A power distribution network distributed reconstruction method based on supply-demand feeder pair identification

Abstract

The application provides a power distribution network distributed reconstruction method based on supply-demand feeder pair identification, takes a feeder cluster with transformer intra / inter-station power flow transfer path as a basic unit, decomposes a reconstruction problem participated by a multi-transformer substation system into intra-zone reconstruction problems of multiple basic decomposition zones, establishes a supply-demand feeder pair identification model with transformer intra-feeder power flow transfer priority, minimum light abandonment and load loss, and minimum reconstruction calculation degree as targets, respectively makes supply-demand feeder pair decisions for the basic decomposition zones in which the feeders with net load transfer demand are located, establishes a supply-demand feeder pair reconstruction model with minimum light abandonment, load loss, and switch action cost based on the supply-demand feeder pair identification results, performs distributed decoupled reconstruction on multiple supply-demand feeder pairs formed by multiple basic decomposition zones with net load transfer demand, and obtains a multiple-type switch action optimization scheme associated with the power flow transfer path. The application can significantly reduce the model solving difficulty of the power distribution network using the traditional centralized reconstruction.

Description

Technical Field

[0001] This invention relates to the field of distribution network reconfiguration, specifically a distributed reconfiguration method for distribution networks based on the identification of supply and demand feeder pairs. Background Technology

[0002] High-quality economic development has led to a surge in electricity demand, resulting in large-scale distribution networks with numerous nodes and branches, and complex topologies. The rapid development of distributed clean energy generation has highlighted the uneven spatial and temporal distribution of net load in distribution networks, leading to problems such as low absorption of clean energy and poor reliability of load supply. Compared to traditional global reconfiguration methods, the "feeder-transformer-substation" multi-level reconfiguration method, based on the hierarchical topology of the distribution network, prioritizes lower-level reconfiguration to respond to net load flexibility requirements, effectively reducing the difficulty of solving the reconfiguration model. However, when the reconfiguration level requirement for feeders is at the substation level, substation-level reconfiguration reduces curtailment and load loss by adjusting the switching combinations of feeder interconnection switches, transformer interconnection switches, and substation interconnection switches and sectionalizing switches across multiple substations. While providing inter-station power flow transfer paths, it cannot effectively reduce the dimensionality of the reconfiguration model, making the reconfiguration problem involving multiple substation sub-regions still difficult to solve. In fact, multiple feeders in the entire network are not strongly coupled, and feeders with high-level net load transfer requirements do not necessarily require all feeders at that level to participate in the transfer simultaneously.

[0003] Therefore, in the face of increasingly complex power grid structures and the net load flexibility requirements arising from the uneven spatial and temporal distribution of net load, it is of great significance to study a distributed reconfiguration method for distribution networks based on the identification of supply and demand feeder pairs. Summary of the Invention

[0004] The technical problem to be solved by this invention is a distributed reconfiguration method for large-scale distribution networks. This method identifies supply and demand feeder pairs by characterizing the connection relationship between different feeders, considering the priority of low-level power flow transfer paths and net load flexibility requirements, and further realizes spatially decoupled distributed parallel reconfiguration solution. It can be applied to the optimized operation of large-scale distribution networks with uneven spatiotemporal distribution of net load.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] A distributed reconfiguration method for distribution networks based on supply and demand feeder pair identification includes the following steps:

[0007] (1) Taking the feeder cluster with power flow transfer paths within transformers / stations / inter-stations as the basic unit, the reconfiguration problem involving multiple substation systems is decomposed into intra-regional reconfiguration problems in multiple basic decomposition regions;

[0008] (2) Identify feeders with net load transfer needs across the entire network. Basic decomposition areas without net load transfer needs do not require reconstruction. Establish a supply and demand feeder pair identification model with the objectives of prioritizing feeder power flow transfer within transformers, minimizing the amount of power curtailment and load loss, and minimizing reconstruction computation. Solve the supply and demand feeder pair identification model. Make supply and demand feeder pair decisions for each basic decomposition area where feeders with net load transfer needs are located, and obtain the supply and demand feeder pair identification results.

[0009] (3) Based on the identification results of the supply and demand feeder pairs in step (2), the basic decomposition area reconstruction problem of the feeder with net load transfer demand is decomposed into the reconstruction problem of multiple supply and demand feeder pairs. A supply and demand feeder pair reconstruction model with the minimum cost of curtailment, load loss and switching action is established. Distributed decoupling reconstruction is carried out on multiple supply and demand feeder pairs formed in the basic decomposition area to obtain multi-type switching action optimization schemes associated with power flow transfer path, thereby responding to the net load transfer demand of each demand feeder and reducing the curtailment and load loss levels under the uneven distribution of net load in time and space.

[0010] Furthermore, the basic decomposition region of step (1) is defined as a feeder cluster with coupling relationship, having the following characteristics:

[0011] 1) Any feeder within the basic decomposition zone has a power flow transfer path with at least one other feeder within the zone, but has no transfer path with any feeders outside the zone;

[0012] 2) The only common node of the feeders in the basic decomposition area is the substation node. If the number of substation nodes in the area is 1, then the basic decomposition area does not contain inter-station power flow transfer paths; if the number of substation nodes in the area is greater than 1, then there is a substation interconnection switch in the basic decomposition area.

[0013] The basic decomposition zone includes four types: 1) Basic decomposition zone Z1: Its feeder power flow transfer path belongs to the power flow transfer within the transformer, which is achieved by adjusting the feeder tie switch and the section switch; 2) Basic decomposition zone Z2: The power flow transfer path includes the power flow transfer within the transformer and the power flow transfer path within the station; 3) Basic decomposition zone Z3: The power flow transfer path includes the power flow transfer within the transformer, the power flow transfer within the station, and the power flow transfer path between stations, which are achieved by the feeder tie switch, the transformer tie switch, and the substation tie switch, respectively; 4) Z4 is a special feeder cluster that contains only one feeder.

[0014] Furthermore, in step (2), the feeders with net load transfer needs across the entire network are identified, and the steps are as follows:

[0015] Traverse all feeders in the entire network and calculate the net load value of a single feeder: 1) State 1: less than 0, needs to be transferred in; 2) State 2: greater than 0, less than the transmission capacity, no need to transfer in or out; 3) State 3: greater than the transmission capacity, needs to be transferred out.

[0016]

[0017] Where: NL k Let be the net load of feeder k; γ(j) represents the set of transformers in substation j, and α(j, f) represents the set of feeders of the f-th transformer in substation j; B k B represents the set of nodes of feeder k. Sub Represents the set of substation nodes; These are the status indicators for the three different net load conditions of the feeder mentioned above. These represent the status indicators for feeder k when it needs to be switched in and when it needs to be switched out, respectively.

[0018] Furthermore, the supply and demand feeder pair identification in step (2) specifically includes:

[0019] First, the network topology of the basic decomposition area is simplified, retaining the branches and feeder branches where the substation interconnection switch, transformer interconnection switch, feeder interconnection switch, and branch section switch are located. Equivalent distributed photovoltaic nodes and load nodes are constructed at both ends of the branches to form a simplified topology diagram.

[0020] Then, based on the simplified topology diagram, a supply and demand feeder pair identification model is established with the objectives of prioritizing the transfer of power flow in the transformer feeders, minimizing the amount of power curtailment and load loss, and minimizing the reconfiguration computation degree. Supply feeder decisions are then made for the demand feeders in states 1 and 3.

[0021] Furthermore, the objective function of the supply and demand feeder identification model is as follows:

[0022] 1) Priority is given to power flow transfer in the transformer's feeder.

[0023]

[0024] In the formula: R Tie，bn R Tie，zn R Tie，zj These represent the sets of power flow transfer paths within the transformer, within the station, and between stations within the basic decomposition region, respectively. These are the status indicators for the reconstruction of supply and demand feeder pairs formed by the feeders on both sides of the power flow transfer path n; the reconstruction quantification cost differs for supply and demand feeder pairs with different power flow transfer paths. bn <c zn <c zj ;

[0025] 2) Minimum waste load

[0026]

[0027] In the formula: M1 and M2 are the penalty costs for load loss and light abandonment, respectively; Bm , For the set of nodes and the set of photovoltaic nodes; and These represent the actual and predicted photovoltaic output values ​​at node j, respectively. This indicates the active power of load reduction at node j;

[0028] 3) Minimal computational complexity in reconstruction

[0029] While ensuring that feeder net load demand is prioritized for response to power flow transfer from lower-level feeders, the required reconfiguration space for demand feeders should be minimized as much as possible:

[0030]

[0031] In the formula: F represents the set of feed lines in the basic decomposition region; This represents the number of nodes in feeder k; These represent the degree of participation of feeder k in power flow transfer within the transformer, within the station, and between stations, respectively. This indicates that feeder k and two feeders with transformer interconnection switches are included in the reconfiguration scope.

[0032] Furthermore, the constraints on the supply and demand feeder identification model include operability switch constraints, node power balance constraints after network topology simplification, and radial constraints.

[0033] Furthermore, the operability switch constraints are as follows:

[0034]

[0035]

[0036] In the formula: These represent the set of feeder tie switches and the total number of branches for the power flow transfer path n within the transformer, respectively. Let n represent the set of branches and the total number of transformer tie switches for power flow transfer path n within the station, respectively. Let n represent the set of branches and the total number of substation interconnection switches for the inter-station power flow transfer path n, respectively. These represent the branch set and total number of the sectionalizing switches for feeder k, respectively; These represent the sets of power flow transfer paths within a transformer, within a station, and between stations, respectively, for a given feeder k.

[0037] Furthermore, the objective function of the supply and demand feeder for reconstructing the model is as follows:

[0038] min f = C PV +C LR +C sw

[0039]

[0040]

[0041]

[0042] In the formula: C PV C LR C SW These represent the costs of curtailment, load reduction, and switch reconfiguration, respectively. The cost per operation for each type of interconnecting switch and sectionalizing switch is respectively. Indicates the switch state change flag for branch ij; E sw，fe E sw，tr E sw，su E sw，se B, B PV Adjustments are made based on the different reconfiguration areas of different feeder reconfiguration pairs; the types of power flow transfer paths included in supply and demand feeder pairs differ, resulting in different types of tie switches within their reconfiguration areas. These correspond to the switching operation costs for supply and demand feeder pairs under the following scenarios: feeder power transfer paths within the transformer, within the station, and between stations. To reconstruct the switching operation cost under two feeder power flow transfer paths within the region; This indicates that feeders with net load transfer requirements must transfer loads to other feeders simultaneously through the transfer path formed by the feeder tie switch, transformer tie switch, and substation tie switch in order to meet the net load flexibility requirements.

[0043] Furthermore, the constraints of the supply and demand feeder on the reconfiguration model include second-order cone power flow constraints, safety constraints, network reconfiguration constraints, load shedding constraints, and PV output constraints.

[0044] The beneficial effects of this invention are as follows: This invention explores a distributed reconfiguration method for large-scale distribution networks. It adopts a basic decomposition area to divide feeder clusters with power flow transfer paths, intra-area interconnection, and decoupling from the outside area. Considering the priority of low-level power flow transfer paths and the minimum reconfiguration computation degree, it identifies supply and demand feeder pairs for basic decomposition areas with net load flexibility requirements. This can maximize the reduction of the reconfiguration range of feeder net load transfer. Furthermore, a supply and demand pair reconfiguration model is established, and distributed reconfiguration solutions are performed for multiple supply and demand feeder pairs generated by multiple basic decomposition areas. This significantly reduces the model solution difficulty of traditional centralized reconfiguration in distribution networks. Attached Figure Description

[0045] Figure 1 This is a flowchart illustrating a distributed reconfiguration method for a distribution network based on the identification of supply and demand feeder pairs, according to an embodiment of the present invention.

[0046] Figure 2 This is a schematic diagram of the distributed reconstruction of the basic decomposition region based on the supply and demand feeder pair identification of the present invention;

[0047] Figure 3 This is the result of the supply and demand feeder pair identification in this invention;

[0048] Figure 4 This is a schematic diagram of the supply and demand feeder pair update process of the present invention. Detailed Implementation

[0049] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0050] like Figure 1 As shown, this invention provides a distributed reconfiguration method for distribution networks based on supply and demand feeder pair identification. Using feeder clusters with power flow transfer paths within transformers / substations / inter-substations as basic units, the reconfiguration problem involving multiple substation systems is decomposed into intra-region reconfiguration problems in multiple basic decomposition zones. Feeders with net load transfer needs across the entire network are identified; basic decomposition zones without net load transfer needs do not require reconfiguration. A supply and demand feeder pair identification model is established with the objectives of prioritizing power flow transfer within transformer feeders, minimizing curtailment and load loss, and minimizing reconfiguration computation. Supply and demand feeder pair decisions are made separately for each basic decomposition zone containing feeders with net load transfer needs. Based on the supply and demand feeder pair identification results, a supply and demand feeder pair reconfiguration model is established to minimize curtailment, load loss, and switching operation costs. Distributed decoupling and reconfiguration are performed on multiple supply and demand feeder pairs formed by multiple basic decomposition zones with net load transfer needs, obtaining optimized switching operation schemes for various types of power flow transfer paths, thereby responding to the net load transfer needs of each demand feeder. The effectiveness of the proposed distributed reconfiguration method for distribution networks based on supply and demand feeder pair identification is verified using a computational example system.

[0051] The basic decomposition region is defined as a feeder cluster with coupling relationships, and has the following characteristics:

[0052] 1) Within the basic decomposition zone, any feeder has a power flow transfer path with at least one other feeder within the zone (within the transformer / within the station / between stations), but has no transfer path with any feeder outside the zone.

[0053] 2) The only common node for feeders within the basic decomposition zone is the substation node. If the number of substation nodes within the zone is 1, then the basic decomposition zone does not contain inter-station power flow transfer paths; if the number of substation nodes within the zone is greater than 1, then the basic decomposition zone contains substation interconnection switches.

[0054] like Figure 2As shown, the basic decomposition area includes four types: 1) Basic decomposition area Z1: its feeder power flow transfer path belongs to the power flow transfer within the transformer, which is achieved by adjusting the feeder tie switch and the section switch; 2) Basic decomposition area Z2: the power flow transfer path includes the power flow transfer within the transformer and the power flow transfer path within the station; 3) Basic decomposition area Z3: the power flow transfer path includes the power flow transfer within the transformer, the power flow transfer within the station and the power flow transfer path between stations, which are achieved by the feeder tie switch, the transformer tie switch and the substation tie switch respectively; 4) Z4 is a special feeder cluster, which contains only one feeder.

[0055] It is evident that the distribution network reconfiguration, which includes the substation S1 and S2 sub-region systems, can be decomposed into intra-region reconfiguration of each basic decomposition zone. Each decomposition zone is completely decoupled and does not need to exchange information for iterative solutions, thus achieving fully distributed reconfiguration. The optimality of the reconfiguration scheme remains unaffected.

[0056] The specific steps for identifying the net load transfer demand of the feeder are as follows:

[0057] Traverse all feeders in the entire network and calculate the net load value of a single feeder: 1) State 1: less than 0, needs to be transferred in; 2) State 2: greater than 0, less than the transmission capacity, no need to transfer in or out; 3) State 3: greater than the transmission capacity, needs to be transferred out.

[0058]

[0059] Where: NL k Let be the net load of feeder k; γ(j) represents the set of transformers in substation j, and α(j, f) represents the set of feeders of the f-th transformer in substation j; B k B represents the set of nodes of feeder k. Sub Represents the set of substation nodes; These are the status indicators for the three different net load conditions of the feeder mentioned above. These represent the status indicators for feeder k when it needs to be switched in and when it needs to be switched out, respectively.

[0060] The identification of supply and demand feeder pairs specifically includes: First, simplifying the network topology of the basic decomposition area, retaining the branches and feeder branches containing substation tie switches, transformer tie switches, feeder tie switches, and branch section switches, and constructing equivalent distributed photovoltaic nodes and load nodes at both ends of the branches to form a simplified topology diagram. Then, based on the simplified topology diagram, establishing a supply and demand feeder pair identification model with the objectives of prioritizing feeder power flow transfer within the transformer, minimizing curtailment load loss, and minimizing reconfiguration computation, and making supply feeder decisions for demand feeders in states 1 and 3.

[0061] The objective function of the supply and demand feeder identification model is:

[0062] 1) Priority is given to power flow transfer in the transformer's feeder.

[0063]

[0064] In the formula: R Tie，bn R Tie，zn R Tie，zj These represent the sets of power flow transfer paths within the transformer, within the station, and between stations within the basic decomposition region, respectively. These are the status indicators for the reconstruction of supply and demand feeder pairs formed by the feeders on both sides of the power flow transfer path n; the reconstruction quantification cost differs for supply and demand feeder pairs with different power flow transfer paths. bn <c zn <c zj .

[0065] 2) Minimum waste load

[0066]

[0067] In the formula: M1 and M2 are the penalty costs for load loss and light abandonment, respectively; B m , For the set of nodes and the set of photovoltaic nodes; and These represent the actual and predicted photovoltaic output values ​​at node j, respectively. This indicates the active power of load reduction at node j.

[0068] 3) Minimal computational complexity in reconstruction

[0069] While ensuring that the net load demand of feeders is prioritized to be responded to by the power flow transfer of lower-level feeders, the required reconfiguration space of demand feeders should be reduced as much as possible.

[0070]

[0071] In the formula: F represents the set of feed lines in the basic decomposition region; This represents the number of nodes in feeder k; These represent the degree of participation of feeder k in power flow transfer within the transformer, within the station, and between stations, respectively. This indicates that feeder k and two feeders with transformer interconnection switches are included in the reconfiguration scope;

[0072] The constraints on the identification model for the supply and demand feeder include operability switch constraints, node power balance constraints after network topology simplification, and radial constraints. The operability switch constraints are as follows:

[0073]

[0074]

[0075] In the formula: These represent the set of feeder tie switches and the total number of branches for the power flow transfer path n within the transformer, respectively. Let n represent the set of branches and the total number of transformer tie switches for power flow transfer path n within the station, respectively. Let n represent the set of branches and the total number of substation interconnection switches for the inter-station power flow transfer path n, respectively. These represent the branch set and total number of the sectionalizing switches for feeder k, respectively; These represent the sets of power flow transfer paths within a transformer, within a station, and between stations, respectively, for a given feeder k.

[0076] Based on the above identification results of supply and demand feeder pairs, the basic decomposition region with net load transfer requirements may form one or more supply and demand feeder pairs, which can be reconstructed and solved based on the original unsimplified network topology. The reconstruction models of different supply and demand feeder pairs are largely the same, differing only in network topology and load scenarios. Under the conditions of satisfying second-order cone power flow constraints, safety constraints, network reconstruction constraints, load shedding constraints, and PV output constraints, each reconstruction object achieves the minimum cost of curtailment, load shedding, and switching operations by optimizing multiple power flow transfer paths within the supply and demand feeder pairs.

[0077] The objective function of the supply and demand feeder for the reconstruction model is as follows:

[0078] min f = C PV +C LR +C sw

[0079]

[0080]

[0081]

[0082] In the formula: C PV C LR C sw These represent the costs of curtailment, load reduction, and switch reconfiguration, respectively. The cost per operation for each type of interconnecting switch and sectionalizing switch is respectively. Indicates the switch state change flag for branch ij; E sw，fe E sw，tr E sw，su E sw，se B, B PV Adjustments are made based on the different reconfiguration areas of different feeder reconfiguration pairs; the types of power flow transfer paths included in supply and demand feeder pairs differ, resulting in different types of tie switches within their reconfiguration areas. These correspond to the switching operation costs for supply and demand feeder pairs under the following scenarios: feeder power transfer paths within the transformer, within the station, and between stations. To reconstruct the switching operation cost under two feeder power flow transfer paths within the region; This indicates that feeders with net load transfer requirements must transfer loads to other feeders simultaneously through the transfer path formed by the feeder tie switch, transformer tie switch, and substation tie switch in order to meet the net load flexibility requirements.

[0083] The constraints on the reconfiguration model of the supply and demand feeder include second-order cone power flow constraints, safety constraints, network reconfiguration constraints, load shedding constraints, and PV output constraints.

[0084] Numerical example verification and analysis:

[0085] Based on an improved 148-node system, the distributed reconfiguration method for distribution networks based on feeder pair identification was validated and analyzed on the MATLAB 2016a simulation platform with built-in CPLEX commercial solver and YALMIP toolbox. The example system is a Z3-type basic decomposition zone with simultaneous intra-transformer power flow transfer, intra-station power flow transfer, and inter-station power flow transfer paths, and some feeders within the zone have net load transfer requirements. Since the reconfiguration problem involving multiple substation systems can be decomposed into multiple basic decomposition zone reconfiguration problems with net load transfer requirements, the effectiveness of the reconfiguration method of this invention can be verified through feeder pair identification and distributed reconfiguration optimization analysis of this example system.

[0086] The connection relationships between the feeders in this basic decomposition region are shown in Table 1 below:

[0087] Table 1 Feeder Connection Relationships

[0088]

[0089] Supply and demand feeder pair identification results:

[0090] Configure a scenario where the net load within this system exhibits uneven spatiotemporal distribution characteristics over 24 hours, such as... Figure 3As shown, during periods 6-7, the power flow transfer paths BN1 and BN3 within the transformer have the need to form supply and demand feeder pairs for reconfiguration. The reconfiguration problem in this basic decomposition area can be decomposed into a reconfiguration problem of two feeder pairs (S1T11-S1T12, S2T11-S1T12). During period 10, the power flow transfer paths ZN1 within the station and BN2, BN3, and BN4 within the transformer have the need to form supply and demand feeder pairs for reconfiguration, resulting in a reconfiguration problem of three feeder pairs (S1T12-S1T21-S1T22, S2T11-S1T12, S2T21-S2T22). During periods 11-16, the power flow transfer path ZJ1 between the stations and BN4 within the transformer have the need to form supply and demand feeder pairs for reconfiguration. The substation-level reconfiguration problem is reduced in dimension to a reconfiguration problem of two feeder pairs (S1T12-S2T11, S2T21-S2T22). As can be seen, the supply and demand feeder pair identification method of the present invention can decompose the large-scale reconfiguration problem into a reconfiguration problem of multiple feeder pairs, thus avoiding the high difficulty of solving the problem caused by all feeders participating in the reconfiguration under the high-level net load transfer demand.

[0091] Based on the supply and demand feeder pair identification results, if a feeder exists in multiple power flow transfer paths with reconfiguration requirements, the supply and demand feeder pair identification results need to be updated, further forming a completely decoupled multiple feeder pair reconfiguration problem. The update flowchart is as follows: Figure 4 As shown.

[0092] All-time switch operation plan:

[0093] Based on the above supply and demand feeder pair identification results, the multiple supply and demand feeder pairs were reconstructed and solved separately. The all-time switching action scheme is shown in Table 2 below. By optimizing the net load transfer of multiple types of power flow transfer paths, the curtailment level can be significantly reduced from 12.5171MWh under a single grid topology to 0.1199MWh, thereby improving the level of clean energy consumption.

[0094] Table 2 Switch Action Scheme

[0095]

[0096] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for distributed reconfiguration of a distribution network based on the identification of supply and demand feeder pairs, characterized in that, Includes the following steps: (1) Taking the feeder cluster with power flow transfer paths within transformers / stations / inter-stations as the basic unit, the reconfiguration problem involving multiple substation systems is decomposed into intra-regional reconfiguration problems in multiple basic decomposition regions; (2) Establish a supply and demand feeder pair identification model with the objectives of prioritizing the transfer of power flow in the transformer feeder, minimizing the amount of power loss due to light curtailment, and minimizing the reconfiguration computation degree. Solve the supply and demand feeder pair identification model and make supply and demand feeder pair decisions for the basic decomposition zone where the feeder with net load transfer demand is located, and obtain the supply and demand feeder pair identification results. (3) Based on the identification results of the supply and demand feeder pairs in step (2), the basic decomposition area reconstruction problem of the feeder with net load transfer demand is decomposed into the reconstruction problem of multiple supply and demand feeder pairs. The supply and demand feeder pair reconstruction model with the minimum cost of curtailment, load loss and switching action is established. The multiple supply and demand feeder pairs formed in the basic decomposition area are distributed decoupled and reconstructed to obtain multi-type switching action optimization schemes associated with power flow transfer path, thereby responding to the net load transfer demand of each demand feeder and reducing the curtailment and load loss levels under the uneven distribution of net load in time and space. In step (2), the feeders with net load transfer requirements across the entire network are identified, and the steps are as follows: Traverse all feeders in the entire network and calculate the net load value of a single feeder: 1) State 1: less than 0, needs to be transferred in; 2) State 2: greater than 0, less than the transmission capacity, no need to transfer in or out; 3) State 3: greater than the transmission capacity, needs to be transferred out. ； In the formula: The net load of feeder k; This represents the set of transformers in substation j. Let f represent the set of feeders for the f-th transformer in substation j. This represents the set of nodes for feeder k. Represents the set of substation nodes; , , These are the status indicators for the three different net load conditions of the feeder mentioned above. , These represent the status indicators for feeder k when it needs to be switched in and when it needs to be switched out, respectively. The supply and demand feeder pair identification in step (2) specifically includes: First, the network topology of the basic decomposition area is simplified, retaining the branches and feeder branches where the substation interconnection switch, transformer interconnection switch, feeder interconnection switch, and branch section switch are located. Equivalent distributed photovoltaic nodes and load nodes are constructed at both ends of the branches to form a simplified topology diagram. Then, based on the simplified topology diagram, a supply and demand feeder pair identification model is established with the objectives of prioritizing the transfer of power flow in the transformer feeders, minimizing the amount of power curtailment and load loss, and minimizing the reconfiguration computation degree. Supply feeder decisions are then made for the demand feeders in states 1 and 3.

2. The distributed reconfiguration method for distribution networks based on supply and demand feeder pair identification according to claim 1, characterized in that, The basic decomposition region in step (1) is defined as a feeder cluster with coupling relationships, and has the following characteristics: 1) Any feeder within the basic decomposition zone has a power flow transfer path with at least one other feeder within the zone, but has no transfer path with any feeders outside the zone; 2) If the only common node of the feeders in the basic decomposition area is the substation node, and the number of substation nodes in the area is 1, then the basic decomposition area does not contain inter-station power flow transfer paths. If the number of substation nodes in the area is greater than 1, then there is a substation interconnection switch in the basic decomposition area. The basic decomposition zone includes four types: 1) Basic decomposition zone Z1: Its feeder power flow transfer path belongs to the power flow transfer within the transformer, which is achieved by adjusting the feeder tie switch and the section switch; 2) Basic decomposition zone Z2: The power flow transfer path includes the power flow transfer within the transformer and the power flow transfer path within the station. 3) Basic decomposition zone Z3: The power flow transfer path includes the power flow transfer within the transformer, the power flow transfer within the station, and the power flow transfer path between stations, which are realized through the feeder tie switch, the transformer tie switch, and the substation tie switch, respectively; 4) Z4 is a special feeder cluster, which contains only one feeder.

3. The distributed reconfiguration method for distribution networks based on supply and demand feeder pair identification according to claim 1, characterized in that, The objective function of the supply and demand feeder identification model is as follows: 1) Priority is given to power flow transfer in the transformer's internal feeder. ； In the formula: , , These represent the sets of power flow transfer paths within the transformer, within the station, and between stations within the basic decomposition region, respectively. , , These are the status indicators for the reconfiguration of supply and demand feeder pairs formed by the feeders on both sides of the power flow transfer path n; the reconfiguration quantification cost differs for supply and demand feeder pairs with different power flow transfer paths. ; 2) Minimum waste load ； In the formula: , These are the penalty costs for loss of load and abandonment of light, respectively. , It consists of a set of nodes and a set of photovoltaic nodes; and These represent the actual and predicted photovoltaic output values ​​at node j, respectively. This indicates the active power of load reduction at node j; 3) Minimal computational complexity in reconstruction While ensuring that the net load demand of feeders is prioritized for response to power flow transfer from lower-level feeders, the required reconfiguration space of demand feeders should be minimized as much as possible: ； In the formula: F represents the set of feed lines in the basic decomposition region; This represents the number of nodes in feeder k; , , These represent the degree of participation of feeder k in power flow transfer within the transformer, within the station, and between stations, respectively. This indicates that feeder k and two feeders with transformer interconnection switches are included in the reconfiguration scope.

4. The distributed reconfiguration method for distribution networks based on supply and demand feeder pair identification according to claim 3, characterized in that, The constraints on the supply and demand feeder identification model include operability switch constraints, node power balance constraints after network topology simplification, and radial constraints.

5. The distributed reconfiguration method for distribution networks based on supply and demand feeder pair identification according to claim 4, characterized in that, The operability switch constraints are as follows: ； ； In the formula: , These represent the branch set and total number of feeder tie switches for power flow transfer path n within the transformer, respectively. , Let n represent the set of transformer tie switches and the total number of branches for the power flow transfer path n within the station, respectively. , Let n represent the set of branches and the total number of substation interconnection switches for the inter-station power flow transfer path n, respectively. , These represent the branch set and total number of the sectionalizing switches for feeder k, respectively; , , These represent the sets of power flow transfer paths within a transformer, within a station, and between stations, respectively, for a feeder k.

6. The method for distributed reconfiguration of distribution networks based on supply and demand feeder pair identification according to claim 1, characterized in that, The objective function of the supply and demand feeder for the reconstruction model is as follows: ； ； ； ； In the formula: , , These represent the costs of curtailment, load reduction, and switch reconfiguration, respectively. , The cost per operation for each type of interconnecting switch and sectionalizing switch is respectively. , Indicates the switch status change flag of branch ij; , , , , , Adjustments are made based on the different reconfiguration areas of different feeder reconfiguration pairs; the types of power flow transfer paths included in supply and demand feeder pairs differ, resulting in different types of tie switches within their reconfiguration areas. , , These correspond to the switching operation costs for supply and demand feeder pairs under the following scenarios: feeder power transfer paths within the transformer, within the station, and between stations. , , To reconstruct the switching operation cost under two feeder power flow transfer paths within the region; This indicates that feeders with net load transfer requirements must transfer loads to other feeders simultaneously through the transfer path formed by the feeder tie switch, transformer tie switch, and substation tie switch in order to meet the net load flexibility requirements.

7. The distributed reconfiguration method for distribution networks based on supply and demand feeder pair identification according to claim 6, characterized in that, The constraints on the reconfiguration model of the supply and demand feeder include second-order cone power flow constraints, safety constraints, network reconfiguration constraints, load shedding constraints, and PV output constraints.

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