Method for analyzing and calculating carbon emission of district and county-level power grid

Abstract

The invention relates to a district and county-level power grid carbon emission analysis and calculation method, which comprises the following steps: carrying out generator set carbon emission characteristic analysis to obtain a generator set carbon emission intensity vector; constructing a load flow calculation matrix; according to the generator set carbon emission intensity vector and the load flow calculation matrix, district and county power grid carbon emission distribution calculation is carried out, a node carbon potential matrix is calculated, and the carbon flow rate of each branch and the load carbon flow rate of the district and county power grid are obtained. Within a short time scale, the power grid is helped to modify the operation mode, and low-carbon optimized operation of the power grid is realized; within a long time scale, carbon emission of the system can be delicately defined and low-carbon responsibility division can be carried out through carbon emission of each node, and by comparing carbon emission conditions of high-voltage levels of power grids in different districts and counties, cost benefits of different emission reduction measures can be evaluated, an emission reduction strategy with the most cost benefits can be determined, and the method is suitable for popularization and application. Data support is provided for the government and decision makers, and making and implementation of emission reduction policies are helped.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon emission analysis of electric power systems, and in particular to a method for analyzing and calculating carbon emission of district and county-level power grids. Background Art

[0002] As the end of the power system, the county-level power grid is directly connected to the majority of users. Its operating efficiency and the implementation of carbon reduction measures are crucial to the realization of the overall carbon reduction target. The traditional carbon emission analysis method is a macro-statistical method, which measures carbon emissions by converting the consumption of primary energy such as coal and oil. In the power system, this method only considers thermal power plants as carbon emission sources for research, which cannot reflect the "network" characteristics of the power grid.

[0003] With the introduction of the concept of carbon emission flow, carbon emissions are combined with power flow to establish the concept and theoretical framework of carbon emission flow in power systems. Carbon emission flow has become a basic analysis tool with clear physical meaning in the power system and can describe in detail the carbon emission conversion relationship in the process of power production and consumption. It provides a good idea for the expansion of low-carbon power research. However, this concept does not take into account the actual operating conditions of the generator set, and is not highly compatible with the district and county power grids with large-scale new energy access. It is mostly used at the medium voltage level, ignoring the carbon emission needs of the high voltage level of the district and county power grids. Therefore, the carbon emission analysis method of the district and county power grid considering the high voltage level needs to be further improved. Summary of the invention

[0004] In order to solve the problem of incompatibility between traditional methods and carbon emission demands of county-level power grids, the purpose of the present invention is to provide a method for analyzing and calculating carbon emissions of county-level power grids that efficiently couples the power flow at the high-voltage level of the county-level power grid with the carbon emission flow, comprehensively considers the impact of a high proportion of clean energy accessed by the county-level power grid on the county-level power grid, and quickly and accurately calculates the distribution of carbon emission flows of the county-level power grid based on the flow calculation, identifies high-carbon emission nodes, and provides a basis for implementing carbon emission reduction measures.

[0005] To achieve the above purpose, the present invention adopts the following technical solution: a method for analyzing and calculating carbon emissions of district and county-level power grids, the method comprising the following steps in order:

[0006] (1) Analyze the carbon emission characteristics of the generator set and obtain the carbon emission intensity vector of the generator set;

[0007] (2) Construct the power flow calculation matrix;

[0008] (3) Based on the carbon emission intensity vector of the generator set and the power flow calculation matrix, the carbon emission distribution of the county power grid is calculated, the node carbon potential matrix is ​​calculated, and the carbon flow rate and load carbon flow rate of each branch of the county power grid are obtained.

[0009] The step (1) specifically refers to: assuming that the total number of nodes at the high-voltage level of the district-level power grid is N, the total number of nodes including generator sets is K, and the total number of nodes including loads is M; different generator sets have different carbon emission characteristics, and the carbon emission characteristics of each unit are characterized by carbon emission intensity, and the carbon emission intensity of each unit constitutes the carbon emission intensity vector of the generator set; assuming that the carbon emission intensity of the kth generator set is e Gk , k=1,2,...,K, then the carbon emission intensity vector E of the generator set G for:

[0010]

[0011] The step (2) specifically refers to: the power flow calculation matrix includes a branch power flow distribution matrix, a unit injection distribution matrix, a load distribution matrix and a node active flux matrix;

[0012] The branch power flow distribution matrix P B For an N-order square matrix, the formula is:

[0013]

[0014] Where N is the total number of nodes at the high voltage level of the county-level power grid, i and j are both county-level power grid nodes, and P Bij is the matrix element, P Bij ∈P B ; If there is a branch connecting node i and node j, i, j = 1, 2, ..., N, and the positive active power flow from node i to node j through this branch is p1, then P Bij =p1,P Bji =0; if the flow flows from node j to node i, then P Bij =0,P Bji =p1; branch power flow distribution matrix P B All elements that are not connected by branches are 0;

[0015] The unit injection distribution matrix P G It is a K×N square matrix, and the formula is:

[0016] P G =(P Gkj ) K×N

[0017] Where P Gkj is the matrix element, P Gkj ∈P G ; K is the total number of nodes containing generators, k is the kth generator, k = 1, 2, ..., K, if the kth generator is connected to node j, and the active power flow injected into node j from the kth node containing a generator is p2, then P Gkj=p2, if node j does not contain a generator set, then P Gkj =0;

[0018] The load distribution matrix P L For an M×N square matrix, the formula is:

[0019] P L =(P Lmj ) M×N

[0020] Where P Lmj is the matrix element, P Lmj ∈P L ; M is the total number of nodes with load, m = 1, 2, ..., M; if node j is the mth node with load, and the active load is p3, then P Lmj = p3, if there is no load on node j, then P Lmj =0;

[0021] The node active flux matrix P N is an N-order square matrix, the node active flux matrix P N Through the branch power distribution matrix P B and the unit injection distribution matrix P G Generate, the node active flux matrix P N The formula is:

[0022] P N =diag(α N+K [P B P G ] T )

[0023] In the formula, α N+K is a row vector of order N+K, α N+K All elements in are 1.

[0024] In step (3), the node carbon potential matrix E N The calculation formula is:

[0025]

[0026] Where P N is the node active flux matrix, P B is the branch power flow distribution matrix, P G Inject the distribution matrix into the unit, E G is the carbon emission intensity vector of the power generation unit;

[0027] Calculate the branch carbon flow rate distribution matrix R of each branch of the power grid B :

[0028] R B=P B diag(E N )

[0029] Branch carbon flow rate distribution matrix R B It is an N-order square matrix, characterized by:

[0030] R B =(R B i j ) N×N

[0031] Where: R B i j is the matrix element of the branch carbon flow rate distribution matrix, which is expressed as the carbon flow rate of the ijth branch, R B i j ∈R B ; i, j are both district and county power grid nodes, i, j = 1, 2, ..., N, N is the total number of nodes at the high voltage level of the district and county power grid; if there is a branch connecting node i and node j, and the positive carbon flow rate from node i to node j through this branch is R, then R Bij =R, R Bji = 0; if the flow flows from node j to node i, then R Bij =0, R Bji =R; branch carbon flow rate distribution matrix R B All elements that are not connected by branches are 0;

[0032] According to the node carbon potential matrix E N and load distribution matrix P L , and the load carbon flow rate vector is obtained, and the calculation formula is:

[0033] R L =P L E N

[0034] The load carbon flow rate vector has M load nodes, which can be represented as:

[0035] R L =[R L1 R L2 ...R LM ] T

[0036] Where: R Lm is the element of the load carbon flow rate vector, indicating the load carbon flow rate of the mth node; R Lm ∈R L , m=1,2,...,M, where M is the total number of nodes with load.

[0037] It can be seen from the above technical scheme that the beneficial effects of the present invention are: first, the present invention is based on a certain time section and can be extended to apply to multi-time period problems to obtain the change process of carbon potential of different nodes in the power grid in different time periods; second, in a short time scale, the present invention helps to assist the power grid to modify its operation mode, or provide an adjustment basis for the user-side low-carbon response mechanism, optimize the energy structure, increase the proportion of renewable energy, and achieve low-carbon optimized operation of the power grid; third, in a long time scale, the present invention can make a more detailed definition and low-carbon responsibility division of the system's carbon emissions through the carbon emissions of each node, and by comparing the carbon emissions of the high-voltage level of the power grid in different counties and districts, it is helpful to evaluate the cost-effectiveness of different emission reduction measures, determine the most cost-effective emission reduction strategy, provide data support for the government and decision makers, and help formulate and implement emission reduction policies. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a flow chart of the method of the present invention;

[0039] Figure 2 is the tidal distribution map;

[0040] Figure 3 This is the carbon flow distribution diagram. DETAILED DESCRIPTION

[0041] like Figure 1 As shown, a method for analyzing and calculating carbon emissions of a county-level power grid includes the following steps in order:

[0042] (1) Analyze the carbon emission characteristics of the generator set and obtain the carbon emission intensity vector of the generator set;

[0043] (2) Construct the power flow calculation matrix;

[0044] (3) Based on the carbon emission intensity vector of the generator set and the power flow calculation matrix, the carbon emission distribution of the county power grid is calculated, the node carbon potential matrix is ​​calculated, and the carbon flow rate and load carbon flow rate of each branch of the county power grid are obtained.

[0045] The step (1) specifically refers to: assuming that the total number of nodes at the high-voltage level of the district-level power grid is N, the total number of nodes including generator sets is K, and the total number of nodes including loads is M; different generator sets have different carbon emission characteristics, and the carbon emission characteristics of each unit are characterized by carbon emission intensity, and the carbon emission intensity of each unit constitutes the carbon emission intensity vector of the generator set; assuming that the carbon emission intensity of the kth generator set is e Gk , k=1,2,...,K, then the carbon emission intensity vector E of the generator set G for:

[0046] E G =[e G1 e G2 …eGK ] T .

[0047] The step (2) specifically refers to: the power flow calculation matrix includes a branch power flow distribution matrix, a unit injection distribution matrix, a load distribution matrix and a node active flux matrix;

[0048] The branch power flow distribution matrix P B For an N-order square matrix, the formula is:

[0049] P B =(P Bij ) N×N

[0050] Where N is the total number of nodes at the high voltage level of the county-level power grid, i and j are both county-level power grid nodes, and P Bij is the matrix element, P Bij ∈P B ; If there is a branch connecting node i and node j, i, j = 1, 2, ..., N, and the positive active power flow from node i to node j through this branch is p1, then P Bij =p1,P Bji =0; if the flow flows from node j to node i, then P Bij =0,P Bji =p1; branch power flow distribution matrix P B All elements that are not connected by branches are 0;

[0051] The unit injection distribution matrix P G It is a K×N square matrix, and the formula is:

[0052] P G =(P Gkj ) K×N

[0053] Where P Gkj is the matrix element, P Gkj ∈P G ; K is the total number of nodes containing generators, k is the kth generator, k = 1, 2, ..., K, if the kth generator is connected to node j, and the active power flow injected into node j from the kth node containing a generator is p2, then P Gkj =p2, if node j does not contain a generator set, then P Gkj =0;

[0054] The load distribution matrix P L For an M×N square matrix, the formula is:

[0055] P L =(P Lmj ) M×N

[0056] Where P Lmj is the matrix element, P Lmj ∈P L ; M is the total number of nodes with load, m = 1, 2, ..., M; if node j is the mth node with load, and the active load is p3, then P Lmj = p3, if there is no load on node j, then P Lmj =0;

[0057] The node active flux matrix P N is an N-order square matrix, the node active flux matrix P N Through the branch power distribution matrix P B and the unit injection distribution matrix P G Generate, the node active flux matrix P N The formula is:

[0058] P N =diag(α N+K [P B P G ] T )

[0059] In the formula, α N+K is a row vector of order N+K, α N+K All elements in are 1.

[0060] In step (3), the node carbon potential matrix E N The calculation formula is:

[0061]

[0062] Where P N is the node active flux matrix, P B is the branch power flow distribution matrix, P G Inject the distribution matrix into the unit, E G is the carbon emission intensity vector of the power generation unit;

[0063] Calculate the branch carbon flow rate distribution matrix R of each branch of the power grid B :

[0064] R B =P B diag(E N )

[0065] Branch carbon flow rate distribution matrix R B It is an N-order square matrix, characterized by:

[0066] R B =(R Bij ) N×N

[0067] Where: R Bij is the matrix element of the branch carbon flow rate distribution matrix, which is expressed as the carbon flow rate of the ijth branch, R Bij ∈R B ; i, j are both district and county power grid nodes, i, j = 1, 2, ..., N, N is the total number of nodes at the high voltage level of the district and county power grid; if there is a branch connecting node i and node j, and the positive carbon flow rate from node i to node j through this branch is R, then R Bij =R, R Bji = 0; if the flow flows from node j to node i, then R Bij =0, R Bji =R; branch carbon flow rate distribution matrix R B All elements that are not connected by branches are 0;

[0068] According to the node carbon potential matrix E N and load distribution matrix P L , and the load carbon flow rate vector is obtained, and the calculation formula is:

[0069] R L =P L E N

[0070] The load carbon flow rate vector has M load nodes, which can be represented as:

[0071] R L =[R L1 R L2 ...R LM ] T

[0072] Where: R Lm is the element of the load carbon flow rate vector, indicating the load carbon flow rate of the mth node; R Lm ∈R L , m=1,2,...,M, where M is the total number of nodes with load.

[0073] Take a county-level power grid with 38 nodes, 15 of which have generator injection, 22 nodes with load, and a known high-voltage hierarchical network topology as an example. Among the 15 nodes injected with generators, 3 are from the large power grid, and the carbon emission intensity is the average carbon emission factor of the large power grid, 763gCO2 / kWh. The remaining units are clean energy, and the carbon emission intensity is 0gCO2 / kWh. Then the carbon emission intensity vector of the generator set is:

[0074] E G =[000000000000763763763] T

[0075] The power flow calculation is performed on the high voltage level of the district and county power grid. The power flow distribution diagram is shown as follows: Figure 2 As shown, Figure 2 The single circle in the middle is a 35kV or 110kV substation, the double circle is a 220kV substation, the small circle is a T-junction node, the square with a slash is a hydropower station, and the square with a horizontal line is a wind farm; the line with an arrow between the two circles is a line, where the arrow indicates the direction of the flow, and the numbers on the line indicate the active value of the flow, in MW.

[0076] Based on the power flow calculation results, the branch power flow distribution matrix, unit injection distribution matrix, load distribution matrix and node active flux matrix are established as shown in Tables 1, 2, 3 and 4. In order to clearly display the data, some row and column data are hidden.

[0077] Table 1 Branch flow distribution matrix (partial display)

[0078]

[0079] Table 2 Unit injection distribution matrix (partial display)

[0080]

[0081]

[0082] Table 3 Load distribution matrix (partial display)

[0083] Load distribution matrix 1 2 3 4 5 34 35 36 37 38 1 0 0 0 0 0 0 0 0 0 0 2 0 1.4 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 4 0 0 0 1.9 0 0 0 0 0 0 5 0 0 0 0 4.9 0 0 0 0 0 34 0 0 0 0 0 3.1 0 0 0 0 35 0 0 0 0 0 0 0 0 0 0 36 0 0 0 0 0 0 0 0 0 0 37 0 0 0 0 0 0 0 0 0 0 38 0 0 0 0 0 0 0 0 0 0

[0084] Table 4 Node active flux matrix (partial display)

[0085]

[0086] Calculate the node carbon potential, and then obtain the carbon flow rate and load carbon flow rate of the high-voltage level branch of the district and county power grid. The calculation results are shown in Tables 5, 6, and 7. The carbon flow distribution diagram is shown in Figure 3 As shown, Figure 3 The G in the middle represents the generator set, and the horizontal line with numbers represents the district and county power grid nodes and node numbers; the lines between nodes are marked with arrows and numbers, where the arrows represent the branch carbon flow direction, and the numbers represent the branch carbon flow rate; the individual arrows and numbers of the nodes indicate that the node is a load node, and the numbers represent the load carbon flow rate. At this point in time, the unit injected carbon flow rate was 35.63gCO2 / kWh, and the load carbon flow rate was 35.63gCO2 / kWh.

[0087] Table 5 Node carbon potential calculation results (partial display)

[0088]

[0089] Table 6 Calculation results of branch carbon flow rate (partial display)

[0090] Node i Node j <![CDATA[Branch carbon flow rate (tCO2 / h)]]> 1 2 0.30 1 3 2.14 1 16 8.76 1 18 10.57 1 29 3.41 31 32 0.16 32 33 -0.11 33 34 -0.27 34 35 -0.44 36 37 -10.45 36 38 0

[0091] Table 7 Load carbon flow rate calculation results (partial display)

[0092] node <![CDATA[Load carbon flow rate (tCO2 / h)]]> <![CDATA[Unit carbon injection flow rate (tCO2 / h)]]> 1 0.00 25.18 2 0.33 0.00 3 0.00 0.00 4 0.44 0.00 5 1.14 0.00 34 0.18 0.00 35 0.00 0.00 36 0.00 0.00 37 0.00 10.45 38 0.00 0.00 total 35.62 35.63

[0093] The present invention is based on a certain time section and can be extended to multiple time period problems to obtain the changing process of carbon potential at different nodes in the power grid at different time periods. In the short time scale, it helps to assist the power grid to modify its operation mode, or provide a basis for adjustment for the low-carbon response mechanism on the user side, optimize the energy structure, increase the proportion of renewable energy, and achieve low-carbon optimized operation of the power grid; in the long time scale, the carbon emissions of the system can be more carefully defined and low-carbon responsibilities can be divided through the carbon emissions of each node. By comparing the carbon emissions of the high-voltage level of power grids in different counties and districts, it helps to evaluate the cost-effectiveness of different emission reduction measures, determine the most cost-effective emission reduction strategy, provide data support for the government and decision makers, and help formulate and implement emission reduction policies.

Claims

1. A method for analyzing and calculating carbon emissions of district and county-level power grids, characterized by: The method comprises the following steps in order: (1) Analyze the carbon emission characteristics of the generator set and obtain the carbon emission intensity vector of the generator set; (2) Construct the power flow calculation matrix; (3) Based on the carbon emission intensity vector of the generator set and the power flow calculation matrix, the carbon emission distribution of the county power grid is calculated, the node carbon potential matrix is ​​calculated, and the carbon flow rate and load carbon flow rate of each branch of the county power grid are obtained.

2. The method for analyzing and calculating carbon emissions of district and county-level power grids according to claim 1 is characterized by: The step (1) specifically refers to: assuming that the total number of nodes at the high-voltage level of the district-level power grid is N, the total number of nodes including generator sets is K, and the total number of nodes including loads is M; different generator sets have different carbon emission characteristics, and the carbon emission characteristics of each unit are characterized by carbon emission intensity, and the carbon emission intensity of each unit constitutes the carbon emission intensity vector of the generator set; assuming that the carbon emission intensity of the kth generator set is e Gk , k=1,2,...,K, then the carbon emission intensity vector E of the generator set G for: AND G =[and G1 And G2 …And GK ] T 。 3. The method for analyzing and calculating carbon emissions of district and county-level power grids according to claim 1 is characterized by: The step (2) specifically refers to: the power flow calculation matrix includes a branch power flow distribution matrix, a unit injection distribution matrix, a load distribution matrix and a node active flux matrix; The branch power flow distribution matrix P B For an N-order square matrix, the formula is: P B =(P Bij ) N×N Where N is the total number of nodes at the high voltage level of the county-level power grid, i and j are both county-level power grid nodes, and P Bij is the matrix element, P Bij ∈P B ; If there is a branch connecting node i and node j, i, j = 1, 2, ..., N, and the positive active power flow from node i to node j through this branch is p1, then P Bij =p1,P Bji =0; if the flow flows from node j to node i, then P Bij =0,P Bji =p1; Branch power flow distribution matrix P B All elements that are not connected by branches are 0; The unit injection distribution matrix P G It is a K×N square matrix, and the formula is: P G =(P Gkj ) K×N Where P Gkj is the matrix element, P Gkj ∈P G ; K is the total number of nodes containing generators, k is the kth generator, k = 1, 2, ..., K, if the kth generator is connected to node j, and the active power flow injected into node j from the kth node containing a generator is p2, then P Gkj =p2, if node j does not contain a generator set, then P Gkj =0; The load distribution matrix P L For an M×N square matrix, the formula is: P L =(P Lmj ) M×N Where P Lmj is the matrix element, P Lmj ∈P L ; M is the total number of nodes with load, m = 1, 2, ..., M; if node j is the mth node with load, and the active load is p3, then P Lmj = p3, if there is no load on node j, then P Lmj =0; The node active flux matrix P N is an N-order square matrix, the node active flux matrix P N Through the branch power flow distribution matrix P B and the unit injection distribution matrix P G Generate, the node active flux matrix P N The formula is: P.S N diag(α N+K [P B P.S G ] T ) In the formula, α N+K is a row vector of order N+K, α N+K All elements in are 1.

4. The method for analyzing and calculating carbon emissions of district and county-level power grids according to claim 1 is characterized by: In step (3), the node carbon potential matrix E N The calculation formula is: Where P N is the node active flux matrix, P B is the branch power flow distribution matrix, P G Inject the distribution matrix into the unit, E G is the carbon emission intensity vector of the power generation unit; Calculate the branch carbon flow rate distribution matrix R of each branch of the power grid B : R B JP B diag(E N ) Branch carbon flow rate distribution matrix R B It is an N-order square matrix, characterized by: R B =(R Bij ) N×N Where: R Bij is the matrix element of the branch carbon flow rate distribution matrix, which is expressed as the carbon flow rate of the ijth branch, R Bij ∈R B ; i, j are both district and county power grid nodes, i, j = 1, 2, ..., N, N is the total number of nodes at the high voltage level of the district and county power grid; if there is a branch connecting node i and node j, and the positive carbon flow rate from node i to node j through this branch is R, then R Bij =R, R Bji = 0; if the flow flows from node j to node i, then R Bij =0, R Bji =R; Branch carbon flow rate distribution matrix R B All elements that are not connected by branches are 0; According to the node carbon potential matrix E N and load distribution matrix P L , and the load carbon flow rate vector is obtained, and the calculation formula is: R L =P L E N The load carbon flow rate vector has M load nodes, which can be represented as: R L =[R L1 R L2 ...R LM ] T Where: R Lm is the element of the load carbon flow rate vector, indicating the load carbon flow rate of the mth node; R Lm ∈R L , m=1,2,...,M, where M is the total number of nodes with load.

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