A generalized node-based carbon metering method for power systems

Abstract

The application provides a generalized node-based carbon metering method for a power system, comprising the following steps: obtaining a power grid topology of a generalized node-based power system; and calculating carbon emission factors of the power system according to the power grid topology. The application proposes a method for calculating carbon emission flow with the participation of generalized nodes, and analyzes the similarities and differences between different generalized node carbon metering methods, which can reduce the high calculation amount caused by the radial structure of the distribution network, improve the efficiency of carbon emission flow calculation, realize the metering of carbon emission factors of users under different spatial resolutions, and take into account the feasibility and fairness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power systems, in particular to a power system carbon metering method based on generalized nodes. BACKGROUND

[0002] The commonly used measurement index for carbon metering in the power industry is the carbon emission factor, which establishes the relationship between power consumption and carbon emissions. Carbon emission factors are widely used in many fields such as greenhouse gas inventory, enterprise greenhouse gas emission accounting, and product carbon footprint. The calculation method of carbon emission flow in the power system makes up for the lack of spatial and temporal characteristics of the carbon emission factor when it is published, and realizes the deep coupling of carbon emission flow and power flow.

[0003] For the power grid, the large number of lines between nodes in the distribution network makes the calculation of carbon emission flow more complex. For users, the carbon emission factor on the power consumption side often shows regional characteristics. Considering the needs of different application scenarios, the spatial resolution of carbon emission flow calculation should be different. The existing carbon emission flow calculation method mainly targets the user level in terms of spatial resolution, but this may affect the fairness due to different power grid topologies. For example, the carbon emission factor of users close to thermal power plants in the same region is much higher than that of users close to new energy users. SUMMARY

[0004] The purpose of the present application is to provide a power system carbon metering method based on generalized nodes.

[0005] The embodiments of the present application are implemented by the following technical solutions:

[0006] A power system carbon metering method based on generalized nodes includes the following steps:

[0007] Obtain the power grid topology structure of the power system based on generalized nodes;

[0008] According to the power grid topology structure, calculate the carbon emission factor of the power system.

[0009] The technical scheme of the embodiment of the present application has at least the following advantages and beneficial effects: the present application proposes a method of generalized nodes participating in carbon emission flow calculation, and analyzes the similarities and differences of different generalized node carbon metering methods, which can reduce the high calculation amount caused by the radial structure of the distribution network, improve the efficiency of carbon emission flow calculation, realize the metering of user carbon emission factors under different spatial resolutions, and balance the feasibility and fairness.

[0010] Further, the power grid topology structure includes a first topology structure, a second topology structure, and a third topology structure.

[0011] Further, the power system adopts the first topology structure, and the generalized node of the power system adopts the distribution network.

[0012] Further, the power system adopts the second topology structure, the generalized node of the power system adopts the user cluster.

[0013] Further, the power system adopts the third topology structure, the generalized node of the power system adopts the distribution network and the user cluster.

[0014] Further, the power system adopts the first topology structure and the generalized node of the power system adopts the grid-side allocation of the loss carbon emission, the calculation formula of the carbon emission factor e of the generalized node is as follows: i

[0015]

[0016] In the formula, P represents the active power flowing into the branch, p represents the branch carbon flow density flowing into the branch, i i represents the set of all branches injecting active power into the node.

[0017] Further, the power system adopts the first topology structure and the generalized node of the power system adopts the user allocation of the loss carbon emission, the calculation formula of the carbon emission factor e' of the generalized node is as follows: i

[0018]

[0019] In the formula, P represents the active power flowing into the branch, p represents the branch carbon flow density flowing into the branch, i i represents the set of all branches injecting active power into the node, represents the set of all outgoing branches of the generalized node, P represents the active power flowing out of the branch. o

[0020] Further, the power system adopts the second topology structure and the user cluster is divided according to the voltage level, the calculation formula of the carbon emission factor e'' of the generalized node is as follows: i

[0021]

[0022] In the formula, P represents the active power flowing into the branch, P represents the active power flowing into the branch, p represents the branch carbon flow density flowing into the branch, o1 o2 o1 o2

[0023] ​​​​​​​​​​​​Furthermore, if the power system adopts a second topology and divides user clusters according to administrative regions, then the carbon emission factor e″′ of the generalized node... i The calculation formula is:

[0024]

[0025] In the formula, P i ρ represents the active power flowing into the branch. i e represents the carbon flux density of the inflow branch. s α represents the carbon emission factor of subregion s. i This indicates the proportion of the load electricity in a sub-region to the inflow electricity into the generalized node's branch. Represents a set of subregions. This represents the set of all branches that inject active power into a node.

[0026] Furthermore, if the power system adopts a third topology, the carbon emission factor C of the generalized node will be... i The calculation formula is:

[0027]

[0028]

[0029] In the formula, e″″ i P represents the carbon emission factor corresponding to the generalized node net load. i ρ represents the active power flowing into the branch. i This indicates the branch carbon flux density flowing into the branch. Let P represent the set of all outgoing branches of a generalized node. o This indicates the active power flowing out of the branch. Let P represent the set of other nodes within the micronet. k ρ represents the active power of other non-distributed power sources within the microgrid. k This represents the carbon emission factor of other non-distributed power sources within the microgrid. Attached Figure Description

[0030] Figure 1 A flowchart of a power system carbon metering method based on generalized nodes provided in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of power flow at nodes in a power network.

[0032] Figure 3 This is a schematic diagram of a generalized node.

[0033] Figure 4 Topological graphs within generalized nodes in different scenarios;

[0034] Figure 5 A schematic diagram of a generalized node in a distribution network;

[0035] Figure 6 A schematic diagram of generalized nodes in a user cluster;

[0036] Figure 7 A schematic diagram illustrating the generalized node classification based on voltage level;

[0037] Figure 8 A schematic diagram showing the generalized nodes divided according to administrative regions;

[0038] Figure 9 This is a schematic diagram of a microgrid as a generalized node. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] like Figure 1 As shown, this invention provides a carbon metering method for power systems based on generalized nodes, comprising the following steps:

[0041] Obtain the power grid topology of a power system based on generalized nodes;

[0042] Calculate the carbon emission factor of the power system based on the power grid topology.

[0043] The establishment of the carbon emission flow theory system enables the measurement of carbon emission responsibility in the power system. Carbon emission flows are commonly measured using two indicators: nodal carbon potential, which describes the indirect carbon emissions corresponding to a unit of electricity consumed at a node, and branch carbon flow density, which describes the indirect carbon emissions corresponding to a unit of electricity flowing through a line. According to the principle of fairness in carbon emission flows, the carbon flow density of all outgoing branches of a node is equal to the carbon emission factor of that node.

[0044] According to the proportional allocation principle, the carbon emission factor of node i is calculated using the following formula:

[0045]

[0046] In the formula, + and Let P represent the set of all branches that inject active power into node i and the set of generator sets connected to node i, respectively; b ρ represents the active power of branch b. b G represents the carbon flux density of branch b; sE represents the active power output of the generator set in direction S. s This represents the carbon emission intensity of generator set s.

[0047] like Figure 2 As shown, all injection branches b of node i 1,…,n The carbon flux density and its injection node j 1,…,n The carbon emission factors of node i are equal. Therefore, the carbon emission factor of node i can be determined by the injection nodes j1, j2, ... j of its injection branch. n Carbon emission factors are used to represent

[0048]

[0049] In the formula, P j→i E represents the active power injected by node j into node i. j Let represent the carbon emission factor injected into node j. For a power system consisting of n nodes, the component form of the iterative equation for the carbon emission factor of each node in the power grid can be expressed as:

[0050]

[0051] In addition to the actual nodes in the power grid, a closed space such as a region, a village, or even a city can be divided into generalized nodes. For example... Figure 3 As shown, a generalized node is a multi-port network. Regardless of its internal structure complexity, the sum of power flowing into the network is always equal to the sum of power flowing out and network losses. Therefore, a generalized node can participate in the calculation of carbon emission flows as a single node. Metering devices need to be installed in the injection and outflow branches to monitor the transfer of carbon emission responsibility between different generalized nodes. All nodes in this space adopt the overall carbon emission factor of the generalized node.

[0052] like Figure 4 As shown, based on the specific power grid topology within the generalized node, the following three cases can be identified:

[0053] 1. The power system within a generalized node consists only of substations, such as certain areas within a transmission or distribution network.

[0054] 2. The power system within a generalized node consists only of user loads, such as a user cluster under a substation of a certain voltage level.

[0055] 3. The power system within a generalized node consists of power sources and user loads, such as microgrids.

[0056] In this embodiment of the invention, the power grid topology includes a first topology, a second topology, and a third topology;

[0057] In this embodiment of the invention, the power system adopts a first topology, and the generalized nodes of the power system adopt a distribution network.

[0058] In this embodiment of the invention, the power system adopts a second topology, and the generalized nodes of the power system adopt a user cluster.

[0059] In this embodiment of the invention, the power system adopts a third topology, and the generalized nodes of the power system are the distribution network and the user cluster.

[0060] In this embodiment of the invention, the distribution network has a radial network structure with a large number of branches between two nodes. Therefore, the iterative algorithm requires a large number of iterations and necessitates the installation of numerous meters for metering. However, the distribution network generally has a small coverage area and a small number of nodes. Figure 5 As shown, the distribution network can be considered a generalized node in carbon emission flow calculations. To ensure carbon conservation on both the generation and consumption sides, carbon emissions caused by network losses cannot be ignored. Currently, there are two ways to share the responsibility for carbon emissions from network losses: sharing by the power grid company and sharing by the users.

[0061] Method 1: The basic idea of ​​sharing network loss responsibility by the power grid company is that network losses occur on the grid side, so the carbon emissions from network losses are first allocated to specific lines to reflect the grid side's responsibility, and then the responsibility is allocated to the trading process. If the power system adopts the first topology and the network loss carbon emission sharing method for generalized nodes in the power system adopts grid-side allocation, then the carbon emission factor e of the generalized nodes... i The calculation formula is:

[0062]

[0063] In the formula, P i ρ represents the active power flowing into the branch. i This indicates the branch carbon flux density flowing into the branch. This represents the set of all branches that inject active power into a node.

[0064] The carbon emissions from network losses at generalized nodes can be expressed as

[0065]

[0066] In the formula, P represents the set of all outgoing branches of the generalized node i; out This indicates the active power flowing out of the branch.

[0067] In this embodiment of the invention, the basic idea of ​​user-shared responsibility for network losses is that the final consumer of electricity is the user, therefore the responsibility for network losses and carbon emissions during the production and transfer of carbon emission streams should be borne by the user. If the power system adopts a first topology and the network loss and carbon emission sharing method for generalized nodes in the power system adopts user-shared responsibility, then the carbon emission factor e of the generalized nodes... i The formula for calculating ′ is:

[0068]

[0069] In the formula, P i ρ represents the active power flowing into the branch. i This indicates the branch carbon flux density flowing into the branch. This represents the set of all branches that inject active power into a node. Let P represent the set of all outgoing branches of a generalized node. o This represents the active power flowing out of the branch. In this mode, the carbon emissions from network losses at generalized nodes are allocated to the user side and do not require separate metering.

[0070] In this embodiment of the invention, a large number of user clusters exist on the user side, and user-level spatial resolution carbon metering may raise feasibility and fairness issues. Typically, these can be divided according to administrative regions or voltage levels, such as... Figure 6 As shown, the user cluster can be viewed as a generalized node participating in carbon emission flow calculation.

[0071] like Figure 7 As shown, user clusters under substations of different voltage levels can be divided into generalized nodes according to actual needs. A generalized node contains all users under a certain 10kV substation, and the carbon emission factor of the generalized node is the same as that of the substation. However, there may be overlapping areas between different generalized nodes, that is, overlapping areas are supplied by two different substations of the same voltage level. Figure 7 For example, the carbon emission factor for this region needs to be measured separately. If the power system adopts a second topology and user clusters are divided according to voltage levels, then the carbon emission factor e″ of the generalized node... i The calculation formula is:

[0072]

[0073] In the formula, P o1 P represents the active power flowing from the first region into the overlapping region of the power system. o2 ρ represents the active power flowing from the second region into the overlapping region. o1 ρ represents the carbon emission factor of the first substation. o2 This indicates the carbon emission factor of the second substation.

[0074] In embodiments of the present invention, such asFigure 8 As shown, a user cluster within an administrative region can be divided into generalized nodes based on actual needs. The inflow branches of a generalized node can originate from multiple substations, and each generalized node may include sub-regions requiring separate and precise metering, such as using dynamic carbon emission factors to guide enterprise participation in demand response. The calculation of the carbon emission factors for generalized nodes and their sub-regions involves two steps: calculating the load-to-electricity ratio of the sub-region using reverse power flow tracing, where α is the proportion of the inflow branch i of the generalized node. i , where P i ρ represents the active power of branch i. i Let the carbon emission factor of branch i be the basis for calculating the carbon emission factor of subregion s:

[0075]

[0076] If the power system adopts a second topology and divides user clusters according to administrative regions, then the carbon emission factor e″′ of the generalized node is... i The calculation formula is:

[0077]

[0078] In the formula, P i ρ represents the active power flowing into the branch. i e represents the carbon flux density of the inflow branch. s α represents the carbon emission factor of subregion s. i This indicates the proportion of the load electricity in a sub-region to the inflow electricity into the generalized node's branch. Represents a set of subregions. This represents the set of all branches that inject active power into a node.

[0079] In this embodiment of the invention, the microgrid contains both power sources and loads. The power sources typically include a large number of renewable energy generation devices, such as distributed photovoltaic systems. Furthermore, the microgrid also transfers carbon emissions with the main distribution grid through electrical energy interaction. Figure 9 As shown, a microgrid can be considered a generalized node for carbon emission flow calculation. Distributed renewable energy sources are widely distributed and numerous, making carbon metering of all distributed sources impractical in reality. To encourage user participation in renewable energy development, the concept of local renewable energy consumption can be introduced into the carbon metering of the generalized node. This assumes that all distributed sources in the microgrid are used for electricity consumption by microgrid users, and indirect carbon emissions within the microgrid originate only from net load. Since the output of distributed renewable energy is difficult to measure accurately, net load can be calculated based on other information. If the power system adopts a third topology, the carbon emission factor C of the generalized node... i The calculation formula is:

[0080]

[0081] In the formula, e″″ i P represents the carbon emission factor corresponding to the generalized node net load. i ρ represents the active power flowing into the branch. i This indicates the branch carbon flux density flowing into the branch. Let P represent the set of all outgoing branches of a generalized node. o This indicates the active power flowing out of the branch. Let P represent the set of other nodes within the micronet. k ρ represents the active power of other non-distributed power sources within the microgrid. k This represents the carbon emission factor of other non-distributed power sources within the microgrid.

[0082] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A carbon metering method for power systems based on generalized nodes, characterized in that, Includes the following steps: Obtain the power grid topology of a power system based on generalized nodes; the power grid topology includes a first topology, a second topology, and a third topology; The carbon emission factor of the power system is calculated based on the power grid topology; if the power system adopts the second topology, then the generalized nodes of the power system adopt a user cluster. The power system adopts a second topology and divides user clusters according to voltage levels. The carbon emission factor of the generalized node is... The calculation formula is: In the formula, P o1 This represents the active power flowing from the first region into the overlapping region of the power system. P o2 This represents the active power flowing from the second region into the overlapping region. ρ o1 This indicates the carbon emission factor of the first substation. ρ o2 This indicates the carbon emission factor of the second substation.

2. A carbon metering method for power systems based on generalized nodes, characterized in that, Includes the following steps: Obtain the power grid topology of a power system based on generalized nodes; the power grid topology includes a first topology, a second topology, and a third topology; The carbon emission factor of the power system is calculated based on the power grid topology; if the power system adopts the second topology, then the generalized nodes of the power system adopt a user cluster. The power system adopts a second topology and divides user clusters according to administrative regions. The carbon emission factor of the generalized nodes... The calculation formula is: In the formula, P i This indicates the active power flowing into the branch. ρ i This indicates the branch carbon flux density flowing into the branch. e s Subregion s carbon emission factors, α i This indicates the proportion of the load electricity in a sub-region to the inflow electricity into the generalized node's branch. Represents a set of subregions. This represents the set of all branches that inject active power into a node.

3. A carbon metering method for power systems based on generalized nodes, characterized in that, Includes the following steps: Obtain the power grid topology of a power system based on generalized nodes; the power grid topology includes a first topology, a second topology, and a third topology; The carbon emission factor of the power system is calculated based on the power grid topology; if the power system adopts a third topology, then the generalized nodes of the power system are the distribution network and the user cluster. The power system adopts a third topology, then the carbon emission factor of the generalized node is... C i The calculation formula is: In the formula, This represents the carbon emission factor corresponding to the net load of the generalized nodes. P i This indicates the active power flowing into the branch. ρ i This indicates the branch carbon flux density flowing into the branch. This represents the set of all outgoing branches of a generalized node. P o This indicates the active power flowing out of the branch. This represents the set of other nodes within the micronet. P k This represents the active power of other non-distributed power sources within the microgrid. This represents the carbon emission factor of other non-distributed power sources within the microgrid.

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