Indirect carbon emission method considering new energy and green power transaction

Abstract

The invention relates to the technical field of power systems, in particular to an indirect carbon emission method considering new energy and green power transactions, which comprises the following steps: S1, load flow calculation and network loss consideration: determining load flow distribution and forming a matrix required by calculation; s2, unit carbon emission intensity calculation and node carbon potential determination: determining the carbon emission property and intensity of the connected unit; s3, carbon emission responsibility affiliation and green power transaction allocation: distinguishing carbon emission responsibilities of contract power and non-contract power; s4, carbon emission property right distribution and time weighted calculation: after obtaining the carbon emission flow rate allocated by the power supply and the load of each unit, multiplying the carbon emission flow rate by a preset time scale to obtain the carbon emission property right limit of each part of each power grid; according to the method, the accuracy of carbon emission accounting is improved, the definition of the carbon emission distribution characteristics of the power system is enhanced, and the method is suitable for analysis of a lossy network and carbon emission management.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular to an indirect carbon emission method considering new energy and green power transactions. Background Art

[0002] Controlling greenhouse gas emissions and responding to climate change have become the focus of global attention and have promoted the development of low-carbon energy transformation. The power industry has made certain progress in reducing carbon emissions, and the intensity of carbon emissions has declined year by year. However, due to the large base of carbon emissions in the power industry, further reducing carbon emissions still faces huge challenges. It is urgent to establish a sound carbon trading market mechanism and a unified and standardized carbon emission measurement and accounting system.

[0003] The existing direct carbon emission accounting method mainly relies on the fuel emission factor method, but there are certain errors and it is difficult to accurately reflect the differences in carbon emissions from different units. In addition, the emission factors for indirect carbon emission accounting have a lag and cannot reflect the actual emissions of the power grid, making it difficult to reflect the temporal and spatial differences in indirect carbon emissions from users' electricity consumption.

[0004] The present invention aims to design an indirect carbon emission method that takes into account the trading of new energy and green electricity. Under the background of dual carbon regulations, the carbon emission tracking model is used to solve the problem of insufficient fairness of traditional methods, and the impact of network loss, new energy output and green electricity trading on indirect carbon emission accounting is comprehensively considered. Summary of the invention

[0005] The present invention provides an indirect carbon emission method considering new energy and green electricity trading.

[0006] An indirect carbon emission method considering new energy and green electricity trading includes the following steps:

[0007] S1, power flow calculation and network loss consideration: select a preset time scale, perform power flow calculation under steady-state power grid, consider network loss, determine power flow distribution and form the matrix required for calculation;

[0008] S2, calculation of unit carbon emission intensity and determination of node carbon potential: determine the carbon emission properties and intensity of the connected units, form the unit carbon emission injection intensity matrix, calculate the node carbon potential on this basis, and determine the amount of each component of the carbon emission structure and the grid distribution;

[0009] S3, Carbon emission responsibility attribution and green power trading allocation: Based on the principle of carbon flow distribution and proportional sharing, carbon emissions are quantitatively attributed, and network loss carbon emissions are allocated to each unit. At the same time, in the context of green power trading, the carbon emission responsibilities of contracted power and non-contracted power are distinguished;

[0010] S4, carbon emission property rights allocation and time-weighted calculation: After obtaining the carbon emission flow rate that should be shared by the power supply and load of each unit, multiply it by the preset time scale to obtain the carbon emission property rights quota of each part of the power grid, and make corresponding deductions for the carbon emissions of green electricity trading users.

[0011] Optionally, the carbon emission responsibility attribution and green power trading allocation in S3 include:

[0012] S31, Carbon emission flow calculation: The calculation of carbon flow is based on the flow calculation. The Newton-Raphson method is used to calculate the flow of power systems with multiple nodes, determine the voltage amplitude and phase angle of each node, calculate the flow distribution of branches and network power loss, and obtain the composition of carbon emission structure and carbon flow distribution;

[0013] S32, Proportional sharing principle and carbon emission allocation: Based on the results of power flow calculation, carbon emissions are allocated according to the proportional sharing principle, and the carbon emissions of network losses are distributed according to the contribution of each generating unit. The active network loss allocated to each unit and its corresponding carbon emission flow rate are calculated through the power flow reverse tracking method to obtain the carbon emission allocation quota of each unit and load;

[0014] S33, calculation of carbon emission flow taking into account new energy: In the process of carbon flow calculation, the output of new energy units is regarded as carbon reduction load, and the equivalent idea is used to handle it. By giving the new energy power generation a negative value, part of the load is offset, thereby quantifying the contribution of new energy to carbon reduction in the power system. When calculating, the carbon reduction rate of new energy is indirectly analyzed from the load perspective, and the corresponding carbon reduction load distribution matrix is ​​proposed to represent the carbon emission changes of different nodes;

[0015] S34, consider the indirect carbon emission accounting of green electricity trading: Green electricity trading enables users to obtain corresponding carbon emission reduction certification by purchasing and consuming green electricity. In the accounting of indirect carbon emissions, the electricity volume of green electricity trading should be treated separately from ordinary electricity volume. Green electricity loads enjoy all the clean electricity stipulated in the contract, minus the corresponding carbon emissions, while loads that do not participate in green electricity trading do not enjoy this emission reduction benefit.

[0016] Optionally, the carbon emission flow calculation in S31 includes:

[0017] S311, power flow calculation: for a power system with n nodes, the voltage amplitude and phase angle of each node are obtained, and the branch power flow distribution and network power loss are obtained, which are the power flow calculation results;

[0018] S312, Establishment of AC system power flow model: Establish the AC system power flow model in polar coordinates;

[0019] S313, calculate the node carbon potential distribution: the carbon emission flow distribution is determined by the carbon emission structure component. In a power system with N nodes, there are K nodes for unit injection nodes and M load nodes. The power system flow distribution matrix is ​​used to calculate the power system node carbon potential distribution vector, which is expressed as:

[0020]

[0021] Among them, P N is the node active power flow matrix, P G Inject the power distribution matrix into the unit, E G is the carbon emission intensity vector of the generator set, P E is the branch outflow power distribution matrix;

[0022] S314, calculate the load carbon flow rate: after the node carbon potential distribution is obtained, calculate the load carbon flow rate vector R L , expressed as:

[0023] R L =P L E N ;

[0024] Among them, P L is the load distribution matrix;

[0025] S315, calculation of carbon emissions caused by branch power loss: The carbon emission flow rate distribution caused by branch power loss is calculated using the N-order square matrix R loss It means that if node i and node j are connected by a line, and the active power loss value on line ij is P ij , the carbon flow rate at the power generation end is R, then The carbon emission flow rate distribution is expressed as:

[0026] R loss =diag(E N ) loss

[0027] Among them, P loss is the branch active power loss distribution matrix;

[0028] S316, Definition of branch inflow and outflow matrices: Branch inflow matrix P in Defined as the active power flowing out of the node at the beginning of the branch, the branch outflow matrix P out Defined as the active power flowing into the end node of the branch, the carbon emission flow rate distribution is expressed as:

[0029] R loss =diag{E N}·(P in -P out ).

[0030] Optionally, the power flow model of the AC system is expressed as:

[0031]

[0032] Among them, P i , Q i The active power and reactive power injected into node i are respectively, U i is the voltage of node i, n is the number of nodes, G ij , B ij are the real and imaginary parts of the node admittance matrix, δ ij is the phase angle difference between nodes i and j.

[0033] Optionally, the proportional sharing principle and carbon emission apportionment in S32 include:

[0034] S321, Application of upstream proportional allocation principle: According to the proportional sharing principle, determine the upstream allocation method of power at each node in the power system. The essence of upstream proportional allocation is to allocate the power of the node according to the power flow ratio upstream of the node;

[0035] S322, application of downstream proportional allocation principle: according to the proportional sharing principle, determine the downstream allocation method of power of each node in the system. The essence of downstream proportional allocation is to allocate the power of the node according to the demand of the downstream node;

[0036] S323, Allocation of carbon emissions from grid losses: For the carbon emissions from grid losses of the power system, based on the principle of proportional sharing, the responsibility for carbon emissions caused by grid losses is allocated to each power plant. Each unit shares the corresponding carbon emissions according to its contribution to the grid losses of the power system. The grid loss carbon emission flow rate borne by each unit is calculated and expressed as:

[0037] R Gk-1 =e Gk P Gk-1 ;

[0038] Among them, R Gk-1 The carbon emission rate that unit k needs to bear, e Gk is the carbon emission intensity of unit k, P Gk-1 is the active network loss borne by unit k;

[0039] S324, Application of the power flow reverse tracking method: According to the power flow reverse tracking method, the contribution of computer group k to the active network loss of the power system is expressed as:

[0040]

[0041] Among them, η N is an N-dimensional unit column vector whose jth element is 1 and the rest are 0, ξN is a column vector with all elements equal to 1, A d is the upstream distribution matrix of the power system;

[0042] S325, calculation of carbon emission rate allocation: the carbon emission rate P caused by the active network loss borne by computer group k G ′ k-1 ;

[0043] S326, calculate the carbon emission property rights: multiply the shared carbon emission flow rate by a preset time scale to obtain the carbon emission property rights of each unit and load node.

[0044] Optionally, the upstream distribution matrix A of the power system d The elements of are represented as:

[0045]

[0046]

[0047] Among them, I is the N-order unit matrix.

[0048] Optionally, the apportioned carbon emission flow rate P G ′ k-1 It is expressed as:

[0049]

[0050] Optionally, the calculation of carbon emission flow taking into account new energy in S33 includes:

[0051] S331, determining power flow distribution: determining power flow distribution in the power system;

[0052] S332, treat the new energy units as carbon reduction loads: For node i, treat the output of the new energy units as negative loads and assign a negative value, indicating that the local network load is offset, representing the carbon reduction contribution of new energy generation to the power system load;

[0053] S333, merge node load: The power system load includes ordinary load and carbon reduction load. At node i, merge node load, expressed as:

[0054]

[0055] Among them, P L is the normal load at node i, is the combined load at node i, P Lclean To reduce carbon load, it is a negative value;

[0056] S334, construct the carbon reduction load distribution matrix: define the carbon reduction load distribution matrix composed of new energy units as P LCi , the elements of the carbon reduction load distribution matrix are defined as: If there is a new energy unit injecting active power flow P at node i, the indirect equivalent load is P LCi = -P, otherwise 0;

[0057] S335, Update the unit carbon emission intensity vector: Update the unit carbon emission intensity vector E ′ G , E ′ G Only the carbon emission intensity of thermal power units is included, and new energy units are not included in the carbon emission intensity vector, which is expressed as:

[0058] E′ G =[e G1 e G2 … e Gl ] T ;

[0059] S336, calculate the carbon potential of the node: calculate the carbon potential of each node in the power system, expressed as:

[0060] E′ N =(P′ N -P′ E ) T ) -1 P′ G TE′ G ;

[0061] S337, calculate carbon flow rate: calculate the branch carbon flow rate and the total load carbon flow rate including the quantified carbon reduction contribution of new energy, expressed as:

[0062] R′ E =P' E diag(E′ N );

[0063]

[0064] Among them, R LC is the carbon flow rate of carbon reduction load obtained by indirect analysis based on the load angle, and θ and μ are unit column vectors.

[0065] Optionally, the indirect carbon emission accounting considering green power trading in S34 includes:

[0066] S341, definition of green power trading: Green power trading is a transaction conducted to meet the needs of power users to purchase and consume green power. Through green power trading, users can obtain green power consumption certification and deduct carbon emissions in the carbon market, while new energy power generation companies can obtain additional environmental value subsidies;

[0067] S342, Emission reduction mechanism of green power trading: The emission reduction mechanism of green power trading is based on the replacement of thermal power units with new energy units, which is equivalent to emission reduction on the user side. Green power trading loads enjoy all clean electricity stipulated in the contract, while loads that are not traded through the contract do not enjoy the carbon emission reduction brought by green power;

[0068] S343, dividing the electricity flow and carbon emission flow: dividing the electricity flow and carbon emission flow in the power system, specifically including:

[0069] The components are natural electricity and natural carbon flows, including the power generation of thermal power generating units and the power generation of new energy sources outside the green power trading contracts;

[0070] The contract part only considers the contractual green power between each unit and the user, and directly supplies the green power users through the virtual trading line;

[0071] S344, Division of total power generation: Total power generation of each type of unit P G Including the basic part and the contract part At any time, the power generation of the thermal power unit The remaining power generation after deducting the green power contract from the new energy units The satisfaction relationship is expressed as:

[0072]

[0073] Among them, N and M are the total power generation of the corresponding power station;

[0074] S345, Load Division: The power system load is divided into contract load that enjoys the emission reduction benefits of the green power trading contract and ordinary load that does not enjoy this part of the emission reduction benefits, expressed as:

[0075]

[0076] S346, calculate the indirect carbon emission factor of the node: based on the division of total power generation and load, obtain the indirect carbon emission factor E′ of each node n after green power trading N,n .

[0077] Optionally, the indirect carbon emission factor E′ N,n It is expressed as:

[0078]

[0079] Beneficial effects of the present invention:

[0080] The present invention, by combining power flow calculation and carbon emission intensity analysis, can effectively solve the problems of poor real-time performance and unsuitability for short-time scale analysis of traditional carbon emission measurement methods, realize the reasonable allocation of carbon emissions in the power system, and ensure that all responsible entities bear carbon emission responsibilities fairly.

[0081] The present invention greatly improves the accuracy of carbon emission accounting by quantifying the carbon reduction contribution of network losses and renewable energy power generation and incorporating green electricity trading into the accounting of carbon emission flows. It also enhances the clarity of the carbon emission distribution characteristics of the power system and is suitable for the analysis of lossy networks and carbon emission management. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0083] Figure 1 A schematic diagram of power flow distribution according to an embodiment of the present invention;

[0084] Figure 2 A schematic diagram of an indirect carbon emission accounting method considering green power trading according to an embodiment of the present invention;

[0085] Figure 3 Schematic diagram of the carbon emission method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0086] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0087] It should be noted that the references to "one embodiment", "an embodiment", "an exemplary embodiment", "some embodiments" and the like in the specification indicate that the embodiments described may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, when a specific feature, structure or characteristic is described in conjunction with an embodiment, it should be within the knowledge of a person skilled in the art to implement such feature, structure or characteristic in conjunction with other embodiments (whether or not explicitly described).

[0088] In general, a term can be understood, at least in part, from its use in context. For example, depending, at least in part, on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but can instead, depending, at least in part, on the context, allow for the presence of other factors that are not necessarily explicitly described.

[0089] like Figure 1-Figure 3 As shown, an indirect carbon emission method considering new energy and green electricity trading includes the following steps:

[0090] 1. Select an appropriate time scale. Perform power flow calculation under a certain power grid steady state, consider network losses, determine the system power flow distribution and form the matrix required for calculation;

[0091] 2. Determine the carbon emission properties and intensity of the units connected to the system, and form a carbon emission injection intensity matrix for the units; on this basis, calculate the carbon potential of the system nodes, and determine the amount of each component of the carbon emission structure and the distribution of the power grid;

[0092] 3. Quantitatively attribute system carbon emissions based on carbon flow distribution and the principle of apportionment;

[0093] 4. After obtaining the carbon emission flow rate that should be shared by the power supply and load of each unit, multiply it by the time period set before calculation, and finally obtain the carbon emission property rights quota of each part of the power grid.

[0094] 3.1 Carbon emission trend calculation:

[0095] The carbon flow of the power system is closely related to the power flow. The calculation of carbon flow is based on the results of power flow calculation. Therefore, before calculating the carbon flow, it is necessary to solve the power flow distribution in the power system.

[0096] For a power system with n nodes, the Newton-Raphson method is used to calculate the voltage amplitude and phase angle of each node, and then the branch flow distribution and network power loss are obtained, which is the flow calculation result. In polar coordinates, the flow model of the AC system can be expressed as:

[0097]

[0098] Where: P i , Q i The active power and reactive power injected into node i are respectively, U i is the voltage of node i, n is the number of nodes, G ij , B ij are the real and imaginary parts of the node admittance matrix, δ ij is the phase angle difference between nodes i and j.

[0099] The determination of the carbon emission structure components is the calculation of the carbon emission flow distribution. In a system with N nodes, there are K nodes for unit injection nodes, M nodes for load nodes, and the network topology is known. When the system power flow distribution matrix is ​​determined, the system node carbon potential distribution vector should be calculated first, and the calculation formula is as follows:

[0100]

[0101] P N is the node active power flow matrix, P G Inject the power distribution matrix into the unit, E G is the carbon emission intensity vector of the generator set, P E is the branch outflow flow distribution matrix. Since the node active power outflow does not directly participate in the calculation of the node carbon intensity, the calculation of carbon emission flow focuses more on the total active power flowing into the node, which is defined as the node active power flux. If the node i and node j are connected by branches, and there is an active power flow of size P flowing from node i to node j on the line, then Specifically, each element can be defined as follows:

[0102] P ii =∑ j P ji +P gi ;

[0103] P ji is the active power flowing into the upstream node, P gi The power injected into the generator sets connected to the node.

[0104] After obtaining the carbon potential distribution of the system nodes, the load carbon flow rate vector R L It can be calculated that:

[0105] R L =P L E N ;

[0106] P L is the load distribution matrix.

[0107] The carbon emission caused by branch power loss is distributed by the N-order square matrix R loss In the matrix, if node i and node j are connected by a line, and the active power loss value on line ij is P ij And corresponding to the carbon flow rate R at the power generation end, then Thus, the carbon emission flow rate distribution can be obtained.

[0108] R loss =diag(E N )loss ;

[0109] P loss is the branch active power loss distribution matrix, which is defined as the N-order matrix of active power loss distribution on the system line and the power network topology structure.

[0110] Branch inflow matrix P in Defined as the active power flowing out of the node at the beginning of the branch, the branch outflow matrix P out Defined as the active power flowing into the end node of the branch.

[0111] R loss =diag{E N}·(P in -P out ).

[0112] 3.2 Proportional sharing principle and carbon emission allocation:

[0113] The proportional distribution principle is an important principle of the power flow tracking algorithm. Its essence is how to distribute the power on a node. This principle embodies fairness and equal opportunities. Figure 1 As shown:

[0114] Upstream Proportion Allocation:

[0115] Downstream Proportion Distribution:

[0116] The carbon emission attribution problem based on the decomposition of carbon emission structure should focus on the allocation of carbon emission of network loss of structural components. According to the allocation principle, we need to allocate carbon emission of network loss to each power plant. The unit should allocate the carbon emission corresponding to the network loss it bears. Then:

[0117] R Gk-1 =e Gk P Gk-1 ;

[0118] R Gk-1 The carbon emission rate that unit k needs to bear, e Gk is the carbon emission intensity of unit k, P Gk-1 is the active network loss borne by unit k. According to the countercurrent tracing method, the contribution of unit k to the active network loss of the system is P Gk-1 for:

[0119]

[0120] η N is an N-dimensional unit column vector whose jth element is 1 and the rest are 0, ξ N is a column vector with all elements equal to 1, A dis the upstream distribution matrix of the power system, and its elements are calculated as follows:

[0121]

[0122] Therefore, the matrix calculation formula is:

[0123]

[0124] I is an N-order unit matrix. Based on the above formula, the carbon emission flow P caused by the active network loss borne by unit k can be obtained: G ′ k-1 for:

[0125]

[0126] After obtaining the allocation result of the carbon emission flow rate using the above model, multiply it by the duration of the time period to obtain the carbon emission property rights of the system units and load distribution. At this point, the carbon emissions generated by all units in the system are allocated.

[0127] 3.3 Calculation of carbon emission flows taking into account new energy sources:

[0128] When calculating carbon emission flow, the output of new energy is defined as the load that reduces the carbon flow rate, which is essentially an equivalent idea. It should be made clear during the calculation process that after the network conversion is completed, the power of each branch and load of the system remains unchanged, the power input and output at the node are balanced, and only the carbon flow rate of the system changes.

[0129] First, determine the power flow distribution of the system. Second, take node i as an example, treat the new energy unit as a carbon reduction load and assign a negative value, which can be regarded as an offset to the local network load. At this time, the system load can be divided into ordinary load and carbon reduction load, and the load at node i is combined:

[0130]

[0131] P L is the normal load at node i, is the combined load at node i, P Lclean To reduce carbon load, it is a negative value.

[0132] Indirectly analyzing the contribution of new energy to the carbon reduction of the system from the perspective of load, the basic idea is to compare the new energy unit to the load in the carbon flow calculation. LC It is stated that a carbon flow calculation method that takes into account the carbon reduction contribution of new energy is proposed.

[0133] In order to analyze the contribution of new energy to carbon reduction, this paper proposes a carbon reduction load distribution matrix P composed of new energy units. LCiThe element is defined as: If there is a new energy unit injecting active power flow P at node i, the indirect equivalent load is P LCi =-P, otherwise 0. Update the unit carbon emission intensity vector E ′ G , which only contains the vector of carbon emission intensity of thermal power units:

[0134] E′ G =[e G1 e G2 … e Gl ] T ;

[0135] The carbon potential of each node in the system is:

[0136] E′ N =(P′ N -P′ E ) T ) -1 P′ G T E′ G ;

[0137] The branch carbon flow rate and the total load carbon flow rate including the quantified carbon reduction contribution of new energy are:

[0138] R′ E =P′ E diag(E′ N );

[0139]

[0140] R LC is the carbon flow rate of carbon reduction load obtained by indirect analysis from the load angle, θ and μ are unit column vectors, and the carbon reduction rate of new energy units under different output conditions can be obtained by P LC E′ N Calculated.

[0141] 3.4 Indirect carbon emission accounting method considering green electricity trading:

[0142] Green power trading refers to the medium- and long-term trading of green power products, which is used to meet the needs of power users to purchase and consume green power. In this process, users obtain corresponding green power consumption certification, which is used to deduct carbon emissions in the carbon market, and new energy power generation companies obtain additional environmental value subsidies. Therefore, in the user's indirect carbon emission accounting, it is necessary to accurately deduct the corresponding carbon emissions from financial green power trading. In principle, the emission reduction of green power trading is the replacement of high-emission thermal power units by clean new energy units, which is equivalent to the user side. Green power trading loads should enjoy all clean electricity stipulated in the contract, while the remaining green power trading loads should not enjoy the carbon emission reduction brought about by this part of green electricity.

[0143] The electricity flow and carbon emission flow in the power system are divided into two parts: the basic components are natural electricity and natural carbon flow, including the power generation of traditional power generation units such as thermal power and the power generation of new energy sources outside the green power trading contract amount. The contract component only considers the contracted green power between each unit and the user, and directly supplies the green power users through the virtual trading line, such as Figure 2 shown.

[0144] As shown in the figure, the total power generation of each type of unit P G Can be divided into basic parts and the contract part For the two parts, the following relationship can be satisfied at any time t[3]:

[0145]

[0146] In the formula, is the power generation of traditional thermal power units, N is the total power generation of its power station, is the remaining power generation of the new energy unit after deducting the green power contract, and M is the total power generation of its power station.

[0147] Similarly, the load is divided as follows:

[0148]

[0149] From this, we can get the indirect carbon emission factor E of node n after green electricity trading: ′ N,n :

[0150]

[0151] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. In addition, in order to avoid unnecessary confusion about the essence of the present invention, well-known methods, processes, procedures, components and circuits are not described in detail.

[0152] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An indirect carbon emission method considering new energy and green power trading, characterized in that: The following steps are involved: S1, power flow calculation and network loss consideration: select a preset time scale, perform power flow calculation under steady-state power grid, consider network loss, determine power flow distribution and form the matrix required for calculation; S2, calculation of unit carbon emission intensity and determination of node carbon potential: determine the carbon emission properties and intensity of the connected units, form the unit carbon emission injection intensity matrix, calculate the node carbon potential on this basis, and determine the amount of each component of the carbon emission structure and the grid distribution; S3, Carbon emission responsibility attribution and green power trading allocation: Based on the principle of carbon flow distribution and proportional sharing, carbon emissions are quantitatively attributed, and network loss carbon emissions are allocated to each unit. At the same time, in the context of green power trading, the carbon emission responsibilities of contracted power and non-contracted power are distinguished; S4, carbon emission property rights allocation and time-weighted calculation: After obtaining the carbon emission flow rate that should be shared by the power supply and load of each unit, multiply it by the preset time scale to obtain the carbon emission property rights quota of each part of the power grid, and make corresponding deductions for the carbon emissions of green electricity trading users.

2. The indirect carbon emission method considering new energy and green power trading according to claim 1 is characterized in that: The carbon emission responsibility attribution and green power trading allocation in S3 include: S31, Carbon emission flow calculation: The calculation of carbon flow is based on the flow calculation. The Newton-Raphson method is used to calculate the flow of power systems with multiple nodes, determine the voltage amplitude and phase angle of each node, calculate the flow distribution of branches and network power loss, and obtain the composition of carbon emission structure and carbon flow distribution; S32, Proportional sharing principle and carbon emission allocation: Based on the results of power flow calculation, carbon emissions are allocated according to the proportional sharing principle, and the carbon emissions of network losses are distributed according to the contribution of each generating unit. The active network loss allocated to each unit and its corresponding carbon emission flow rate are calculated through the power flow reverse tracking method to obtain the carbon emission allocation quota of each unit and load; S33, calculation of carbon emission flow taking into account new energy: In the process of carbon flow calculation, the output of new energy units is regarded as carbon reduction load, and the equivalent idea is used to handle it. By giving the new energy power generation a negative value, part of the load is offset, thereby quantifying the contribution of new energy to carbon reduction in the power system. When calculating, the carbon reduction rate of new energy is indirectly analyzed from the load perspective, and the corresponding carbon reduction load distribution matrix is ​​proposed to represent the carbon emission changes of different nodes; S34, consider the indirect carbon emission accounting of green electricity trading: Green electricity trading enables users to obtain corresponding carbon emission reduction certification by purchasing and consuming green electricity. In the accounting of indirect carbon emissions, the electricity volume of green electricity trading should be treated separately from ordinary electricity volume. Green electricity loads enjoy all the clean electricity stipulated in the contract, minus the corresponding carbon emissions, while loads that do not participate in green electricity trading do not enjoy this emission reduction benefit.

3. The indirect carbon emission method considering new energy and green power trading according to claim 2 is characterized in that: The carbon emission flow calculation in S31 includes: S311, power flow calculation: for a power system with n nodes, the voltage amplitude and phase angle of each node are obtained, and the branch power flow distribution and network power loss are obtained, which are the power flow calculation results; S312, Establishment of AC system power flow model: Establish the AC system power flow model in polar coordinates; S313, calculate the node carbon potential distribution: the carbon emission flow distribution is determined by the carbon emission structure component. In a power system with N nodes, there are K nodes for unit injection nodes and M load nodes. The power system flow distribution matrix is ​​used to calculate the power system node carbon potential distribution vector, which is expressed as: Among them, P N is the node active power flow matrix, P G Inject the power distribution matrix into the unit, E G is the carbon emission intensity vector of the generator set, P E is the branch outflow power distribution matrix; S314, calculate the load carbon flow rate: after the node carbon potential distribution is obtained, calculate the load carbon flow rate vector R L , expressed as: R L =P L E N ; Among them, P L is the load distribution matrix; S315, calculation of carbon emissions caused by branch power loss: The carbon emission flow rate distribution caused by branch power loss is calculated using the N-order square matrix R loss It means that if node i and node j are connected by a line, and the active power loss value on line ij is P ij , the carbon flow rate at the power generation end is R, then , the carbon emission flow rate distribution is expressed as: R loss diag(E N )P loss 100. Among them, P loss is the branch active power loss distribution matrix; S316, Definition of branch inflow and outflow matrices: Branch inflow matrix P in Defined as the active power flowing out of the node at the beginning of the branch, the branch outflow matrix P out Defined as the active power flowing into the end node of the branch, the carbon emission flow rate distribution is expressed as: R loss =diag{E N }·(P in -P out )。 4. The indirect carbon emission method considering new energy and green power trading according to claim 3 is characterized in that: The power flow model of the AC system is expressed as: Among them, P i , Q i The active power and reactive power injected into node i are respectively, U i is the voltage of node i, n is the number of nodes, G ij , B ij are the real and imaginary parts of the node admittance matrix, δ ij is the phase angle difference between nodes i and j.

5. The indirect carbon emission method considering new energy and green power trading according to claim 4 is characterized in that: The proportional sharing principle and carbon emission allocation in S32 include: S321, Application of upstream proportional allocation principle: According to the proportional sharing principle, determine the upstream allocation method of power at each node in the power system. The essence of upstream proportional allocation is to allocate the power of the node according to the power flow ratio upstream of the node; S322, application of downstream proportional allocation principle: according to the proportional sharing principle, determine the downstream allocation method of power of each node in the system. The essence of downstream proportional allocation is to allocate the power of the node according to the demand of the downstream node; S323, Allocation of carbon emissions from grid losses: For the carbon emissions from grid losses of the power system, based on the principle of proportional sharing, the responsibility for carbon emissions caused by grid losses is allocated to each power plant. Each unit shares the corresponding carbon emissions according to its contribution to the grid losses of the power system. The grid loss carbon emission flow rate borne by each unit is calculated and expressed as: R Gk-1 =e Gk P Gk-1 ; Among them, R Gk-1 The carbon emission rate that unit k needs to bear, e Gk is the carbon emission intensity of unit k, P Gk-1 is the active network loss borne by unit k; S324, Application of the power flow reverse tracking method: According to the power flow reverse tracking method, the contribution of computer group k to the active network loss of the power system is expressed as: Among them, η N is an N-dimensional unit column vector whose jth element is 1 and the rest are 0, ξ N is a column vector with all elements equal to 1, A d is the upstream distribution matrix of the power system; S325, calculation of carbon emission rate allocation: the carbon emission rate P′ caused by the active network loss borne by computer group k Gk-1 ; S326, calculating carbon emission property rights: multiplying the shared carbon emission flow rate by a preset time scale to obtain the carbon emission property rights of each unit and load node.

6. The indirect carbon emission method considering new energy and green power trading according to claim 5 is characterized in that: The upstream distribution matrix A of the power system d The elements of are represented as: Among them, I is the N-order unit matrix.

7. The indirect carbon emission method considering new energy and green power trading according to claim 6 is characterized in that: The apportioned carbon emission flow rate P′ Gk-1 It is expressed as:

8. The indirect carbon emission method considering new energy and green power trading according to claim 7 is characterized in that: The calculation of carbon emission flow taking into account new energy in S33 includes: S331, determining power flow distribution: determining power flow distribution in the power system; S332, treat the new energy units as carbon reduction loads: For node i, treat the output of the new energy units as negative loads and assign a negative value, indicating that the local network load is offset, representing the carbon reduction contribution of new energy generation to the power system load; S333, merge node load: The power system load includes ordinary load and carbon reduction load. At node i, merge node load, expressed as: Among them, P L is the normal load at node i, is the combined load at node i, P Lclean To reduce carbon load, it is a negative value; S334, construct the carbon reduction load distribution matrix: define the carbon reduction load distribution matrix composed of new energy units as P LCi , the elements of the carbon reduction load distribution matrix are defined as: If there is a new energy unit injecting active power flow P at node i, the indirect equivalent load is P LCi = -P, otherwise 0; S335, Update the unit carbon emission intensity vector: Update the unit carbon emission intensity vector E′ G , E′ G Only the carbon emission intensity of thermal power units is included, and new energy units are not included in the carbon emission intensity vector, which is expressed as: AND' G =[and G1 And G2 …And Gl ] T ; S336, calculate the carbon potential of the node: calculate the carbon potential of each node in the power system, expressed as: AND' N =(P′ N -P′ E ) T ) -1 P′ G T AND' G ; S337, calculate carbon flow rate: calculate the branch carbon flow rate and the total load carbon flow rate including the quantified carbon reduction contribution of new energy, expressed as: R′ E NP′ E diag(E′ N )4 Among them, R LC is the carbon flow rate of carbon reduction load obtained by indirect analysis based on the load angle, and θ and μ are unit column vectors.

9. The indirect carbon emission method considering new energy and green power trading according to claim 8 is characterized in that: The indirect carbon emission accounting considering green electricity trading in S34 includes: S341, definition of green power trading: Green power trading is a transaction conducted to meet the needs of power users to purchase and consume green power. Through green power trading, users can obtain green power consumption certification and deduct carbon emissions in the carbon market, while new energy power generation companies can obtain additional environmental value subsidies; S342, Emission reduction mechanism of green power trading: The emission reduction mechanism of green power trading is based on the replacement of thermal power units with new energy units, which is equivalent to emission reduction on the user side. Green power trading loads enjoy all clean electricity stipulated in the contract, while loads that are not traded through the contract do not enjoy the carbon emission reduction brought by green power; S343, dividing the electricity flow and carbon emission flow: dividing the electricity flow and carbon emission flow in the power system, specifically including: The components are natural electricity and natural carbon flows, including the power generation of thermal power generating units and the power generation of new energy sources outside the green power trading contracts; The contract part only considers the contractual green power between each unit and the user, and directly supplies the green power users through the virtual trading line; S344, Division of total power generation: Total power generation of each type of unit P G Including the basic part and the contract part At any time, the power generation of the thermal power unit The remaining power generation after deducting the green power contract from the new energy units The satisfaction relationship is expressed as: Among them, N and M are the total power generation of the corresponding power station; S345, Load Division: The power system load is divided into contract load that enjoys the emission reduction benefits of the green power trading contract and ordinary load that does not enjoy this part of the emission reduction benefits, expressed as: S346, calculate the indirect carbon emission factor of the node: based on the division of total power generation and load, obtain the indirect carbon emission factor E′ of each node n after green power trading N，n .

10. The indirect carbon emission method considering new energy and green power trading according to claim 9, characterized in that: The indirect carbon emission factor E' N，n It is expressed as:

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