A method for calculating carbon potential of a node containing energy storage equipment based on carbon emission flow theory

Abstract

The application discloses a new method for calculating carbon potential of a node containing energy storage equipment based on carbon emission flow theory, and comprises the following steps: (1) constructing a basic topology model of carbon emission flow containing energy storage equipment; (2) determining the working state of the energy storage equipment, including two states of power generation and charging, if the state is power generation, the energy storage equipment is regarded as a generator set, a carbon flow analysis model is established to solve the carbon potential of each node; (3) if the energy storage equipment is in the discharging state, the energy storage equipment is regarded as a generator set, because the charging efficiency and the energy loss problem exist in the energy storage process, the carbon potential of the node is different from that of the node in the charging state. The application considers the carbon flow calculation method containing the energy storage equipment, and ensures the conservation of carbon content and the accurate calculation of the carbon potential of each node.

Description

Technical Field

[0001] This invention is designed for the field of low-carbon power, and in particular relates to a new method for the carbon potential of nodes containing energy storage devices based on carbon emission flow theory. Background Technology

[0002] As a major force in energy conservation and emission reduction, the power industry urgently needs to analyze and control carbon emissions from power systems. Therefore, methods for calculating power system carbon emission flows are rapidly developing and being applied. Currently, the calculation of power system carbon emission flows mainly relies on power flow calculations and proportionality principles to analyze carbon flow and obtain relevant carbon flows such as carbon potential at each node and line carbon flow density.

[0003] Existing research mainly focuses on simple power grid models consisting only of generating units and loads. These calculation methods ignore power grid structures with energy storage devices. As distributed power sources and energy storage devices are established, these calculation methods are gradually becoming inapplicable, thus affecting the analysis and monitoring of carbon emissions from the power system. Summary of the Invention

[0004] The present invention aims to overcome at least one defect and deficiency of the prior art and provide a method for calculating the carbon potential of nodes containing energy storage devices based on carbon emission flow theory.

[0005] In view of this, the present invention proposes a novel method for calculating the carbon potential of nodes containing energy storage devices based on carbon emission flow theory, comprising the following steps: Step 1. Constructing a basic topological model of carbon emission flow containing energy storage devices; Step 2. Determining the operating state of the energy storage devices, including both power generation and charging states. If in power generation state, it is treated as a generator set, and a carbon flow analysis model is established to solve for the carbon potential of each node; Step 3. If the energy storage device is in a discharging state, it is treated as a generator set. Due to the charging efficiency and partial energy loss issues during energy storage, the node carbon potential differs from that in the charging state. This invention considers a carbon flow calculation method containing energy storage devices, ensuring both carbon content conservation and accurate calculation of the carbon potential of each node, thus guaranteeing a fair and equitable allocation of carbon responsibility.

[0006] Specifically:

[0007] Step 1 includes:

[0008] Step 1.1: Establish a basic topological model of the carbon emission flow containing energy storage devices, and construct a computational problem for the carbon emission flow containing energy storage devices;

[0009] Step 2 includes:

[0010] Step 2.1: Calculation of node carbon potential of energy storage device in charging state;

[0011] Step 3 includes:

[0012] Step 3.1: Considering that energy storage devices will lose energy during charging, and the carbon content of carbon nodes does not change with energy loss, the energy storage device is regarded as a generator in the discharge state. The carbon emission intensity of the node in the discharge state will inevitably be different from that of the node in the charging state.

[0013] Step 3.2: Follow the trend;

[0014] Step 3.3: Calculation of node carbon potential under charging conditions.

[0015] This invention considers a carbon flow calculation method that includes energy storage devices, which ensures both the conservation of carbon content and the accurate calculation of carbon potential at each node, thus guaranteeing a fair and equitable allocation of carbon responsibility. Attached Figure Description

[0016] Figure 1 This is a flowchart of the present invention.

[0017] Figure 2 This is a graph showing the relationship between node carbon potential and branch carbon flux density in this invention.

[0018] Figure 3 This is a schematic diagram of the circuit of the present invention.

[0019] Figure 4 This is a diagram of an IEEE 14 bus test system according to an embodiment of the present invention.

[0020] Figure 5 This is a daily load power diagram according to an embodiment of the present invention.

[0021] Figure 6 This is a diagram showing the charging and discharging power of the energy storage device according to an embodiment of the present invention.

[0022] Figure 7 This is a graph showing the relationship between charging time and carbon emission intensity in an embodiment of the present invention.

[0023] Figure 8 This is a graph showing the carbon content per unit of electricity per day in an embodiment of the present invention.

[0024] Figure 9 This is a graph showing the energy and carbon content of a 24-hour energy storage device according to an embodiment of the present invention.

[0025] Figure 10 This is a node carbon potential diagram of the energy storage device within 24 hours according to an embodiment of the present invention. Detailed Implementation

[0026] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the invention. To better illustrate the following embodiments, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions; it is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0027] like Figure 1 As shown, this invention discloses a novel method for determining the carbon potential of nodes containing energy storage devices based on carbon emission flow theory, comprising the following steps:

[0028] Step 1: Construct a basic topological model of the carbon emission flow containing energy storage devices;

[0029] Step 2: Determine the operating status of the energy storage device, including both power generation and charging states. If it is in power generation state, treat it as a generator set and establish a carbon flow analysis model to solve the carbon potential of each node.

[0030] Step 3: If the energy storage device is in a discharging state, it is considered as a generator set. Due to the charging efficiency and partial energy loss issues during the energy storage process, the node carbon potential is different from the node carbon potential in the charging state. It is necessary to recalculate the node potential in the power generation state and then recalculate the carbon potential of other nodes.

[0031] Specifically, step 1 includes:

[0032] Step 1.1: Establish a basic topological model of the carbon emission flow containing energy storage devices, and construct the computational problem of the carbon emission flow containing energy storage devices:

[0033] The following is an important conclusion derived from the basic idea of ​​power flow tracing, which reveals the relationship between the carbon potential of a node and the carbon flow density of its adjacent branches in carbon flow analysis.

[0034] Suppose a node n in a power system and its adjacent branches are as follows: Figure 2 As shown.

[0035] Let N be the set of branches for the inflow and outflow nodes n. + and N - Then the active power flow from the i-th branch into node n and from the j-th branch out of node n are respectively P i and P j (i∈N + j∈N - According to the principle of proportional sharing, every branch of the outflowing tidal current contains a component of every inflowing tidal current. Let P be the component of the j-th branch of the outflowing tidal current containing the i-th branch of the inflowing tidal current. j.i ,have

[0036]

[0037] If from line i (i∈N) + The carbon flux density of the active power flow flowing into node n is ρ. i Then the carbon flow rate of the active power flow in the j-th outflow branch should be the same as that of all N. + The sum of the contributions of the middle branch to the carbon flow rate of branch j is expressed as follows:

[0038]

[0039] Therefore, the carbon flux density ρ' of branch j i (j∈N - )for:

[0040]

[0041] From equation (1.1), we get

[0042]

[0043] Substituting equation (1.4) into equation (1.3), and eliminating P... j,i , can be obtained

[0044]

[0045] As can be seen from equation (1.5), given the tidal currents and carbon flow densities (carbon flows) of all inflow nodes, the carbon flow density of the outflow tidal currents is independent of the branches and is always a constant. Therefore, the carbon flow density of all outflow tidal currents from a node is equal to the carbon potential of that node. This concludes the introduction to the nodal carbon potential involved in carbon emission flow theory. The basic approach to carbon flow calculation will now be introduced.

[0046] Step 2: Determine the operating status of the energy storage device, including both power generation and charging states. If it is in power generation state, treat it as a generator set and establish a carbon flow analysis model to solve for the carbon potential at each node.

[0047] Specifically, step 2 includes:

[0048] Step 2.1: Calculation of node carbon potential for energy storage devices in the charging state:

[0049] If the energy storage devices are in a charging state, they are treated as loads. Given a system with N nodes, K nodes have generator injections, M1 nodes have loads, and M2 energy storage devices are in a charging state, equivalent to M = M1 + M2 loads, and the network topology is known (the non-degraded node-branch association matrix is ​​known). To clearly describe the carbon emission flow of the power system and perform carbon flow analysis, the following matrix needs to be established within the existing power system flow calculation framework.

[0050] (1) Branch power flow distribution matrix

[0051] The branch power flow distribution matrix is ​​an N-order square matrix, represented by P = (P Bji ) N×N This matrix is ​​defined to describe the active power flow distribution of a power system, providing boundary conditions for carbon emission flow distribution at the power network level. The matrix contains both topological information of the power network and information on the steady-state active power flow distribution. The elements of the branch power flow distribution matrix are defined as follows.

[0052] 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 p, then P Bij =p, P Bji =0; If the active power flow p flowing through this branch is a reverse power flow, then, P Bij =0P Bji =p; in other cases P Bij =P Bji = 0. Specifically, for all diagonal elements, P = 0. Nii =0 (i,j=1,2…N).

[0053] (2) Unit injection distribution matrix

[0054] The unit injection distribution matrix is ​​a K×N matrix, denoted by P. G =(P Gij ) K×N This matrix is ​​defined to describe the connections between all generator sets and the power system, as well as the active power injected into the system by the generator sets. It also serves to facilitate the description of the boundary conditions for carbon emission flows generated by the generator sets in the system. The specific definitions of the elements in the matrix are as follows.

[0055] If the k-th (k = 1, 2, ..., K) generator unit is connected to node j, and the active power flow injected into node j from the k-th node containing a generator is p, then P Gij =p, otherwise P Gij =0.

[0056] (3) Load distribution matrix

[0057] The load distribution matrix is ​​an M×N matrix, denoted by P. L =(P Lmj ) M×N This matrix is ​​defined to describe the connection relationships between all electrical loads and the power system, as well as the active power load, in order to describe the boundary conditions of carbon emission flows from electricity user consumption within the system. The specific definitions of the elements in the matrix are as follows.

[0058] If node J is the m-th (m = 1, 2, ..., M) node with load and its active load is p, then PLmi =p, otherwise P Lmi =0.

[0059] (4) Nodal active flux matrix

[0060] The active flux matrix of a node is an N-order diagonal matrix, denoted by P. N =(P Nij ) N×N According to Kirchhoff's Current Law, at any given moment for any node, the absolute values ​​of all branch currents flowing into and out of that node are equal, and their algebraic sum is always equal to 0. Therefore, in power flow analysis, the net injected power at any node is 0. However, in carbon flow calculations, the node carbon potential is only affected by the injected power flow; the power flow flowing out of the node has no effect on the node carbon potential. Therefore, compared to the algebraic sum of the currents flowing through the node and the power flow, carbon flow calculations focus more on the "absolute amount" of the active power flow flowing into the node under the power flow direction, which is called the node active flux. This concept is not used or defined in power flow analysis. In carbon flow calculations, this concept will be used to describe the contribution of generator units to nodes and nodes to node carbon potential. The specific definitions of the elements of the node active flux matrix are as follows.

[0061] For node i, let I + Let p represent the set of branches that have power flowing into node i. Bs Let S be the active power of branch S, then we have

[0062]

[0063] In the formula: p Gi The output of the generator set connected to node i is determined by the following condition: if the node has no generator set or the generator set output is 0, then p... Gi All off-diagonal elements P in this matrix Nij =0, (i≠j).

[0064] Based on the definitions of the three matrices above, P N The diagonal element of the i-th row of the matrix is ​​equal to P. B Matrix and P G The sum of the elements in the i-th column of the matrix.

[0065] If P Z =[P B P G ] T It is not difficult to see that:

[0066] P N =diag(ξ N+K P Z (1.45)

[0067] In the formula ξ N+KIt is an N+K order row vector, and all elements in the vector are 1 (the same applies below).

[0068] The formula shows that when the P of the power system B and P G When the matrix is ​​known, P N Through P B and P G The matrix is ​​generated directly.

[0069] (5) Carbon emission intensity vector of generator set

[0070] Different generator sets have different carbon emission characteristics, which are known conditions in carbon flow calculations and can be used to form a system's generator set carbon emission intensity vector. Let the carbon emission intensity of the k-th (k=1,2…K) generator set be e. Gk Then the carbon emission intensity vector of the generator set can be expressed as:

[0071] E G =[e G1 ,e G2 ,e G3 ...e GK ] T (1.46)

[0072] (6) Nodal carbon potential vector

[0073] The primary objective in calculating carbon emission flows in a power system is the carbon potential of all nodes. Let the carbon potential of the i-th (i = 1, 2, ..., N) node be e. Ni Then the nodal carbon potential vector can be expressed as:

[0074] E N =[e N1 ,e N2 ,...e NN ] T (1.47)

[0075] (7) Branch carbon flow rate distribution matrix

[0076] After calculating the nodal carbon potential vector, the carbon flux rate of each branch in the system can be further obtained. Therefore, the branch carbon flux rate distribution matrix is ​​defined as an N-order square matrix, and R0 is used. B =(R Bi ) N×N express.

[0077] The element definition of the branch carbon flow rate distribution matrix is ​​similar to that of the branch tidal flow distribution matrix. If there is a branch connecting node i and node j (i,j=1,2..N), 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 carbon flow rate R through this branch is in the reverse direction, then RBij =0,R Bji =R; otherwise R Bij =R Bji = 0. Specifically, for all diagonal elements, R = 0. Bii =0 (i=1,2…N).

[0078] Based on the analysis above, there are

[0079] R B =P B diag(E N (1.48)

[0080] (8) Loading carbon flow rate vector

[0081] After calculating the nodal carbon potential vector, the node

[0082] R L =P L E N (1.49)

[0083] The carbon emission intensity of a load is equal to its carbon potential at that node. Combining this with the load distribution matrix, the carbon flow rate corresponding to all loads can be obtained, which physically represents the amount of carbon emissions generated per unit time by the power generation side for supplying the loads at the nodes. For the (m = 1, 2…M)th node with loads, the carbon flow rate corresponding to its load is R. Lm Then the load carbon flow rate vector can be expressed as:

[0084] R L =[R L1 ,R L2 ,...R LM ] T (1.50)

[0085] Based on the analysis above, there are

[0086] From the definition of nodal carbon potential, the carbon potential e of node i in the system can be obtained. Ni for:

[0087]

[0088] In the formula: ρ s Let be the carbon flux density of branch s.

[0089] The physical meaning of the equation is that the carbon potential of node i is determined by the combined effect of the carbon emission flow generated by the generator set connected to that node and the carbon emission flow flowing into that node from other nodes. The numerator and denominator on the right-hand side of the equation represent the contributions of node i to the carbon emission flow from the two types of nodes mentioned above, and the tidal flow, respectively. Based on the properties of the carbon emission flow, the branch carbon flux density ρ... s The carbon potential at the branch's starting node can be used as a substitute, and the equation can be rewritten in the following matrix form:

[0090]

[0091] In the formula: Let be an N-dimensional unit row vector, where the i-th element is 1 (the same applies below).

[0092] According to the definition of the active flux matrix at each node, we can obtain:

[0093]

[0094] From equations (1.14) and (1.15), we can obtain:

[0095]

[0096] Because of P N Since the matrix is ​​a diagonal matrix, extending equation (1.16) to the entire system dimension yields:

[0097]

[0098] After simplification, the formula for calculating the carbon potential of all nodes in the system is as follows:

[0099]

[0100] By constructing the corresponding matrix, the carbon potential of each node can be obtained using the formula. Based on the relationship between the node carbon potential and the line carbon flow rate, the distribution of carbon emission flow in the system can be obtained.

[0101] Assuming node i is the node connecting the energy storage device, its carbon potential is:

[0102]

[0103] Assume the carbon content of the energy storage device is as follows, given that the charging state time is from t1 to t:

[0104]

[0105] Where, p i The load power is used to charge node i.

[0106] Step 3: Carbon potential of energy storage device nodes under discharge conditions

[0107] Step 3.1: Considering that energy storage devices experience energy loss during charging, the carbon content of carbon nodes does not change with energy loss. Furthermore, we treat the energy storage device as a generator in a discharging state; therefore, the carbon emission intensity of a node in a discharging state will inevitably differ from that of a node in a charging state.

[0108] Assume that node i in the system is an energy storage node, and define the following symbols.

[0109] E i，t Energy stored at time t: Energy storage node i.

[0110] C i，t : Carbon content of energy storage node i at time t;

[0111] E i，t-1 Energy stored at time (t-1) (the previous time step);

[0112] C i，t-1 : The carbon content of energy storage node i at time (t-1) (the previous time);

[0113] P in : The charging power of the node corresponding to the charging state;

[0114] P out : The node discharge power corresponding to the discharge state;

[0115] η in : Charging efficiency of energy storage devices;

[0116] η out The discharge efficiency of energy storage devices;

[0117] Δt: The time interval between the two calculations;

[0118] β: The loss coefficient β of the energy storage device is formulated as follows:

[0119]

[0120] The state of the energy storage device at time t changes from time t

[0121]

[0122] Carbon flow analysis results of the etching system and (t-1) time

[0123]

[0124] The state of the energy storage device determines the overall situation:

[0125]

[0126]

[0127] Where, P in P out =0.

[0128] Therefore, the node carbon potential in the charging state is:

[0129]

[0130] Where ΔC is the change per unit time, and its calculation formula is:

[0131]

[0132] Step 3.2: Following the trend

[0133] Power flow tracing is a topology analysis method that determines the correspondence between generated power and consumed power, and the amount of generated and consumed power flowing through transmission elements, by tracing the power flow in a transmission line. Depending on the object being traced (generator or load), it can be divided into downstream tracing and upstream tracing.

[0134] Flow tracing starts from the generator node and traces the actual power flow direction to determine the distribution of power output among various loads. Flow tracing can determine the extent to which the generators are utilizing the line.

[0135] Assuming Figure 3 The power grid shown has n nodes, b branches, s generators, and l loads. Let the two nodes connected by the j-th branch be x and y, and let active power be injected from node x, flowing through branch j to node y. It is agreed that branch xy and branch j refer to the same branch. P B,x-y,from P represents the active power injected by node x into the j-th branch. B,x-y,to P represents the active power injected from the j-th branch into node y. loss,x-y This represents the line loss of branch j.

[0136] Based on the above definition, the following relationship can be obtained:

[0137] P B,x-y,from -P B,x-y,to =P B,x-y,loss (1.66)

[0138]

[0139] Among them, P N,i P represents the active power flux of node i. i This represents the active power injected into node 7i by the generator connected to node i. This represents the set of nodes connected to node i and injecting active power into node i.

[0140] Two parameters α are defined by the following formula. j-i ,β j-i :

[0141] α j-i ·P B,j-i,from =PB,j-i,to (1.68)

[0142] β j-i ·P N,,j =P B,j-i,from (1.69)

[0143] Among them, P N,i This represents the active power flux of node j, and at this time, node j injects active power into branch i.

[0144] Combining equations (1.7), (1.8), and (1.9), we get:

[0145]

[0146] Right now

[0147]

[0148] or

[0149] A1P N =P G (1.72)

[0150] Where: P N Let P be the active power flux vector of each node. G The active power vector injected into each generator node of the power grid has the following values ​​for each element:

[0151] [P G ] i =P G,i (1.73)

[0152] Note: When no generator is injecting active power into node i.

[0153] Let A1 be an n×n matrix with the following elements:

[0154]

[0155] From equation (1.12), we can obtain:

[0156]

[0157] From equation (1.14), it can be seen that the active power flow contributed by generator k (where k is the generator number and it is connected to node j) to node i is:

[0158]

[0159] pass This allows us to determine the active power contributed by each generator to any node. Furthermore, the KCL (Knowledge, Current, and Logic) can be used to determine the active power contributed by each generator to each branch. This completes the task of downstream tracing.

[0160] Step 3.4: Calculation of nodal carbon potential under charging conditions

[0161] If the energy storage device is in a discharging state, it is treated as a generator set. Given a system with N nodes, K1 nodes have generator injection, M nodes have loads, and K2 energy storage devices are in a charging state, equivalent to having K = K1 + K2 generator sets. The carbon emission intensity of this generator set is:

[0162]

[0163] According to equations (1.50) and (1.33), it can be expressed as:

[0164] E N =P N E G ′ (0.1)

[0165] A case study was conducted on this system. The system consists of 5 generators, 20 branch lines, and 11 load nodes. Power flow analysis and carbon flow analysis were performed on the system. The test system is as follows: Figure 4 As shown, the power flow distribution and direction of the branches are marked. Node 3 connects the energy storage device and the photovoltaic generator. Figure 4 The red generators are configured as high-carbon-intensity coal-fired units. The green generators are configured as zero-carbon-intensity units (solar in this case study). The rest are configured as gas turbine generators, as shown in Table I. The 24-hour load power of node 3 is as follows: Figure 5 As shown, the charging and discharging power of the energy storage device is as follows: Figure 6 As shown.

[0166] Table 1 Carbon intensity generated by different types of generating units

[0167] Production type <![CDATA[Unit carbon potential (kgCO2 / kWh)]]> Coal-fired power units 0.875 Gas turbine unit 0.520 New energy units 0

[0168] Results of the energy storage device's state of charge

[0169] η in η out In this simulation, the charging and discharging efficiencies are set to 0.9. β is set to 0.99 in this simulation. n Test results are as follows Figure 7 As shown, where represents the carbon emission intensity of energy storage node 3.

[0170] according to It can be obtained

[0171] (ei ) 10 = 0.24 kg CO2 / kWh

[0172] (e i ) 11 = 0.18 kg CO2 / kWh

[0173] (e i ) 12 = 0.15 kg CO2 / kWh

[0174] (e i ) 13 = 0.12 kg CO2 / kWh

[0175] (e i ) 14 =0.04kgCO2 / kwh

[0176] (e i ) 15 =0 kg CO2 / kwh

[0177] (e i ) 16 =0.07kgCO2 / kwh

[0178] (e i ) 17 = 0.11 kg CO2 / kWh

[0179] When the energy storage device begins charging at 10:00 AM, the storage node is close to the photovoltaic (PV) generator, whose carbon content is zero. Most of the charging power comes from the PV generator. Therefore, as charging time increases, the stored energy increases, but the carbon content of the storage device increases only slightly. According to the definition of carbon emission intensity, the carbon emission intensity of the energy storage device will decrease. However, after 3:00 PM, the PV generator can no longer generate sufficient power. At this time, some of the charging power comes from other non-zero carbon units, so the carbon emission intensity of the energy storage node will increase.

[0180] Results of the discharge problem of energy storage devices

[0181] When the energy storage device discharges, we treat it as a load. We are interested in how the stored energy of the device changes during discharge and how the coupled carbon content changes. Figure 8 The carbon content per unit of electricity consumed per day. Figure 9 This shows the changes in electrical energy and coupled carbon content of the energy storage device throughout the day. Figure 10 It shows the change in node carbon potential of the energy storage device over a day.

[0182] Based on these results, we can draw the following observations.

[0183] The carbon content per unit of electricity can be divided into two main phases: From 10:00 to 15:00, the energy storage device is charging, primarily from photovoltaic power generation (0 carbon), thus reducing the carbon content per unit of energy in the storage device. After 15:00, the energy storage device is generating electricity. Its carbon flows from the storage device to the load along with the electrical energy. Its carbon content decreases, but its carbon content per unit remains unchanged. Between 1:00 and 10:00, the carbon content per unit of electricity (CCPE) gradually increases. This is mainly because the energy storage device itself experiences losses, resulting in reduced power, but the carbon content does not decrease. The CCPE gradually increases, but the increase is not significant.

[0184] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A method for calculating the carbon potential of a node containing energy storage devices based on carbon emission flow theory, comprising the following steps: Step 1: Construct a basic topological model of the carbon emission flow containing energy storage devices; Step 2: Determine the operating status of the energy storage device, including both power generation and charging states. If it is in power generation state, treat it as a generator set and establish a carbon flow analysis model to solve the carbon potential of each node. Step 3: If the energy storage device is in a discharging state, it is considered a generator set. Due to charging efficiency and partial energy loss during the energy storage process, the node carbon potential differs from that in the charging state. Therefore, it is necessary to recalculate the node potential in the power generation state and then recalculate the carbon potentials of other nodes. The key feature is that... Step 1 includes: Step 1.1: Establish a basic topological model of the carbon emission flow containing energy storage devices, and construct a computational problem for the carbon emission flow containing energy storage devices; Step 2 includes: Step 2.1: Calculation of node carbon potential of energy storage device in charging state; Step 3 includes: Step 3.1: Considering that energy storage devices will lose energy during charging, and the carbon content of carbon nodes does not change with energy loss, the energy storage device is regarded as a generator in the discharge state. The carbon emission intensity of the node in the discharge state will inevitably be different from that of the node in the charging state. Step 3.2: Follow the trend; Step 3.3: Calculation of node carbon potential under charging conditions; Step 1.1: Establish a basic topological model of the carbon emission flow containing energy storage devices, and construct the specific calculation process for the carbon emission flow containing energy storage devices as follows: Let there be a node n in a power system and its adjacent branches, and let the sets of branches into which the power flow flows and out of node n be respectively... and Then the active power flow into node n from branch i and the active power flow out of node n from branch j are respectively and ,in According to the principle of proportional sharing, every branch of the outflowing tidal current contains a component of every inflowing tidal current. Let the j-th branch of the outflowing tidal current contain the component of the i-th branch of the inflowing tidal current. ,have If from the line ,in The carbon flow density of the active power flow flowing into node n is Then the carbon flow rate of the active power flow in the j-th outflow branch should be all The sum of the contributions of the middle branch to the carbon flow rate of branch j is expressed as follows: Therefore, the carbon flux density of branch j ,in ,for: From equation (1.1) we get Substituting equation (1.4) into equation (1.3) and eliminating... , can be obtained As can be seen from equation (1.5), for all inflow nodes, the carbon flow density, i.e., carbon flow, is given, while the carbon flow density of outflowing tidal current is independent of the branch and is a constant. Therefore, the carbon flow density of all outflowing tidal currents from a node is equal to the carbon potential of that node.

2. The method for calculating the node carbon potential containing energy storage devices based on carbon emission flow theory according to claim 1, characterized in that, The specific calculation process for step 2.1, calculating the node carbon potential of the energy storage device in the charging state, is as follows: Assuming the energy storage device is in a charging state, it is treated as a load. Given a system with N nodes, K of which have generator injection points, Each node has a load. One energy storage device is in a charging state, which is equivalent to having Given a load and a known network topology (i.e., non-degraded nodes),... The branch correlation matrix is ​​known; to clearly describe the carbon emission flow of the power system and perform carbon flow analysis, the following matrix needs to be established within the existing power system flow calculation framework: 2.1.1 Branch Power Flow Distribution Matrix The branch power flow distribution matrix is ​​an N-order square matrix, using This matrix is ​​defined to describe the active power flow distribution of a power system, providing boundary conditions for carbon emission flow distribution at the power network level. It contains both the topological information of the power network and the distribution information of the system's steady-state active power flow. The specific definitions of the elements in the branch power flow distribution matrix are as follows: If there is a branch connecting node i and node j, where i, j = 1, 2 ... N, and the positive active power flow from node i to node j through this branch is p, then If the active power flow p flowing through this branch is a reverse power flow, then, In other cases For all diagonal elements, we have ,in ; 2.1.2 Unit Injection Distribution Matrix The unit injection distribution matrix is ​​a K×N order matrix, using This matrix is ​​defined to describe the connection relationships between all generator sets and the power system, as well as the active power injected into the system by the generator sets. It also serves to facilitate the description of the boundary conditions for carbon emission flows generated by the generator sets in the system. The specific definitions of the elements in the matrix are as follows: If the first The generator set is connected to node j, where, And if the active power flow injected into node j from the k-th node containing a generator is p, then... ,otherwise ; 2.1.3 Load Distribution Matrix The load distribution matrix is ​​an M×N matrix, using This matrix is ​​defined to describe the connection between all electrical loads and the power system, as well as the active power load, in order to describe the boundary conditions of carbon emission flows from electricity user consumption in the system. The specific definitions of the elements in the matrix are as follows: If node J is the first There are nodes with load, among which And the active load is p, then ,otherwise ; 2.1.4 Node Active Flux Matrix The active flux matrix of a node is an N-order diagonal matrix, using According to Kirchhoff's Current Law, at any given moment for any node, the absolute values ​​of all branch currents flowing into and out of that node are equal, and their algebraic sum is always equal to 0. Therefore, in power flow analysis, the net injected power at any node is 0. In carbon flow calculations, the node carbon potential is only affected by the injected power flow; the power flow flowing out of the node has no effect on the node carbon potential. Therefore, compared to the algebraic sum of the currents flowing through the node and the power flow, carbon flow calculations focus more on the absolute amount of active power flowing into the node under the power flow direction, which is called the node active flux. In power flow analysis, the concept of node active flux is not used or defined; in carbon flow calculations, this concept will be used to describe the contribution of generator units to nodes and nodes to node carbon potential. The specific definitions of the elements of the node active flux matrix are as follows: For node i, let Let i represent the set of branches into which power flows into node i. Let S be the active power of branch S, then we have In the formula: The output of the generator set connected to node i is determined by the following condition: if the node has no generator set or the generator set output is 0, otherwise... All off-diagonal elements in the matrix ,in, ; Based on the definitions of the branch power flow distribution matrix, the unit injection distribution matrix, and the node active power flux matrix, the above three matrices are... The diagonal element of the i-th row of the matrix is ​​equal to Matrix and The sum of the elements in the i-th column of the matrix; make ,but: In the formula It is an N+K order row vector, and all elements in the vector are 1; The above formula shows that when the power system and When the matrix is ​​known, pass and Matrix generated directly; 2.1.5 Carbon Emission Intensity Vector of Generator Sets Different generator sets have different carbon emission characteristics, which are known conditions in carbon flow calculations. The carbon emission intensity vector of the generator sets constituting the system is given; let the first... The carbon emission intensity of the generator set is ,in, The carbon emission intensity vector of the generator set is then expressed as: 2.1.6 Nodal Carbon Potential Vector The primary objective in calculating carbon emission flows in a power system is the carbon potential at all nodes; let the first node be... The carbon potential of each node is ,in, The nodal carbon potential vector is then represented as: 2.1.7 Branch Carbon Flow Rate Distribution Matrix After calculating the nodal carbon potential vector, the carbon flux rate of each branch of the system is further obtained; therefore, the branch carbon flux rate distribution matrix is ​​defined as an N-order square matrix, and... express; The definition of elements in the branch carbon flow rate distribution matrix is ​​similar to that in the branch power flow distribution matrix; if node i and node... There are branch roads connecting them, among which And the positive carbon flow rate from node i to node j via this branch is ,but If the carbon flow rate R through this branch is in the reverse direction, then In other cases For all diagonal elements, we have ,in ; Based on the analysis above, there are 2.1.8 Loading Carbon Flow Rate Vector After calculating the nodal carbon potential vector, the node The carbon emission intensity of the load is equal to the carbon potential of that node; combined with the load distribution matrix, the carbon flow rate corresponding to all loads can be obtained, which physically represents the amount of carbon emissions generated by the power generation side per unit time for the load supplying the node; for the th There are nodes with load, among which The carbon flow rate corresponding to its load is The load carbon flow rate vector is then expressed as: Based on the analysis above, there are From the definition of nodal carbon potential, the carbon potential of node i in the system can be obtained. for: In the formula: Let be the carbon flux density of branch s; The carbon potential of node i is determined by the combined effect of carbon emission flows from generators connected to that node and carbon emission flows into that node from other nodes; the numerator and denominator on the right-hand side of the equation represent the contributions of node i to carbon emission flows from generators and other nodes, and the tidal flow, respectively; based on the nature of the carbon emission flows, the branch carbon flow density... Substituting the carbon potential at the branch's starting node, the equation can be rewritten in the following matrix form: In the formula: , is an N-dimensional unit row vector, where the i-th element is 1; According to the definition of the active flux matrix at each node, we can obtain: From equations (1.14) and (1.15), we can obtain: because Since the matrix is ​​a diagonal matrix, extending equation (1.16) to the entire system dimension, we get: After simplification, the formula for calculating the carbon potential of all nodes in the system is as follows: By constructing the corresponding matrix, the carbon potential of each node can be obtained using the formula. Based on the relationship between the node carbon potential and the line carbon flow rate, the distribution of carbon emission flow in the system can be obtained. Assuming node i is the node connecting the energy storage device, its carbon potential is: Assuming the charging state time starts from arrive The carbon content of energy storage devices is: in, The load power is used to charge node i.

3. The method for calculating the node carbon potential containing energy storage devices based on carbon emission flow theory according to claim 2, characterized in that, Step 3.1: Considering that energy storage devices will lose energy during charging, and the carbon content of carbon nodes does not change with energy loss, the energy storage device is treated as a generator in the discharging state. The carbon emission intensity of the node in the discharging state will inevitably be different from that of the node in the charging state. The specific calculation process is as follows: Assume that node i in the system is an energy storage node, and define the following symbols: Energy stored at time t: Energy storage node i. : Carbon content of energy storage node i at time t; Energy storage node i in Energy stored at all times; Energy storage node i in Carbon content at any given time; : The charging power of the node corresponding to the charging state; : The node discharge power corresponding to the discharge state; : Charging efficiency of energy storage devices; The discharge efficiency of energy storage devices; The time interval between the two calculations; Loss coefficient of energy storage equipment The formula is as follows: The state of the energy storage device at time t is determined by the carbon flow analysis results of the system at time t and The state of the energy storage device determines everything at any given moment: in, ; The node carbon potential in the charging state is: in, The change per unit time is calculated using the following formula:

4. The method for calculating the node carbon potential containing energy storage devices based on carbon emission flow theory according to claim 3, characterized in that, Step 3.2: The specific calculation process for following the current flow is as follows: By tracking the power flow in the transmission line, the correspondence between power generation and power consumption, as well as the amount of power generation and power consumption flowing through the transmission elements, can be determined. Depending on the generator or load being tracked, it is divided into downstream tracking and upstream tracking. Downstream tracking starts from the generator node and traces along the actual power flow direction to determine the distribution of power output among various loads. Flow tracing determines the extent to which the generator is used on the line; Suppose a power grid has n nodes, b branches, s generators, and l loads; let x and y be the two nodes connected to the j-th branch of the power grid, and let active power be injected from node x, flowing to node y after passing through branch j, with the following conventions: branch x y and branch j refer to the same branch; This represents the active power injected by node x into the j-th branch. This represents the active power injected by the j-th branch into node y. The line loss of branch j is represented by the line loss. Based on the definitions of branch, active power, and line loss, the following relationships can be obtained: in, The active power flux of node i represents the node's active power flux. This represents the active power injected into node 7i by the generator connected to node i. This represents the set of nodes connected to node i and injecting active power into node i; Two parameters are defined by the following formula. : in, This represents the active power flux of node j, and at this time node j injects active power into branch i; Combining equations (1.7), (1.8), and (1.9), we get: Right now or in: This represents the active power flux vector at each node. The active power vector injected into each generator node of the power grid has the following values ​​for each element: When no generator is injecting active power into node i; set up Let be an n×n matrix, with the following elements: From equation (1.12), we can obtain: From equation (1.12), we can obtain: From equation (1.14), it can be seen that the active power flow contributed by generator k to node i is: Where k is the generator number, and it is connected to node j, via This allows us to determine the active power contributed by each generator to any node, and then use KCL to determine the active power contributed by each generator to each branch, thus completing the task of downstream tracing.

5. The method for calculating the node carbon potential containing energy storage devices based on carbon emission flow theory according to claim 4, characterized in that, The specific calculation process for step 3.3: node carbon potential calculation under charging state is as follows: The energy storage device is in a discharging state and is treated as a generator unit. A system has N nodes, of which K1 nodes have generator injection and M nodes have loads. One energy storage device is in a charging state, which is equivalent to having For each generating unit, the carbon emission intensity of the generator unit at this time is: According to equations (1.12) and (1.33), it can be expressed as follows: 。

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