A carbon flow analysis and calculation method based on all factors under uncertain power grid flow

Abstract

This invention discloses a method for carbon flow analysis and calculation based on all elements of a power grid under uncertain power flow. First, it calculates the interval values ​​of branch power flow and node load in the power grid using interval-affine techniques. Then, based on downstream and upstream tracking methods, it constructs a power flow distribution matrix to accurately allocate generator power to each node load, branch power, and network loss. Finally, utilizing the "electricity-carbon" coupling relationship, it establishes a carbon emission responsibility allocation model to derive the interval values ​​of carbon emissions in the power system, achieving fair and reasonable allocation of carbon emissions and completing the research and analysis of the carbon footprint of all elements of the power grid. Therefore, this invention solves the problems of uneven carbon flow allocation under uncertain power flow in new power systems and inaccurate assessment of the carbon reduction contribution of new energy units. It can be used to explore the potential for carbon emission reduction in the power sector, guide interactive carbon reduction among power users, accurately guide power grid operation, improve power grid safety and reliability, reduce carbon emissions, and enhance the economic efficiency of the power grid.

Description

Technical Field

[0001] This invention relates to the field of low-carbon power development technology, and in particular to a method for carbon flow analysis and calculation considering all elements under uncertain power flow in the power grid. Background Technology

[0003] Due to the volatility and intermittency of new energy power generation, carbon emissions from the power system fluctuate. Developing an effective and comprehensive method for measuring and analyzing carbon emission flows in the power system would deepen our understanding of power system carbon emissions, allow us to analyze carbon emissions and carbon flow patterns at nodes and branches of complex power supply and consumption networks, and identify the distribution of "high-carbon elements" (nodes with high carbon potential and lines with high carbon flow rates). This would enable targeted optimization measures and provide technical support for addressing key issues hindering the development of low-carbon smart grids in my country, such as exploring collaborative low-carbon development models and new green certificate purchase models.

[0004] A search revealed Chinese patent CN107769192A, which discloses a method for calculating carbon flow in nodes / branches of a power system's power supply and distribution network. This method proposes a technical solution for quantitatively determining the flow state of carbon flow based on power flow distribution, thus achieving carbon flow analysis. However, it does not consider the allocation of carbon emission responsibility. A fairer and more effective allocation of carbon responsibility across all elements of the power grid would be beneficial for accurately guiding grid operation, reducing carbon emissions, and improving the safety, reliability, and economy of the power grid.

[0005] Chinese patent CN117455104A discloses a method for carbon flow analysis and calculation based on all elements of a power grid. It proposes a scheme that can use carbon flow analysis of all elements of the power grid to obtain the carbon footprint of each node and user, and to generate a carbon footprint distribution map.

[0006] However, the concept of carbon reduction and emission control has gained international acceptance, and an international carbon emission accounting system covering multiple levels, including national, city, and enterprise levels, has been initially established. Accurate carbon measurement of carbon emissions across all stages of the power system has also become one of the key scientific issues for the power system in the context of low-carbon development.

[0007] The carbon footprint is increasing year by year, which puts pressure on and challenges to achieving low-carbon and green development goals. Therefore, accurate and comprehensive carbon measurement and analysis methods for the power system are urgently needed to quantify electricity-related carbon emission data, clarify the current status of carbon emissions in the power industry, explore the carbon reduction potential of the entire power system, and guide electricity users to participate in carbon reduction. Summary of the Invention

[0008] The purpose of this invention is to delve into the carbon emissions situation in the existing power grid system, track carbon flows, and study a fairer and more effective way to share carbon responsibility between the generation side and the load side. Therefore, it proposes a carbon flow analysis and calculation method that considers all elements under uncertain power flow in the power grid.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A method for carbon flow analysis and calculation based on all elements under uncertain power flow in a power grid includes the following steps:

[0011] (1) Based on the interval-affine power flow calculation method, solve the interval distribution of node voltage and power flow of each branch in the new energy power system, and obtain the affine values ​​and upper and lower limits of node voltage amplitude and active and reactive power of each branch.

[0012] (2) Based on the calculated power flow results, the power flow tracing method is used to construct a power flow distribution matrix to reasonably allocate the power, and the branch power, network loss power and node load are allocated to the generator side respectively.

[0013] (3) Based on the power flow distribution results of the entire network, the electricity-carbon coupling relationship is constructed, and carbon emissions are reasonably distributed to both the source and load sides, including new energy sources. The carbon flow distribution of all elements of the power grid is calculated to obtain the carbon footprint of each user, and carbon footprint monitoring at all voltage levels is realized.

[0014] Furthermore, in step (1), power flow calculations are performed based on affine intervals to solve for the interval values ​​of node voltages and branch power flows, specifically including the following steps:

[0015] S101: Set conditions before calculation:

[0016] The injected power at each node is independent of each other;

[0017] The network status of each node is determined: that is, random line faults are not considered, only random disturbances in node power are considered;

[0018] S102: Constrained power flow model based on affine interval uncertainty: The uncertainty of parameters in the power system is expressed in the form of intervals, and the situations of reactive power and voltage exceeding limits are considered. Complementary conditions are introduced to establish a nonlinear programming model based on power flow equations.

[0019] S103: Solving the nonlinear programming model obtained from S102: Applying the extreme value theory of intervals, this uncertain optimization problem is transformed into two deterministic sub-optimization problems of the same type for solving, respectively obtaining the upper and lower bounds of the carbon emissions of the power system. The specific steps are as follows:

[0020]

[0021] In formula (1): Represents an interval variable. In the formula, x0 is The central value of an affine polynomial; x i for The noise coefficient of the i-th term of the affine polynomial; ε i for The i-th noise element of the affine polynomial takes a value in [-1, 1].

[0022]

[0023] In formula (2) and x , , represent the upper and lower limits of the variable, respectively.

[0024] Furthermore, in step (2), the power distribution matrix is ​​constructed based on the power flow tracing method to reasonably distribute the power, specifically as follows:

[0025] First, define the power flow distribution matrix A. u , (A u ∈R n×n ):

[0026]

[0027] In formula (14): (A u ) ji Let matrix A u The element in the j-th row and i-th column. Further, this can be achieved through the power flow distribution matrix A. u Establish the generator power P G The relationship between the node power P and the node current:

[0028] A u P = P G (15)

[0029] In equation (15), P = [P1, P2, ..., P n ] T This is a vector formed by the power flowing through each node;

[0030] The power is then distributed proportionally. The load P at node k... Lk This can be expressed as the sum of the contributions of each generator:

[0031]

[0032] In equation (16) e k ∈R n×1 P is a column vector where the i-th component is 1 and the rest are 0; k Let be the power flowing through node k;

[0033] Then the power component P of the load at node k distributed from the generator at node i Lk,Gi Represented as:

[0034]

[0035] In equation (17) e i ∈R n×1 Let be a column vector where the i-th component is 1 and the rest are 0; similarly, the apportionment formulas for branch and network loss are given:

[0036]

[0037] Equations (18) and (19) are the power calculation equations for the branch power allocated from the generator side, where P kj This represents the power flowing from node k to node j on branch kj.

[0038]

[0039] Equations (20) and (21) are the equations for calculating the share of network losses in generator power, where This represents the power loss that occurs when power flows from node k to node j on branch kj.

[0040] Furthermore, in step (3), from the multi-angle carbon footprint tracking perspective of load carbon flow rate, branch carbon flow rate, network loss carbon flow rate, branch carbon flow density, and node carbon potential, the carbon flow analysis of all elements of the power grid is calculated to obtain the carbon footprint of each user. The specific steps are as follows:

[0041] a. Characteristic equation for the carbon flow rate under load:

[0042]

[0043] In equation (22): R Lk The carbon flow rate of the load at node k represents the equivalent carbon dioxide emissions generated per hour by the load on the generation side, expressed in units of... diag(P G ) indicates that column vector P G Transform into a diagonal matrix; E G This is a vector representing the carbon emission intensity of the generating unit.

[0044] Further, the carbon flow rate component R of unit i allocated to the load at node k is obtained. Lk,Gi for:

[0045] R Lk,Gi =P Lk,Gi E Gi (twenty three)

[0046] b. Characteristic equation for the carbon flow rate of the branch:

[0047]

[0048] In equation (24), R kj The carbon flow rate corresponding to the power flowing through branch kj is represented by R, which is further connected to the generator at node i and allocated to the carbon flow rate in branch kj. kj,Gi It is represented as:

[0049] R kj,Gi =P kj,Gi E Gi (25)

[0050] c. Characteristic equation for carbon flow rate at network loss:

[0051]

[0052] In equation (26) This represents the carbon flow rate corresponding to the power loss of branch kj, and further connects to the carbon flow rate allocation of the generator at node i on the power loss of branch kj. It is represented as:

[0053]

[0054] d. Characteristic equation for branch carbon flux density:

[0055]

[0056] In equation (28) ρ kj Branch carbon flux density represents the equivalent carbon emissions on the generation side per unit of electrical energy transmitted in a branch, expressed in units of...

[0057] e. The carbon potential of a node is the ratio of the sum of the carbon flow rates of the branches flowing into the node to the power flowing through that node. Its characteristic equation is:

[0058]

[0059] Equation (29)E Nj Let be the carbon potential of node j, representing the equivalent carbon emissions generated on the power generation side per unit of electrical energy consumed by the node, in units of .

[0060] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0061] 1. Considering the fluctuations and uncertainties in carbon emissions in the power system under the access of new energy units, how to handle them.

[0062] 2. By reasonably allocating the responsibility for carbon emissions, the problem of uneven carbon flow distribution under uncertain power flow conditions in the new power system has been solved.

[0063] 3. Based on the analysis of carbon flow of all elements of the power grid, the allocation of carbon emission rights to users is carried out, which makes the assessment of the carbon reduction contribution of new energy units more accurate. Attached Figure Description

[0064] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0065] Figure 1 This is a flowchart of power flow calculation based on interval-affine calculation in an embodiment of the present invention;

[0066] Figure 2 This is a flowchart illustrating the calculation of the power grid carbon footprint based on power flow results in an embodiment of the present invention. Detailed Implementation

[0067] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0068] Reference Figure 1-2 A method for analyzing and calculating carbon flow based on all elements under uncertain power flow in a power grid includes the following steps:

[0069] (1) Based on the interval-affine power flow calculation method, the interval distribution of node voltage and power flow of each branch in the new energy power system is solved, and the affine values ​​and upper and lower limits of the node voltage amplitude and the active and reactive power of each branch are obtained.

[0070] (2) Based on the calculated power flow results, the power flow tracing method is used to construct a power flow distribution matrix to reasonably allocate the power, and the branch power, network loss power and node load are allocated to the generator side respectively.

[0071] (3) Based on the power flow distribution results across the entire network, an "electricity-carbon" coupling relationship is constructed to reasonably distribute carbon emissions to both the source and load sides, including new energy sources. The carbon footprint of each user is obtained by calculating the carbon flow distribution of all elements of the power grid. Carbon footprint monitoring is achieved across all voltage levels.

[0072] In a specific embodiment of this application, step (1) involves power flow calculation based on affine intervals to solve for the interval values ​​of node voltages and branch power flows, specifically including the following steps:

[0073] Based on the affine algorithm model, this uncertain optimization problem is transformed into two deterministic sub-optimization problems of the same type for solution:

[0074]

[0075] In formula (1): Represents an interval variable. In the formula, x0 is The central value of an affine polynomial; x i for The noise coefficient of the i-th term of the affine polynomial; ε i for The i-th noise element of the affine polynomial takes a value in [-1, 1].

[0076]

[0077] In formula (2) and x , , represent the upper and lower limits of the variable, respectively.

[0078] In a specific embodiment of this application, the method for obtaining the interval values ​​of node voltage amplitude and active and reactive power of each branch based on interval-affine power flow calculation in step (1) is as follows:

[0079] 11) Given the system network structure and parameters, construct an affine model of the output and load power variations of each distributed generation (DG). Since the uncertainty of load is much greater than the uncertainty of system structure in actual power systems, the case where node power is uncertain is generally studied, represented by intervals. Its affine expansion is as follows:

[0080]

[0081] In formula (3) and Let Ω be the noise element representing the active power of node i and the reactive power of node j, respectively, and let Ω be the number of intervals in the range [-1, 1]. n Ω represents the set of nodes after removing the balancing nodes, where the index n represents the total number of nodes remaining after removing the balancing nodes. r Let r be the set of PQ nodes, where the index r is the number of PQ nodes.

[0082] Further constructing the power flow balance equations for the power system intervals yields:

[0083]

[0084] In equation (4), SP represents a specified value; the superscript ^ of each quantity represents an affine number, used to distinguish it from a fixed value.

[0085]

[0086] In equation (5), where, and The result of the power flow calculation in the k-th iteration is the affine number; θ (k) , Δ P , V (k) , Δ Q ε represents the upper and lower limits of the power flow interval result at the k-th iteration, respectively, and is a point value. θi and ε Vj These are the phase angle noise element of node i and the voltage amplitude noise element of node j, respectively.

[0087] The type of each node is further retrieved, the node type is determined, PQ node is defined as 1, PV node is defined as 2, and balanced node is defined as 3. The power flow iterative calculation is performed according to the different node types.

[0088] 12) Solve using the Newton-Raphson method to obtain the voltage amplitude at each node. and angle The affine number has the following characteristic equation:

[0089]

[0090] In the formula: Let be the affine numbers of the active and reactive power of the generator at access node i, respectively; These are the affine numbers of active and reactive loads of access node i, respectively; G ij B ij These are the negative values ​​of the conductance and susceptance of branch ij, respectively; These are the voltage amplitudes at nodes i and j, respectively. Let be the voltage angle difference between node i and node j, i.e. in and are the voltage angles at nodes i and j, respectively.

[0091] Based on the power flow calculation results above, the formulas for calculating the active power and loss of each branch are as follows:

[0092]

[0093] In the formula: Let be the active power flowing through branch ij, with its positive direction being from node i to node j; Let be the active power loss of branch ij.

[0094] Then, based on the calculation criteria of affine-interval power flow iteration, the interval is converged, specifically as follows:

[0095]

[0096] Equation (11) considers the correlation of the same noise element and takes the difference of the affine numbers of the interval results of voltage amplitude and phase angle. wid represents the interval width of the affine number. When the infinite norm of the difference width of the affine numbers of the two consecutive interval results is less than a small value, it is considered to be converged.

[0097] In summary, step (1) is completed to obtain the node voltage and the interval distribution of power flow in each branch of the new energy power system.

[0098] In a specific embodiment of this application, step (2) involves constructing a power flow distribution matrix to reasonably allocate power, specifically as follows:

[0099] Carbon emissions from power systems primarily originate from the exhaust gases produced by burning fossil fuels in power generation, and are generally expressed using the carbon emission intensity index. Carbon emission intensity is the amount of carbon dioxide emitted per unit of electricity produced by a generating unit, measured in units of... For hydroelectric power units, and other new energy units such as wind power and solar power, the carbon emissions are essentially zero. Therefore, considering the current operating status and real-time power output of thermal power units, the formula for calculating the coal consumption per kilowatt-hour for coal-fired units is:

[0100]

[0101] In equation (12): a i b i c i These are the characteristic parameters of the unit i's coal consumption per unit of electricity under normal operating conditions. i The coal consumption per kilowatt-hour for unit i is g / (kW·h); ζ i This is a correction factor, and its value depends on the unit's operating state. Under normal conditions, ζ i Take 1.0, in the shutdown state, ζ i When ζ is set to 0, during deep peak shaving and rapid load increases / decreases, i Take 1.01.

[0102] Then define the carbon emission intensity E of coal-fired power units. Gi Its characteristic equation is:

[0103]

[0104] In formula (13) M is the molar mass of carbon dioxide, taken as 44 g / mol; C η is the molar mass of carbon, taken as 12 g / mol; i Let ξ be the carbon content of the coal used in unit i. i The carbon oxidation rate of coal burned in unit i is taken as 98%; μ iThe carbon capture rate depends on the technical performance of the carbon capture devices installed in the power plant.

[0105] The carbon emission responsibility will then be allocated, starting with power allocation. The power flow distribution matrix A is defined. u , (A u ∈R n×n ):

[0106]

[0107] In formula (14): (A u ) ji Let matrix A u The element in the j-th row and i-th column. Further, this can be achieved through the power flow distribution matrix A. u Establish the generator power P G The relationship between the node power P and the node current:

[0108] A u P = P G (15)

[0109] In equation (15), P = [P1, P2, ..., P n ] T It is a vector representing the power flowing through each node.

[0110] The power is then distributed proportionally. The load P at node k... Lk This can be expressed as the sum of the contributions of each generator:

[0111]

[0112] In equation (16) e k ∈R n×1 P is a column vector where the k-th component is 1 and the rest are 0; k Let P be the power flowing through node k. Then, the power component P of the load at node k allocated from the generator at node i is... Lk,Gi It can be represented as:

[0113]

[0114] In equation (17) e i ∈R n×1 Let be a column vector where the i-th component is 1 and the rest are 0; similarly, the apportionment formulas for branch and network loss are given:

[0115]

[0116] Equations (18) and (19) are the power calculation equations for the branch power allocated from the generator side, where P kj This represents the power flowing from node k to node j on branch kj.

[0117]

[0118] Equations (20) and (21) are the equations for calculating the share of network losses in generator power, where This represents the power loss that occurs when power flows from node k to node j on branch kj.

[0119] In a specific embodiment of this application, step (3) considers a comprehensive analysis of the carbon flow of the power grid to obtain the carbon footprint of each user, thereby achieving carbon footprint monitoring. This is manifested as a multi-angle carbon footprint tracking perspective, considering load carbon flow rate, branch carbon flow rate, network loss carbon flow rate, branch carbon flow density, and node carbon potential. Specifically:

[0120] a. Characteristic equation for the carbon flow rate under load:

[0121]

[0122] In equation (22): R Lk The carbon flow rate of the load at node k represents the equivalent carbon dioxide emissions generated per hour by the load on the generation side, expressed in units of... diag(P G ) indicates that column vector P G Transform into a diagonal matrix; E G This is a vector representing the carbon emission intensity of the generating units. Further, the carbon flow rate component R of unit i allocated to the load at node k is obtained. Lk,Gi for:

[0123] R Lk,Gi =P Lk,Gi E Gi (twenty three)

[0124] b. Characteristic equation for the carbon flow rate of the branch:

[0125]

[0126] In equation (24), R kj The carbon flow rate corresponding to the power flowing through branch kj is represented by R, which is further connected to the generator at node i and allocated to the carbon flow rate in branch kj. kj,Gi It is represented as:

[0127] R kj,Gi =P kj,Gi E Gi (25)

[0128] c. Characteristic equation for carbon flow rate at network loss:

[0129]

[0130] In equation (26) This represents the carbon flow rate corresponding to the power loss of branch kj, and further connects to the carbon flow rate allocation of the generator at node i on the power loss of branch kj. It can be represented as:

[0131]

[0132] d. Characteristic equation for branch carbon flux density:

[0133]

[0134] In equation (28) ρ kj Branch carbon flux density represents the equivalent carbon emissions on the generation side per unit of electrical energy transmitted in a branch, expressed in units of...

[0135] e. The carbon potential of a node is the ratio of the sum of the carbon flow rates of the branches flowing into the node to the power flowing through that node. Its characteristic equation is:

[0136]

[0137] Equation (29)E Nj Let be the carbon potential of node j, representing the equivalent carbon emissions generated on the power generation side per unit of electrical energy consumed by the node, in units of .

[0138] Finally, the distribution of carbon flow across all elements of the power grid was calculated, yielding the carbon footprint of each node and user. A carbon footprint distribution map was then generated.

[0139] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for carbon flow analysis and calculation based on all elements under uncertain power flow in a power grid, characterized in that, Includes the following steps: (1) Based on the interval-affine power flow calculation method, solve the interval distribution of node voltage and power flow of each branch in the new energy power system, and obtain the affine values ​​and upper and lower limits of node voltage amplitude and active and reactive power of each branch. (2) Based on the calculated power flow results, the power flow tracing method is used to construct a power flow distribution matrix to reasonably allocate the power, and the branch power, network loss power and node load are allocated to the generator side respectively. (3) Based on the power flow distribution results of the entire network, the electricity-carbon coupling relationship is constructed, and carbon emissions are reasonably distributed to both the source and load sides, including new energy sources. The carbon flow distribution of all elements of the power grid is calculated to obtain the carbon footprint of each user, and carbon footprint monitoring at all voltage levels is realized.

2. The carbon flow analysis and calculation method based on all elements under uncertain power flow in a power grid as described in claim 1, characterized in that, In step (1), power flow calculations are performed based on affine intervals to solve for the interval values ​​of node voltages and branch power flow. Specifically, the following steps are included: S101: Set conditions before calculation: The injected power at each node is independent of each other; The network status of each node is determined: that is, random line faults are not considered, only random disturbances in node power are considered; S102: Constrained power flow model based on affine interval uncertainty: The uncertainty of parameters in the power system is expressed in the form of intervals, and the situations of reactive power and voltage exceeding limits are considered. Complementary conditions are introduced to establish a nonlinear programming model based on power flow equations. S103: Solving the nonlinear programming model obtained from S102: Applying the extreme value theory of intervals, this uncertain optimization problem is transformed into two deterministic sub-optimization problems of the same type for solving, respectively obtaining the upper and lower bounds of the carbon emissions of the power system. The specific steps are as follows: In formula (1): Represents an interval variable. In the formula, x0 is The central value of an affine polynomial; x i for The noise coefficient of the i-th term of the affine polynomial; ε i for The i-th noise element of the affine polynomial takes values ​​in [-1, 1]: In formula (2) and x , , represent the upper and lower limits of the variable, respectively.

3. The carbon flow analysis and calculation method based on all elements under uncertain power flow in a power grid, as described in claim 2, is characterized in that... In step (2), the power flow tracing method is used to construct a power flow distribution matrix to reasonably distribute power, specifically as follows: First, define the power flow distribution matrix A. u , (A u ∈R n×n ): In formula (14): (A u ) ji Let matrix A u The element in the j-th row and i-th column; Further through the power flow distribution matrix A u Establish the generator power P G The relationship between the node power P and the node current: A u P=P G (15) In equation (15), P = [P1, P2, ..., P n ] T This is a vector formed by the power flowing through each node; Then, the power is distributed according to the principle of proportional allocation; Load P of node k Lk This can be expressed as the sum of the contributions of each generator: In equation (16) e k ∈R n×1 P is a column vector where the i-th component is 1 and the rest are 0; k Let be the power flowing through node k; Then the power component P of the load at node k distributed from the generator at node i Lk,Gi Represented as: In equation (17) e i ∈R n×1 Let be a column vector where the i-th component is 1 and the rest are 0; similarly, the apportionment formulas for branch and network loss are given: Equations (18) and (19) are the power calculation equations for the branch power allocated from the generator side, where P kj This represents the power flowing from node k to node j on branch kj. Equations (20) and (21) are the equations for calculating the share of network losses in generator power, where This represents the power loss that occurs when power flows from node k to node j on branch kj.

4. The carbon flow analysis and calculation method based on all elements under uncertain power flow in a power grid, as described in claim 3, is characterized in that... In step (3), the carbon footprint of each user is obtained by calculating the carbon flow analysis of all elements of the power grid from multiple perspectives of load carbon flow rate, branch carbon flow rate, network loss carbon flow rate, branch carbon flow density, and node carbon potential. The specific steps are as follows: a. Characteristic equation for the carbon flow rate under load: In equation (22): R Lk The carbon flow rate of the load at node k represents the equivalent carbon dioxide emissions generated per hour by the load on the generation side, expressed in units of... diag(P G ) indicates that column vector P G Transform into a diagonal matrix; E G This is a vector representing the carbon emission intensity of the generating unit. Further, the carbon flow rate component R of unit i allocated to the load at node k is obtained. Lk,Gi for: R Lk,Gi =P Lk,Gi E Gi (23) b. Characteristic equation for the carbon flow rate of the branch: In equation (24), R kj The carbon flow rate corresponding to the power flowing through branch kj is represented by R, which is further connected to the generator at node i and allocated to the carbon flow rate in branch kj. kj,Gi It is represented as: R kj,Gi =P kj,Gi E Gi (25) c. Characteristic equation for carbon flow rate at network loss: In equation (26) This represents the carbon flow rate corresponding to the power loss of branch kj, and further connects to the carbon flow rate allocation of the generator at node i on the power loss of branch kj. It is represented as: d. Characteristic equation for branch carbon flux density: In equation (28) ρ kj Branch carbon flux density represents the equivalent carbon emissions on the generation side per unit of electrical energy transmitted in a branch, expressed in units of... e. The carbon potential of a node is the ratio of the sum of the carbon flow rates of the branches flowing into the node to the power flowing through that node. Its characteristic equation is: Equation (29)E Nj Let be the carbon potential of node j, representing the equivalent carbon emissions generated on the power generation side per unit of electrical energy consumed by the node, in units of .

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