Flexible power distribution network carbon emission responsibility allocation calculation method based on carbon emission flow

Abstract

A flexible power distribution network carbon emission responsibility allocation calculation method based on a carbon emission flow belongs to the technical field of power system carbon emission management, and comprises the following steps: firstly, analyzing the carbon emission characteristics of a flexible power distribution network, and establishing a flexible power distribution network carbon emission flow calculation method; then, establishing a flexible power distribution network low-carbon optimization operation model based on an improved carbon emission flow theory; and finally, solving the model and introducing a Shapley value theory, researching the carbon emission responsibility allocation of the load side of the flexible power distribution network from the perspective of cooperative game, and determining the carbon emission responsibility of the terminal user of the flexible power distribution network. According to the method, each load node in the flexible power distribution network can have a reasonable carbon emission responsibility interval, stepped carbon prices are specified in different intervals, and stepped pricing of load side carbon emission responsibility can be more fair.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon emission management of power systems, and in particular relates to a method for calculating carbon emission responsibility allocation of a flexible distribution network based on carbon emission flows. Background Art

[0002] At present, the power industry has become the main force in CO2 emission reduction. In the traditional sense, only the power generation link in the power system has actual carbon emissions, and the transmission and consumption links do not directly produce carbon emissions. Therefore, most researchers focus on the power generation side of the power system. For the calculation of carbon emissions on the power generation side, macro-statistical methods and full life cycle methods are generally used for analysis. However, the macro method can only calculate the size of carbon emissions on the power generation side, ignoring the network structure and transmission characteristics of the power system, and also ignoring that the power generation side, transmission network, and user side are a unified and continuous whole, and there are connections between them. Therefore, there is little research on how to reduce carbon emissions on the user side of the distribution network.

[0003] At present, in the field of low-carbon electricity, many scholars have proposed the concept of carbon emission flow in power systems, and realized that the real-time carbon potential of any node in the system can be obtained based on any known system flow distribution. At the same time, effective methods for calculating and analyzing carbon emissions in power systems have been established, which can calculate and attribute carbon emissions on the power generation side to the load side, thus providing new ideas for the reasonable allocation of carbon emission responsibilities in flexible distribution networks. However, the current method of allocating carbon emission responsibilities lacks rationality in the division of carbon emission responsibility intervals on the load side, resulting in poor fairness in the allocation of carbon emission responsibilities on the load side.

[0004] Therefore, a new technical solution is urgently needed in the prior art to solve this problem. Summary of the invention

[0005] The technical problem to be solved by the present invention is: to provide a method for calculating carbon emission responsibility allocation in a flexible distribution network based on carbon emission flow to solve the technical problem that the current method for allocating carbon emission responsibility lacks rationality in the division of carbon emission responsibility intervals on the load side, resulting in poor fairness in the allocation of carbon emission responsibility on the load side.

[0006] A method for calculating carbon emission responsibility allocation of a flexible distribution network based on carbon emission flow includes the following steps, which are performed in sequence:

[0007] Step 1: According to the carbon emission characteristics of the flexible distribution network, a calculation method for the carbon emission flow of the flexible distribution network is established;

[0008] Step 2: According to the characteristics of power electronic equipment in the flexible distribution network, a low-carbon optimization operation model of the flexible distribution network is established based on the improved carbon emission flow theory. The model takes the minimum total cost C of the flexible distribution network FDN as the objective function and obtains the carbon emission flow distribution of the entire FDN;

[0009] Step 3: Solve the low-carbon optimization operation model of the flexible distribution network and introduce the Shapley value theory to allocate the carbon emission responsibility on the load side of the flexible distribution network from the perspective of cooperative game and determine the carbon emission responsibility of the end users of the flexible distribution network.

[0010] The objective function in step 2 is:

[0011] minC=C1+C2+C3+C4;

[0012] Among them, C1 is the power generation cost, C2 is the cost of purchasing electricity from the transmission network, C3 is the network loss cost, and C4 is the carbon emission cost.

[0013] The carbon emission flow distribution of the entire FDN obtained in step 2 is:

[0014] Get the carbon emission intensity vector E of the generator set DG G , and calculate the node carbon potential vector E N :

[0015]

[0016] ①. The carbon emission flow on the power supply side is calculated as follows:

[0017] The carbon emission intensity vector of DG is multiplied by the active power injected by DG into FDN to obtain the carbon emission size on the power supply side;

[0018] ②. The carbon emission flow on the grid side is calculated as follows:

[0019] The branch power distribution matrix P B Get the branch carbon flow rate distribution matrix R B :

[0020] R B =diag(E N ) B ;

[0021] ③. The carbon emission flow on the load side is calculated as follows:

[0022] The carbon emission intensity of a load node is equal to the carbon potential of the node, which is represented by the load distribution matrix P L Get the load carbon flow rate vector R L :

[0023] R L =P L E N.

[0024] The method for determining the carbon emission responsibility of the terminal users of the flexible distribution network in step 3 is as follows:

[0025] Assume that alliance N = {1, 2, ... n}, where n represents n subnode load members. Any subnode load member S of N corresponds to a carbon emission function c(S), and c(S) represents the carbon emission responsibility of the alliance. The function satisfies:

[0026]

[0027] Where φ is the intersection of alliance S1 and alliance S2;

[0028] The carbon emission responsibility shared by the load members in the alliance is determined by the average marginal contribution:

[0029]

[0030] In the formula, x i is the carbon emission responsibility shared by alliance member i; S is the sub-alliance composed of sub-alliance members ranked before alliance member i; P(S) is the probability of the occurrence of sub-alliance S; S∪{i} is the new alliance formed by incorporating alliance member i into alliance S; c(S∪{i})-c(S) represents the marginal impact generated when alliance member i joins sub-alliance S;

[0031] in,

[0032] According to the rationality of carbon emissions, the carbon emission responsibility of the sub-alliance members is set to be no greater than the maximum value of the marginal effect of the sub-alliance members x max (i) At the same time, it is not less than the minimum value x of its marginal effect min (i), that is:

[0033] x min (i)≤x(i)≤x max (i) ;

[0034] x max (i) = max(c(SU{i}) - c(S)) ;

[0035] x min (i) = min(c(SU{i}) - c(S));

[0036] According to the maximum x of the marginal effect of carbon emission responsibility max , minimum value x min and the mean value x ave , in each period, the carbon emission responsibility range of each load node is divided into 4 intervals: free carbon responsibility price interval 0-x min, low carbon responsibility price range x min -x ave 、China Carbon Responsibility Price Range x ave -x max , High Carbon Responsibility Price Range x max -∞;

[0037] Among them, x ave =P(S1)(c(S1 U{i})-c(S1))+P(S2)(c(S2 U{i})-c(S2));

[0038] In different intervals, a tiered carbon price is applied to node carbon emissions according to different intervals:

[0039]

[0040] In the formula, λ is the step carbon emission cost, in units of RMB / tCO2, E i,t is the carbon emission per unit time of the load node; λ1, λ2, λ3, and λ4 are the step carbon emission costs in different carbon emission ranges;

[0041] Calculate the total cost of carbon emissions C based on the tiered carbon price CE,i,t , that is, the carbon emission responsibility of the end users of the flexible distribution network is:

[0042]

[0043] Through the above design scheme, the present invention can bring the following beneficial effects:

[0044] (1) The present invention establishes a low-carbon optimization operation model for FDN based on the improved carbon emission flow theory. Based on the operation mode of the traditional distribution network, taking into account the operation characteristics of DG and SOP, the impact of both on the carbon emissions of FDN is explored, and through the coordinated operation of DG and SOP, the areas with large carbon emissions in the distribution network are reasonably optimized to reduce carbon emissions.

[0045] (2) The present invention proposes a method for calculating carbon emission responsibility allocation for a flexible distribution network based on carbon emission flow. The cooperative game theory and Shapley value theory are briefly described, and the carbon emission responsibility allocation on the load side is studied from the perspective of cooperative game. The Shapley value theory is introduced to find the reasonable range of carbon emission responsibility of each regional load, and then the carbon responsibility is allocated to make the tiered pricing of carbon emission responsibility on the load side more fair. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present invention is further described below with reference to the accompanying drawings and specific embodiments:

[0047] Figure 1 The present invention is a flow chart of a method for calculating carbon emission responsibility sharing in a flexible distribution network based on carbon emission flow.

[0048] Figure 2 It is a schematic diagram of the embodiment of the carbon emission flow in the power system in the carbon emission responsibility allocation calculation method of the flexible distribution network based on the carbon emission flow of the present invention;

[0049] Figure 3 It is a SOP installation location diagram in a carbon emission responsibility allocation calculation method for a flexible distribution network based on carbon emission flow of the present invention;

[0050] Figure 4 A schematic diagram of a carbon emission flow model considering SOP in a carbon emission responsibility allocation calculation method for a flexible distribution network based on carbon emission flow according to the present invention;

[0051] Figure 5 It is a flow chart of carbon emission flow calculation of the whole process of FDN in a method for calculating carbon emission responsibility sharing of a flexible distribution network based on carbon emission flow of the present invention;

[0052] Figure 6 It is an improved IEEE33-node distribution network structure diagram in a carbon emission responsibility allocation calculation method for a flexible distribution network based on carbon emission flow of the present invention;

[0053] Figure 7 This is a graph of the range of tiered carbon prices for each alliance in a method for calculating carbon emission responsibility sharing in a flexible distribution network based on carbon emission flow according to the present invention. DETAILED DESCRIPTION

[0054] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention are described in further detail below.

[0055] A carbon emission responsibility allocation calculation method for a flexible distribution network based on carbon emission flow, such as Figure 1 As shown, the calculation method includes the following steps:

[0056] Step 1: First, the existing carbon emission flow theory of the power system is introduced, the relevant concepts of the carbon emission flow theory are derived, and the FDN with extensive DG access and the carbon emission characteristics of FDN are specifically analyzed, and an improved FDN carbon emission flow calculation method is proposed;

[0057] Step 2: Then, for the newly connected power electronic equipment in FDN, a low-carbon optimization operation model of FDN based on the improved carbon emission flow theory was established. On the basis of the traditional distribution network operation, the influence of the coordinated operation of DG and SOP on the carbon emissions of the distribution network was explored;

[0058] Step 3: Finally, based on steps 1 and 2, the model is solved to obtain the carbon emission flow distribution of FDN, and the carbon emission responsibility allocation on the load side is studied from the perspective of cooperative game. The Shapley value theory is introduced to find the reasonable range of carbon emission responsibility of each regional load and allocate the carbon emission responsibility.

[0059] In summary, the embodiment of the present invention can quickly and accurately solve the real-time distribution of the entire FDN carbon emission flow and the result of the load-side carbon emission responsibility allocation through the above steps 1 to 3.

[0060] Example 1

[0061] The above scheme is described in detail below with specific calculation formulas and examples. See the following description for details:

[0062] Step 1: Electric energy in the power system flows to the user side through five links: power generation, transmission, transformation, distribution, and consumption. The carbon emission flow is attached to the flow of electric energy. The transfer of electric energy is accompanied by the transfer of carbon emissions. The establishment of the carbon emission flow theory clearly reveals the distribution characteristics of carbon emission flows in the power grid, such as Figure 2 The relevant definitions of carbon emission flow theory and the relationship between carbon emission flow and power flow of power system are shown in Table 1.

[0063] Table 1 Theoretical related indicators of carbon emission flow in power system

[0064]

[0065]

[0066] When the active power flow and carbon flow density flowing into a node branch are given, the carbon flow density of the branch flow flowing out of the node is equal to the node carbon potential of the node, as shown in formula (1).

[0067] I L,l =I N,i l∈Ω i- (1);

[0068] In the formula, Ω i- is the set of branches outflowing from node i; l is the branch number.

[0069] 1) Carbon emission flow model considering intelligent soft switching

[0070] SOP can replace the normally open point (NOP) in the traditional distribution network, realize the normalized flexible interconnection between feeders, avoid the safety hazards caused by frequent position changes, make the distribution network have the advantages of both open-loop and closed-loop operation, improve the flexibility and rapidity of distribution network control, and realize the control of active and reactive power flows between feeders. The installation position of SOP is as follows: Figure 3 As shown. With the development of operation control technology, SOP no longer has the traditional "normally open" feature. In traditional AC distribution networks, switches connecting different feeders are disconnected during normal operation, while in FDN, SOP always remains closed, so that the feeders are connected to each other in a closed loop. After determining the installation position of SOP in FDN, active power flows from one end node of SOP to the other end node, and carbon emission flow depends on active power to flow in the distribution network. Therefore, SOP can be regarded as a "branch" that allows active power to pass through and can emit reactive power. When SOP adjusts the active power in the distribution network, it can also adjust the carbon flow distribution in the distribution network, such as Figure 4 The active power flow in SOP is from node i to node j. According to the relevant characteristics of SOP and the relationship between the node carbon potential and the branch carbon flow density, the carbon flow rate calculation formula flowing through SOP is shown in equations (2)-(5).

[0071] P SOP,i +P SOP,j =0 (2);

[0072] |P SOP,i |=|P SOP,j |=|P SOP,ij | (3);

[0073]

[0074] R SOP,ij =I SOP,ij P SOP,ij (5);

[0075] Where P SOP,i , P SOP,j are the active power injected by SOP at nodes i and j respectively; P SOP,ij is the actual active power flowing from node i to node j in SOP; I SOP,ij is the carbon flow density of SOP; R SOP,ij is the carbon flow rate flowing over the SOP; Ω i+ is the set of branches into which the flow flows into node i; P l is the active power flowing through branch l.

[0076] 2) Calculation of carbon emission flows of flexible distribution networks

[0077] The carbon emission flow calculation method of the flexible distribution network includes the carbon emission flow calculation on the power supply side, the carbon emission flow calculation on the grid side and the carbon emission flow calculation on the load side.

[0078] In an FDN with N nodes, there are K nodes connected to DG and M nodes connected to load. Based on the needs of FDN carbon emission flow calculation, the key matrices and vectors are defined as shown in Table 2.

[0079] Table 2 Key matrices and vectors

[0080]

[0081] Statistical generator set carbon emission intensity vector E G , calculate the node carbon potential vector E N , as shown in formula (6).

[0082]

[0083] ①. Calculation of carbon emission flow on the power supply side

[0084] The carbon emission intensity of DG is multiplied by the active power injected by DG into FDN to obtain the carbon emission size on the power supply side.

[0085] ②Calculation of carbon emission flow on the grid side

[0086] The branch power distribution matrix P B Get the branch carbon flow rate distribution matrix R B , as shown in formula (7).

[0087] R B =diag(E N ) B (7);

[0088] ③. Calculation of carbon emission flow on the load side

[0089] The carbon emission intensity of a load node is equal to the carbon potential of the node, which is represented by the load distribution matrix P L Get the load carbon flow rate vector R L , as shown in formula (8).

[0090] R L =P L E N (8);

[0091] By calculating the carbon emission flows on the FDN power supply side, grid side, and load side, carbon emissions are materialized in the form of network flows in the power system, such as Figure 5 shown.

[0092] Step 2: Establish a low-carbon optimization operation model of FDN based on the improved carbon emission flow theory. The model takes the minimum total cost C of FDN as the objective function, as shown in formula (9), which mainly includes four items, namely, power generation cost C1, power purchase cost from the transmission network C2, network loss cost C3, and carbon emission cost C4.

[0093] minC=C1+C2+C3+C4 (9);

[0094] 1) Power generation cost:

[0095]

[0096] Where T is the time period; N bus is the number of FDN nodes; c M T,c WT 、c PV are the power generation costs of the corresponding DG per unit of electricity; P MT,i,t , P WT,i,t , P PV,i,t are the active power output of the corresponding DG installed at node i at time t. The subscripts MT, WT, and PV represent micro gas turbines, distributed wind power, and distributed photovoltaics, respectively;

[0097] 2) Cost of purchasing electricity from the transmission network:

[0098]

[0099] In the formula, λ i,t P is the unit cost of the i-th node of FDN purchasing electricity from the transmission grid at time t; TSO,i,t is the active power injected into node i in FDN by the transmission network at time t.

[0100] 3) Network loss costs:

[0101]

[0102] In the formula, Ω L is the branch set of FDN; c loss is the unit cost of FDN network loss, which is 0.35 yuan / (kW·h); P loss,l,t is the active power loss of branch l at time t.

[0103] 4) Carbon emission costs:

[0104]

[0105] In the formula, I MT,i,t is the carbon emission coefficient of the MT installed at node i at time t; TSO,i,t is the carbon potential injected into FDN node i by the transmission grid at time t; c The unit carbon emission price is 150 yuan / (tCO2).

[0106] Constraints:

[0107] 1) Node power balance equation:

[0108]

[0109] Where Ψ and Φ are the sets of the first and last nodes of the branch respectively; Pki,t and Q ki,t are the active and reactive power flowing through branch ki at time t, flowing from node k to node i; I ki,t is the square of the current flowing through branch ki at time t; r ki and x ki are the resistance and reactance of branch ki respectively; P ij,t and Q ij,t are the active power and reactive power flowing through branch ij at time t, flowing from node i to node j; P D,i,t and Q D,i,t are the active load and reactive load connected to node i at time t respectively; Q MT,i,t , Q WT,i,t , Q PV,i,t They are the reactive power output of the corresponding DG installed at node i at time t.

[0110] 2) Voltage balance equation:

[0111]

[0112] u i,min ≤u i,t ≤u i,max (16);

[0113] In the formula, u i,t is the square of the voltage at node i at time t; u j,t, is the square of the voltage at node j at time t; u i，max and u i，min are the maximum and minimum values ​​of the voltage at node i, respectively; I ij,t is the square of the current flowing through branch ij at time t; r ij and x ij are the resistance and reactance of branch ij respectively.

[0114] 3) Branch flow constraints:

[0115] ||[2P ij,t 2Q ij,t I ij,t -u i,t ] T ||2≤I ij,t +u i,t (17);

[0116] 4) Branch capacity constraints:

[0117] S l,t ≤S l,max (18);

[0118] In the formula, S l,t is the transmission power of branch l at time t; Sl,max is the upper limit of the power allowed to be transmitted by branch l.

[0119] 5) DG operation constraints:

[0120]

[0121] Where P MT,max , P WT,max , P PV,max are the corresponding DG active output upper limits; P MT,min , P WT,min , P PV,min are the lower limits of the corresponding DG active output; Q MT,max , Q WT,max , Q PV,max are the corresponding DG reactive output upper limits; Q MT,min , Q WT,min , Q PV,min are the corresponding lower limits of DG reactive output respectively.

[0122] 6) SOP operation constraints:

[0123]

[0124] 7) Load node carbon emission equation constraint:

[0125] E i,t =P D,i,t I N,,t (twenty two);

[0126] In the formula, E i,t is the carbon emission of load node i at time t; I N,i,t is the node carbon potential of load node i at time t.

[0127] 8) Branch carbon flow density constraint:

[0128] I L,l,t =I N,i,t (l∈Ω i- ) (twenty three);

[0129] In the formula, I L,l,t is the carbon flow density of branch l at time t.

[0130] 9) Node carbon potential equality constraint:

[0131]

[0132] Where P l,t is the active power flowing through branch l at time t; I SOP,ji,t is the carbon flow density of SOP at branch ji at time t.

[0133] 10) Calculation of carbon emission flow of FDN:

[0134] From equations (6)-(8), the carbon emission flow distribution of the entire FDN is obtained.

[0135] Step 3: Solve the above model and introduce the Shapley value theory to study the carbon emission responsibility allocation on the load side of the flexible distribution network from the perspective of cooperative game, and determine the carbon emission responsibility of the end users of the flexible distribution network.

[0136] In dealing with the problem of carbon emission responsibility sharing on the load side, how to adopt a more reasonable responsibility sharing than before the cooperative game, and at the same time meet the necessary conditions for carbon emission responsibility sharing, etc. The carbon emission responsibility sharing method based on Shapley value not only meets the above standard requirements, but also fully considers the capacity size, network location, and mutual influence factors of load members. It has good fairness, compatibility, and stability, and can calculate the load side carbon emission responsibility sharing results for a long period of time. Shapley value is a cooperative game problem involving multiple subjects. The benefits are reasonably distributed according to the contribution of each subject in the cooperative project. This project adopts a carbon emission responsibility sharing method based on Shapley value, emphasizing the marginal effect of each sub-alliance on the alliance. According to the theoretical definition of Shapley value sharing, it is assumed that the alliance N = {1,2,…n} is n load members, and any sub-node member S of N corresponds to a carbon emission function c(S), which satisfies:

[0137]

[0138] In the formula, c(S) is the carbon emission responsibility of the alliance, and φ is the intersection of alliance S1 and alliance S2. The carbon emission responsibility shared by the load members in the alliance is determined by the marginal effect average:

[0139]

[0140] In the formula, x i is the carbon emission responsibility shared by alliance member i; S is the sub-alliance composed of sub-alliance members ranked before alliance member i; P(S) is the probability of sub-alliance S occurring; S∪{i} is the new alliance formed by incorporating alliance member i into alliance S; c(S∪{i})-c(S) represents the marginal impact generated when alliance member i joins sub-alliance S.

[0141]

[0142] According to rationality: the carbon emission responsibility assumed by the sub-alliance members should be within a certain range and not greater than the maximum value x of the marginal effect of the sub-alliance members max (i) is not less than the minimum value x of its marginal effectmin (i), that is:

[0143] x min (i)≤x(i)≤x max (i) (28);

[0144] x max (i)=max(c(SU{i})-c(S)) (29);

[0145] x min (i)=min(c(SU{i})-c(S)) (30);

[0146] According to the maximum x of the marginal effect of carbon emission responsibility max , minimum value x min and the mean value x ave , a reasonable range of carbon emissions can be formed, and a step-by-step carbon price can be set within this range. In each period, the reasonable range of carbon emission responsibility of each load node is divided into 4 intervals: free carbon responsibility price interval 0-x min , low carbon responsibility price range x min -x ave 、China Carbon Responsibility Price Range x ave -x max , High Carbon Responsibility Price Range x max -∞.

[0147] Among them, x ave =P(S1)(c(S1 U{i})-c(S1))+P(S2)(c(S2 U{i})-c(S2)).

[0148] In different intervals, a tiered carbon price is applied to node carbon emissions according to different intervals.

[0149]

[0150] In the formula, λ is the step carbon emission cost, in units of RMB / tCO2, E i,t is the carbon emission of the load node per unit time, λ1, λ2, λ3, and λ4 are the step carbon emission costs in different carbon emission ranges.

[0151] Calculate the total cost of carbon emissions C based on the tiered carbon price CE,i,t That is, the carbon emission responsibility of the end users of the flexible distribution network is:

[0152]

[0153] Example 2

[0154] The feasibility of the solution in Example 1 is verified by combining specific experiments, as described below:

[0155] The carbon emission responsibility allocation on the load side is studied from the perspective of cooperative game, and the Shapley value theory is introduced to find the reasonable range of carbon emission responsibility of each regional load and allocate the carbon emission responsibility. The system includes: 1 MT, 3 WT, 3 PV, 32 transmission lines and 32 load nodes. The use of Shapley value will lead to combinatorial explosion problems. In order to solve such problems, the loads are divided into three alliances. The improved 33-node distribution network is divided into 3 areas, represented by Alliance 1, Alliance 2 and Alliance 3 respectively, and each alliance is connected by SOP. The improved IEEE 33-node distribution network is as follows Figure 6 Table 3 introduces the specific alliance scope and the units included in the alliance.

[0156] Table 3 Load Alliance

[0157]

[0158] The entire alliance is N = {1, 2, 3}, with a total of 7 non-empty sub-alliances. Taking t = 19 as an example, the flexible distribution network operation model under different sub-alliance conditions is solved, and the system carbon emission responsibility results are shown in Table 4.

[0159] Table 4 Carbon emissions of each alliance

[0160]

[0161] Taking Alliance 1 at t=19 as an example, calculate x min 、x ave 、x max , we get x min =372.79 kgCO2 / h, x mave =635.00kgCO2 / h, x max =767.33kgCO2 / h, and the parameters of the step carbon price are λ1=0, λ2=35, λ3=70, λ4=140, in units of RMB / tCO2. The step carbon responsibility cost allocation results of Alliance 1 at t=19 are as follows:

[0162]

[0163] After carbon responsibility allocation based on the Shapley value method, the reasonable range of carbon emission responsibility of each alliance in 24 periods can be calculated, and then the ladder carbon price range is divided. The ladder carbon price range of each alliance is as follows: Figure 7 shown.

[0164] Depend on Figure 7It can be seen that converting the indirect carbon emission analysis problem into the classic carbon emission responsibility sharing problem can achieve fair sharing of carbon emission responsibilities of each load node in FDN, and the trend of carbon emissions is basically the same as the load trend. There is a large amount of electricity consumption in the high-carbon period and a small amount of electricity consumption in the low-carbon period. The carbon emission responsibility sharing method based on Shapley value can more reasonably perform the step-by-step segmentation of carbon emission responsibilities in each period. The installed capacity of new energy units in FDN is large and the electricity consumption in the low-carbon period is small, which leads to small carbon emissions in the low-carbon period. When in the high-carbon period, the output of new energy units decreases and as the electricity consumption increases, the high-carbon electricity purchased by FDN from the upper power grid increases. In order to ensure the fairness of the carbon emission responsibility sharing of each load node, the free quota range of carbon emissions of each alliance is significantly increased during the high-carbon period.

[0165] In addition, combined with the topology of FDN, it can be seen that the allocation of carbon emission responsibility is closely related to the load size and location. Alliance 1 is directly connected to the upper power grid in terms of geographical location. The carbon-containing electricity purchased by the distribution network from the upper power grid will be first injected into Alliance 1, and the load of Alliance 1 is higher than that of Alliance 2 and Alliance 3, so Alliance 1 bears the greatest carbon emission responsibility. Alliance 2 has the smallest carbon emission responsibility, on the one hand because the load of Alliance 2 is small, and on the other hand because the geographical location of Alliance 2 is far from the upper power grid, and Alliance 2 receives zero-carbon and low-carbon electricity from Alliance 1 and Alliance 3, which reduces the carbon emission intensity of some nodes in Alliance 2, so the carbon emissions generated are small and the corresponding carbon emission responsibility is small.

[0166] In summary, this method can enable each load node in the flexible distribution network to have a reasonable carbon emission responsibility range, and stipulate a tiered carbon price in different ranges, which can make the tiered pricing of carbon emission responsibility on the load side fairer.

Claims

1. A method for calculating carbon emission responsibility allocation in a flexible distribution network based on carbon emission flow, characterized by: The method comprises the following steps, and the following steps are performed in sequence: Step 1: According to the carbon emission characteristics of the flexible distribution network, a calculation method for the carbon emission flow of the flexible distribution network is established; Step 2: According to the characteristics of power electronic equipment in the flexible distribution network, a low-carbon optimization operation model of the flexible distribution network is established based on the improved carbon emission flow theory. The model takes the minimum total cost C of the flexible distribution network FDN as the objective function and obtains the carbon emission flow distribution of the entire FDN; Step 3: Solve the low-carbon optimization operation model of the flexible distribution network and introduce the Shapley value theory to allocate the carbon emission responsibility on the load side of the flexible distribution network from the perspective of cooperative game and determine the carbon emission responsibility of the end users of the flexible distribution network.

2. According to a method for calculating carbon emission responsibility allocation of a flexible distribution network based on carbon emission flow according to claim 1, it is characterized by: The objective function in step 2 is: min C=C1+C2+C3+C4; Among them, C1 is the power generation cost, C2 is the cost of purchasing electricity from the transmission network, C3 is the network loss cost, and C4 is the carbon emission cost.

3. According to a method for calculating carbon emission responsibility allocation of a flexible distribution network based on carbon emission flow according to claim 1, it is characterized by: The carbon emission flow distribution of the entire FDN obtained in step 2 is: Get the carbon emission intensity vector E of the generator set DG G , and calculate the node carbon potential vector E N : ①. The carbon emission flow on the power supply side is calculated as follows: The carbon emission intensity vector of DG is multiplied by the active power injected by DG into FDN to obtain the carbon emission size on the power supply side; ②. The carbon emission flow on the grid side is calculated as follows: The branch power distribution matrix P B Get the branch carbon flow rate distribution matrix R B : R B diag(E N )P B 100. ③. The carbon emission flow on the load side is calculated as follows: The carbon emission intensity of a load node is equal to the carbon potential of the node, which is represented by the load distribution matrix P L Get the load carbon flow rate vector R L : R L =P L E N 。 4. According to a method for calculating carbon emission responsibility allocation of a flexible distribution network based on carbon emission flow according to claim 1, it is characterized by: The method for determining the carbon emission responsibility of the terminal users of the flexible distribution network in step 3 is as follows: Assume that alliance N = {1, 2, ... n}, where n represents n subnode load members. Any subnode load member S of N corresponds to a carbon emission function c(S), and c(S) represents the carbon emission responsibility of the alliance. The function satisfies: Where φ is the intersection of alliance S1 and alliance S2; The carbon emission responsibility shared by the load members in the alliance is determined by the average marginal contribution: In the formula, x i is the carbon emission responsibility shared by alliance member i; S is the sub-alliance composed of sub-alliance members ranked before alliance member i; P(S) is the probability of the occurrence of sub-alliance S; S∪{i} is the new alliance formed by incorporating alliance member i into alliance S; c(S∪{i})-c(S) represents the marginal impact generated when alliance member i joins sub-alliance S; in, According to the rationality of carbon emissions, the carbon emission responsibility of the sub-alliance members is set to be no greater than the maximum value of the marginal effect of the sub-alliance members x max (i) At the same time, it is not less than the minimum value x of its marginal effect min (i), that is: x min (i)≤x(i)≤x max (i); x max (i)=max(c(SU{i})-c(S)); x min (i)=min(c(SU{i})-c(S)); According to the maximum x of the marginal effect of carbon emission responsibility max , minimum value x min and the mean value x ave , in each period, the carbon emission responsibility range of each load node is divided into 4 intervals: free carbon responsibility price interval 0-x min , low carbon responsibility price range x min -x ave 、China Carbon Responsibility Price Range x ave -x max , High Carbon Responsibility Price Range x max -∞; Among them, x ave =P(S1)(c(S1U{i})-c(S1))+P(S2)(c(S2U{i})-c(S2)); In different intervals, a tiered carbon price is applied to node carbon emissions according to different intervals: In the formula, λ is the step carbon emission cost, in units of RMB / tCO2, E i,t is the carbon emission per unit time of the load node; λ1, λ2, λ3, and λ4 are the step carbon emission costs in different carbon emission ranges; Calculate the total cost of carbon emissions C based on the tiered carbon price CE,i,t , that is, the carbon emission responsibility of the end users of the flexible distribution network is:

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