Multi-scale low-carbon economic optimization operation method for comprehensive energy system

Abstract

The invention belongs to the field of comprehensive energy systems, and particularly relates to a multi-scale low-carbon economic optimization operation method for a comprehensive energy system, which comprises the following steps of: establishing a comprehensive energy system model; establishing a carbon emission permit model, a carbon emission model and a stepped carbon transaction mechanism of the integrated energy system; based on different speeds and modes of load response, establishing comprehensive demand response of the comprehensive energy system; constraint conditions of all devices of the integrated energy system are constructed, low-carbon economic operation targets of energy purchase cost, carbon emission cost and demand response cost are used, an original problem is converted into a mixed integer linear problem, and a CPLEX commercial solver is used for solving. According to the method, the condition that different responses have different response speeds is considered, mixed demand response models of different time scales are established, and different energy consumption is flexibly adjusted.

Description

Technical Field

[0001] The present invention belongs to the field of integrated energy systems, and specifically relates to a multi-scale low-carbon economic optimization operation method for integrated energy systems. Background Art

[0002] Analyzing the current national conditions, the structural transformation of energy is a long-term and difficult process. We must always pay attention to the diversity and coupling of energy to form a transitional situation of multi-energy complementarity and coordinated development. Therefore, we must ensure the stability and reliability of the current energy supply, and also consider the issue of energy transformation from a green, low-carbon and clean perspective. This is not only an urgent need to respond to global climate change and environmental protection, but also an inevitable choice to promote high-quality economic development.

[0003] Integrated energy is constrained by conditions such as diversified energy structure, deepening multi-energy coupling, low-carbon and clean energy, a high proportion of renewable energy, load fluctuations, and demand response. As the uncertainty of these conditions continues to increase, higher requirements are placed on the operation of the integrated energy system, and new problems arise in the planning of the integrated energy system.

[0004] In traditional power systems, demand response guides users to adjust their electricity consumption through market prices or incentives, promotes coordination between power supply and demand, and thus reduces the operating pressure of the power grid. However, facing the current situation of the mutual coupling of electricity, thermal energy, natural gas and other energies in the integrated energy system, the traditional demand response method seems to be unable to cope with it.

[0005] Based on the above technical problems, it is necessary to design a multi-scale low-carbon economic optimization operation method for an integrated energy system that considers multiple energy storage and hybrid demand response. Summary of the invention

[0006] In order to solve the problem that the demand response mode of the current mutual coupling of energy sources such as electricity, heat and natural gas in the integrated energy system is unable to cope with the demand, the present invention provides a multi-scale low-carbon economic optimization operation method of the integrated energy system considering multiple energy storage and hybrid demand response.

[0007] The present invention is implemented by the following technical solution: a multi-scale low-carbon economic optimization operation method of an integrated energy system considering multiple energy storage and hybrid demand response, comprising the following steps:

[0008] S1. Establish a comprehensive energy system model to clarify the equipment included in the system and the output of each equipment;

[0009] S2. Based on the different carbon emission coefficients of the system's equipment and the carbon flow relationship, establish a carbon emission rights model, a carbon emission model and a tiered carbon trading mechanism for the integrated energy system;

[0010] S3. Establish a comprehensive demand response for the integrated energy system based on the speed and mode of load response. According to the different corresponding modes, it can be divided into price-based and incentive-based responses. Price-based demand response is to change the electricity price to make the demand side actively change the electricity consumption behavior, while incentive-based directly adopts incentive policies and compensation methods to induce the demand side to participate in the load reduction projects required by the system.

[0011] S4. Construct the constraints of each device in the integrated energy system and the low-carbon economic operation target based on energy purchase cost, carbon emission cost, and demand response cost, transform the original problem into a mixed integer linear problem, and use the CPLEX commercial solver to solve it.

[0012] As a further improvement of the technical solution of the present invention, in step S1, the equipment includes a cogeneration unit, a heating device, an energy storage device, and a carbon capture device; the output load type consists of electrical load, thermal load, gas load and cooling load; the heating equipment includes a gas boiler and a hydrogen fuel cell in the power-to-gas process; the energy storage equipment includes electrical energy storage, thermal energy storage, hydrogen energy storage, gas energy storage and carbon energy storage; the electrical load of the integrated energy system is supplied by renewable energy, a cogeneration unit, a hydrogen fuel cell in the two-stage power-to-gas process and an external power grid; the gas load is supplied by the methanation reaction in the two-stage power-to-gas process and an external gas grid; the thermal load is supplied by all the system heating equipment; and the cooling load is supplied by an absorption chiller.

[0013] As a further improvement of the technical solution of the present invention, the renewable energy in the comprehensive energy system includes a wind turbine generator set and solar generators ; Gas boilers have a constant gas-to-heat ratio, while the cogeneration unit and hydrogen fuel cells in the two-stage power-to-gas process are thermoelectric production equipment with an adjustable heat-to-electricity ratio. The sum of the heat and electricity energy conversion efficiency can be regarded as a constant;

[0014]

[0015]

[0016] Where: for Natural gas power consumed by gas boilers during the period; for The heat energy output by the gas boiler during the period; for Natural gas input to the cogeneration unit during the period; , They are Output electricity and heat energy of the cogeneration unit during the time period; for The hydrogen energy input into the hydrogen fuel cell during the period; , They are Output electricity and heat energy of hydrogen fuel cells during time periods; , , They are the conversion energy efficiency of gas boilers, cogeneration units, and hydrogen fuel cells.

[0017] As a further improvement of the technical solution of the present invention, the electric energy storage, thermal energy storage, hydrogen energy storage, and gas energy storage are uniformly modeled, and the energy loss during the energy storage process is considered. For carbon energy storage, a solution storage device is introduced, as follows:

[0018]

[0019]

[0020] In the formula, For the Energy storage devices The actual increase in energy storage power during the period; , The integrated energy system is Energy storage device The charging power of the time period, Energy storage device The actual power input to the integrated energy system during the period; , Respectively The charging and discharging efficiency of various energy storage devices; For solution storage The volume of solution required to release CO2 at any given moment; and are the molar masses of liquid and CO2 respectively; is the analysis amount of the regeneration tower; is the concentration of the alcoholamine solution; is the density of amine solution.

[0021] As a further improvement of the technical solution of the present invention, the power-to-gas conversion is specifically as follows:

[0022] First, the electrical energy is converted into hydrogen energy. Part of the hydrogen energy is input into the methanation reactor to synthesize with CO2 into natural gas, which is supplied to gas loads, gas boilers, and cogeneration units. Part of the hydrogen energy is directly transported to hydrogen fuel cells to be converted into electricity and heat energy, and another part is stored in hydrogen storage equipment.

[0023]

[0024] In the formula, for The hydrogen energy output of the electrolyzer during the period; for The hydrogen energy input power of the methanation reactor during the period; for The hydrogen energy of the hydrogen fuel cell is input during the period.

[0025] As a further improvement of the technical solution of the present invention, in step S2, the carbon trading model of the integrated energy system is as follows:

[0026] The quota method of free quota is adopted. For different sources of energy, the carbon emission rights coefficient is different. The unit electricity quota coefficient purchased from the external power grid is , quota coefficient of natural gas consumption per unit of natural gas-fired units ; The main sources of carbon emissions in the integrated energy system are gas boilers and cogeneration units. For carbon emissions that exceed the carbon emission quota model, the role of the tiered carbon trading mechanism is considered, and the excess emissions are purchased using the carbon trading model;

[0027]

[0028] Where: The power exceeding the allocated emission rights quota; is the actual carbon emissions of the integrated energy system; It is the total carbon emission quota of the comprehensive energy system.

[0029] As a further improvement of the technical solution of the present invention, in step S3, the comprehensive demand response of the comprehensive energy system has different response speeds according to different responses, and a comprehensive demand response model of different time scales is established. The comprehensive demand response model of different time scales is divided into response types of 24 hours before the day, 4 hours within the day and 15 minutes in real time; the day-ahead electric load demand includes price-type demand response and incentive-type demand response of replaceable electric load, and the intraday and real-time demand response is an incentive-type demand response;

[0030]

[0031] In the formula, Represents electricity, cooling and heating loads; is the reduction amount and maximum reduction amount of different loads at time t; is the transfer amount of different loads at time t; The conversion amount of different loads at time t.

[0032] As a further improvement of the technical solution of the present invention, in step S4, the constraints of each device of the integrated energy system are specifically: the output and climbing power of the integrated energy system equipment are limited to ensure the safe and stable operation of the system, and under the premise of satisfying the constraints of normal operation of the units in the system, the minimum comprehensive operating cost is used as the low-carbon operation objective function; the objective function includes the day-ahead purchase of electricity and gas costs, carbon trading costs, and demand response costs. The specific objective function is as follows:

[0033]

[0034] Where: is the total cost of system operation; Fees for purchasing carbon emission rights to participate in tiered carbon trading; For the day before Time-of-use electricity price; for Gas price during the period; for Total cost of time-of-day incentive demand response.

[0035] The multi-scale low-carbon economic optimization operation method of the integrated energy system considering multiple energy storage and hybrid demand response provided by the present invention has the following advantages compared with the prior art:

[0036] 1. The cogeneration units and hydrogen fuel cells with adjustable heat-to-electricity ratio can adjust the electricity and heat output according to the real-time electricity and heat energy demand, making the system energy supply more flexible and improving the stability of the energy supply balance.

[0037] 2. In order to alleviate the mismatch between the energy supply side and the energy demand side, energy storage devices are configured in the integrated energy system to achieve energy shifting in different time periods. When the integrated energy system's required load power is lower than the supplied load power or when the energy price is low, due to the low energy consumption, part of the energy can be absorbed and stored in the energy storage device. When the integrated energy system's required load power is higher than the supplied load power or when the energy price is high, due to the high energy consumption, the stored energy output is used for load supply. Energy storage devices can smooth out the volatility of both the supply and demand sides to achieve the purpose of supply and demand balance and meet the reliability requirements of the system.

[0038] 3. The traditional operation mode with energy cost as the objective function is affected by many aspects of price cost, and the demand for clean and low-carbon energy on the energy demand side is not significant. Compared with the traditional carbon trading mechanism, the introduction of a step-by-step carbon trading mechanism in the system operation can more effectively mobilize the system's enthusiasm for participating in energy conservation and emission reduction, and demonstrate its advantages in low-carbon and environmentally friendly development.

[0039] 4. In the face of the mutual coupling of electricity, heat, natural gas and other energies in the integrated energy system, the traditional single electricity demand response method is difficult to meet the energy supply and demand relationship of the system. Considering that different responses have different response speeds, a hybrid demand response model with different time scales is established to flexibly adjust different energy consumption.

[0040] 5. Since the integrated energy system is affected by the uncertainty of multiple loads and renewable energy power generation itself, the uncertainty of prediction errors, the uncertainty of price changes, etc., the operation plan results of a longer time scale may not be the optimal choice, and there may be a large deviation from the actual optimal operation plan. Usually, the uncertainty of multiple loads and renewable energy decreases as the time scale decreases. Therefore, in order to improve the energy supply stability of the system and achieve the goal of a low-carbon economy, multi-time scale operation optimization is carried out on the day-ahead, intraday, and real-time basis. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 This is a model diagram of the comprehensive energy system of the present invention;

[0044] Figure 2 This is a detailed diagram of the two-stage power-to-gas conversion of the present invention;

[0045] Figure 3 It is a schematic diagram of the operating principle of the present invention. DETAILED DESCRIPTION

[0046] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0047] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0048] The specific embodiments of the present invention are described in detail below.

[0049] like Figures 1 to 3 As shown, the present invention provides a specific embodiment of a multi-scale low-carbon economic optimization operation method for an integrated energy system considering multiple energy storage and hybrid demand response, comprising the following steps:

[0050] S1. Establish a comprehensive energy system model to clarify the equipment included in the system and the output of each equipment;

[0051] S2. Based on the different carbon emission coefficients of the system's equipment and the carbon flow relationship, establish a carbon emission rights model, a carbon emission model and a tiered carbon trading mechanism for the integrated energy system;

[0052] S3. Establish a comprehensive demand response for the integrated energy system based on the speed and mode of load response. According to the different corresponding modes, it can be divided into price-based and incentive-based responses. Price-based demand response is to change the electricity price to make the demand side actively change the electricity consumption behavior, while incentive-based directly adopts incentive policies and compensation methods to induce the demand side to participate in the load reduction projects required by the system.

[0053] S4. Construct the constraints of each device in the integrated energy system and the low-carbon economic operation target based on energy purchase cost, carbon emission cost, and demand response cost, transform the original problem into a mixed integer linear problem, and use the CPLEX commercial solver to solve it.

[0054] like Figure 1 This is a model diagram of the integrated energy system of the present invention. The direction of energy flow in the integrated energy system can be obtained by analyzing the diagram.

[0055] The equipment includes cogeneration units, heating equipment, energy storage equipment, and carbon capture devices; the output load types are composed of electrical load, thermal load, gas load, and cooling load; the heating equipment includes gas boilers and hydrogen fuel cells in the power-to-gas process; the energy storage equipment includes electrical energy storage, thermal energy storage, hydrogen energy storage, gas energy storage, and carbon energy storage; the electrical load of the integrated energy system is supplied by renewable energy, cogeneration units, hydrogen fuel cells in the two-stage power-to-gas process, and an external power grid; the gas load is supplied by the methanation reaction in the two-stage power-to-gas process and an external gas grid; the thermal load is supplied by all the system heating equipment; and the cooling load is supplied by an absorption chiller.

[0056] The output models of various types of equipment are as follows:

[0057] 1.1 The renewable energy in the comprehensive energy system includes wind turbines and solar generators , wind turbines and solar generators Used for comprehensive energy system load power supply and grid-connected electricity sales. The specific relationship is as follows:

[0058] (1)

[0059] Where: for The electric energy input from wind turbines into the integrated energy system during the period; , They are The electricity produced by wind turbines and solar generators during the period.

[0060] 1.2 A combined heat and power (CHP) unit with adjustable heat-to-electricity ratio is used. The specific model formula is as follows:

[0061] (2)

[0062] (3)

[0063] (4)

[0064] (5)

[0065] (6)

[0066] (7)

[0067] (8)

[0068] (9)

[0069] Where: for Natural gas input to CHP during the period; , They are Output electricity and heat energy of CHP during the time period; , , are the conversion rates of CHP into the sum of electrical and thermal energy, electricity, and thermal energy respectively; Represents the ramp power of natural gas consumed by the CHP unit in adjacent periods; , They are the upper and lower limits of natural gas consumption of CHP units, respectively; , They are the upper and lower limits of the natural gas consumption ramp of the CHP unit; , They are the upper and lower limits of the heat-to-electricity ratio of the CHP unit respectively.

[0070] 1.3 Gas boiler has a constant gas-to-heat ratio. The mathematical relationship between the output thermal power of a gas boiler and the natural gas consumption is as follows:

[0071] (10)

[0072] (11)

[0073] (12)

[0074] Where: for Natural gas power consumed by gas boilers during the period; for The heat energy output by the gas boiler during the period; is the energy conversion rate of the gas boiler; Represents the ramp power of natural gas consumed by the gas boiler in adjacent periods; , They represent the upper and lower limits of natural gas consumption of gas boilers respectively; , They represent the upper and lower limits of the natural gas consumption of gas boilers respectively.

[0075] Figure 2 This is a two-stage detailed diagram of the power-to-gas process of the present invention. By analyzing the diagram, the energy conversion direction of the power-to-gas process can be obtained.

[0076] Different charging and discharging coefficients are set for different energy storage equipment input and output powers. The specific unified mathematical model of electricity, gas and heat energy storage can be expressed as follows:

[0077] (13)

[0078] (14)

[0079] (15)

[0080] (16)

[0081] (17)

[0082] (18)

[0083] (19)

[0084] Where: , The integrated energy system is Energy storage device The charging power of the time period, Energy storage device The actual power input to the integrated energy system during the period; , are the charging and discharging efficiencies of the th type of energy storage device respectively; For the Energy storage devices The actual increase in energy storage power during the period; For the Energy storage devices The capacity of the time slot; To provide a comprehensive energy system Energy storage device The charging power of the time period is Energy storage device The difference in actual power input to the integrated energy system during each period; , are binary variables, Energy storage devices Time period charging and discharging status parameters, Indicates that it is in charging state. Indicates that it is in a state of releasing energy; , For the The maximum power of a single charge and discharge of an energy storage device; , Respectively The charging and discharging efficiency of various energy storage devices; , Respectively The upper and lower limits of the capacity of the energy storage equipment.

[0085] The hydrogen fuel cell in the two-stage process of cogeneration unit and power-to-gas is a thermoelectric production equipment with adjustable heat-to-electricity ratio. The sum of heat and electricity energy conversion efficiency can be regarded as a constant; the full process model of P2G includes multiple links such as hydrogen production, consumption, storage, natural gas generation, electricity consumption, production, and heat generation. The mathematical formula of P2G is as follows:

[0086] (20)

[0087] (twenty one)

[0088] (twenty two)

[0089] (twenty three)

[0090] (twenty four)

[0091] (25)

[0092] (26)

[0093] (27)

[0094] (28)

[0095] (29)

[0096] (30)

[0097] (31)

[0098] (32)

[0099] (33)

[0100] (34)

[0101] (35)

[0102] (36)

[0103] In the formula, for The power consumption of the electrolytic cell during the period; for The hydrogen energy output of the electrolyzer during the period; is the electricity-to-hydrogen conversion rate of the electrolyzer; Represents the electric energy ramp power of the electrolyzer in adjacent time periods; , They represent the upper and lower limits of the electric energy consumption of the input electrolyzer respectively; , They represent the upper and lower limits of the electrolytic cell's energy consumption respectively. for The hydrogen energy input power of the methanation reactor during the period; is the hydrogen-to-natural gas conversion efficiency of the methanation reactor; for The natural gas output from the methanation reactor during the period; is the electrical energy consumed by the methanation reactor per unit of natural gas produced; The electrical energy consumed by the methanogenation reactor; Represents the ramp power of hydrogen energy input to the methanation reactor in adjacent time periods; , They represent the upper and lower limits of hydrogen energy input to the methanation reactor; , They represent the upper and lower limits of the hydrogen energy ramp input into the methanation reactor respectively. for The hydrogen energy input into the hydrogen fuel cell during the period; , They are Output electricity and heat energy of hydrogen fuel cells during time periods; , are the conversion rates of hydrogen fuel cells into electricity and heat energy, respectively; Represents the ramp power of hydrogen energy input into the hydrogen fuel cell in adjacent time periods; , They are the upper and lower limits of the thermal-to-electricity ratio of hydrogen fuel cells; , They are the upper and lower limits of hydrogen energy input into hydrogen fuel cells; , They are the upper and lower limits of the hydrogen energy climbing of the input hydrogen fuel cell respectively.

[0104] The power-to-gas process is detailed. First, electricity is converted into hydrogen energy. Part of the hydrogen energy is input into the methanation reactor and synthesized with CO2 into natural gas, which is supplied to gas loads, gas boilers, and cogeneration units. Part of the hydrogen energy is directly transported to hydrogen fuel cells to be converted into electricity and heat energy, and part of the hydrogen energy is stored in hydrogen storage equipment.

[0105]

[0106] In the formula, for The hydrogen energy output of the electrolyzer during the period; for The hydrogen energy input power of the methanation reactor during the period; for The hydrogen energy of the hydrogen fuel cell is input during this period.

[0107] The electric energy storage, thermal energy storage, hydrogen energy storage, and gas energy storage are uniformly modeled, and the energy loss during the energy storage process is considered. For carbon energy storage, a solution storage device is introduced, as follows:

[0108] (37)

[0109] (38)

[0110] (39)

[0111] (40)

[0112] (41)

[0113] (42)

[0114] (43)

[0115] In the formula, , Respectively in The carbon dioxide released and absorbed by the solution storage at all times; For solution storage The volume of solution required to release CO2 at any given moment; and are the molar masses of liquid and CO2 respectively; is the analysis amount of the regeneration tower; is the concentration of the alcoholamine solution; is the density of amine solution. and For each unit The rich liquid storage and lean liquid storage are The volume of solution during the time period; For the crew The capacity of the solution reservoir.

[0116] The absorption chiller converts heat energy into cold energy, and the electric heating equipment converts electrical energy into heat energy. The conversion relationship is as follows:

[0117] (44)

[0118] (45)

[0119] In the formula, , Respectively in Cold and heat energy are constantly transformed; , Respectively in The thermal energy and electrical energy are converted at all times. The conversion factor of electricity to cooling, The conversion factor from electricity to heat.

[0120] Furthermore, in step S2, the integrated energy system carbon trading model is as follows:

[0121] The quota method of free quota is adopted. For different sources of energy, the carbon emission rights coefficient is different. The unit electricity quota coefficient purchased from the external power grid is , quota coefficient of natural gas consumption per unit of natural gas-fired units The main sources of carbon emissions in the integrated energy system are gas boilers and cogeneration units. For carbon emissions that exceed the carbon emission quota model, the role of the tiered carbon trading mechanism is considered, and the excess emissions are purchased using the carbon trading model.

[0122] Among them, the specific formula of the carbon emission quota model is as follows:

[0123] (46)

[0124] (47)

[0125] (48)

[0126] (49)

[0127] Where: The total carbon emission quota for the integrated energy system; Carbon emission quotas for combined heat and power units; Carbon emission quota for gas boilers; Carbon emission quotas for purchasing electricity for integrated energy systems; , They are the carbon emission quota coefficients for purchasing a unit of electricity and consuming a unit of natural gas; for The amount of electric power purchased from the grid during a period.

[0128] The specific formula of the actual carbon emission model is as follows:

[0129] (50)

[0130] (51)

[0131] (52)

[0132] Where: is the actual carbon emissions of the integrated energy system; The actual carbon emissions of gas-fired units in the integrated energy system; The total power stored in the carbon storage device for the combined energy; It is the sum of the thermal power and electrical power output of the cogeneration unit and the thermal power output of the gas boiler; , , Carbon emission relationship parameters of natural gas units consumed per unit.

[0133] In summary, the system excess emission formula is as follows:

[0134] (53)

[0135] Where: The power that exceeds the allocated emission rights quota.

[0136] The carbon trading model is as follows:

[0137] (54)

[0138] Where: is the basic price of carbon trading, is the price growth rate, is the length of the step-by-step carbon emission interval, represents the carbon trading cost.

[0139] Furthermore, in step S3 of the embodiment of the present invention, the comprehensive demand response of the integrated energy system has different response speeds according to different responses, and comprehensive demand response models of different time scales are established. The comprehensive demand response models of different time scales are divided into response types of 24 hours before the day, 4 hours within the day, and 15 minutes in real time; the day-ahead electric load demand includes price-type demand response and incentive-type demand response of replaceable electric load, and the intraday and real-time demand response is an incentive-type demand response.

[0140] For price-based demand response, a price elasticity matrix is ​​generally used to describe the loads participating in the response, that is, the electricity price is used to guide users to adjust their energy consumption strategies to smooth the load curve. The day-ahead electricity load participating in the price-based model of the present invention is obtained based on the elasticity matrix as follows:

[0141] Δ P CL , t e = P CL , t e 0 [ ∑ j = 0 24 E CL ( t , j ) ρ j − ρ j 0 ρ j 0 ] (55)

[0142] Δ P SL , t e = P SL , t e 0 [ ∑ j = 0 24 E SL ( t , j ) ρ j − ρ j 0 ρ j 0 ] (56)

[0143] After DR The electricity price changes from time to time; represents the initial electricity price; After DR The load variation can be reduced at any time; Indicates the initial load reduction amount; , They represent the price demand elasticity coefficients of the abatable and transferable electric loads respectively;

[0144] For incentive-based demand response, according to the flexible characteristics of electricity, cooling and heating loads, the demand response model of each load can be obtained as follows:

[0145]

[0146] Where: Indicates electricity, cooling and heating loads; , , respectively represent different loads in The reduction amount at the moment and the maximum reduction amount; , Represents different loads The amount of transfer at a moment; , Respectively represent the thermal and electric loads in The amount of conversion at the moment; , Respectively expressed in The electronegative substitution amount and the maximum substitutable amount at the moment, Represents different loads The electrical substitution coefficient at the time; , , Respectively The cost coefficients of load shedding incentives, transfer incentives, and substitution incentives at the time; express The total cost of load incentives at the time.

[0147] In the embodiment provided by the present invention, in step S4, in order to improve the flexibility and economy of the integrated energy system, a two-way link of buying and selling to the superior power grid and gas grid is added. The day-ahead electricity and gas load balance constraint relationship is as follows:

[0148] (62) (63)

[0149] Where: , for The electricity and gas load power predicted for each time period.

[0150] The heat load balance constraint relationship is as follows:

[0151] (64)

[0152] The hydrogen balance constraint relationship is as follows:

[0153] (65)

[0154] The cold balance constraint relationship is as follows:

[0155] (66)

[0156] In the formula, for Hydrogen power delivered to hydrogen storage equipment by time-period integrated energy system and hydrogen storage equipment The difference in actual hydrogen power delivered to the integrated energy system during each period; for The cooling load power predicted for the time period.

[0157] Considering that the final amount of carbon dioxide in the carbon storage equipment must be the same as the initial amount of carbon dioxide in order to determine the carbon emissions of the integrated energy system, the constraint condition relationship for the carbon storage equipment is added as follows:

[0158] (67)

[0159] In the formula, for Transmission power of carbon dioxide from the integrated energy system to the carbon storage device and the carbon storage device The difference in actual carbon power delivered to the integrated energy system during each period.

[0160] Under the premise of satisfying the constraints of normal operation of the units in the system, the low-carbon operation objective function is to minimize the comprehensive operating cost. The objective function includes the cost of purchasing electricity and gas, carbon trading costs, and demand response costs. The specific objective function is as follows:

[0161] (68)

[0162] Where: is the total cost of system operation; Fees for purchasing carbon emission rights to participate in tiered carbon trading; For the day before Time-of-use electricity price; for Gas price during the period; for The total cost of time-of-day incentive demand response;

[0163] Figure 3 The schematic diagram of the operating principle of the present invention is shown in Figure 5. The specific process of optimizing the operation of the integrated energy system can be obtained by analyzing the figure. Since equation (51) is a quadratic function, it is necessary to perform piecewise linearization on the quadratic function. The linearization process is as follows.

[0164] 1) According to the required accuracy, select Segment points [ L 1 , … L m + 1 ] , divide the original function into interval.

[0165] 2) Add continuous auxiliary variable [ B 1 , … B m + 1 ] and Binary auxiliary variables [ A 1 , … A m + 1 ] .

[0166] (69)

[0167] 3) Replace the nonlinear function with a linear expression as shown in formula (A2).

[0168] (70)

[0169] 4) The step price in equation (54) is already a piecewise function, so step 1 can be omitted and steps 2 and 3 can be combined for linear transformation.

[0170] By reasonably establishing a mathematical model, the cplex solver is used to solve the objective function of equation (68) in terms of day-ahead, day-intraday, and real-time operation. The obtained unit operation plan, energy plan, and demand response plan are then input into the next step of optimization operation as basic data and solved again. Finally, through multi-time scale solutions, the actual operating conditions of the system can be met and the goal of a low-carbon economy can be achieved.

[0171] The above is only a specific implementation of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A multi-scale low-carbon economic optimization operation method for an integrated energy system considering multiple energy storage and hybrid demand response, characterized in that: The steps include: S1. Establish a comprehensive energy system model to clarify the equipment included in the system and the output of each equipment; S2. Based on the different carbon emission coefficients of the system's equipment and the carbon flow relationship, establish a carbon emission rights model, a carbon emission model and a tiered carbon trading mechanism for the integrated energy system; S3. Establish a comprehensive demand response for the integrated energy system based on the speed and mode of load response. According to the different corresponding modes, it can be divided into price-based and incentive-based responses. Price-based demand response is to change the electricity price to make the demand side actively change the electricity consumption behavior, while incentive-based directly adopts incentive policies and compensation methods to induce the demand side to participate in the load reduction projects required by the system. S4. Construct the constraints of each device in the integrated energy system and the low-carbon economic operation target based on energy purchase cost, carbon emission cost, and demand response cost, transform the original problem into a mixed integer linear problem, and use the CPLEX commercial solver to solve it.

2. According to claim 1, a multi-scale low-carbon economic optimization operation method for an integrated energy system considering multiple energy storage and hybrid demand response is characterized in that: In step S1, the equipment includes a cogeneration unit, a heating device, an energy storage device, and a carbon capture device; the output load type consists of an electrical load, a thermal load, a gas load, and a cooling load; the heating equipment includes a gas boiler and a hydrogen fuel cell in a power-to-gas process; the energy storage equipment includes electrical energy storage, thermal energy storage, hydrogen energy storage, gas energy storage, and carbon energy storage; the electrical load of the integrated energy system is supplied by renewable energy, a cogeneration unit, a hydrogen fuel cell in a two-stage power-to-gas process, and an external power grid; the gas load is supplied by a methanation reaction in a two-stage power-to-gas process and an external gas grid; the thermal load is supplied by all the system heating equipment; and the cooling load is supplied by an absorption chiller.

3. A multi-scale low-carbon economic optimization operation method for an integrated energy system considering multiple energy storage and hybrid demand response according to claim 2, characterized in that: The renewable energy in the comprehensive energy system includes a wind turbine and solar generators ; Gas boilers have a constant gas-to-heat ratio, while the cogeneration unit and hydrogen fuel cells in the two-stage power-to-gas process are thermoelectric production equipment with an adjustable heat-to-electricity ratio. The sum of the heat and electricity energy conversion efficiency can be regarded as a constant; ； ； Where: for Natural gas power consumed by gas boilers during the period; for The heat energy output by the gas boiler during the period; for Natural gas input to the cogeneration unit during the period; , They are Output electricity and heat energy of the cogeneration unit during the time period; for The hydrogen energy input into the hydrogen fuel cell during the period; , They are Output electricity and heat energy of hydrogen fuel cells during time periods; , , They are the conversion energy efficiency of gas boilers, cogeneration units, and hydrogen fuel cells.

4. According to claim 2, a multi-scale low-carbon economic optimization operation method for an integrated energy system considering multiple energy storage and hybrid demand response is characterized in that: The electric energy storage, thermal energy storage, hydrogen energy storage, and gas energy storage are uniformly modeled, and the energy loss during the energy storage process is considered. For carbon energy storage, a solution storage device is introduced, as follows: ； ； In the formula, For the Energy storage devices The actual increase in energy storage power during the period; , The integrated energy system is Energy storage device The charging power of the time period, Energy storage device The actual power input to the integrated energy system during the period; , Respectively The charging and discharging efficiency of various energy storage devices; For solution storage The volume of solution required to release CO2 at any given moment; and are the molar masses of liquid and CO2 respectively; is the analysis amount of the regeneration tower; is the concentration of the alcoholamine solution; is the density of amine solution.

5. According to claim 2, a multi-scale low-carbon economic optimization operation method for an integrated energy system considering multiple energy storage and hybrid demand response is characterized in that: Power-to-gas conversion is as follows: First, the electrical energy is converted into hydrogen energy. Part of the hydrogen energy is input into the methanation reactor to synthesize with CO2 into natural gas, which is supplied to gas loads, gas boilers, and cogeneration units. Part of the hydrogen energy is directly transported to hydrogen fuel cells to be converted into electricity and heat energy, and another part is stored in hydrogen storage equipment. ； In the formula, for The hydrogen energy output of the electrolyzer during the period; for The hydrogen energy input power of the methanation reactor during the period; for The hydrogen energy of the hydrogen fuel cell is input during this period.

6. The multi-scale low-carbon economic optimization operation method of an integrated energy system considering multiple energy storage and hybrid demand response according to claim 2 is characterized in that: In step S2, the integrated energy system carbon trading model is as follows: The quota method of free quota is adopted. For different sources of energy, the carbon emission rights coefficient is different. The unit electricity quota coefficient purchased from the external power grid is , quota coefficient of natural gas consumption per unit of natural gas-fired units ; The main sources of carbon emissions in the integrated energy system are gas boilers and cogeneration units. For carbon emissions that exceed the carbon emission quota model, the role of the tiered carbon trading mechanism is considered, and the excess emissions are purchased using the carbon trading model; ； Where: The power exceeding the allocated emission rights quota; is the actual carbon emissions of the integrated energy system; It is the total carbon emission quota of the comprehensive energy system.

7. A multi-scale low-carbon economic optimization operation method for an integrated energy system considering multiple energy storage and hybrid demand response according to claim 2, characterized in that: In step S3, the comprehensive demand response of the integrated energy system has different response speeds according to different responses, and a comprehensive demand response model of different time scales is established. The comprehensive demand response model of different time scales is divided into response types of 24 hours before the day, 4 hours within the day, and 15 minutes in real time; the day-ahead electric load demand includes price-type demand response and incentive-type demand response of replaceable electric load, and the intraday and real-time demand response is an incentive-type demand response; ； In the formula, Represents electricity, cooling and heating loads; is the reduction amount and maximum reduction amount of different loads at time t; is the transfer amount of different loads at time t; The conversion amount of different loads at time t.

8. The multi-scale low-carbon economic optimization operation method of an integrated energy system considering multiple energy storage and hybrid demand response according to claim 2 is characterized in that: In step S4, the constraints of each device in the integrated energy system are as follows: the output and ramp power of the integrated energy system equipment are limited to ensure the safe and stable operation of the system. Under the premise of satisfying the constraints of the normal operation of the units in the system, the low-carbon operation objective function is to minimize the comprehensive operating cost; the objective function includes the day-ahead purchase of electricity and gas costs, carbon trading costs, and demand response costs. The specific objective function is as follows: ； Where: is the total cost of system operation; Fees for purchasing carbon emission rights to participate in tiered carbon trading; For the day before Time-of-use electricity price; for Gas price during the period; for Total cost of time-of-day incentive demand response.

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