Fast calculation method of interval carbon flow considering fluctuation of carbon emission factor of generator set

Abstract

The present application relates to a method for fast calculation of interval carbon flow considering fluctuation of carbon emission factor of generator set, comprising: determining carbon flow related matrix and vector, combining flow properties of carbon emission, establishing a static carbon flow calculation model of power system, wherein the matrix and vector are used for centralized fast calculation; introducing interval Krawczyk factor iteration algorithm in the static carbon flow calculation model of power system, constructing a fast calculation model of interval carbon flow of power system; based on the fast calculation model of interval carbon flow of power system, calculating interval carbon flow considering fluctuation of carbon emission factor of generator set. The present application fully considers the uncertainty of generator set state and the high conservativeness problem existing in general interval calculation method, and lays a foundation for future exploration of carbon responsibility allocation and carbon reduction measures.

Description

Technical Field

[0001] This invention relates to the field of energy emission accounting technology, and in particular to a method for rapid calculation of interval carbon flow taking into account the fluctuation of carbon emission factors of generator sets. Background Technology

[0002] A power system is an energy production and consumption system composed of power plants, transmission and transformation lines, power distribution stations, and electricity consumers. Its function is to convert primary energy from nature into electrical energy through power generation devices, and then supply this electrical energy to various users through transmission, transformation, and distribution. The operation of a power system generates carbon emissions. With the continuous progress of human civilization and the growing awareness of environmental protection, the concept of "dual carbon targets" has made carbon emission reduction a crucial task within the power system. The measurement of carbon emissions is the foundation for all carbon emission reduction efforts.

[0003] Traditional deterministic carbon flow calculations are performed only at a specific time point or under defined operating conditions, failing to quantify the impact of uncertainties on the power system. This severely affects the accuracy of carbon emission flow calculations for the power system and is detrimental to practical applications. Therefore, given the increasing complexity of the power system operating environment, this invention aims to achieve inter-regional carbon flow calculations for the power system, taking into account fluctuations in the carbon emission factors of generating units. Summary of the Invention

[0004] The purpose of this invention is to provide a rapid calculation method for interval carbon flow that takes into account the fluctuation of carbon emission factors of generator sets. This method overcomes the shortcomings of existing technologies, which do not fully incorporate the interval characteristics of carbon emission factors of generator sets during the carbon flow calculation process. As a result, the accuracy of the carbon flow calculation results of the power system is low, and the rationality of the subsequent carbon responsibility allocation of the power system cannot be effectively guaranteed.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A rapid calculation method for interval carbon flow taking into account the fluctuation of carbon emission factors of generator sets, including:

[0007] A static carbon flow calculation model for a power system is established by determining the carbon flow-related matrices and vectors and combining them with the flow properties of carbon emissions. The matrices and vectors are used for centralized and rapid calculation.

[0008] An interval Krawczyk factor iteration algorithm is introduced into the static carbon flow calculation model of the power system to construct a fast calculation model of interval carbon flow of the power system.

[0009] Based on the aforementioned fast calculation model for inter-regional carbon flow in the power system, inter-regional carbon flow calculations are performed, taking into account the fluctuations in the carbon emission factor of generator units.

[0010] Furthermore, the matrix includes:

[0011] Branch power flow distribution matrix, used to represent the distribution of active power flow in the system;

[0012] The generator injection distribution matrix is ​​used to represent the topology of generator sets in the power system network and the magnitude of active power injected into the system by the generator sets;

[0013] The load distribution matrix is ​​used to represent the topological relationship between the load and the system and the amount of active power consumed by the load.

[0014] The node active power flux matrix is ​​used to represent the total active power flow into the node.

[0015] The branch carbon flow rate distribution matrix is ​​used to represent the distribution of carbon flow rate in the system.

[0016] Further, the vector comprises:

[0017] The generator set carbon emission intensity vector is used to represent the carbon emission characteristics of each generator set.

[0018] The node carbon potential vector is used to represent the carbon emission characteristics of each node.

[0019] The load carbon flow rate vector is used to represent the amount of carbon emissions generated per unit time by the power generation side supplying electricity to the load.

[0020] Furthermore, the representation method of the matrix and vector includes: adopting a distributed storage method to record the row and column positions of the non-zero elements of the matrix and vector in the matrix, as well as the numerical value of the element.

[0021] Furthermore, establishing the static carbon flow calculation model of the power system includes: based on the matrix and vector, combining the power system power flow calculation method and the advanced power network analysis method, establishing the static carbon flow calculation model of the power system.

[0022] Furthermore, the static carbon flow calculation model for the power system is as follows:

[0023]

[0024]

[0025] R L =P L E N

[0026] Among them, E N It is the nodal carbon potential vector matrix, P N It is the nodal active flux matrix, P B It is the branch power flow distribution matrix, P G It is the unit injection distribution matrix, EG It is the carbon emission factor vector of the generator set, R B It is the carbon flow rate of the branch. It is the dot product symbol, repmat(E N (1, N) is E N This N-dimensional column vector is flattened N times to form an N×N relation matrix, R L It is the carbon flow rate under load, P L It is the load distribution matrix.

[0027] Furthermore, in the power system static carbon flow calculation model Need to ensure Invertibility, if there exists a node with a node active flux matrix P N The diagonal element is 0, at this time If the process is irreversible, the node, along with its connected generator sets and branches, will be removed from the matrix. After calculating the distribution of carbon emissions in the system, the node will be added back to the result matrix.

[0028] Furthermore, constructing the fast calculation model for inter-regional carbon flow in the power system includes: collecting inter-regional data on the fluctuation of carbon emission factors of generator units in the power system, introducing the inter-regional Krawczyk factor iterative algorithm into the static carbon flow calculation model of the power system, and constructing the fast calculation model for inter-regional carbon flow in the power system.

[0029] Furthermore, introducing the interval Krawczyk factor iterative algorithm into the power system static carbon flow calculation model includes:

[0030] The static carbon flow calculation model of the power system Transform the equation into standard form, preprocess the transformed interval equation, and obtain the vector solution x of the interval equation in the i-th iteration. (i) The interval Krawczyk factor iteration algorithm is used for iteration until x is reached. (i) The component radius no longer decreases, and the iteration terminates.

[0031] The beneficial effects of this invention are as follows:

[0032] (1) The basic calculation model of carbon flow in power system of the present invention can perform carbon flow calculation on power system with known power flow, and obtain carbon-related physical quantities such as node carbon potential, branch carbon flow rate, and load carbon flow rate, laying the foundation for the research on low-carbon power-related issues in the future.

[0033] (2) The present invention adopts the interval Krawczyk factor iterative calculation method, which can calculate the interval equation and effectively reduce the computational conservatism.

[0034] (3) This invention takes into account the uncertainty of energy consumption on the power generation side, improves the accuracy of the carbon flow calculation results of the power system, and effectively ensures the rationality of the subsequent carbon responsibility allocation of the power system. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a flowchart of a method for rapid calculation of interval carbon flow considering the fluctuation of carbon emission factor of generator sets according to an embodiment of the present invention;

[0037] Figure 2 This is a power network topology diagram of an IEEE 14-bus 5-unit system according to an embodiment of the present invention;

[0038] Figure 3 The diagram shows the results of two interval calculation methods based on interval arithmetic operations and interval Krawczyk factor iteration method, according to embodiments of the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] This embodiment provides a rapid calculation method for interval carbon flow that takes into account the fluctuation of carbon emission factors of generator sets, such as Figure 1 As shown, the specific process includes:

[0042] (a) Construct relevant matrices and vectors to establish a static carbon flow calculation model.

[0043] Suppose a system has N nodes, including K generator nodes and M load nodes. Ignoring network losses, and since carbon emissions are only related to active power distribution, and reactive power has little impact on the active power distribution in the power system, reactive power is ignored. The power flow distribution is then calculated using the DC power flow method.

[0044] (1) Branch power flow distribution matrix

[0045] Branch power flow distribution matrix P B It is an N×N square matrix describing the active power flow distribution in the system. Its elements are defined as follows: if there is a positive active power flow p from node i to node j, then P... Bij =p, P Bji =0; if there is a reverse active power flow p from node i to node j, then P Bij =0, P Bji =p; in other cases P Bij =P Bji =0.

[0046] (2) Unit injection distribution matrix

[0047] Unit injection distribution matrix P G It is a K×N matrix describing the topology of generator sets in the power system network and the magnitude of active power injected into the system by the generator sets. Its elements are defined as follows: If the k-th generator set is at node j, and the generator set injects active power p, then P Gkj =p; otherwise, P Gkj =0.

[0048] (3) Load distribution matrix

[0049] Load distribution matrix P L It is an M×N matrix that describes the topological relationship between the load and the system and the magnitude of the active power consumed by the load. Its elements are defined as follows: If the m-th load is at node j and the active power consumed by the load is p, then P Lmj =p; otherwise P Lmj =0.

[0050] (4) Nodal active flux matrix

[0051] Node active flux matrix P N It is an N-order diagonal matrix that describes the total active power flow into the nodes. Its diagonal elements are calculated as follows:

[0052]

[0053] Among them, I + p is the set of upstream branches of node i. Bs It is the active power of branch s, p Gi It is the generator injection power at node i.

[0054] According to P B P G P N Based on the definition, the relationship among the three can be derived as follows:

[0055]

[0056] Where, ζ N+K It is an (N+K) order row vector, with all elements being 1, P B It is the branch power flow distribution matrix, P G It is the unit injection distribution matrix.

[0057] (5) Carbon emission intensity vector of generator set

[0058] The carbon emission vector of generator sets is one of the factors influencing carbon flow distribution and is also one of the known quantities in carbon flow calculations. Generator set carbon emission intensity vector E G This is a K-order column vector describing the carbon emission characteristics of each generator set, which can be represented as:

[0059]

[0060] Where K is the number of generator nodes in the system, e Gi (i = 1, 2, ..., K) is the carbon emission factor of the i-th generator unit.

[0061] (6) Nodal carbon potential vector

[0062] The first problem to solve in carbon flow calculations is the nodal carbon potential. The nodal carbon potential vector E N It is an N-order column vector describing the carbon emission characteristics of each node, and can be represented as:

[0063]

[0064] Where K is the number of generator nodes in the system, e Ni (i = 1, 2, ..., N) is the carbon potential of the i-th node.

[0065] (7) Branch carbon flow rate distribution matrix

[0066] Once the nodal carbon potential is obtained, the branch carbon flow rate can be calculated based on the nodal carbon potential and the branch power flow distribution. The branch carbon flow rate distribution matrix R... B It is an N×N matrix describing the distribution of carbon flux in the system. Its elements are defined as follows: if there is a positive carbon flux r flowing from node i to node j, then R is... Bij =r,R Bji =0; if there is a reverse carbon flow rate r from node i to node j, then R = 0; Bij =0, R Bji =r; otherwise R Bij =R Bji =0.

[0067] According to P BE N R B Based on the definition, the relationship between the three can be derived as follows:

[0068]

[0069] in, It is the dot product symbol, repmat(E N (1, N) is E N This N-dimensional column vector is flattened N times to form an N×N relation matrix.

[0070] (8) Loading carbon flow rate vector

[0071] After obtaining the nodal carbon potential, the load carbon flow rate is obtained based on the carbon potential of the load nodes and the power flow distribution of the load. The load carbon flow rate vector R L It is an M-order column vector describing the carbon emissions generated per unit time by the power generation side supplying electricity to the load, and can be represented as:

[0072] R L =P L E N (6)

[0073] (9) Establish a static carbon flow calculation model:

[0074]

[0075] Among them, e Ni I is the carbon potential of the i-th node. + p is the set of upstream branches of node i. Bs It is the active power of branch s, ρ s p is the branch carbon flux density of branch s. Gi e is the active power generated by the generator at node i. Gi It is the carbon emission intensity of the generator at node i.

[0076] The matrix form of formula (7) is:

[0077] Among them, E N It is the nodal carbon potential vector matrix, P N It is the nodal active flux matrix, P B It is the branch power flow distribution matrix, P G It is the unit injection distribution matrix, E G It is the carbon emission factor vector of the generator set.

[0078] E is obtained according to formula (8) N Then, the carbon flow rate R of the branch is calculated using formulas (9) and (10). B and load carbon flow rate RL The calculations ultimately complete the calculation of the carbon flow distribution of the entire system.

[0079]

[0080] R L =P L E N (10)

[0081] Since the relevant matrices or vectors (such as branch power flow distribution matrix, unit injection distribution matrix, load distribution matrix, generator carbon emission intensity vector, etc.) are sparse matrices related to the power system topology, fully utilizing sparsity techniques can greatly improve the solution speed of the power system static carbon flow calculation method. In this embodiment, a distributed storage method is adopted to record the row and column positions of non-zero elements in the matrix, as well as the numerical value of the element, and then substitute them into the model for solution.

[0082] Because formula (8) requires... To find the inverse, we need to ensure its reversibility: if the system has isolated nodes, or if in steady state a node's connected lines have zero power flow, then P will... N The corresponding diagonal element is 0, and because P B If all diagonal elements are 0, it will result in... If there are diagonal elements that are 0, then... If the situation is irreversible, the node, along with its connected generator sets and branches, must first be removed from the matrix. After calculating the system's carbon emission flow distribution, it can then be added back to the resulting matrix. If the above is not the case, then... All diagonal elements are non-zero, so calculations can be performed directly.

[0083] (II) Constructing a fast calculation model for carbon flow in power system intervals.

[0084] In actual production, the carbon emission factor of generator units is not constant and often varies within a certain range depending on factors such as unit operation, energy combustion, and energy type. Therefore, based on the above static carbon flow calculation model, it is necessary to introduce the interval Krawczyk factor iteration algorithm to construct a fast interval carbon flow calculation model for the power system, and complete the interval carbon flow calculation taking into account the fluctuation of the generator unit's carbon emission factor.

[0085] Transform formula (8) into the standard form of Ax = b:

[0086]

[0087] in, E GThe carbon emission factor, which is a fluctuation of the generator set, is an input in interval form.

[0088] The interval Krawczyk factor iteration method first requires preprocessing the interval equation Ax = b by multiplying it by the inverse of the midpoint matrix of A, denoted as C, to obtain:

[0089]

[0090] in, x (i) The vector solution to the interval equation for the i-th iteration satisfies:

[0091]

[0092] in, Let ∑(A,b) be the smallest radius interval vector containing the solution set ∑(A,b) of Ax=b.

[0093] get:

[0094]

[0095] Next, the Krawczyk factor iteration formula is given:

[0096] x (i+1) = (Cb+(I-CA)x (i) )∩x (i) (15)

[0097] To begin the iteration, we need to provide the initial value vector x. (0) , so that:

[0098]

[0099]

[0100] Find a feasible x using the following formula (0) :

[0101] x (0) =([-α,α],...,[-α,α]) T (18)

[0102] in,

[0103] If through iteration, x (i) The iteration can terminate when the component radii no longer decrease rapidly. The sum of these radii can be calculated after each iteration and compared with the previous sum.

[0104] Using the interval Krawczyk factor iteration method described above, E in formula (11) can be obtained. NSolving for E yields an interval vector. N Substituting into formulas (9) and (10), the interval calculation of carbon emission flow rate of branch and load can be completed.

[0105] This completes the rapid calculation of power system range carbon flow taking into account fluctuations in generator carbon emission factors.

[0106] To verify the effectiveness of the proposed method for rapid calculation of interval carbon flow considering the fluctuation of generator carbon emission factors in this embodiment, the interval carbon flow in the IEEE 14-bus power system scenario was solved using the method designed in this embodiment in the MATLAB 2017a environment. The topology diagram of the system is shown below. Figure 2 As shown.

[0107] This simulation example is based on the following three scenarios:

[0108] (1) Without considering the fluctuation of the carbon emission factor of the generator set, the carbon potential (i.e. carbon emission factor) of the generator set is a constant value, and the carbon emission related parameters (numerical form) are calculated.

[0109] (2) Considering the carbon emission factor of the generator set, and directly using the interval arithmetic operation rules, calculate the carbon emission related parameters (interval form);

[0110] (3) Consider the carbon emission factor of the generator set and use the Krawczyk factor iteration method to calculate the carbon emission related parameters (interval form).

[0111] In the three scenarios described above, the carbon emission factor E of the generator set... G As shown in Table 1, the carbon potential E is calculated using either the basic carbon emission flow calculation model or a carbon emission flow calculation model that considers fluctuations in the carbon emission factor. N The calculation results are shown in Table 2.

[0112] As shown in Table 2, the nodal carbon potential results obtained using the interval Krawczyk factor iteration method are narrower than those obtained using the interval arithmetic rules, and the former is contained within the latter. Specifically, the average width of the former is 13.59% of the width of the latter, with 57.14% of the cases having a width less than 10%, 92.86% less than 30%, and 100% less than 55%, indicating that the Krawczyk factor iteration method has good accuracy.

[0113] Table 1

[0114]

[0115] Table 2

[0116]

[0117]

[0118] like Figure 3 The diagram shows the results for two interval calculation methods. It can be seen that using the Krawczyk factor iteration method can significantly reduce the interval width of the results, thereby reducing interval conservatism.

[0119] Table 3 shows a comparison of computation time in the IEEE 13659 example when the correlation matrix is ​​used as a full matrix or a sparse matrix. It can be seen that when the correlation matrix is ​​used as a sparse matrix, the average computation time is only 18.93% of the average time when the correlation matrix is ​​used as a full matrix. Therefore, when the number of nodes in a power system is large, sparse techniques can significantly reduce computation time.

[0120] Table 3

[0121]

[0122] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for rapid calculation of interval carbon flow taking into account fluctuations in the carbon emission factor of generator sets, characterized in that, include: A static carbon flow calculation model for a power system is established by determining the carbon flow-related matrices and vectors and combining them with the flow properties of carbon emissions. The matrices and vectors are used for centralized and rapid calculation. In the static carbon flow calculation model of the power system, the interval Krawczyk factor iteration algorithm is introduced, that is, the interval data of the carbon emission factor fluctuation of the generator units of the power system are collected, and the interval Krawczyk factor iteration algorithm is introduced into the static carbon flow calculation model of the power system to construct a fast calculation model of the interval carbon flow of the power system. Based on the aforementioned fast calculation model for inter-regional carbon flow in the power system, inter-regional carbon flow calculations are performed, taking into account fluctuations in the carbon emission factors of generating units: The nodal carbon potential vector is obtained according to the aforementioned fast calculation model for inter-regional carbon flow in the power system. According to the node carbon potential vector Obtain the branch carbon flow rate distribution matrix from the power flow distribution of the branches. According to the node carbon potential vector Obtain the load carbon flow rate vector from the load power flow distribution. Finally, the carbon flow distribution calculation for the entire system was completed.

2. The method for rapid calculation of interval carbon flow taking into account the fluctuation of carbon emission factors of generator sets according to claim 1, characterized in that, The matrix includes: Branch power flow distribution matrix, used to represent the distribution of active power flow in the system; The generator injection distribution matrix is ​​used to represent the topology of generator sets in the power system network and the magnitude of active power injected into the system by the generator sets; The load distribution matrix is ​​used to represent the topological relationship between the load and the system and the amount of active power consumed by the load. The node active power flux matrix is ​​used to represent the total active power flow into the node. The branch carbon flow rate distribution matrix is ​​used to represent the distribution of carbon flow rate in the system.

3. The method for rapid calculation of interval carbon flow considering the fluctuation of carbon emission factors of generator sets according to claim 1, characterized in that, The vector includes: The generator set carbon emission intensity vector is used to represent the carbon emission characteristics of each generator set. The node carbon potential vector is used to represent the carbon emission characteristics of each node. The load carbon flow rate vector is used to represent the amount of carbon emissions generated per unit time by the power generation side supplying electricity to the load.

4. The method for rapid calculation of interval carbon flow considering the fluctuation of carbon emission factors of generator sets according to claim 1, characterized in that, The representation method of the matrix and vector includes: adopting a scattered storage method to record the row and column positions of the non-zero elements of the matrix and vector in the matrix, as well as the numerical value of the element.

5. The method for rapid calculation of interval carbon flow taking into account the fluctuation of carbon emission factors of generator sets according to claim 1, characterized in that, The establishment of the static carbon flow calculation model of the power system includes: based on the matrix and vector, and combining the power system power flow calculation method and the advanced power network analysis method, the static carbon flow calculation model of the power system is established.

6. The method for rapid calculation of interval carbon flow taking into account the fluctuation of carbon emission factors of generator sets according to claim 5, characterized in that, The static carbon flow calculation model for the power system is as follows: in, It is the nodal carbon potential vector. It is the active flux matrix of the nodes. It is the branch power flow distribution matrix. It is the unit injection distribution matrix. It is the carbon emission intensity vector of the generator set. It is the branch carbon flow rate distribution matrix. It is the dot product symbol. It is This N Tiling of column vectors N Secondary formation N × N Relationship matrix, It is the load carbon flow rate vector. It is the load distribution matrix.

7. The method for rapid calculation of interval carbon flow taking into account the fluctuation of carbon emission factors of generator sets according to claim 5, characterized in that, The static carbon flow calculation model of the power system Need to ensure Invertibility, if there exists a node with a node active flux matrix P N The diagonal element is 0, at this time If the process is irreversible, the node, along with its connected generator sets and branches, will be removed from the matrix. After calculating the distribution of carbon emissions in the system, the node will be added back to the result matrix.

8. The method for rapid calculation of interval carbon flow taking into account the fluctuation of carbon emission factors of generator sets according to claim 1, characterized in that, Introducing the interval Krawczyk factor iteration algorithm into the power system static carbon flow calculation model includes: The static carbon flow calculation model of the power system The equations are converted into standard form, and the converted interval equations are preprocessed to obtain the vector solution of the interval equations in the i-th iteration. Iterate using the interval Krawczyk factor iteration algorithm until... The component radius no longer decreases, and the iteration terminates.

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