Transmission and distribution collaborative low-carbon economic dispatching method and system based on target cascade method

Abstract

The invention provides a transmission and distribution collaborative low-carbon economic dispatching method based on a target cascade method, and the method comprises the steps: building a power transmission and distribution network layered dispatching framework, and analyzing the interaction power characteristics under typical load output; setting a power transmission and distribution network decoupling variable in combination with a physical coupling relationship, and constructing a related criterion of transmission and distribution collaborative consistency based on a target cascade method; and constructing a transmission and distribution collaborative low-carbon optimization model based on a target cascade method by combining constraint conditions such as voltage constraint and power flow constraint and considering an electricity-carbon coupling calculation method according to the hierarchical scheduling architecture of the power transmission and distribution network. The transmission and distribution collaborative low-carbon economic dispatching method based on the target cascading method is applied to transmission and distribution collaborative dispatching, the influence of a dynamic carbon emission factor on electricity purchasing and selling power of a transmission network and a power distribution network is considered, and compared with traditional transmission and distribution collaborative dispatching, the transmission network layer can be guided to purchase clean electric energy; and the carbon emission of a traditional unit is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid resource optimization and dispatching, and in particular, relates to a transmission and distribution coordinated low-carbon economic dispatching method and system based on a target cascade method. Background Art

[0002] As the core part connecting the main power grid and power consumption terminals, the distribution network plays a vital role in achieving the dual carbon goals and building a new power system. At present, the active distribution network has gradually evolved into an integrated distribution system that can accommodate the large-scale access and coordinated operation of distributed new energy, electric vehicle charging stations, electrified railways and other power electronic equipment, while promoting the substitution of clean energy at both the power generation and power consumption ends. With the large-scale access of distributed power generation and impact loads such as electric vehicles and railways, the power electronics level of the distribution network has been significantly improved, and the characteristics of uncertainty and two-way flow have become more obvious.

[0003] As the penetration rate of new energy continues to increase, the operating status of the distribution network has become more diversified, and the power generation mode has also changed from traditional synchronous machine power generation to the coordinated power generation of traditional units and new energy, making the changes in transmission and distribution power more complicated. In order to achieve the best economic dispatch in such a new environment, the traditional centralized control is gradually changing to intelligent, multi-level coordinated operation.

[0004] With the introduction of the concept of carbon emission flow, carbon emissions in the power system are not only the environmental cost of power production, but also an important indicator to characterize the low-carbon characteristics of each link of the power system. The electric-carbon coupling calculation method based on carbon emission flow can effectively allocate the carbon emissions generated by thermal power units to each node of the power grid according to the output, so as to achieve the purpose of reasonably allocating carbon emission responsibilities.

[0005] Through the above analysis, the problems and defects of the prior art are as follows:

[0006] (1) It is difficult for existing technologies to directly participate in the optimization and dispatching of active distribution networks as an independent entity. If the solution is directly obtained, it may lead to problems such as the explosion of the dimension 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 field of power systems. There is little research on the clustering of distributed resources that serve the optimal scheduling of distribution networks, which makes actual scheduling lack of reference and is not conducive to the optimal scheduling of regulatory resources.

[0008] (3) At present, the coordinated economic dispatch of transmission and distribution is mainly based on fixed carbon emissions, and less consideration is given to the impact of dynamic carbon emission factors on the distribution network's power purchase and sales behavior. The distribution network's power purchase and sales situation under the electricity-carbon coupling scenario is still unclear. Summary of the invention

[0009] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a transmission and distribution coordinated low-carbon economic dispatching method and system based on the target cascade method. By applying a transmission and distribution coordinated low-carbon economic dispatching method based on the target cascade method to the transmission and distribution coordinated dispatching, the influence of dynamic carbon emission factors on the power purchased and sold by the transmission network and the distribution network is considered. Compared with the traditional transmission and distribution coordinated dispatching, it can guide the transmission network layer to purchase clean electricity and reduce the carbon emissions of traditional units.

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

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

[0012] The decoupling variables of the transmission and distribution network are set in combination with the physical coupling relationship, and the transmission and distribution coordination consistency criterion is constructed based on the target cascade method and the physical structure of the transmission and distribution network;

[0013] Based on the above-mentioned hierarchical dispatching framework of the transmission and distribution network, 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 transmission and distribution networks is established, including:

[0015] The power grid with a voltage level of 220kV and above and which plays the main role in power supply is divided into the transmission network layer, and 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 and which plays a major role in electricity consumption is divided into the distribution network layer, and its controllable resources are photovoltaic output, energy storage system output and interactive power on the distribution network side;

[0017] The transmission network and distribution networks operate in the mode of "power self-consistency within the layer - information interaction between layers".

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

[0019] The power self-consistency within the layer is used to first achieve internal power balance between the transmission network layer and the distribution network layer, and then schedule the remaining power on the grid;

[0020] The inter-layer information interaction is used to transmit the power purchase and sales demand and the carbon potential of the coupling point node to the distribution network layer after optimization in the execution layer, and the distribution network layer transmits the power required by this layer to the transmission network layer, so that the two realize complete information sharing.

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

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

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

[0024] After the optimization in each layer is completed, it is only necessary to consider whether the transmission power meets the following consistency criteria to determine whether it has converged.

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

[0026] The consistency criterion between the layers of the transmission and distribution network is that the difference in the interaction power does not exceed the given threshold, and the calculation formula is:

[0027]

[0028] In the formula, When the transmission network is dispatched at the transmission network level, the transmission network transmits power to the distribution network, which is equivalent to a virtual active load. It represents the transmission network supplying power to the distribution network, and vice versa, it represents the distribution network transmitting power to the transmission network. It is the active power purchased by the distribution network from the transmission network during the distribution network dispatching, which is equivalent to the active power of the virtual generator. It represents the power transmitted from the distribution network to the transmission network, and vice versa, it represents the power supplied from the transmission network to the distribution network. ε is the convergence accuracy of the two-layer model. The same variable without an overline represents that the variable is a substitution variable.

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

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

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

[0032] During the dispatching cycle, the distribution network layer aims to optimize the overall economic performance while taking into account the transmission and distribution consistency objectives. 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 transmission network layer and the distribution network layer perform result judgment and algorithm multiplier update steps.

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

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

[0036] The second calculation module is used to set the 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 above-mentioned hierarchical scheduling framework of the transmission and distribution network, combined with preset constraints and taking into account the electricity-carbon coupling calculation method.

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

[0039] According to one aspect of the present specification, a non-transitory computer-readable storage medium is provided, wherein the non-transitory computer-readable storage medium stores computer instructions, and the computer instructions enable the computer to execute the steps of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascade method.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The present invention provides a transmission and distribution coordinated low-carbon economic dispatching method based on the target cascade method, comprising: establishing a hierarchical dispatching framework for the transmission and distribution network, analyzing the interactive power characteristics under typical load output; setting the transmission and distribution network decoupling variables in combination with the physical coupling relationship, and constructing relevant criteria for transmission and distribution coordinated consistency based on the target cascade method; based on the above-mentioned hierarchical dispatching framework for the transmission and distribution network, combining voltage constraints, flow constraints and other constraints and considering the electricity-carbon coupling calculation method, constructing a transmission and distribution coordinated low-carbon optimization model based on the target cascade method.

[0042] 2. The present invention applies a transmission and distribution coordinated low-carbon economic dispatching method based on the target cascade method to the transmission and distribution coordinated dispatching, taking into account the impact of dynamic carbon emission factors on the power purchased and sold by the transmission network and the distribution network. Compared with the traditional transmission and distribution coordinated dispatching, it can guide the transmission network layer to purchase clean electricity and reduce the carbon emissions of traditional units. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings used in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 It is a flow chart of a transmission and distribution coordinated low-carbon economic dispatching method based on a target cascade method provided in an embodiment of the present invention;

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

[0046] Figure 3 It is a schematic diagram of the decoupling mechanism of the transmission and distribution network layer of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascade method provided in an embodiment of the present invention;

[0047] Figure 4 It is an iterative flow chart of a transmission and distribution coordinated two-layer economic dispatch model based on a target cascade method provided by an embodiment of the present invention;

[0048] Figure 5 (a)-(b) are topological diagrams of the IEEE6+IEEE33 node power transmission and distribution system according to the embodiment of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascade method provided in the embodiment of the present invention;

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

[0050] Figure 7 It is a curve chart of the number of model iterations of an embodiment of a transmission and distribution coordinated low-carbon economic dispatch method based on a target cascade method provided in an embodiment of the present invention;

[0051] Figure 8 It is a transmission and distribution network interactive power curve diagram of an embodiment of a transmission and distribution coordinated low-carbon economic dispatch method based on a target cascade method provided in an embodiment of the present invention;

[0052] Fig. 9It is a distribution network source-load-storage power curve diagram of an embodiment of a transmission and distribution coordinated low-carbon economic dispatch method based on a target cascade method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions, for example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to the steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0054] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, the technical features in the various embodiments or single embodiments provided by the present invention are arbitrarily combined with each other to form a new technical solution. This combination is not restricted by the sequence of steps and / or the structural composition mode, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that this combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0055] An embodiment of the present invention provides a transmission and distribution coordinated low-carbon economic dispatching method based on the target cascade method. First, a hierarchical dispatching framework of the transmission and distribution network is established, and the interactive power characteristics under typical load output are analyzed; then, the transmission and distribution network decoupling variables are set in combination with the physical coupling relationship, and relevant criteria for transmission and distribution coordinated consistency are constructed based on the target cascade method; then, according to the above-mentioned hierarchical dispatching framework of the transmission and distribution network, combined with voltage constraints, flow constraints and other constraints and considering the electricity-carbon coupling calculation method, a transmission and distribution coordinated low-carbon optimization model based on the target cascade method is constructed.

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

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

[0058] S102, setting inter-layer decoupling variables based on transmission and distribution coupling characteristics, and building consistency criteria by combining relevant concepts of the target cascade method and the physical structure of the transmission and distribution network;

[0059] S103, considering the grid structure of the transmission and distribution network and related constraints, constructing a low-carbon economic optimization model for transmission and distribution coordination, determining the consistency of the interactive power between layers and correcting the parameters.

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

[0061] The power grid with a voltage level of 220kV and above and which plays the main role in power supply is divided into the transmission network layer, and 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 and a major power consumption function (supplying power to the transmission grid during certain periods) is classified as a distribution network layer, and its controllable resources are photovoltaic output, energy storage system output, and interactive power on the distribution network side;

[0063] The transmission network and distribution networks operate in the mode of "intra-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" means that the transmission network layer and the distribution network layer first achieve internal power balance, and then dispatch the remaining power to the grid;

[0066] "Inter-layer information interaction" means that after optimization within the execution layer, the transmission network layer transmits the power purchase and sales 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 this layer to the transmission network layer, and the two realize complete information sharing.

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

[0068] Based on the basic principle of the target cascade method, the coupled interaction power between the transmission and distribution networks is taken as a shared variable, and the phase angle difference at the coupling point of the transmission and distribution networks is not considered;

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

[0070] After the optimization in each layer is completed, it is only necessary to consider whether the transmission power meets the following consistency criteria to determine whether it has converged.

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

[0072] The consistency criterion between the layers of the transmission and distribution network is that the difference in the interaction power does not exceed the given threshold, and the calculation formula is:

[0073]

[0074] In the formula, When the transmission network is dispatched at the transmission network level, the transmission network transmits power to the distribution network, which is equivalent to a virtual active load. It represents the transmission network supplying power to the distribution network, and vice versa, it represents the distribution network transmitting power to the transmission network. It is the active power purchased by the distribution network from the transmission network during the distribution network dispatching, which is equivalent to the active power of the virtual generator. It represents the power transmitted from the distribution network to the transmission network, and vice versa, it represents the power supplied from the transmission network to the distribution network. ε is the convergence accuracy of the two-layer model. The same variable without an overline represents that the variable is a substitution variable.

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

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

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

[0078] During the dispatching cycle, the distribution network layer aims to optimize the overall economic performance while taking into account the transmission and distribution consistency objectives. 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.

[0079] The transmission network layer and the distribution network layer perform result judgment and algorithm multiplier update steps.

[0080] Furthermore, the 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:

[0082]

[0083] In the formula, F TN is the overall objective function of the transmission network layer, is the active output of the i-th generator at time t, c0, c1, c2 are the constant term, first-order term coefficient and second-order term coefficient of the unit output cost, v and w are the correction coefficients in the consistency target, N G is the total number of traditional units, T is the total scheduling cycle;

[0084] The power flow constraint adopts the DC power flow model, ignoring the voltage amplitude change in the transmission network. The calculation formula is:

[0085]

[0086] In the formula, θ t , B TN , They are the node voltage phase angle matrix, node admittance matrix and node injection power matrix of the transmission network, They are respectively the active output of thermal power units in the transmission network, purchased power, load power and sold power, x ij,TN is the transmission line reactance, is the line active power transmitted from node i to node j, P line,max,TN It is the maximum active power that can be transmitted by the transmission grid line.

[0087] The calculation formula for the relevant constraints of thermal power units is:

[0088]

[0089] In the formula, are the maximum active output and the maximum reactive output of the i-th generator, is the maximum ramp rate of the ith generator, which is 2% / min.

[0090] The calculation formula for the power purchase and sale of the transmission network layer and its interaction power with the distribution network layer is:

[0091]

[0092] In the formula, is the maximum transmission and distribution coupling power.

[0093] Furthermore, the node carbon potential calculation method of the transmission and distribution coupling node includes:

[0094] First, we construct the transmission network related matrix. Assuming that the transmission network layer has N nodes, M branches, and K nodes with generators, the matrix name, physical meaning, and representation are shown in Table 1:

[0095] Table 1 Correlation matrix of electro-carbon coupling calculation

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

[0097] When the power flow distribution is known, the node active flux matrix, branch active flux matrix, generator active matrix and generator unit carbon emission matrix are constructed, and the calculation formula of the node carbon potential is obtained as follows:

[0098]

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

[0100] During the dispatching cycle, the optimization goal of the distribution network layer is to optimize the economy, which mainly includes the upper power purchase cost and the energy storage operation cost. At the same time, the carbon emission cost borne by the distribution network is calculated based on the node carbon potential of the transmission and distribution coupling node. The objective function calculation formula is:

[0101]

[0102] In the formula, F DN is the total objective function of the distribution network layer, are the energy storage charging and discharging power of distribution network node i at time t, c ess , c carbon They are the unit operating cost of energy storage, the unit electricity purchase cost of the upper power grid, and the unit carbon emission cost of the distribution network. is the node carbon potential at the transmission and distribution coupling point at time t, are the power purchased and sold from the distribution network to the transmission network, N ess is the total number of solar-storage nodes, and Δt is the scheduling period.

[0103] The power flow constraint adopts the Distflow power flow model and related constraints, and the calculation formula is:

[0104]

[0105] In the formula, are the active power and reactive power injected into the node i of the distribution network at time t respectively; is the active and reactive power output of the i-th photovoltaic unit at time t; are the load active power and reactive power of node i in the distribution network at time t respectively; are the active power and reactive power of the lines between nodes i and m, and between nodes n and i in the distribution network at time t; r DN,ni 、x DN,ni are the line resistance and reactance between node n and node i in the distribution network at time t respectively; is the square value of the node voltage of the distribution network node m at time t, is the square value of the line current between node n and node i in the distribution network at time t, Indicates the square value of the line current flowing from node i to node m; b is the transmission and distribution coupling mark on the distribution network side, b i =1 means that node i has a coupling relationship with the transmission network, otherwise b i =0.

[0106] The node voltage constraint calculation formula is:

[0107]

[0108] Where V DN,max 、V DN,min are the maximum voltage values ​​of node i in the distribution network.

[0109] The calculation formula for energy storage related constraints is:

[0110]

[0111] Where P ess,i,max is the maximum output of energy storage i, is the energy stored in the energy storage at time t, η is the efficiency of the energy storage system, S ess,i,max is the rated capacity of energy storage i, are the SOC states of energy storage i at time t, initial time, and at the end of scheduling, respectively. min , SOC max They are the maximum and minimum energy storage SOC respectively.

[0112] The calculation formula for the power purchased and sold at the distribution network layer and its interaction power with the transmission network layer is:

[0113]

[0114] Furthermore, the steps of judging the economic dispatch result at the distribution network layer and updating the algorithm multiplier include:

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

[0116]

[0117] Where γ is the algorithm multiplier update coefficient.

[0118] In order to demonstrate the creativity and technical value of the technical solution of the present invention, the following section is an application example of the technical solution on specific products or related technologies.

[0119] In the embodiment of the present invention, the IEEE 6-node system is selected as the transmission network, the reference voltage of the system is 230kV, and the reference capacity is 100MVA; the IEEE 33-node system is selected as the distribution network, the reference voltage of the system is 12.66kV, and the reference capacity is 10MVA. The 3 nodes in the transmission network and the 1 node in the distribution network are combined as power coupling points to form a T6D33 example system. The network topology of the research object is as follows: Figure 5As shown in (a)-(b), the total load fluctuation curve of the distribution network and the transmission network, the output curve of each photovoltaic power station in the distribution network and the upper-level power purchase price are as follows Figure 6 (a)-(c) are shown, the PV storage configuration parameters 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 PV storage configuration parameters and algorithm initial parameters

[0121] Parameter name Parameter Value Photovoltaic rated power (MW) 3 / 2.4 / 2.4 / 2.4 Energy storage rated charge and discharge power (MW) / rated capacity (MW·h) 1 / 1.5 Energy storage initial SOC 0.3 Energy storage maximum / minimum SOC 0.9 / 0.1 Energy storage operation efficiency 95％ Algorithm initial penalty parameters v,w,γ 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 effects during the development or use process, and indeed have great advantages over the prior art. The following content is described in conjunction with data, charts, etc. of the test process.

[0126] 1) Relationship between power purchase and sales on distribution networks and photovoltaic output and carbon potential

[0127] Considering the low-carbon factor, the power purchased and sold by the distribution network and the carbon potential curve of the transmission and distribution coupling point node within one day are as follows: 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, there is no photovoltaic output but the load is light, and the distribution network purchases a moderate amount of electricity; from 9:00 to 16:00, photovoltaic power generation is large, the load output is moderate, the distribution network stops purchasing electricity, and sells electricity for profit; from 17:00 to 24:00, there is no photovoltaic output and the load is heavy, and the distribution network purchases a large amount of electricity.

[0128] The power curve of power purchase and sale of distribution network without considering low carbon factors is as follows: Figure 8 As shown. Figure 7 and Figure 8 It can be seen that after considering the node carbon potential, when the load is light (1:00-8:00), the distribution network slightly reduces the amount of electricity purchased to minimize the carbon emission quota it needs to bear; when the load is heavy (17:00-24:00), the distribution network follows the principle of "buying more electricity with low carbon potential and less electricity with high carbon potential", and this method effectively reduces the carbon emission cost it needs to bear.

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

[0130] The output of each unit in the transmission network and the carbon potential curve of the transmission and distribution coupling point in one day are as follows: Fig. 9 As shown in the figure, it can be seen that the 1-node unit acts as a "carbon regulation" unit due to its high carbon emission intensity, and only outputs at peak times. The PCC point carbon potential changes with the output of the unit. The carbon emission intensity of the 2nd and 6-node units is relatively low, and changes with the load of the transmission network.

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

[0132] The various costs of the transmission and distribution network before and after considering the dynamic carbon emission factor are shown in the following table. As can be seen from Table 4, after considering the dynamic carbon emission factor, the transmission network unit operating cost is reduced by 2,209 yuan, the distribution network power purchase cost is reduced by 44.1 yuan, and the energy storage operating cost is increased by 70.4 yuan. This shows that for the transmission network, the method proposed in this patent can effectively reduce the unit operating cost and reduce its carbon emissions; for the distribution network, the method proposed in this patent can effectively increase the utilization rate of energy storage, reduce the distribution network power purchase cost, and improve the economic efficiency of the distribution network operation.

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

[0134]

[0135] The implementation basis of each embodiment of the present invention is implemented by programmed processing through a device with a processor function. Therefore, in engineering practice, the technical solutions and functions of each embodiment of the present invention are encapsulated into various modules. Based on this reality, on the basis of the above embodiments, an embodiment of the present invention provides a transmission and distribution coordinated low-carbon economic dispatching system based on the target cascade method, which is used to execute a transmission and distribution coordinated low-carbon economic dispatching method based on the target cascade method in the above method embodiment.

[0136] The system includes: a first calculation module, which is used to establish a hierarchical scheduling framework for the transmission and distribution network and analyze the interactive power characteristics under typical load output; a second calculation module, which is used to set the decoupling variables of the transmission and distribution network in combination with the physical coupling relationship, and to construct a transmission and distribution coordination consistency criterion based on the target cascade method and the physical structure of the transmission and distribution network; a third calculation module, which is used to construct a low-carbon economic optimization model for transmission and distribution coordination based on the above-mentioned hierarchical scheduling framework for the transmission and distribution network, combined with preset constraints and taking into account the electricity-carbon coupling calculation method.

[0137] A transmission and distribution coordinated low-carbon economic dispatching system based on the target cascade method provided in an embodiment of the present invention is aimed at the current situation of traditional transmission and distribution coordinated dispatching. It adopts the above-mentioned several modules, and applies a transmission and distribution coordinated low-carbon economic dispatching method based on the target cascade method to transmission and distribution coordinated dispatching. It considers the impact of dynamic carbon emission factors on the power purchased and sold by the transmission network and the distribution network. Compared with traditional transmission and distribution coordinated dispatching, it can guide the transmission network layer to purchase clean electricity and reduce the carbon emissions of traditional units.

[0138] It should be noted that the system embodiments provided by the present invention are not only used to implement the methods in the above-mentioned method embodiments, but also used to implement the methods in other method embodiments provided by the present invention. The only difference lies in the setting of corresponding functional modules, and the principles thereof are basically the same as the principles of the above-mentioned system embodiments provided by the present invention. As long as technical personnel in this field refer to the specific technical solutions in other method embodiments on the basis of the above-mentioned system embodiments, obtain corresponding technical means and technical solutions composed of these technical means by combining technical features, and on the premise of ensuring the practicality of the technical solutions, they will improve the modules in the above-mentioned system embodiments to obtain corresponding system class embodiments for implementing the methods in other method class embodiments.

[0139] Based on the same inventive concept as the aforementioned embodiment, an embodiment of the present invention also provides a transmission and distribution coordinated low-carbon economic dispatching device based on the target cascade method, comprising a memory and a processor, wherein the memory stores program instructions 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 cascade method.

[0140] Based on the same inventive concept as the aforementioned embodiment, an embodiment of the present invention also provides a non-transitory computer-readable storage medium, which stores computer instructions, and the computer instructions enable the computer to execute the steps of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascade method.

[0141] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. It can be understood by a person of ordinary skill in the art that the above-mentioned devices and methods can be implemented using computer executable instructions and / or contained in a processor control code, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. Such code is provided on the carrier medium. The device and its modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, etc., or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, and can also be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0142] In summary of the above embodiments, the present invention provides a transmission and distribution coordinated low-carbon economic dispatching method based on the target cascade method, including: establishing a hierarchical dispatching framework for the transmission and distribution network, analyzing the interactive power characteristics under typical load output; setting the transmission and distribution network decoupling variables in combination with the physical coupling relationship, and constructing relevant criteria for transmission and distribution coordinated consistency based on the target cascade method; according to the above-mentioned hierarchical dispatching framework for the transmission and distribution network, combining voltage constraints, flow constraints and other constraints and considering the electric-carbon coupling calculation method to construct a transmission and distribution coordinated low-carbon optimization model based on the target cascade method. The present invention applies a transmission and distribution coordinated low-carbon economic dispatching method based on the target cascade method to the transmission and distribution coordinated dispatching, and considers the impact of dynamic carbon emission factors on the purchase and sale of electricity between the transmission network and the distribution network. Compared with the traditional transmission and distribution coordinated dispatching, it can guide the transmission network layer to purchase clean electricity and reduce the carbon emissions of traditional units.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A transmission and distribution coordinated low-carbon economic dispatch method based on target cascade method, characterized in that: include: Establish a hierarchical dispatching framework for transmission and distribution networks and analyze interactive power characteristics under typical load output; The decoupling variables of the transmission and distribution network are set in combination with the physical coupling relationship, and the transmission and distribution coordination consistency criterion is constructed based on the target cascade method and the physical structure of the transmission and distribution network; Based on the above-mentioned hierarchical dispatching framework of the transmission and distribution network, 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.

2. According to claim 1, a transmission and distribution coordinated low-carbon economic dispatch method based on the target cascade method is characterized in that: Establish a hierarchical dispatching framework for transmission and distribution networks, including: The power grid with voltage level of 220kV and above and which plays the main role of power supply is divided into the transmission network layer, and 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 and which plays a major role in electricity consumption is divided into the distribution network layer, and its controllable resources are photovoltaic output, energy storage system output and distribution network-side interactive power; The transmission network and distribution networks operate in the mode of "power self-consistency within the layer - information interaction between layers".

3. According to claim 2, a transmission and distribution coordinated low-carbon economic dispatch method based on target cascade method is characterized in that: The operation mode of "intra-layer power self-consistency-inter-layer information interaction" includes: The power self-consistency within the layer is used to first achieve internal power balance between the transmission network layer and the distribution network layer, and then schedule the remaining power on the grid; The inter-layer information interaction is used to transmit the power purchase and sales demand and the carbon potential of the coupling point node to the distribution network layer after optimization in the execution layer, and the distribution network layer transmits the power required by this layer to the transmission network layer, so that the two realize complete information sharing.

4. According to the target cascade method, the transmission and distribution coordinated low-carbon economic dispatch method is characterized in that: The decoupling variables of the transmission and distribution network are set in combination with the physical coupling relationship, and the transmission and distribution coordination consistency criterion is constructed based on the target cascade method and the physical structure of the transmission and distribution network, including: Based on the principle of target cascade method, the coupling interaction power between transmission and distribution networks is taken as a shared variable, without considering the phase angle difference at the coupling point of transmission and distribution networks; When optimizing the transmission network layer, the interactive power is considered as an equivalent load to participate in the optimization, and when optimizing the distribution network layer, the interactive power is considered as an equivalent generator to participate in the optimization; After the optimization in each layer is completed, it is only necessary to consider whether the transmission power meets the following consistency criteria to determine whether it has converged.

5. According to claim 4, a transmission and distribution coordinated low-carbon economic dispatch method based on target cascade method is characterized in that: The inter-layer consistency criterion of the transmission and distribution network includes: The consistency criterion between the layers of the transmission and distribution network is that the difference in the interaction power does not exceed the given threshold, and the calculation formula is: In the formula, When the transmission network is dispatched at the transmission network level, the transmission network transmits power to the distribution network, which is equivalent to a virtual active load. It represents the transmission network supplying power to the distribution network, and vice versa, it represents the distribution network transmitting power to the transmission network. It is the active power purchased by the distribution network from the transmission network during the distribution network dispatching, which is equivalent to the active power of the virtual generator. It represents the power transmitted from the distribution network to the transmission network, and vice versa, it represents the power supplied from the transmission network to the distribution network. ε is the convergence accuracy of the two-layer model. The same variable without an overline represents that the variable is a substitution variable.

6. According to the target cascade method, the transmission and distribution coordinated low-carbon economic dispatch method is characterized in that: Construct a low-carbon economic optimization model for transmission and distribution coordination, including: During the dispatching period, the transmission network layer aims to minimize the operating cost of thermal power units, while considering the transmission and distribution consistency goal. The constraints include power flow constraints, node voltage constraints, thermal power unit-related constraints, and transmission network layer interactive power constraints. After the calculation of the transmission network layer is completed, the node carbon potential of the transmission and distribution coupling point is calculated based on the electricity-carbon coupling mechanism and the carbon emission flow calculation method, combined with the active output of the thermal power units and the carbon emission factor; During the dispatching cycle, the distribution network layer aims to optimize the overall economic performance while taking into account the transmission and distribution consistency objectives. 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. The transmission network layer and the distribution network layer perform result judgment and algorithm multiplier update steps.

7. A transmission and distribution coordinated low-carbon economic dispatching system based on target cascade method, characterized in that: include: The first calculation module is used to establish a hierarchical dispatching framework for the transmission and distribution network and analyze the interactive power characteristics under typical load output; The second calculation module is used to set the 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 above-mentioned hierarchical scheduling framework of the transmission and distribution network, combined with preset constraints and taking into account the electricity-carbon coupling calculation method.

8. A transmission and distribution coordinated low-carbon economic dispatching device based on target cascade method, characterized in that: It includes a memory and a processor, the memory stores program instructions executed by the processor, and the processor calls the program instructions to execute the steps of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascade method as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium stores computer instructions, which enable the computer to execute the steps of the transmission and distribution coordinated low-carbon economic dispatch method based on the target cascade method as described in any one of claims 1 to 6.

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