A method and system for dispatching and distribution coordination low-carbon economy based on target cascade method

Abstract

The application provides a kind of transmission and distribution coordination low carbon economic dispatching method based on target cascade method, comprising: establishing transmission and distribution network hierarchical dispatching framework, analyzing interactive power characteristics under typical load output;Combined with physical coupling relationship, set transmission and distribution network decoupling variable, and based on target cascade method, build related criterion of transmission and distribution coordination consistency;According to the above transmission and distribution network hierarchical dispatching framework, combined with voltage constraint, power flow constraint and other constraint conditions and considering electric carbon coupling calculation method, build transmission and distribution coordination low carbon optimization model based on target cascade method.The application applies a kind of transmission and distribution coordination low carbon economic dispatching method based on target cascade method to transmission and distribution coordination dispatching, considers the influence of dynamic carbon emission factor on power purchase and sale of transmission network and distribution network, compared with traditional transmission and distribution coordination dispatching, can guide transmission network layer to purchase clean electric energy, reduce carbon emission of traditional unit.

Description

Technical Field

[0001] This invention belongs to the field of power grid resource optimization and scheduling technology, and in particular relates to a transmission and distribution coordinated low-carbon economic scheduling method and system based on the target cascading method. Background Technology

[0002] As the core component connecting the main power grid and end-users, the distribution network plays a crucial role in achieving dual-carbon goals and building a new power system. Currently, the active distribution network is gradually evolving into a comprehensive distribution system capable of accommodating the large-scale integration and coordinated operation of distributed renewable energy sources, electric vehicle charging stations, electrified railways, and other power electronic equipment, while simultaneously promoting the substitution of clean energy at both the generation and consumption ends. With the large-scale integration of distributed generation and impact loads such as electric vehicles and railways, the level of power electronics in the distribution network has significantly increased, and its characteristics of uncertainty and bidirectional flow have become more pronounced.

[0003] As the penetration rate of new energy sources continues to increase, the operation of power distribution networks is becoming more diversified, and the power generation mode is shifting from traditional synchronous generator generation to coordinated power generation of traditional units and new energy sources, making the changes in transmission and distribution power more complex. In order to achieve optimal economic dispatch in this new environment, traditional centralized control is gradually transforming into intelligent, multi-level coordinated operation.

[0004] Since the introduction of the concept of carbon emission flows, carbon emissions in the power system have become not only the environmental cost of power production, but also an important indicator characterizing the low-carbon features of various links in the power system. The electricity-carbon coupling calculation method based on carbon emission flows can effectively allocate the carbon emissions generated by thermal power units to various nodes of the power grid according to their output, thereby achieving the goal of reasonably allocating carbon emission responsibilities.

[0005] Based on the above analysis, the problems and shortcomings of the existing technology are as follows:

[0006] (1) Existing technologies make it difficult to directly participate in the optimal scheduling of active distribution networks as an independent entity. Directly solving the problem may lead to problems such as the explosion of decision variables and difficulty in converging the solution results.

[0007] (2) Most traditional clustering algorithms have poor reliability and convergence when applied in the power system field. There is very little research on distributed resource clustering for distribution network optimization scheduling, which makes actual scheduling lack reference and is not conducive to the optimization scheduling of adjustment resources.

[0008] (3) At present, the coordinated economic dispatch of transmission and distribution is mainly based on fixed carbon emissions, and rarely considers the impact of dynamic carbon emission factors on the power purchase and sale behavior of the distribution network. The power purchase and sale situation of the distribution network under the scenario of electricity-carbon coupling is still unclear. Summary of the Invention

[0009] To overcome the shortcomings of the prior art, this invention provides a transmission and distribution coordinated low-carbon economic dispatch method and system based on the target cascade method. By applying a transmission and distribution coordinated low-carbon economic dispatch method based on the target cascade method to transmission and distribution coordinated dispatch, the impact of dynamic carbon emission factors on the power purchase and sale of the transmission and distribution networks is considered. Compared with traditional transmission and distribution coordinated dispatch, it can guide the transmission network layer to purchase clean energy and reduce the carbon emissions of traditional units.

[0010] According to one aspect of the present invention, a method for coordinated low-carbon economic dispatching of transmission and distribution based on the target cascade method is provided, comprising:

[0011] Establish a hierarchical dispatching framework for the power transmission and distribution network and analyze the interactive power characteristics under typical load output;

[0012] Decoupling variables for the power transmission and distribution network are set in combination with physical coupling relationships, and a consistency criterion for power transmission and distribution coordination is constructed based on the target cascading method and the physical structure of the power transmission and distribution network.

[0013] Based on the aforementioned hierarchical dispatching framework for transmission and distribution networks, and combined with preset constraints and considering the electricity-carbon coupling calculation method, a low-carbon economic optimization model for transmission and distribution coordination is constructed.

[0014] As a further technical solution, a hierarchical dispatching framework for the power transmission and distribution network is established, including:

[0015] The power grid with a voltage level of 220kV and above, which plays a major power supply role, is assigned to the transmission network layer. Its controllable resources are the output of thermal power units and the interactive power on the transmission network side.

[0016] The power grid with a voltage level below 220kV that plays a major role in electricity consumption is assigned to the distribution network layer, and its controllable resources are photovoltaic power output, energy storage system power output and distribution network side interactive power.

[0017] The transmission network and each distribution network operate in a mode of "intra-layer power self-consistency - inter-layer information interaction".

[0018] As a further technical solution, the "intra-layer power self-consistency - inter-layer information interaction" operation mode includes:

[0019] The intra-layer power self-consistency is used to schedule power according to the principle of first achieving internal power balance between the transmission network layer and the distribution network layer, and then sending the remaining power to the grid.

[0020] The inter-layer information interaction is used so that after optimization within the execution layer, the transmission network layer transmits the electricity purchase and sale demand and the carbon potential of the coupling point nodes to the distribution network layer, and the distribution network layer transmits the electricity required by its own layer to the transmission network layer, so that the two can achieve complete information sharing.

[0021] As a further technical solution, decoupling variables for the transmission and distribution network are set in conjunction with the physical coupling relationship, and a transmission and distribution coordination consistency criterion is constructed based on the target cascading method and the physical structure of the transmission and distribution network, including:

[0022] Based on the principle of the target cascade method, the coupling and interaction power between the transmission and distribution networks is taken as a shared variable, without considering the phase angle difference at the coupling point of the transmission and distribution networks;

[0023] When optimizing the transmission network layer, the interactive power is treated as an equivalent load and participates in the optimization; when optimizing the distribution network layer, the interactive power is treated as an equivalent generator and participates in the optimization.

[0024] After optimization within each layer is completed, convergence can be determined by considering whether the transmission power meets the following consistency criteria.

[0025] As a further technical solution, the consistency criterion between transmission and distribution network layers includes:

[0026] The consistency criterion between transmission and distribution network layers is based on the fact that the difference in interactive power does not exceed a given threshold. The calculation formula is as follows:

[0027]

[0028] In the formula, When the transmission network is dispatched at the transmission network level, the power transmitted from the transmission network to the distribution network is equivalent to virtual active power load. This represents the power supply from the transmission network to the distribution network, and vice versa, the power transmission from the distribution network to the transmission network. This refers to the active power purchased by the distribution network from the transmission network during distribution network layer dispatching, which is equivalent to the active power of a virtual generator. ε represents the power transmitted from the distribution network to the transmission network, and vice versa. ε is the convergence accuracy of the two-level model. Variables without an overline are considered as alternative variables.

[0029] As a further technical solution, a low-carbon economic optimization model for coordinated transmission and distribution is constructed, including:

[0030] During the scheduling cycle, the transmission network layer aims to minimize the operating cost of thermal power units while also considering the transmission and distribution consistency objective. The constraints include power flow constraints, node voltage constraints, thermal power unit-related constraints, and transmission network layer interactive power constraints.

[0031] After the power transmission network layer calculation is completed, based on the electric carbon coupling mechanism and carbon emission flow calculation method, combined with the active power output and carbon emission factor of thermal power units, the nodal carbon potential of the transmission and distribution coupling point is calculated.

[0032] During the scheduling period, the distribution network layer aims for optimal overall economic efficiency while also considering transmission and distribution consistency. The constraints include power flow constraints, node voltage constraints, energy storage system-related constraints, photovoltaic output-related constraints, and distribution network layer interactive power constraints.

[0033] The steps for judging the execution results and updating the algorithm multipliers at the transmission network layer and distribution network layer.

[0034] According to one aspect of the present invention, a low-carbon economic dispatch system for coordinated transmission and distribution based on the target cascade method is provided, comprising:

[0035] The first calculation module is used to establish a hierarchical scheduling framework for the power transmission and distribution network and analyze the interactive power characteristics under typical load output.

[0036] The second calculation module is used to set decoupling variables of the transmission and distribution network in combination with the physical coupling relationship, and to construct the transmission and distribution coordination consistency criterion based on the target cascade method and the physical structure of the transmission and distribution network.

[0037] The third calculation module is used to construct a low-carbon economic optimization model for transmission and distribution coordination based on the aforementioned hierarchical scheduling framework of the transmission and distribution network, combined with preset constraints and considering the electricity-carbon coupling calculation method.

[0038] According to one aspect of the present invention, a transmission and distribution coordinated low-carbon economic dispatching device based on the target cascading method is provided, comprising a memory and a processor, wherein the memory stores program instructions that are executed by the processor, and the processor invokes the program instructions to execute the steps of the transmission and distribution coordinated low-carbon economic dispatching method based on the target cascading method.

[0039] According to one aspect of the present invention, a non-transitory computer-readable storage medium is provided, the non-transitory computer-readable storage medium storing computer instructions that cause the computer to perform the steps of the target cascading method-based transmission and distribution coordinated low-carbon economic dispatch method.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] 1. This invention provides a low-carbon economic dispatching method for transmission and distribution coordination based on the objective cascading method, comprising: establishing a hierarchical dispatching framework for the transmission and distribution network and analyzing the interactive power characteristics under typical load output; setting decoupling variables for the transmission and distribution network in combination with physical coupling relationships, and constructing relevant criteria for transmission and distribution coordination consistency based on the objective cascading method; and constructing a low-carbon optimization model for transmission and distribution coordination based on the objective cascading method, in combination with constraints such as voltage constraints and power flow constraints and considering the calculation method of electricity-carbon coupling, according to the above-mentioned hierarchical dispatching architecture of the transmission and distribution network.

[0042] 2. This invention applies a low-carbon economic dispatch method based on the target cascade method to the coordinated dispatch of transmission and distribution, taking into account the impact of dynamic carbon emission factors on the power purchase and sale of transmission and distribution networks. Compared with traditional coordinated dispatch of transmission and distribution, it can guide the transmission network layer to purchase clean energy and reduce the carbon emissions of traditional units. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascade method provided in the embodiments of the present invention;

[0045] Figure 2 This is a schematic diagram of the hierarchical scheduling framework of the transmission and distribution coordinated low-carbon economic scheduling method based on the target cascading method provided in the embodiments of the present invention;

[0046] Figure 3 This is a schematic diagram of the decoupling mechanism of the power transmission and distribution network layer in the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascading method provided in this embodiment of the invention.

[0047] Figure 4 This is an iterative flowchart of the two-layer economic scheduling model for coordinated transportation and distribution based on the target cascading method provided in this embodiment of the invention;

[0048] Figure 5 (a)-(b) are the topology diagrams of the IEEE6+IEEE33 node power transmission and distribution system of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascading method provided in the embodiments of the present invention.

[0049] Figure 6 (a)-(c) are schematic diagrams of the source-load characteristics of the power transmission and distribution system in the embodiments of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascading method provided in the present invention.

[0050] Figure 7 This is a graph showing the iteration count of the model in an embodiment of the low-carbon economic dispatching method based on the target cascade method provided in this invention.

[0051] Figure 8 This is a power curve diagram of the transmission and distribution network interaction of an embodiment of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascading method provided in this invention.

[0052] Figure 9This is a power curve diagram of the power generation, load and storage of the distribution network, based on the target cascading method, provided in an embodiment of the present invention. Detailed Implementation

[0053] The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and accompanying drawings of this invention are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that includes a series of steps or units, not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0054] 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, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined to form new technical solutions. Such combinations are not bound by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0055] This invention provides a low-carbon economic dispatching method for transmission and distribution coordination based on the target cascade method. First, a hierarchical dispatching framework for the transmission and distribution network is established, and the interactive power characteristics under typical load output are analyzed. Next, decoupling variables of the transmission and distribution network are set in combination with physical coupling relationships, and relevant criteria for transmission and distribution coordination consistency are constructed based on the target cascade method. Then, based on the above-mentioned hierarchical dispatching architecture of the transmission and distribution network, combined with constraints such as voltage constraints and power flow constraints, and considering the calculation method of electricity-carbon coupling, a low-carbon optimization model for transmission and distribution coordination based on the target cascade method is constructed.

[0056] like Figure 1 As shown in the figure, the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascade method provided in this embodiment of the invention includes the following steps:

[0057] S101, Establish a hierarchical dispatching framework for the power transmission and distribution network, and analyze the interactive power characteristics under typical load output;

[0058] S102, based on the transmission and distribution coupling characteristics, set inter-layer decoupling variables, and combine the relevant concepts of the target cascade method with the physical structure of the transmission and distribution network to construct a consistency criterion;

[0059] S103. Considering the power transmission and distribution network structure and related constraints, construct a low-carbon economic optimization model for power transmission and distribution coordination, determine the consistency of power interaction between layers, and correct the parameters.

[0060] Furthermore, the construction of the hierarchical dispatching framework for the power transmission and distribution network in S101 includes:

[0061] The power grid with a voltage level of 220kV and above, which plays a major power supply role, is assigned to the transmission network layer. Its controllable resources are the output of thermal power units and the interactive power on the transmission network side.

[0062] The power grid with a voltage level below 220kV that plays a major role in power consumption (supplying the transmission network during some periods) is assigned to the distribution network layer. Its controllable resources are photovoltaic power output, energy storage system power output, and power exchange on the distribution network side.

[0063] The transmission network and each distribution network operate in a mode of "inter-layer power self-consistency - inter-layer information interaction", and have a certain degree of autonomy in scheduling.

[0064] Furthermore, the "intra-layer power self-consistency - inter-layer information interaction" operation mode includes:

[0065] "Intra-layer power self-consistency" refers to the principle that the transmission network layer and the distribution network layer first achieve internal power balance, and the remaining power is then dispatched to the grid.

[0066] "Inter-layer information interaction" refers to the process where, after optimization within the execution layer, the transmission network layer transmits the electricity purchase and sale demand and the carbon potential of the coupling point nodes to the distribution network layer, and the distribution network layer transmits the electricity required by its own layer to the transmission network layer, thus achieving complete information sharing between the two.

[0067] Furthermore, such as Figure 2 , Figure 3 As shown, the setting of inter-layer decoupling variables and consistency criteria in S102 includes:

[0068] Based on the basic principle of the target cascade method, the coupling and interaction power between the transmission and distribution networks is taken as a shared variable, without considering the phase angle difference at the coupling point of the transmission and distribution networks.

[0069] When optimizing the transmission network layer, the interactive power is treated as an equivalent load and participates in the optimization; when optimizing the distribution network layer, the interactive power is treated as an equivalent generator and participates in the optimization.

[0070] After optimization within each layer is completed, convergence can be determined by considering whether the transmission power meets the following consistency criteria.

[0071] Furthermore, the consistency criterion between transmission and distribution network layers includes:

[0072] The consistency criterion between transmission and distribution network layers is based on the fact that the difference in interactive power does not exceed a given threshold. The calculation formula is as follows:

[0073]

[0074] In the formula, When the transmission network is dispatched at the transmission network level, the power transmitted from the transmission network to the distribution network is equivalent to virtual active power load. This represents the power supply from the transmission network to the distribution network, and vice versa, the power transmission from the distribution network to the transmission network. This refers to the active power purchased by the distribution network from the transmission network during distribution network layer dispatching, which is equivalent to the active power of a virtual generator. ε represents the power transmitted from the distribution network to the transmission network, and vice versa. ε is the convergence accuracy of the two-level model. Variables without an overline are considered as alternative variables.

[0075] Furthermore, such as Figure 4 As shown, the setting of the economic optimization model for the transmission network layer and distribution network layer in S103 includes:

[0076] During the scheduling cycle, the transmission network layer aims to minimize the operating cost of thermal power units while also considering the transmission and distribution consistency objective. The constraints include power flow constraints, node voltage constraints, thermal power unit-related constraints, and transmission network layer interactive power constraints.

[0077] After the power transmission network layer calculation is completed, based on the electric carbon coupling mechanism and carbon emission flow calculation method, combined with the active power output and carbon emission factor of thermal power units, the nodal carbon potential of the transmission and distribution coupling point is calculated.

[0078] During the scheduling cycle, the distribution network layer aims for optimal overall economic efficiency while also considering transmission and distribution consistency. Constraints include power flow constraints, node voltage constraints, energy storage system-related constraints, photovoltaic output-related constraints, and distribution network layer interactive power constraints.

[0079] The steps for judging the execution results and updating the algorithm multipliers at the transmission network layer and distribution network layer.

[0080] Furthermore, the power transmission network layer economic dispatch model includes:

[0081] The objective function is to minimize the operating cost of thermal power units, and the calculation formula is as follows:

[0082]

[0083] In the formula, F TN Let the overall objective function of the power transmission network layer be , Let N be the active power output of the i-th generator at time t, where c0, c1, and c2 are the constant term, primary coefficient, and secondary coefficient of the unit output cost, respectively, and v and w are the correction coefficients in the consistency target. G Where T is the total number of traditional generating units, and T is the total scheduling cycle.

[0084] Power flow constraints are implemented using a DC power flow model, neglecting voltage amplitude variations within the transmission network. The calculation formula is as follows:

[0085]

[0086] In the formula, θ t B TN , These represent the node voltage phase angle matrix, node admittance matrix, and node injected power matrix of the transmission network, respectively. These represent the active power output, purchased power, load power, and sold power of thermal power units in the power transmission network, respectively. ij,TN For the reactance of the transmission line, P represents the active power transmitted from node i to node j. line,max,TN This refers to the maximum active power that a power transmission line can transmit.

[0087] The formula for calculating the relevant constraints of thermal power units is as follows:

[0088]

[0089] In the formula, Let be the maximum active power output and the maximum reactive power output of the i-th generator, respectively. Let be the maximum gradeability of the i-th generator, taken as 2% / min.

[0090] The formulas for calculating the power purchased and sold at the transmission network level and its interaction power with the distribution network level are as follows:

[0091]

[0092] In the formula, This represents the maximum power of the transmission and distribution coupling.

[0093] Furthermore, the method for calculating the nodal carbon potential of the transport and distribution coupling node includes:

[0094] First, construct the transmission network related matrix. Assume that the transmission network layer has N nodes, M branches, and K nodes with generators. The matrix names, physical meanings, and representations are shown in Table 1.

[0095] Table 1. Correlation matrix for electrocarbon coupling calculation

[0096] Matrix name Physical meaning Dimension <![CDATA[P node ]]> Active power flowing into the node and N×N <![CDATA[P branch ]]> Active power flowing in the forward direction through the branch N×N <![CDATA[P gen ]]> Active power output of each generator N×K <![CDATA[E gen,TN ]]> Carbon emission factors of each generator K×1

[0097] Given the power flow distribution, construct the nodal active power flux matrix, branch active power flux matrix, generator active power matrix, and generator unit carbon emission matrix. The resulting formula for calculating the nodal carbon potential is:

[0098]

[0099] Furthermore, the economic dispatch model for the distribution network layer includes:

[0100] During the scheduling cycle, the optimization objective of the distribution network layer is to achieve economic optimization, mainly including the upstream power purchase cost and energy storage operation cost. Simultaneously, the carbon emission cost borne by the distribution network is calculated based on the nodal carbon potential of the transmission and distribution coupling nodes. The objective function calculation formula is as follows:

[0101]

[0102] In the formula, F DN The overall objective function for the distribution network layer is... Let c be the energy storage charging and discharging power of node i in the distribution network at time t. ess , c carbon These are the unit operating cost of energy storage, the unit electricity purchase cost of the upstream power grid, and the unit carbon emission cost of the distribution network. Let be the nodal carbon potential at the transport coupling point at time t. These represent the power purchased and sold from the distribution network to the transmission network, respectively, N. ess Δt represents the total number of optical storage nodes and Δt represents the scheduling period.

[0103] The power flow constraints adopt the Distflow power flow model and related constraints, and the calculation formula is as follows:

[0104]

[0105] In the formula, These represent the active and reactive power injected into node i of the distribution network at time t, respectively. Let i be the active and reactive power output of the i-th photovoltaic unit at time t; Let be the active power and reactive power of the load at node i in the distribution network at time t, respectively. These represent the active and reactive power of the lines between node i and node m, and between node n and node i in the distribution network at time t; r DN,ni x DN,ni Let n and i be the line resistance and reactance between node n and node i in the distribution network at time t, respectively. Let be the squared value of the node voltage at node m in the distribution network at time t. Let be the squared value of the line current between node n and node i in the distribution network at time t. This represents the square of the line current flowing from node i to node m; b is the transmission and distribution coupling flag on the distribution network side. i =1 indicates that node i is coupled with the transmission network, otherwise b i =0.

[0106] The formula for calculating node voltage constraints is:

[0107]

[0108] In the formula, V DN,max V DN,min These represent the maximum and minimum voltage values ​​of node i within the distribution network.

[0109] The formula for calculating energy storage-related constraints is as follows:

[0110]

[0111] In the formula, P ess,i,max The maximum output of energy storage i is given. Let S be the energy stored at time t, η be the efficiency of the energy storage system, and S be the energy stored in the system. ess,i,max For the rated capacity of energy storage i, The SOC states of energy storage i at time t, the initial time, and the end of the scheduling are respectively. min SOC max These represent the maximum and minimum SOC values ​​for energy storage, respectively.

[0112] The formulas for calculating the power purchased and sold at the distribution network level and its interaction power with the transmission network level are as follows:

[0113]

[0114] Furthermore, the steps for judging the economic dispatch result and updating the algorithm multipliers at the distribution network level include:

[0115] The transmission network layer and the distribution network layer are optimized in parallel. After each layer completes its optimization, they exchange power information and determine whether the iteration count, iteration accuracy, and consistency indicators meet the requirements. If the requirements are met, the system outputs the optimization result. If the requirements are not met, the algorithm multipliers are updated and each layer is re-optimized. The algorithm multiplier update calculation formula is as follows:

[0116]

[0117] In the formula, γ is the algorithm multiplier update coefficient.

[0118] To demonstrate the inventiveness and technical value of the present invention, the following section provides specific product or related technology application examples of the technical solution.

[0119] This invention selects an IEEE 6-node system as the transmission network, with a base voltage of 230kV and a base capacity of 100MVA; and an IEEE 33-node system as the distribution network, with a base voltage of 12.66kV and a base capacity of 10MVA. Three nodes in the transmission network and one node in the distribution network are combined as power coupling points to form the T6D33 example system. The network topology of the research object is as follows: Figure 5As shown in (a)-(b), the total load fluctuation curves of the distribution network and transmission network, the output curves of each photovoltaic power station in the distribution network, and the upstream electricity purchase price are as follows: Figure 6 As shown in (a)-(c), the configuration parameters of the optical storage system and the initial parameters of the algorithm are shown in Table 2, and the relevant unit costs are shown in Table 3.

[0120] Table 2. Photovoltaic and energy storage configuration parameters and initial algorithm parameters

[0121] Parameter name Parameter values Rated photovoltaic power (MW) 3 / 2.4 / 2.4 / 2.4 Rated charge / discharge power of energy storage (MW) / Rated capacity (MW·h) 1 / 1.5 Initial State of Charge (SOC) of Energy Storage 0.3 Maximum / Minimum SOC of Energy Storage 0.9 / 0.1 Energy storage operating efficiency 95％ Initial penalty parameters v, w, γ of the algorithm 0.5 / 0.5 / 1.5 Maximum convergence accuracy of the model <![CDATA[1×10 -4 ]]>

[0122] Table 3 Relevant Unit Costs

[0123]

[0124]

[0125] The embodiments of the present invention have achieved some positive results during the research and development or use process, and have indeed great advantages compared with the prior art. The following content describes them in conjunction with the data, charts and other information of the experimental process.

[0126] 1) Relationship between power purchase and sale in distribution networks, photovoltaic output, and carbon potential

[0127] The following curves show the power purchase and sale of the distribution network and the carbon potential at the transmission and distribution coupling points within one day, after considering low-carbon factors: Figure 7 As shown in the figure, the power purchase and sale situation of the distribution network is as follows: from 1:00 to 8:00, the photovoltaic system has no output but the load is relatively light, and the distribution network purchases a moderate amount of electricity; from 9:00 to 16:00, the photovoltaic system generates a large amount of electricity, the load output is moderate, the distribution network stops purchasing electricity, and profits are made from selling electricity; from 17:00 to 24:00, the photovoltaic system has no output and the load is relatively heavy, and the distribution network purchases a large amount of electricity.

[0128] Distribution network power purchase and sale curves without considering low-carbon factors, such as Figure 8 As shown. Comparison Figure 7 and Figure 8 It can be seen that after considering the carbon potential of nodes, when the load is light (1:00-8:00), the distribution network slightly reduces the amount of electricity purchased to minimize its own carbon emission quota; when the load is heavy (17:00-24:00), the distribution network follows the principle of "purchasing more electricity when the carbon potential is low and purchasing less electricity when the carbon potential is high". This method effectively reduces the carbon emission costs it needs to bear.

[0129] 2) Relationship between power output and carbon potential of power transmission units

[0130] The output curves of each unit in the power transmission network and the carbon potential curves at the transmission and distribution coupling points within a day are as follows: Figure 9 As shown in the figure, the unit at node 1, due to its high carbon emission intensity, acts as a "carbon control" unit, only outputting power during peak periods, and the carbon potential at point PCC changes with the unit's output. The units at nodes 2 and 6 have lower carbon emission intensities, and their emissions fluctuate with the transmission network load.

[0131] 3) Consider the impact of dynamic carbon emission factors on various costs of the power transmission and distribution network.

[0132] The costs of the transmission and distribution networks before and after considering the dynamic carbon emission factor are shown in Table 4 below. As shown in Table 4, after considering the dynamic carbon emission factor, the operating cost of the transmission network units decreased by RMB 2209, the electricity purchase cost of the distribution network decreased by RMB 44.1, and the energy storage operating cost increased by RMB 70.4. This indicates that for the transmission network, the method proposed in this patent can effectively reduce the operating cost of the units and decrease their carbon emissions; for the distribution network, the method proposed in this patent effectively improves the utilization rate of energy storage, reduces the electricity purchase cost of the distribution network, and improves the economic efficiency of the distribution network operation.

[0133] Table 4. Overall operating cost of the power transmission and distribution system under different scheduling strategies.

[0134]

[0135] The implementation of the various embodiments of the present invention is based on programmed processing by a device with processor functionality. Therefore, in practical engineering, the technical solutions and functions of the various embodiments of the present invention are encapsulated into various modules. Based on this reality, and building upon the above embodiments, the embodiments of the present invention provide a transmission and distribution coordinated low-carbon economic scheduling system based on the target cascade method. This system is used to execute a transmission and distribution coordinated low-carbon economic scheduling method based on the target cascade method described in the above method embodiments.

[0136] The system includes: a first calculation module for establishing a hierarchical scheduling framework for the power transmission and distribution network and analyzing the interactive power characteristics under typical load output; a second calculation module for setting decoupling variables of the power transmission and distribution network in combination with physical coupling relationships, and constructing a consistency criterion for power transmission and distribution coordination based on the target cascading method and the physical structure of the power transmission and distribution network; and a third calculation module for constructing a low-carbon economic optimization model for power transmission and distribution coordination based on the above-mentioned hierarchical scheduling framework for the power transmission and distribution network, combined with preset constraints and considering the electricity-carbon coupling calculation method.

[0137] This invention provides a low-carbon economic dispatch system for transmission and distribution coordination based on the target cascade method. Addressing the current state of traditional transmission and distribution coordination dispatch, this system employs several modules and applies a low-carbon economic dispatch method based on the target cascade method to transmission and distribution coordination dispatch. It considers the impact of dynamic carbon emission factors on the power purchase and sale of the transmission and distribution networks. Compared with traditional transmission and distribution coordination dispatch, this system can guide the transmission network layer to purchase clean energy and reduce the carbon emissions of traditional generating units.

[0138] It should be noted that the system embodiments provided by the present invention are used not only to implement the methods in the above method embodiments, but also to implement the methods in other method embodiments provided by the present invention. The only difference is that corresponding functional modules are set. The principle is basically the same as that of the above system embodiments provided by the present invention. As long as those skilled in the art can improve the modules in the above system embodiments by referring to the specific technical solutions in other method embodiments and combining technical features to obtain corresponding technical means and technical solutions composed of these technical means, on the basis of the above system embodiments, and on the premise of ensuring the practicality of the technical solutions, they can obtain corresponding system-like embodiments for implementing the methods in other method-like embodiments.

[0139] Based on the same inventive concept as the foregoing embodiments, this embodiment of the invention also provides a transmission and distribution coordinated low-carbon economic dispatching device based on the target cascading method, including a memory and a processor. The memory stores program instructions that are executed by the processor, and the processor calls the program instructions to execute the steps of the transmission and distribution coordinated low-carbon economic dispatching method based on the target cascading method.

[0140] Based on the same inventive concept as the foregoing embodiments, this embodiment of the invention also provides a non-transitory computer-readable storage medium storing computer instructions that cause the computer to execute the steps of the target cascading method-based coordinated low-carbon economic dispatching method.

[0141] It should be noted that embodiments of the present invention can be implemented in hardware, software, or a combination of both. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by a suitable instruction execution system, such as a microprocessor or dedicated-design hardware. Those skilled in the art will understand that the above-described devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuitry such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field-programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of the above-described hardware circuitry and software, such as firmware.

[0142] In summary, this invention provides a low-carbon economic dispatching method for transmission and distribution coordination based on the target cascade method. The method includes: establishing a hierarchical dispatching framework for the transmission and distribution network and analyzing the interactive power characteristics under typical load output; setting decoupling variables for the transmission and distribution network based on physical coupling relationships and constructing relevant criteria for transmission and distribution coordination consistency based on the target cascade method; and constructing a low-carbon optimization model for transmission and distribution coordination based on the target cascade method, considering voltage constraints, power flow constraints, and other constraints, as well as the carbon coupling calculation method, according to the aforementioned hierarchical dispatching architecture of the transmission and distribution network. This invention applies a low-carbon economic dispatching method for transmission and distribution coordination based on the target cascade method to transmission and distribution coordinated dispatching, considering the impact of dynamic carbon emission factors on the power purchase and sale of the transmission and distribution networks. Compared with traditional transmission and distribution coordinated dispatching, it can guide the transmission network layer to purchase clean energy, reducing the carbon emissions of traditional generating units.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A low-carbon economic dispatching method for coordinated transmission and distribution based on the target cascade method, characterized in that, include: Establish a hierarchical dispatching framework for the power transmission and distribution network and analyze the interactive power characteristics under typical load output; Decoupling variables for the power transmission and distribution network are set in combination with physical coupling relationships, and a consistency criterion for power transmission and distribution coordination is constructed based on the target cascading method and the physical structure of the power transmission and distribution network. Based on the aforementioned hierarchical dispatch framework for transmission and distribution networks, combined with preset constraints, and considering the dynamic carbon potential of transmission and distribution coupling nodes obtained based on the electric-carbon coupling mechanism and carbon emission flow calculation methods, a low-carbon economic optimization model for transmission and distribution coordination is constructed, including: During the scheduling cycle, the transmission network layer aims to minimize the operating cost of thermal power units while also considering the transmission and distribution consistency objective. The constraints include power flow constraints, node voltage constraints, thermal power unit-related constraints, and transmission network layer interactive power constraints. After the transmission network layer calculation is completed, based on the electric carbon coupling mechanism and carbon emission flow calculation method, combined with the active power output and carbon emission factor of thermal power units, the nodal carbon potential of the transmission and distribution coupling point is calculated to be transferred to the distribution network layer. During the scheduling cycle, the distribution network layer aims for optimal overall economic efficiency, including calculating the carbon emission costs borne by the distribution network based on the nodal carbon potential of transmission and distribution coupling nodes, while also considering the transmission and distribution consistency objective. The constraints include power flow constraints, nodal voltage constraints, energy storage system-related constraints, photovoltaic output-related constraints, and distribution network layer interactive power constraints. The steps for judging the execution results and updating the algorithm multipliers at the transmission network layer and distribution network layer.

2. The method for coordinated low-carbon economic dispatching of power transmission and distribution based on the target cascade method according to claim 1, characterized in that, Establish a hierarchical dispatch framework for the power transmission and distribution network, including: The power grid with a voltage level of 220kV and above, which plays a major power supply role, is assigned to the transmission network layer. Its controllable resources are the output of thermal power units and the interactive power on the transmission network side. The power grid with a voltage level below 220kV that plays a major role in electricity consumption is assigned to the distribution network layer, and its controllable resources are photovoltaic power output, energy storage system power output and distribution network side interactive power. The transmission network and each distribution network operate in a mode of "intra-layer power self-consistency - inter-layer information interaction".

3. The method for coordinated low-carbon economic dispatching of power transmission and distribution based on the target cascade method according to claim 2, characterized in that, The "intra-layer power self-consistency - inter-layer information interaction" operation mode includes: The intra-layer power self-consistency is used to schedule power according to the principle of first achieving internal power balance between the transmission network layer and the distribution network layer, and then sending the remaining power to the grid. The inter-layer information interaction is used so that after optimization within the execution layer, the transmission network layer transmits the electricity purchase and sale demand and the carbon potential of the coupling point nodes to the distribution network layer, and the distribution network layer transmits the electricity required by its own layer to the transmission network layer, so that the two can achieve complete information sharing.

4. The method for coordinated low-carbon economic dispatching of transmission and distribution based on the target cascade method according to claim 1, characterized in that, Decoupling variables for the transmission and distribution network are set based on physical coupling relationships, and a transmission and distribution coordination consistency criterion is constructed based on the target cascading method and the physical structure of the transmission and distribution network, including: Based on the principle of the target cascade method, the coupling and interaction power between the transmission and distribution networks is taken as a shared variable, without considering the phase angle difference at the coupling point of the transmission and distribution networks; When optimizing the transmission network layer, the interactive power is treated as an equivalent load and participates in the optimization; when optimizing the distribution network layer, the interactive power is treated as an equivalent generator and participates in the optimization. Once the optimization within each layer is completed, it is only necessary to consider whether the transmission power meets the consistency criterion to determine whether convergence has occurred.

5. The method for coordinated low-carbon economic dispatching of transmission and distribution based on the target cascade method according to claim 4, characterized in that, The transmission and distribution coordination consistency criterion includes: The transmission and distribution coordination consistency criterion is based on the fact that the difference in interaction power does not exceed a given threshold. The calculation formula is as follows: ， In the formula, When the transmission network is dispatched at the transmission network level, the power transmitted from the transmission network to the distribution network is equivalent to virtual active power load. This represents the power supply from the transmission network to the distribution network, and vice versa, the power transmission from the distribution network to the transmission network. This refers to the active power purchased by the distribution network from the transmission network during distribution network layer dispatching, which is equivalent to the active power of a virtual generator. This represents the power transmitted from the distribution network to the transmission network, and vice versa, the power supplied from the transmission network to the distribution network. To indicate the convergence accuracy of the two-level model, identical variables without an overline are considered as substitute variables.

6. A low-carbon economic dispatch system for coordinated transmission and distribution based on the target cascade method, used to implement the low-carbon economic dispatch method for coordinated transmission and distribution based on the target cascade method as described in any one of claims 1 to 5, characterized in that, include: The first calculation module is used to establish a hierarchical scheduling framework for the power transmission and distribution network and analyze the interactive power characteristics under typical load output. The second calculation module is used to set decoupling variables of the transmission and distribution network in combination with the physical coupling relationship, and to construct the transmission and distribution coordination consistency criterion based on the target cascade method and the physical structure of the transmission and distribution network. The third calculation module is used to construct a low-carbon economic optimization model for transmission and distribution coordination based on the aforementioned hierarchical scheduling framework of the transmission and distribution network, combined with preset constraints and considering the electricity-carbon coupling calculation method.

7. A low-carbon economic dispatching device for coordinated transmission and distribution based on the target cascade method, characterized in that, The method includes a memory and a processor, wherein the memory stores program instructions that are executed by the processor, and the processor invokes the program instructions to perform the steps of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascading method as described in any one of claims 1 to 5.

8. A non-transitory computer-readable storage medium, characterized in that, The non-transitory computer-readable storage medium stores computer instructions that cause the computer to perform the steps of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascading method as described in any one of claims 1 to 5.

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