a third scene without considering CCS, the four-carbon emission amount of the scene is reduced by 0.109t, and the wind and light utilization rate is respectively improved by 6.69% and 3.85%.

3) The P2G two-stage operation is considered, so that the wind and light efficiency can be improved, and the potential of high energy efficiency of hydrogen energy can be effectively explored; in addition, the EL and HFC can bear part of the thermoelectric supply of CHP and MT, thereby reducing the carbon emission of CHP and MT and reducing the operation cost. Compared with the traditional scheduling model (scenario two) without considering P2G, the model provided by the invention has the advantages that the operation cost is reduced by 18.17 ten thousand yuan; compared with the scheduling model (scene four) considering the traditional P2G, the method reduces by 3.88 ten thousand yuan.

Claims (8)

1. An integrated energy system, comprising: the comprehensive energy system is built under the consideration of a cascade carbon trading mechanism and electricity-to-gas two-stage operation, and comprises a wind power photovoltaic power generation unit, a carbon trading market unit, a carbon capture system, a P2G two-stage operation related device, a CHP unit, a micro gas turbine unit, an electric refrigerator and various loads; wherein, the P2G two-stage operation related device comprises a methane reactor, an electrolytic bath and a hydrogen fuel cell; various loads include electrical loads, thermal loads, air loads, and cold loads; wind power and photovoltaic provide clean renewable energy for the comprehensive energy system; the CHP and hydrogen fuel cell are important power supplies of electricity and heat in the system; the carbon capture system captures carbon dioxide generated by the CHP unit so as to improve carbon emission reduction; the electrolytic cell is used for the cogeneration of heat and hydrogen and is an important element for realizing the coupling of electric energy, hydrogen and heat energy; the methane reactor converts hydrogen energy into natural gas energy; the micro gas turbine burns natural gas to provide electric heating and cooling energy for the system, so that the coupling between the gas energy and the cooling, heating and power energy is realized; the gas load is provided by the coordination of a gas source and a methane reactor; the electric refrigerator and the micro gas turbine set provide cold energy required by cold load; and the carbon dioxide discharged by the coal-fired CHP unit is traded through a stepped carbon trading market when the micro gas turbine unit and the P2G link stop running.

2. An integrated energy system optimal scheduling method based on the integrated energy system of claim 1, characterized by comprising the following steps:

step 1, constructing each unit model in the system, wherein the unit model comprises a carbon capture system and an electricity-to-gas two-stage coordinated operation model, a cascade carbon transaction mechanism model and operation models of other links;

step 2, comprehensively considering the carbon transaction cost, the system operation cost and the wind and light abandoning cost, and constructing an optimized operation objective function of the comprehensive energy system;

step 3, setting up power balance constraint conditions and operation constraint conditions of each link of the system;

and 4, solving by using an IPOPT commercial solver called by Yalmip.

3. The optimal scheduling method of the integrated energy system according to claim 2, wherein: the carbon capture system and electricity-to-gas two-stage coordinated operation model in the step 1 specifically comprises a CHP cogeneration link and an electricity-to-gas two-stage operation link, and the model of each link is as follows:

(1) CHP cogeneration link:

cogeneration uses coal to generate electricity for supplying electricity to a carbon capture system, an electrolytic cell and an electric load, and uses heat generated in the power generation process to supply the heat load, wherein the expression of the electric energy is

P _CHP,e (t)＝P _CHP,e1 (t)+P _CHP,e2 (t)+P _CHP,e3 (t) (1)

In the formula: p _CHP,e (t) generating power of cogeneration in a t period; p _CHP,e1 (t)、P _CHP,e2 (t) and P _CHP,e3 (t) power supplied to the grid, the carbon capture system and the electrolyzer for cogeneration at time t, respectively;

(2) Two-stage operation link for converting electricity into gas

According to the comprehensive energy system, the following steps are carried out: in the first stage of electricity-to-gas conversion, the carbon capture system consumes the electric energy provided by cogeneration to capture the carbon dioxide discharged by the cogeneration and transmits the carbon dioxide to the methane reactor, and the electrolytic cell produces hydrogen and simultaneously introduces a heat recovery device to recycle the generated heat; in the second stage, the methane reactor utilizes part of hydrogen energy to synthesize methane; the hydrogen fuel cell directly converts the residual hydrogen energy into the electric heat energy, and compared with the method of synthesizing methane and then burning for energy supply, the energy loss and the emission of carbon dioxide are reduced; therefore, after the two-stage operation of electricity-gas conversion is considered, the refined utilization of energy can be realized, and the energy utilization efficiency is improved; the specific energy conversion relationship is as follows:

1) A carbon capture system carbon dioxide capture link: the carbon capture system captures carbon dioxide discharged by the coal-fired cogeneration unit for power supply, gas conversion and recycling, so that the carbon emission is effectively reduced, and the economy of the system is improved; the carbon capture amount of which is expressed as

C _CC (t)＝λ _CC P _CHP,e2 (t) (2)

In the formula: c _CC (t) is the carbon dioxide capture amount of the carbon capture system during the period t; lambda _CC Is the capture coefficient of the carbon capture system;

2) And (3) a heat and hydrogen co-production link of the electrolytic cell: in the process, a heat recovery device is introduced to recover heat generated by the electrolytic cell, and electric energy in a wind and light high-power generation period is converted into heat energy and hydrogen energy; the energy conversion relationship is

P _EL,h (t)＝λ _EL,h P _CHP,e3 (t) (4)

In the formula:

and P _EL,h (t) hydrogen production and heat production power of the electrolyzer in the period t, respectively; lambda [ alpha ] _EL,H2 And λ _EL,h The conversion coefficients of the electrolytic cell for hydrogen production and heat production are respectively;

3) A methane reactor methane preparation link; the methane reactor synthesizes methane by using carbon dioxide captured by the carbon capture system and hydrogen generated by the electrolytic cell on site, so that the cost and risk caused by long-distance transmission and storage of the carbon dioxide are avoided; the energy conversion relationship is

P _MR,gs (t)＝λ _MR,gs P _MR,H2 (t) (5)

In the formula: p _MR,gs (t) is the gas production power of the methane reactor in the period t; p is _MR,H2 (t) hydrogen power supplied to the methane reactor by the electrolyzer for a period of t; lambda _MR,gs Is the hydrogen conversion coefficient of the methane reactor;

4) A hydrogen fuel cell cogeneration link: when the inside of the hydrogen fuel cell is subjected to oxidation-reduction reaction, electrons directionally move to generate direct-current voltage, the direct-current voltage is converted into alternating-current voltage through an inverter, and then the alternating-current voltage is boosted through a transformer to transmit electric energy to an electric load; the chemical reaction generates electricity and simultaneously generates heat, so that the heat output of other equipment is reduced, the cogeneration is finally realized, and meanwhile, the cogeneration gives full play to the electric heating characteristic of the hydrogen fuel cell, and the sum of the heat and power efficiencies of the hydrogen fuel cell is approximately taken as a fixed constant; the energy conversion relationship is

P _HFC,e (t)＝λ _HFC,e P _HFC,H2 (t) (6)

P _HFC,h (t)＝λ _HFC,h P _HFC,H2 (t) (7)

λ _HFC,e +λ _HFC,h ＝λ _HFC,max (8)

In the formula: p _HFC,H2 (t) hydrogen power supplied to the hydrogen fuel cell by the electrolyzer for a period of t; p _HFC,e (t) and P _HFC,h (t) power generation and heat generation of the hydrogen fuel cell are respectively performed in a period t; lambda _HFC,e And λ _HFC,h The electrical and thermal efficiencies of the hydrogen fuel cell are respectively; lambda [ alpha ] _HFC,max Is the maximum sum of the thermoelectric efficiencies of the hydrogen fuel cells.

4. The optimal scheduling method of the integrated energy system according to claim 2, wherein: the operation models of other links in the step 1 comprise a micro gas turbine unit electricity heat and cold cogeneration link and an electric refrigerator operation model, wherein:

(1) The electricity-heat-cold joint production link of the micro gas turbine set is specifically as follows: the micro gas turbine unit recovers waste heat in high-temperature flue gas discharged by methane combustion to provide cold, heat and electricity energy; the energy conversion relationship of the energy conversion system is,

P _MT,e (t)＝λ _MT,e P _MT,gs (t) (9)

in the formula, P _MT,gs (t) the gas consumption power of the micro gas turbine set in the time period t; p _MT,e (t) generating power of the micro gas turbine set in a time period t; p _MT,h (t) and P _MT,c (t) the heat production and refrigeration power of the bromine cooler at time t, respectively; lambda [ alpha ] _MT,e The power generation coefficient of the micro gas turbine set; lambda _MT,h And λ _MT,c Are respectively bromine coldThe heat production and refrigeration coefficients of the cooler; eta _r Is the coefficient of heat loss; eta _l The recovery rate of the waste heat of the flue gas is the bromine cooler;

(2) The operation model of the electric refrigerator is specifically

P _ER,c (t)＝λ _ER,c P _ER,e (t) (12)

In the formula, P _ER,e (t) is the electrical power consumed by the electrical refrigerator during time t; p _ER,c (t) is the refrigerating power of the electric refrigerator in the t period; lambda [ alpha ] _ER,c Is the refrigeration coefficient of the electric refrigerator.

5. The optimal scheduling method of the integrated energy system according to claim 2, wherein: the step carbon transaction mechanism model in the step 1 specifically comprises the following steps:

(1) Actual carbon emission of system

The carbon emission source in the comprehensive energy system mainly comprises cogeneration and a micro gas turbine unit, and in addition, the carbon capture system can capture part of carbon to supply the methane reactor to synthesize methane; the actual carbon emission is expressed as

In the formula: e _CHP,CO2 And E _MT,CO2 Carbon emissions of the cogeneration unit and the micro gas turbine unit are respectively; e _CO2,a The actual carbon emission of the system; p _CHP,h (t) heat production power for cogeneration over a period of t; a is _co2 、b _co2 And c _co2 The carbon emission coefficient is the combined heat and power generation carbon emission coefficient; d _co2 Is a micro gasCarbon emission coefficient of the turbine set;

(2) Carbon emission quota for system

In the formula: e ₀ The carbon emission quota of the system; p _MT,e (t)、P _wind (t)、P _pv (t) the micro gas turbine set, the wind power generation power and the light power generation power are respectively in the time period of t; a is carbon emission quota per unit power;

(3) Incremental carbon trading cost

Carbon emission right trading amount E participating in carbon trading market _CO2 The difference between the actual carbon emission amount of the system and the carbon emission quota; the expression is

E _CO2 ＝E _CO2,a -E ₀ (17)

The step carbon transaction mechanism divides the transaction amount of the carbon emission right into a plurality of sections, the corresponding transaction price is higher after the sections are more, and the carbon transaction cost m is ₁ Comprises the following steps:

in the formula: gamma is a carbon trading base price; alpha is carbon transaction price growth rate; l is the length of the carbon emission interval.

6. The optimal scheduling method of the integrated energy system according to claim 2, wherein: in the step 2, the carbon transaction cost, the system operation cost and the wind and light abandoning cost are comprehensively considered, and the specific process of constructing the optimized operation objective function M of the comprehensive energy system is as follows:

minM＝m ₁ +m ₂ +m ₃ (19)

in the formula, carbon transaction cost m ₁ See formula (18);

system running cost m ₂ Comprises the cogeneration of heat and electricity, an electrolytic cell, a methane reactor and carbon captureThe running costs of the system, the hydrogen fuel cell, the micro gas turbine unit and the electric refrigerator,

m ₂ ＝C ₁ +C ₂ +C ₃ +C ₄ +C ₅ +C ₆ +C ₇ (27)

in the formula: c ₁ 、C ₂ 、C ₃ 、C ₄ 、C ₅ 、C ₆ 、C ₇ The running costs of the cogeneration, the electrolytic cell, the methane reactor, the carbon capture system, the hydrogen fuel cell, the micro gas turbine unit and the electric refrigerator are respectively calculated; a is ₁ 、b ₁ Operating cost factor for cogeneration；c ₁ Is the running cost coefficient of the electrolytic cell; d ₁ Is the methane reactor operating cost factor; e.g. of the type ₁ Is the carbon capture system operating cost factor; f. of ₁ Is a carbon dioxide sequestration cost factor; g ₁ The cost coefficients of cogeneration power generation and heat production are respectively; h is ₁ Is the running cost coefficient of the micro gas turbine set; i.e. i ₁ Is the operating cost coefficient of the electric refrigerator;

wind and light abandoning cost m ₃ Comprises the following steps:

in the formula: j is a function of ₁ And k ₁ Respectively, the cost coefficient of abandoned wind and abandoned light, P _cwind (t) and P _cpv And (t) respectively representing the abandoned wind power and the abandoned light power in the t period.

7. The optimal scheduling method of the integrated energy system according to claim 2, wherein: the power balance constraint in the step 3 comprises an electric power constraint, a thermal power constraint, a cold power constraint, a gas power constraint and a hydrogen power constraint; wherein:

(1) Under the constraint condition of electric power, the generated energy at any moment is equal to the electricity consumption of the load;

/>

in the formula: p _pl (t) electrical load power for a period of t;

(2) Thermal power constraints, since the inertia of the heat supply network can maintain the temperature, the imbalance between the heat supply and the demand can be in a limited range;

in the formula: p is _hl (t) thermal load power for a period of t; delta. For the preparation of a coating _1,max And delta _1,min The upper limit proportion and the lower limit proportion of the thermal load adjustment are respectively;

(3) The cold power constraint condition is that the cold power is similar to the thermal power, and inertia also exists;

in the formula: p _cl (t) the cold load power for a period of t; delta _2,max And delta _2,min The upper limit proportion and the lower limit proportion of the cold load adjustment are respectively;

(4) Under the constraint condition of gas power, the methane synthesized by the methane reactor and a gas source supply the micro gas turbine unit and the gas load together;

P _gl (t)+P _MT,gs (t)＝P _s (t)+P _MR,gs (t) (32)

in the formula: p is _gl (t) gas load power for time period t, respectively; p _s (t) gas source power for a period of t;

(5) Hydrogen power constraint conditions, hydrogen produced by the electrolytic cell is supplied to the hydrogen energy requirements of the hydrogen fuel cell and the methane reactor;

P _HFC,H2 (t)+P _MR,H2 (t)＝P _EL,H2 (t) (33)。

8. the optimal scheduling method of the integrated energy system according to claim 2, wherein: the operation constraint conditions of each link of the system in the step 3 comprise the operation constraints of cogeneration, a carbon capture system, an electrolytic cell, a methane reactor, a hydrogen fuel cell and other links; wherein:

(1) Cogeneration operating output constraint

In the formula:

and &>

Respectively an upper limit and a lower limit of the cogeneration power; />

And &>

The upper limit and the lower limit of heat production power for cogeneration; c _ν1 And C _ν2 The electric-heat conversion coefficients are respectively the minimum and maximum power of the combined heat and power; c _m Linear supply slope for cogeneration thermoelectric power; p _CHP,h0 The heat power is the heat power when the cogeneration power is the minimum;

(2) Carbon capture system, electrolyzer, methane reactor, hydrogen fuel cell operation constraints

/>

In the formula:

and &>

Respectively supplying upper and lower limits of electric power to the carbon capture system for cogeneration during the period t; />

And &>

The upper limit and the lower limit of electric power supplied to the electrolytic cell for cogeneration; />

And &>

The upper limit and the lower limit of the hydrogen power supplied to the methane reactor by the electrolytic cell are respectively set; />

And &>

Upper and lower limits of the power of hydrogen supplied to the hydrogen fuel cell by the EL; />

And &>

Respectively restricting the upper limit and the lower limit for the climbing of the electrolytic cell; />

And &>

Respectively restricting the upper limit and the lower limit for the climbing of the methane reactor; />

And &>

Respectively restricting the upper limit and the lower limit for the hydrogen fuel cell climbing;

(3) Other link operation constraints

In the formula:

and &>

The electric power upper limit and the electric power lower limit of the micro gas turbine set; />

And &>

The upper limit and the lower limit of the power consumption of the electric refrigerator; />

The upper limit and the lower limit of the air source power are respectively; />

And &>

The upper limit and the lower limit are respectively restricted by the climbing of the micro gas turbine unit; />

And &>

The upper limit and the lower limit are respectively restricted by the climbing of the electric refrigerator. />

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