A method for calculating energy flow and carbon flow distribution in an integrated energy system

Abstract

The present invention discloses a method for calculating the energy flow and carbon flow distribution of an integrated energy system, and belongs to the field of integrated energy systems. A method for calculating the energy flow and carbon flow distribution of an integrated energy system, comprising: establishing an energy flow model of an integrated energy system; establishing a carbon flow model of an integrated energy system; establishing an energy flow-carbon flow collaborative optimization model of an integrated energy system; solving the model using a weighted method; calculating the network carbon flow distribution using a carbon emission flow analysis method; The present invention proposes a method for calculating the carbon emission flow of heterogeneous energy flows in an integrated energy system, and obtains the carbon emission flow distribution corresponding to multiple energy flows in the integrated energy system. The proposed method can more intuitively analyze the source, flow direction and distribution of carbon emissions in a multi-energy network, identify network nodes with higher carbon emission intensity, and guide the formulation of low-carbon policies.

Description

Technical Field

[0001] The present invention relates to the field of integrated energy systems, and in particular to a method for calculating energy flow and carbon flow distribution of an integrated energy system. Background Art

[0002] In the context of low-carbon development, the power system is facing a comprehensive transformation. The integrated energy system, which aims to improve energy utilization efficiency by coupling and complementing multiple energy sources, has attracted widespread attention. However, there are still many challenges in achieving the coordinated optimization of energy flow and carbon flow. On the one hand, there is a coupling relationship between the power and heating systems in multiple links such as production, transmission, distribution and utilization. Independent analysis, planning and operation cannot fully utilize the synergistic and complementary characteristics between systems. On the other hand, the energy flow and carbon flow in the integrated energy system have a complex coupling relationship in multiple links of source, grid and load, and the coupling mechanism of different links is significantly different. It is necessary to systematically analyze the coupling relationship between multiple energy flows and the coupling relationship between energy flow and carbon flow, and realize the mathematical characterization and analytical calculation of the coupling relationship between energy flow and carbon flow. Secondly, in the context of low carbon, there is a certain contradiction between the economic operation of the system and the reduction of carbon emissions. How to minimize the carbon emissions of the system while ensuring the economy of the system, coordinate the whole system, achieve the optimization of energy flow and carbon flow in the integrated energy system, and maximize carbon emission reduction is a difficult problem that needs to be solved in engineering applications. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention proposes a method, system and device for calculating the energy flow and carbon flow distribution of an integrated energy system.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A method for calculating energy flow and carbon flow distribution of a comprehensive energy system, characterized by comprising the following steps:

[0006] An energy flow model of the integrated energy system is constructed with the integrated energy system cost and the integrated energy system carbon emission as the objective function, the integrated energy system network and equipment operation as the constraint and the integrated energy system carbon emission as the constraint; a carbon flow model of the integrated energy system is constructed with the node carbon potential and carbon flow rate as the output value;

[0007] The energy flow model of the integrated energy system and the carbon flow model of the integrated energy system are combined to construct the energy flow-carbon flow collaborative optimization model of the integrated energy system; the weighted method is used to solve the energy flow-carbon flow collaborative optimization model of the integrated energy system; the carbon emission flow analysis method is used to calculate the carbon flow distribution of the integrated energy system.

[0008] Furthermore, the constraints on the operation of the integrated energy system network and equipment include grid interconnection line capacity constraints, heat network pipeline constraints, energy storage device storage / discharge constraints, renewable energy output constraints, and establishment of coupled equipment operation constraints;

[0009] The capacity constraint of the grid tie line is:

[0010] in, represents the active power flow on branch b at time t; Indicates the upper limit of active power flow in branch b; V i Indicates the upper and lower limits of the voltage of node i;

[0011] The heat network pipeline constraints include heat source power balance constraints, power and temperature equations of heat source and heat load nodes, pipeline transmission delay and heat loss constraints, heat network node power balance constraints, heat network node water temperature mixing constraints, and heat network supply and return water temperature upper and lower limit constraints;

[0012] The heat source power balance constraint is:

[0013] in, E is the variable of thermal power injected into the thermal network during period t; chp 、E eb It is the index collection of cogeneration units and electric boilers; is the thermal output power variable of CHP unit i during period t; is the heat output power variable of electric boiler i during period t;

[0014] The power and temperature equations for the heat source and heat load nodes are:

[0015]

[0016] in, are the pipeline index sets flowing out / into node k respectively; Φ sn , Φ ln are the index sets of source nodes and load nodes in the heating network respectively; c w is the specific heat capacity of water; m j is the mass flow rate of heat medium in pipeline j; is the heat medium temperature variable at node k in the water supply and return network at time t; is the heat load power variable at node k during period t;

[0017] The pipeline transmission delay and heat loss constraints are:

[0018]

[0019] Among them, Φ pA collection of heat network pipeline indexes; is the coefficient related to the transmission delay of pipeline j; parameter β j is the insulation coefficient of pipe j; is the pipeline ambient temperature at time t; is the temperature variable of the heat medium at the inlet and outlet of the water supply pipe j at time t; is the heat medium temperature variable at the inlet and outlet of the return pipe j at time t;

[0020] The power balance constraint of the heating network node is:

[0021] Among them, Φ in is the set of intersection nodes in the heat network; is the heat medium temperature at node k in the water supply and return network during period t;

[0022] The water temperature mixing constraint of the heating network node is:

[0023] Among them, Φ in is the set of intersection nodes in the heat network; is the heat medium temperature at node k in the water supply and return network during period t;

[0024] The upper and lower limits of the supply and return water temperatures of the heating network are:

[0025] in, τ s The upper and lower limits of water supply temperature for the heating network; τ r It is the upper and lower limit of the return water temperature of the heating network.

[0026] The storage / discharge constraints of the energy storage device are:

[0027] in, It is a variable of 0-1 indicating the charging and discharging flag of the j-th energy storage device at time t; Charge or discharge energy for the j-th energy storage device at time t; is the maximum value of charging and discharging of the j-th energy storage device at time t; E t,j ,E t-1,j is the total energy stored in the j-th energy storage device at time t and time t-1; E min,j / E max,j is the minimum or maximum total energy stored in the jth energy storage device; η ch,j / η dis,j The charging or discharging efficiency of the j-th energy storage device.

[0028] The renewable energy output constraint is: 0≤P t wt≤P t wind

[0029] Among them, P t wind is the predicted output of the wind turbine at time t;

[0030] The coupled equipment operating constraints are:

[0031] Among them, P max,i is the upper limit of the capacity of the i-th coupling device; ΔR max,i is the climbing power limit of the i-th coupling device; and They are the heat-to-electricity ratio of the CHP unit and the electric-to-heat conversion efficiency of the electric boiler.

[0032] Furthermore, the carbon flow model of the integrated energy system includes a carbon flow model of the power grid of the integrated energy system and a carbon flow model of the heat network of the integrated energy system.

[0033] Furthermore, the carbon flow model of the integrated energy system power grid includes the carbon potential of the power grid nodes, the carbon flow rate of the power grid branches, the carbon flow rate of the power grid units, the carbon flow rate of the power grid loads and the carbon flow rate of the power grid losses;

[0034] The carbon potential of the power grid node is used to express the relationship between the carbon flow and the active power flow at the node. The carbon potential of the power grid node is expressed as:

[0035] Where P s is the active power of branch s; ρ s is the carbon flow density of branch s; P i Ge is the active output of the generator connected to node i; is the carbon potential of the generator set connected to node i;

[0036] The carbon flow rate of the power grid branch is: R B =diag{E N}·P; where E N is the carbon potential matrix of the power grid nodes, and P is the power flow distribution matrix of the power grid branches;

[0037] The carbon flow rate of the power grid unit is: R G =diag{E G}·P Gen ; Among them, E G is the carbon potential matrix of the grid source node units, P Gen It is the power grid unit output matrix;

[0038] The carbon flow rate of the grid load is: R L =diag{E L}·P load ; Among them, EL is the carbon potential matrix of the power grid load nodes, P load is the electric load matrix;

[0039] The grid loss carbon flow rate is: R BL =diag{E N}·P loss ; Among them, E N is the carbon potential matrix of the power grid nodes, P loss is the power grid branch loss distribution matrix.

[0040] Furthermore, the carbon flow model of the heat network of the integrated energy system includes the carbon potential of the heat network nodes, the carbon flow rate of the heat network pipelines, the carbon flow rate of the heat network units, the carbon flow rate of the heat network loads and the carbon flow rate of the heat network losses;

[0041] The carbon potential of the heating network node is used to express the relationship between the carbon flow and the thermal energy flow at the heating network node. The carbon potential expression of the heating network node is:

[0042]

[0043] in, represents the node carbon potential of heating network node n, kgCO2 / kWh; is the node carbon flow rate of heating network node n, kgCO2 / h; c is the specific heat capacity of water, kJ / (kg·℃); m n is the mass flow rate injected into node n, kg; T n is the temperature of node n, °C; is the carbon flow density of the pipeline injected into node n, kgCO2 / kWh; m k is the mass flow rate of pipeline k injected into node n, kg; T n is the temperature of node n, °C; is the outlet temperature of pipe k injecting into node n, °C; is the temperature loss of pipe k injected into node n, °C; is the unit carbon potential of unit i, kgCO2 / kWh; is the heat output of heat generating unit i, kWh; Ω N It is a collection of heating network nodes.

[0044] The carbon flow rate of the heat network pipeline is: R P =diag{ρ N}·H; where ρ N is the carbon potential matrix of the heating network nodes, and H is the flow matrix of the heating network pipelines;

[0045] The carbon flow rate of the heating network unit is: R G =diag{ρ G}·H Gen ; where ρ Gis the carbon potential matrix of the heat network source node units, H Gen It is the output matrix of the heating network units;

[0046] The carbon flow rate of the heat network load is: R L =diag{ρ L}·H load ; where ρ L is the carbon potential matrix of the heat network load nodes, H load is the heat load matrix;

[0047] The carbon flow rate of the heat network loss is: R BL =diag{ρ N}·H loss ; where ρ N is the carbon potential matrix of the heating network nodes, H loss is the heat loss distribution matrix of the heating network pipelines.

[0048] Furthermore, the energy flow-carbon flow coordinated optimization model of the integrated energy system is expressed as:

[0049]

[0050] stx e ∈X e

[0051] x h ∈X h

[0052] (x e ,x h )∈X couple

[0053]

[0054]

[0055]

[0056] Among them, f1 is the cost objective function of the integrated energy system, f2 is the carbon emission objective function of the integrated energy system; X e , X h and X couple are the variables of power grid, heat network and total; M e 、M h and M total They are carbon emissions from the power system, thermal system and integrated energy system; and They are the carbon emission constraints for the power system, thermal system and integrated energy system respectively.

[0057] Furthermore, the weighted method is used to solve the energy flow-carbon flow coordinated optimization model of the integrated energy system, which includes the following steps:

[0058] The cost objective function f1 of the integrated energy system and the carbon emission objective function f2 of the integrated energy system are respectively optimized and solved as single objectives;

[0059] Standardize the optimization target. is the standardized target value;

[0060] Given the weight coefficients before the cost objective function and the carbon emission objective function, the dual objective is transformed into a single objective function. Perform optimization solution.

[0061] Furthermore, the carbon emission flow analysis method is used to calculate the carbon flow distribution of the integrated energy system, including the following steps:

[0062] Solve the distribution of carbon emission flow in the power grid, including:

[0063] Establish node active flux matrix P N :

[0064] Among them, P B is the branch power flow distribution matrix; P G is the active power output matrix of the unit; η N (i) = [0 0 … 1 … 0], which is an N-dimensional row vector. Except for the i-th element which is 1, all other elements are 0.

[0065] The carbon potential of the grid node is: Solve the carbon emission flow distribution of the heat network, including:

[0066] Establish the node heat flux matrix H N :

[0067] Among them, H P is the pipeline heat energy distribution matrix; H G is the output matrix of the heat source unit; η N (i) = [0 0 … 1 … 0], which is an N-dimensional row vector. Except for the i-th element which is 1, all other elements are 0.

[0068] Carbon potential of heating network nodes:

[0069] On the other hand, the present invention also provides an energy flow and carbon flow distribution system for an integrated energy system, comprising the following modules:

[0070] Energy flow module: The energy flow model of the integrated energy system is constructed with the integrated energy system cost and the integrated energy system carbon emission as the objective function, the integrated energy system network and equipment operation as the constraints, and the integrated energy system carbon emission as the constraints;

[0071] Carbon flow module: Constructs a comprehensive energy system carbon flow model with node carbon potential and carbon flow rate as output values;

[0072] Collaborative optimization model: Combine the energy flow model of the integrated energy system and the carbon flow model of the integrated energy system to build a collaborative optimization model of energy flow and carbon flow of the integrated energy system;

[0073] Weighted method module: Use the weighted method to solve the energy flow-carbon flow coordinated optimization model of the integrated energy system;

[0074] Carbon emission flow analysis module: uses carbon emission flow analysis method to calculate the carbon flow distribution of the integrated energy system.

[0075] In a third aspect, the present invention also provides an energy flow and carbon flow distribution device for an integrated energy system, comprising a storage unit, wherein the storage unit stores an execution program, and the execution program is used to execute any of the above-mentioned methods; or the execution program is used to execute the above-mentioned system.

[0076] Beneficial effects of the present invention:

[0077] The method for calculating the energy flow and carbon flow distribution of an integrated energy system of the present invention takes into account the operating cost and the optimal operating plan for carbon emissions, and calculates the carbon emission flow distribution of the heterogeneous energy flow of the integrated energy system. The proposed method can more intuitively analyze the source, flow direction and distribution of carbon emissions in a multi-energy network, identify network nodes with higher carbon emission intensity, and guide the formulation of low-carbon policies. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] The present invention will be further described below in conjunction with the accompanying drawings.

[0079] Figure 1 It is a structural diagram of the comprehensive energy system of the present invention;

[0080] Figure 2 It is a flow chart of a method for energy flow-carbon flow coordinated optimization and carbon distribution calculation of an integrated energy system based on carbon flow theory of the present invention;

[0081] Figure 3 is a structural diagram of a distribution network of a comprehensive energy system according to Embodiment 2 of the present invention;

[0082] Figure 4 is a heating network structure diagram of a comprehensive energy system according to Embodiment 2 of the present invention;

[0083] Figure 5is the carbon potential of load nodes in different time periods of the integrated energy system distribution network of embodiment 2 of the present invention;

[0084] Figure 6 is the carbon potential of the load nodes of the heat network of the integrated energy system in different time periods of the embodiment 2 of the present invention;

[0085] Figure 7 It is the carbon flow rate of power generation and heat generation of the source node 10 of the integrated energy system of embodiment 2 of the present invention.

[0086] Figure 8 It is the carbon flow rate of load nodes in different time periods of the integrated energy system distribution network of Example 2 of the present invention.

[0087] Fig. 9 It is the carbon flow rate of the load nodes at different time periods of the heat network of the integrated energy system of Example 2 of the present invention. DETAILED DESCRIPTION

[0088] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0089] In the description of the present invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inside", "all around" and the like indicating orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0090] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0091] Example 1

[0092] This embodiment is applied to a comprehensive energy system, and the structure of the comprehensive energy system is as follows: Figure 1 shown.

[0093] A method for energy flow-carbon flow coordinated optimization and carbon distribution calculation of integrated energy system based on carbon flow theory, such as Figure 2 As shown, the following steps are included:

[0094] S1. Establishing energy flow model of integrated energy system:

[0095] S11. Establish the objective function of the comprehensive energy system cost:

[0096] S111, Power purchase cost C grid :

[0097]

[0098] in, are the IES electricity purchase and sales prices at time t; P t buy , P t sell They are the electricity purchased and sold by IES at time t respectively.

[0099] S112. Equipment maintenance cost C m :

[0100]

[0101] Among them, i represents fans, cogeneration units and electric boilers; j represents batteries and heat storage tanks; m i and m j are the maintenance costs of the i-th unit or energy coupling device and the j-th energy storage device respectively; P t,i Output of the i-th unit or energy coupling device at time t; and are the energy charged and released by the j-th energy storage device at time t respectively.

[0102] S113, Equipment operating cost C run :

[0103]

[0104] Among them, a, b, c, d, e, and f are the cost coefficients of CHP unit operation; P t,CHP , H t,CHP They are the electrical output and thermal output of the CHP unit at time t respectively.

[0105] S12. Establish the objective function of carbon emissions of the integrated energy system:

[0106] S121. Carbon emissions from power grids 2e :

[0107]

[0108] Among them, P tCHP is the power generation of the CHP unit at time t; The carbon dioxide emission coefficient of the unit's power generation. Wind turbines are clean energy power generation, with zero carbon dioxide emissions.

[0109] S122, carbon emissions from heating network 2h :

[0110]

[0111] in, is the power and heat production of the CHP unit at time t; The CO2 emission coefficient for heat production of the unit.

[0112] S123, Carbon emissions from electricity purchase and sales by the upper-level power grid 2grid :

[0113]

[0114] Among them, γ grid It is the equivalent carbon dioxide emission coefficient of purchasing and selling electricity to the superior power grid.

[0115] S13. Establish integrated energy system network and equipment operation constraints:

[0116] S131. Establishment of grid tie line capacity constraints:

[0117]

[0118]

[0119] in, is the active power on branch b at time t; Indicates the upper limit of active power flow in branch b; B i Indicates the upper and lower limits of the voltage at node i.

[0120] S132. Establish heat network pipeline constraints:

[0121] Establish heat source power balance constraints:

[0122]

[0123] in, E is the variable of thermal power injected into the thermal network during period t; chp 、E eb It is the index collection of cogeneration units and electric boilers; is the thermal output power variable of CHP unit i during period t; is the thermal output power variable of electric boiler i during period t.

[0124] Establish the power and temperature equations of the heat source and heat load nodes:

[0125]

[0126] in, are the pipeline index sets flowing out / into node k respectively; Φ sn , Φ ln are the index sets of source nodes and load nodes in the heating network respectively; c w is the specific heat capacity of water; m j is the mass flow rate of heat medium in pipeline j; is the heat medium temperature variable at node k in the water supply and return network at time t; is the heat load power variable at node k during period t.

[0127] Establish pipeline transmission delay and heat loss constraints:

[0128]

[0129] Among them, Φ p A collection of heat network pipeline indexes; is the coefficient related to the transmission delay of pipeline j; parameter β j is the insulation coefficient of pipe j; is the pipeline ambient temperature at time t; is the temperature variable of the heat medium at the inlet and outlet of the water supply pipe j at time t; is the heat medium temperature variable at the inlet and outlet of the return pipe j at time t.

[0130] Establish power balance constraints for heating network nodes:

[0131]

[0132] Among them, Φ in is the set of intersection nodes in the heat network; It is the heat medium temperature at node k in the water supply and return network during period t.

[0133] Establish water temperature mixing constraints at heating network nodes:

[0134]

[0135] Among them, Φ in is the set of intersection nodes in the heat network; It is the heat medium temperature at node k in the water supply and return network during period t.

[0136] Establish upper and lower limit constraints for supply and return water temperatures in the heating network:

[0137]

[0138] in, τ s The upper and lower limits of water supply temperature for the heating network; τ r It is the upper and lower limit of the return water temperature of the heating network.

[0139] S133. Establish energy storage / discharge constraints for energy storage devices:

[0140]

[0141] in, and They are 0-1 variables for the charging and discharging flags of the j-th energy storage device at time t; Charge or discharge energy for the j-th energy storage device at time t; and are the maximum values ​​of charging and discharging of the j-th energy storage device at time t; E t,j and E t-1,j are the total energy stored in the j-th energy storage device at time t and time t-1; E min,j / E max,j is the minimum or maximum total energy stored in the jth energy storage device; η ch,j and η dis,j are the charging and discharging efficiencies of the j-th energy storage device respectively.

[0142] S134. Establish renewable energy output constraints:

[0143] 0≤P t wt ≤P t wind

[0144] Among them, P t wind is the predicted output of the wind turbine at time t.

[0145] S135. Establishing coupling equipment operation constraints:

[0146]

[0147] Among them, P max,i is the upper limit of the capacity of the i-th coupling device; ΔR max,i is the climbing power limit of the i-th coupling device; and They are the heat-to-electricity ratio of the CHP unit and the electric-to-heat conversion efficiency of the electric boiler.

[0148] S14. Establish carbon emission constraints for the integrated energy system:

[0149]

[0150] in, Indicates the upper limit of system carbon emissions.

[0151] S2. Establish a carbon flow model for an integrated energy system:

[0152] S21. Establish a carbon flow model for the integrated energy system grid:

[0153] S211, grid node carbon potential is used to indicate the relationship between carbon flow and active power flow at the node. The unit is generally kgCO2 / (kW·h), which is numerically equal to the carbon flow density ρ of all branches injected into node n. i Active current P i is the weighted average of the weights. N The physical meaning of is the carbon emissions on the power generation side caused by consuming unit electricity at this node. The specific calculation formula is:

[0154]

[0155] Where: P s is the active power of branch s; ρ s is the carbon flow density of branch s; P i Ge is the active output of the generator connected to node i (if there is no generator at this node or the generator output is 0, then P i Ge =0); is the carbon potential of the generator set connected to node i.

[0156] S212, branch carbon flow rate R B :

[0157] R B =diag{E N}·P

[0158] Among them, E N is the carbon potential matrix of the power grid nodes, and P is the power flow distribution matrix of the power grid branches.

[0159] S213, unit carbon flow rate R G :

[0160] R G =diag{E G}·P Gen

[0161] Among them, E G is the carbon potential matrix of the grid source node units, P Gen It is the power grid unit output matrix.

[0162] S214, load carbon flow rate R L :

[0163] R L =diag{E L}·P load

[0164] Among them, E L is the carbon potential matrix of the power grid load nodes, P load is the electric load matrix.

[0165] S215, network loss carbon flow rate R BL :

[0166] R BL =diag{E N}·P loss

[0167] Among them, E N is the carbon potential matrix of the power grid nodes, P loss is the power grid branch loss distribution matrix.

[0168] S22. Establish a carbon flow model for the heat network of an integrated energy system:

[0169] S221. Carbon potential of heating network node is used to express the relationship between carbon flow and thermal energy flow at heating network node. The unit is generally kgCO2 / (kW·h). The value is equal to the carbon flow density ρ of all pipelines injected into node n. k Heat energy H k is the weighted average of the weights, and its physical meaning is the carbon emissions on the heat source side caused by consuming unit heat at this node. The specific calculation formula is:

[0170]

[0171] in, represents the node carbon potential of heating network node n, kgCO2 / kWh; is the node carbon flow rate of heating network node n, kgCO2 / h; c is the specific heat capacity of water, kJ / (kg·℃); m n is the mass flow rate injected into node n, kg; T n is the temperature of node n, °C; is the carbon flow density of the pipeline injected into node n, kgCO2 / kWh; m k is the mass flow rate of pipeline k injected into node n, kg; T n is the temperature of node n, °C; is the outlet temperature of pipe k injecting into node n, °C; is the temperature loss of pipe k injected into node n, °C; is the unit carbon potential of unit i, kgCO2 / kWh; is the heat output of heat generating unit i, kWh; Ω N It is a collection of heating network nodes.

[0172] S222, pipeline carbon flow rate R p :

[0173] R P =diag{ρ N}·H

[0174] Among them, ρ N is the carbon potential matrix of the heating network nodes, and H is the heat network pipeline flow matrix.

[0175] S223, unit carbon flow rate R G :

[0176] R G =diag{ρ G}·H Gen

[0177] Among them, ρ G is the carbon potential matrix of the heat network source node units, H Gen It is the output matrix of heating network units.

[0178] S224, load carbon flow rate R L :

[0179] R L =diag{ρ L}·H load

[0180] Among them, ρ L is the carbon potential matrix of the heat network load nodes, H load is the heat load matrix.

[0181] S225, network loss carbon flow rate R BL :

[0182] R BL =diag{ρ N}·H loss

[0183] Among them, ρ N is the carbon potential matrix of the heating network nodes, H loss is the heat loss distribution matrix of the heating network pipelines.

[0184] S3. Based on the carbon emission flow theory, a coordinated optimization model of energy flow and carbon flow in the integrated energy system is established. Its mathematical form is as follows:

[0185]

[0186] stx e ∈Xe

[0187] x h ∈X h

[0188] (x e ,x h )∈X couple

[0189]

[0190]

[0191]

[0192] Among them, f1 is the cost objective function of the integrated energy system, f2 is the carbon emission objective function of the integrated energy system; X e , X h and X couple are the variables of power grid, heat network and total; M e 、M h and M total They are carbon emissions from the power system, thermal system and integrated energy system; and They are the carbon emission constraints for the power system, thermal system and integrated energy system respectively.

[0193] S4. Solve the model using the weighted method:

[0194] S41, performing single-objective optimization solutions for the integrated energy system cost objective function f1 and the integrated energy system carbon emission objective function f2 respectively;

[0195] S42, standardize the optimization target, is the standardized target value;

[0196] S43, given the weight coefficients before the cost objective function and the carbon emission objective function, the dual objective is transformed into a single objective function Perform optimization solution.

[0197] S5. Calculate the network carbon flow distribution using the carbon emission flow analysis method:

[0198] S51. Solve the distribution of carbon emission flow in the power grid:

[0199] S511, establish node active flux matrix P N :

[0200]

[0201] Among them, P B is the branch power flow distribution matrix; PG is the active power output matrix of the unit; η N (i) = [0 0 … 1 … 0], which is an N-dimensional row vector. Except for the i-th element which is 1, all other elements are 0.

[0202] S512, grid node carbon potential E N :

[0203]

[0204] S52. Solve the carbon emission flow distribution of the heat network.

[0205] S521. Establish node heat flux matrix H N :

[0206]

[0207] Among them, H P is the pipeline heat energy distribution matrix; H G is the output matrix of the heat source unit; η N (i) = [0 0 … 1 … 0], which is an N-dimensional row vector. Except for the i-th element which is 1, all other elements are 0.

[0208] S522, carbon potential of heating network nodes ρ N :

[0209]

[0210] Example 2

[0211] The multi-energy flow system of this embodiment consists of a 33-node power distribution system and a 51-node heating system. Figure 3 As shown in the figure, the system includes a 4MW cogeneration unit, a 2MW electric boiler, and four fans with a rated power of 1MW. The optimization period is 24h, the scheduling time interval is 1h, the upper and lower limits of the indoor temperature of the building are set to 27℃ and 17℃ respectively, and the weights before the cost objective function and the carbon emission objective function in the weighted method are set to 0.5 and 0.5 respectively.

[0212] According to the steps of the present invention, the economic low-carbon collaborative optimization of the integrated energy system is carried out. When the integrated energy system is running, the carbon potential of the load nodes in different periods is as follows: Figure 4 As shown, the carbon flow rate of power generation and heat generation at the source node 10 of the integrated energy system is as follows: Figure 5 As shown in the figure, the carbon flow rate of load nodes in the integrated energy system at different times is as follows: Figure 6As shown in the figure, it can be seen that there are obvious differences in carbon potential and carbon flow rate at different nodes in the integrated energy system. The proposed method can more intuitively analyze the source, flow direction and distribution of carbon emissions in the multi-energy network, identify network nodes with higher carbon emission intensity, and guide the formulation of low-carbon policies.

[0213] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for calculating energy flow and carbon flow distribution of a comprehensive energy system, characterized in that: The following steps are involved: An energy flow model of the integrated energy system is constructed with the integrated energy system cost and the integrated energy system carbon emission as the objective function, the integrated energy system network and equipment operation as the constraint and the integrated energy system carbon emission as the constraint; a carbon flow model of the integrated energy system is constructed with the node carbon potential and carbon flow rate as the output value; Combine the energy flow model of the integrated energy system and the carbon flow model of the integrated energy system to construct the energy flow-carbon flow collaborative optimization model of the integrated energy system; use the weighted method to solve the energy flow-carbon flow collaborative optimization model of the integrated energy system; use the carbon emission flow analysis method to calculate the carbon flow distribution of the integrated energy system; The constraints on the operation of the integrated energy system network and equipment include the capacity constraints of the grid interconnection lines, the constraints of the heat network pipelines, the storage / discharge constraints of the energy storage devices, the output constraints of renewable energy sources, and the operation constraints of the established coupling equipment; The capacity constraint of the grid tie line is: in, represents the active power flow on branch b at time t; Indicates the upper limit of active power flow in branch b; V i Indicates the upper and lower limits of the voltage of node i; The heat network pipeline constraints include heat source power balance constraints, power and temperature equations of heat source and heat load nodes, pipeline transmission delay and heat loss constraints, heat network node power balance constraints, heat network node water temperature mixing constraints, and heat network supply and return water temperature upper and lower limit constraints; The heat source power balance constraint is: in, E is the variable of thermal power injected into the thermal network during period t; chp 、E eb It is the index collection of cogeneration units and electric boilers; is the thermal output power variable of CHP unit i during period t; is the heat output power variable of electric boiler i during period t; The power and temperature equations for the heat source and heat load nodes are: in, are the pipeline index sets flowing out / into node k respectively; Φ sn , Φ ln are the index sets of source nodes and load nodes in the heating network respectively; c w is the specific heat capacity of water; m j is the mass flow rate of heat medium in pipeline j; is the heat medium temperature variable at node k in the water supply and return network at time t; is the heat load power variable at node k during period t; The pipeline transmission delay and heat loss constraints are: Among them, Φ p A collection of heat network pipeline indexes; is the coefficient related to the transmission delay of pipeline j; parameter β j is the insulation coefficient of pipe j; is the pipeline ambient temperature at time t; is the temperature variable of the heat medium at the inlet and outlet of the water supply pipe j at time t; is the heat medium temperature variable at the inlet and outlet of the return pipe j at time t; The power balance constraint of the heating network node is: Among them, Φ in is the set of intersection nodes in the heat network; is the heat medium temperature at node k in the water supply and return network during period t; The water temperature mixing constraint of the heating network node is: Among them, Φ in is the set of intersection nodes in the heat network; is the heat medium temperature at node k in the water supply and return network during period t; The upper and lower limits of the supply and return water temperature of the heating network are: in, τ s The upper and lower limits of water supply temperature for the heating network; τ r The upper and lower limits of the return water temperature of the heating network; The energy storage / discharge constraints of the energy storage device are: in, It is a variable of 0-1 indicating the charging and discharging flag of the j-th energy storage device at time t; Charge or discharge energy for the j-th energy storage device at time t; is the maximum value of charging and discharging of the j-th energy storage device at time t; E t,j ,E t-1,j is the total energy stored in the j-th energy storage device at time t and time t-1; E min,j / E max,j is the minimum or maximum total energy stored in the jth energy storage device; η ch,j / η dis,j The efficiency of charging or discharging the j-th energy storage device; The renewable energy output constraint is: 0≤P t wt ≤P t wind Among them, P t wind is the predicted output of the wind turbine at time t; The coupled equipment operating constraints are: Among them, P max,i is the upper limit of the capacity of the i-th coupling device; ΔR max,i is the climbing power limit of the i-th coupling device; and They are the heat-to-electricity ratio of the CHP unit and the electric-to-heat conversion efficiency of the electric boiler.

2. The method for calculating energy flow and carbon flow distribution of an integrated energy system according to claim 1, characterized in that: The carbon flow model of the integrated energy system includes the carbon flow model of the power grid of the integrated energy system and the carbon flow model of the heat network of the integrated energy system.

3. The method for calculating energy flow and carbon flow distribution of an integrated energy system according to claim 2, characterized in that: The carbon flow model of the integrated energy system power grid includes the carbon potential of the grid nodes, the carbon flow rate of the grid branches, the carbon flow rate of the grid units, the carbon flow rate of the grid loads and the carbon flow rate of the grid losses. The carbon potential of the power grid node is used to express the relationship between the carbon flow and the active power flow at the node. The carbon potential of the power grid node is expressed as: Where P s is the active power of branch s; ρ s is the carbon flow density of branch s; P i Ge is the active output of the generator connected to node i; is the carbon potential of the generator set connected to node i; The carbon flow rate of the power grid branch is: R B =diag{E N }·P; where E N is the carbon potential matrix of the power grid nodes, and P is the power flow distribution matrix of the power grid branches; The carbon flow rate of the power grid unit is: R G =diag{E G }·P Gen ; Among them, E G is the carbon potential matrix of the grid source node units, P Gen It is the power grid unit output matrix; The carbon flow rate of the grid load is: R L =diag{E L }·P load ; Among them, E L is the carbon potential matrix of the power grid load nodes, P load is the electric load matrix; The grid loss carbon flow rate is: R BL =diag{E N }·P loss ; Among them, E N is the carbon potential matrix of the power grid nodes, P loss is the power grid branch loss distribution matrix.

4. The method for calculating energy flow and carbon flow distribution of an integrated energy system according to claim 1, characterized in that: The carbon flow model of the heat network of the comprehensive energy system includes the carbon potential of the heat network nodes, the carbon flow rate of the heat network pipelines, the carbon flow rate of the heat network units, the carbon flow rate of the heat network loads and the carbon flow rate of the heat network losses. The carbon potential of the heating network node is used to express the relationship between the carbon flow and the thermal energy flow at the heating network node. The carbon potential expression of the heating network node is: in, represents the node carbon potential of heating network node n, kgCO2 / kWh; is the node carbon flow rate of heating network node n, kgCO2 / h; c is the specific heat capacity of water, kJ / (kg·℃); m n is the mass flow rate injected into node n, kg; T n is the temperature of node n, °C; is the carbon flow density of the pipeline injected into node n, kgCO2 / kWh; m k is the mass flow rate of pipeline k injected into node n, kg; T n is the temperature of node n, °C; is the outlet temperature of pipe k injecting into node n, °C; is the temperature loss of pipe k injected into node n, °C; is the unit carbon potential of unit i, kgCO2 / kWh; is the heat output of heat generating unit i, kWh; Ω N is the set of nodes in the heating network; The carbon flow rate of the heat network pipeline is: R P =diag{ρ N }·H; where ρ N is the carbon potential matrix of the heating network nodes, and H is the flow matrix of the heating network pipelines; The carbon flow rate of the heating network unit is: R G =diag{ρ G }·H Gen ; where ρ G is the carbon potential matrix of the heat network source node units, H Gen It is the output matrix of the heating network units; The carbon flow rate of the heat network load is: R L =diag{ρ L }·H load ; where ρ L is the carbon potential matrix of the heat network load nodes, H load is the heat load matrix; The carbon flow rate of the heat network loss is: R BL =diag{ρ N }·H loss ; where ρ N is the carbon potential matrix of the heating network nodes, H loss is the heat loss distribution matrix of the heating network pipelines.

5. The method for calculating energy flow and carbon flow distribution of a comprehensive energy system according to claim 1, characterized in that: The expression of the energy flow-carbon flow coordinated optimization model of the integrated energy system is: s.t.x e ∈X e x h ∈X h (x e ,x h )∈X couple Among them, f1 is the cost objective function of the integrated energy system, f2 is the carbon emission objective function of the integrated energy system; X e , X h and X couple are the variables of power grid, heat network and total; M e 、M h and M total They are carbon emissions from the power system, thermal system and integrated energy system; and They are the carbon emission constraints for the power system, thermal system and integrated energy system respectively.

6. The method for calculating energy flow and carbon flow distribution of an integrated energy system according to claim 1, characterized in that ,The weighted method is used to solve the energy flow and carbon flow ,coordinated optimization model of the integrated energy system includes the following steps: The cost objective function f1 of the integrated energy system and the carbon emission objective function f2 of the integrated energy system are respectively optimized and solved as single objectives; Standardize the optimization target. is the standardized target value; Given the weight coefficients before the cost objective function and the carbon emission objective function, the dual objective is transformed into a single objective function. Perform optimization solution.

7. The method for calculating energy flow and carbon flow distribution of an integrated energy system according to claim 1, characterized in that ,The calculation of the carbon flow distribution of the ,integrated energy system using the carbon emission flow analysis ,method includes the following steps: ,Solving the carbon emission flow distribution of the power grid, ,includes: Establish node active flux matrix P N : Among them, P B is the branch power flow distribution matrix; P G is the active power output matrix of the unit; η N (i) = [0 0 … 1 … 0], which is an N-dimensional row vector. Except for the i-th element which is 1, all other elements are 0. The carbon potential of the grid node is: Solve the carbon emission flow distribution of the heat network, including: Establish the node heat flux matrix H N : Among them, H P is the pipeline heat energy distribution matrix; H G is the output matrix of the heat source unit; η N (i) = [0 0 … 1 … 0], which is an N-dimensional row vector. Except for the i-th element which is 1, all other elements are 0. Carbon potential of heating network nodes:

8. An integrated energy system energy flow and carbon flow distribution system, characterized in that , including the following modules: Energy flow module: The energy flow model of the integrated energy system is constructed with the integrated energy system cost and the integrated energy system carbon emissions as the objective function, the integrated energy system network and equipment operation as the constraints, and the integrated energy system carbon emissions as the constraints; Carbon flow module: Constructs a comprehensive energy system carbon flow model with node carbon potential and carbon flow rate as output values; Collaborative optimization model: Combine the energy flow model of the integrated energy system and the carbon flow model of the integrated energy system to build a collaborative optimization model of energy flow and carbon flow of the integrated energy system; Weighted method module: Use the weighted method to solve the energy flow-carbon flow coordinated optimization model of the integrated energy system; Carbon emission flow analysis module: uses carbon emission flow analysis method to calculate the carbon flow distribution of the integrated energy system.

9. An energy flow and carbon flow distribution device for an integrated energy system, characterized in that: It comprises a storage unit, the storage unit stores an execution program, the execution program is used to execute any one of the methods described in claims 1-7; or the execution program is used to execute the system of claim 8.

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