Layered power distribution network system, construction method and cooperative load transfer control method

Abstract

The invention relates to the technical field of power distribution network frames, and provides a layered power distribution network system, a building method and a cooperative load transfer control method.The layered power distribution network system comprises a trunk layer which comprises three or four switching stations, and all the switching stations included in the trunk layer are connected through cables to form a closed looped network structure; the total number of power supply paths of the closed looped network structure is two times of the number of the switching stations; the secondary trunk layer comprises a plurality of segments formed by dividing a power supply line, the segments are interconnected through a ring main unit, and the segments are respectively connected to different trunk layer switching stations to form a single-ring network or double-ring network structure; the user layer comprises a power distribution room, the power distribution room is provided with dual-power access equipment, the dual-power access equipment comprises a first access point and a second access point, the first access point is connected with the secondary layer ring main unit, and the second access point is connected with the main layer switching station. The method solves the problem that self-healing is difficult to implement under the conditions of shortage of transformer substation interval resources and limitation of line galleries.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network racks, and in particular to a layered distribution network system, a construction method, and a coordinated load transfer control method. Background Art

[0002] In recent years, with the surge in urban load density and the high penetration of distributed energy, distribution network construction faces two core contradictions: First, substation bay resources are severely limited. Traditional double-ring and radial grids require independent bays for each line. A single 110kV substation requires 12 10kV outgoing line bays to meet the dual-ring network architecture. This results in a bay utilization rate exceeding 85%, directly hindering the implementation of the target grid.

[0003] Second, redundant line corridor connections conflict with self-healing logic. To alleviate spacing pressure, existing technologies tend to add line connection points within limited corridors, forming a complex, multi-segmented ring network structure. However, this solution ineffectively implements self-healing strategies. Excessive connection points complicate coordination of protection settings, and centralized master stations are unable to complete multi-branch fault path searches within 500ms, resulting in a high rate of misjudgment. Furthermore, this leads to overdrawn corridor resources, forcing a single cable channel to carry three or four line cross-connections, increasing the risk of fault spread.

[0004] At its root, attempts to solve the problem through homogeneous redundancy (such as a full double-ring network) or excessive communication have further exacerbated the consumption of interval and corridor resources, forming a vicious cycle of "reliability improvement-resource overload-control failure." Summary of the Invention

[0005] To this end, the purpose of the present invention is to overcome the problem of difficulty in implementing self-healing under the conditions of tight substation interval resources and restricted line corridors in the prior art, and to provide a hierarchical distribution network system, a construction method and a collaborative load transfer control method. Through the hierarchical decoupling topology architecture design and cross-level differentiated communication collaboration, without relying on complex control equipment, the bottlenecks of interval and corridor resources of the traditional distribution network are directly broken through. At the same time, cross-level data interaction is used to provide infrastructure support for self-healing collaboration, forming a distribution network system that is both resource-saving and highly reliable in power supply.

[0006] In a first aspect, in order to solve the above technical problems, the present invention provides a hierarchical distribution network system, comprising: A backbone layer includes three or four switch stations, all of which are connected by cables to form a closed ring network structure; wherein the total number of power supply paths in the closed ring network structure is equal to twice the number of the switch stations; The secondary trunk layer includes multiple segments formed by dividing the power supply lines. Each of the segments is interconnected through a ring network cabinet, and each of the segments is connected to a different trunk layer switch station to form a single ring network or a double ring network structure; The user layer includes a power distribution room, wherein the power distribution room is equipped with a dual power access device, wherein the dual power access device includes a first access point and a second access point, wherein the first access point is connected to the secondary trunk layer ring network cabinet, and the second access point is connected to the trunk layer switch station; Among them, data interaction is achieved between the backbone layer, secondary backbone layer and user layer through differentiated communication protocols.

[0007] Preferably, the four switch stations are respectively a first switch station, a second switch station, a third switch station and a fourth switch station, and the four switch stations form the closed ring network structure based on quadrilateral interconnection; wherein the first switch station is connected to the second switch station through a first cable and to the fourth switch station through a second cable; the second switch station is connected to the third switch station through a third cable; and the third switch station is connected to the fourth switch station through a fourth cable.

[0008] Preferably, the cross-sectional area of ​​the cable is ≥400 mm².

[0009] Preferably, it also includes a layered self-healing system, which includes an optical differential protection device and a backup protection device configured at the backbone layer; wherein, after the optical differential protection device detects a fault, it sends a locking signal to the backup protection device, and the backup protection device performs load transfer after receiving the locking signal; a wireless communication module configured at the secondary backbone layer, the wireless communication module communicates with the main station based on the LoRKG1WKG1N protocol or the 4G communication protocol, and uploads the load data and fault information of the ring network cabinet to the main station, and the main station generates the optimal transfer path based on topology analysis, and issues instructions to the target ring network cabinet; and, a voltage monitoring module and a backup automatic transfer device configured at the user layer; wherein, the voltage monitoring module monitors the power supply data on the user side in real time; when the voltage on the user side drops beyond the threshold, the backup automatic transfer device is triggered to switch to the backup power supply; wherein, the priorities of the backup automatic transfer device, the backup protection device and the self-healing control of the secondary backbone layer master station are level I, level II and level III, respectively.

[0010] Preferably, the master station generates the optimal transfer path based on topological analysis, including constructing an adjacency matrix with the ring network cabinet as the node and the line impedance as the weight; generating a candidate path set from the fault point to the backup power supply based on the Dijkstra algorithm; arranging the candidate path set in ascending order of impedance to obtain a candidate path set ; Based on the candidate path set Obtain a shortest impedance path; verify the shortest impedance path according to the following verification conditions: Irated ≥max(1.2I max , I fault ); If the shortest impedance path meets the verification condition, the shortest impedance path is the optimal transfer path; if not, the suboptimal path verification is started; wherein, I rated The real-time current carrying capacity of the line with the shortest impedance path; I max is the historical maximum load; I fault is the instantaneous load before the fault.

[0011] Preferably, the master station generates the optimal transfer path based on topological analysis, and further comprises traversing the candidate path set. If the optimal transfer path is not determined, cross-layer collaborative transfer is triggered.

[0012] Preferably, during the switching of the standby automatic switching device, the operating instructions of the secondary trunk layer and the main trunk layer for the voltage drop exceeding the threshold circuit are locked, which includes sending a locking signal to the secondary trunk layer ring network cabinet and the main trunk layer standby switching protection device 100μs before the start of the switching; the locking signal is released after the switching is completed and the voltage is restored to the rated value ±5% for a set time; after the locking signal is released, a status recovery instruction is sent to the secondary trunk layer ring network cabinet for the secondary trunk layer master station to synchronously update the topology data.

[0013] Preferably, data interaction is achieved between the backbone layer, secondary backbone layer and user layer through differentiated communication protocols, including the backbone layer switch station being directly connected to the substation dispatching system based on a dual-ring optical fiber channel, and the channel switching delay of the dual-ring optical fiber channel being ≤10ms; the secondary backbone layer ring network cabinet interacting with the main station based on a wireless communication gateway; and the user layer interacting with the secondary backbone layer ring network cabinet based on an Internet of Things terminal.

[0014] In a second aspect, in order to solve the above technical problems, the present invention also provides a multi-level coordinated load transfer control method, which is executed based on the hierarchical distribution network system. The load transfer control method includes: When the backbone layer detects a complete outage of the substation, load transfer is performed based on the backup protection device within the closed loop network structure; If the main layer fails to transfer power, the wireless communication module of the secondary layer is triggered to send a cross-layer transfer request to the master station. The master station generates a cross-layer transfer path based on topology analysis and controls the opening and closing of the secondary layer ring network cabinet according to the cross-layer transfer path. If the secondary main layer fails to transfer power, the backup automatic transfer device of the user layer is triggered to switch to the backup power supply based on the voltage monitoring result; wherein, a pre-switching instruction is sent to the backup automatic transfer device of the user layer to make it enter the backup power supply hot standby state; non-critical user loads are cut off, and the power supply capacity of critical users is prioritized.

[0015] In a third aspect, in order to solve the above technical problems, the present invention also provides a method for constructing a hierarchical distribution network, which is characterized by comprising: Divide the target area into multiple power supply grids based on urban planning and load density distribution, and further divide each power supply grid into several power supply units; Planning a backbone layer within the power supply grid, wherein the backbone layer includes three or four switch stations, and all the switch stations included in the backbone layer are connected by cables to form a closed ring network structure; Planning a secondary trunk layer within the power supply unit, the secondary trunk layer includes multiple segments formed by dividing the power supply line, each of the segments is interconnected through a ring main unit, and each of the segments is connected to a different trunk layer switch station, forming a single ring network or a double ring network structure; A user layer is deployed on the user side, the user layer includes a power distribution room, the power distribution room is equipped with a dual power access device, the dual power access device includes a first access point and a second access point, the first access point is connected to the secondary trunk layer ring network cabinet, and the second access point is connected to the trunk layer switch station; A hierarchical communication system is configured, including the main layer switch station equipped with an optical fiber communication terminal, which is directly connected to the substation dispatching system; the secondary layer ring network cabinet is equipped with a wireless communication gateway to interact with the master station; the user layer power distribution room is equipped with an Internet of Things terminal to communicate with the secondary layer ring network cabinet; A layered self-healing system is configured, including the installation of optical differential protection devices and backup protection devices in the main layer switch station; the integration of wireless communication modules in the secondary layer ring network cabinet; and the configuration of backup automatic switching devices and voltage monitoring modules in the user layer distribution room.

[0016] The above technical solution of the present invention has the following beneficial effects compared with the prior art: The hierarchical distribution network system, construction method and collaborative load transfer control method described in the present invention directly break through the interval and corridor resource bottlenecks of traditional distribution networks through hierarchical decoupling topological architecture design and cross-level differentiated communication collaboration without relying on complex control equipment. At the same time, cross-level data interaction provides infrastructure support for self-healing collaboration, forming a distribution network system that is both resource-saving and highly reliable in power supply.

[0017] Among them, three or four switch stations are connected end to end through cables to form a closed ring network (such as a double-ring network or a multi-ring network). The total number of power supply paths is equal to twice the number of switch stations, so that a single-loop interval can carry multi-directional power supply tasks (such as one switch station simultaneously supplies power to two ring network directions). The interval resource reuse rate is increased by more than 40%, breaking through the exclusive occupation of the interval by the traditional single-ring network / radial structure.

[0018] The secondary trunk power supply line is divided into multiple sections, each of which is interconnected through a ring main unit and connected to a different trunk switch station. For example, a single circuit is divided into three sections, each connected to three switch stations, forming a redundant loop through the ring main unit, reducing the line spacing requirements of a single switch station.

[0019] When the secondary trunk layer is interconnected through the ring network cabinet to form a single ring network or a double ring network, the existing cable channel can be directly used to avoid repeated excavation for new communication lines, thereby improving the utilization rate of the corridor.

[0020] The secondary trunk layer ring network structure is based on segmented access to the trunk layer, reducing complex multi-circuit line cross-connections and lowering the path search complexity of the self-healing strategy.

[0021] The user-layer distribution room obtains dual power supplies through the first access point and the second access point to achieve cross-layer redundant power supply. When the secondary trunk layer fails, the user can directly maintain power supply through the main trunk layer power supply, reducing the probability of power outages on the user side.

[0022] The backbone layer, secondary backbone layer, and user layer implement data interaction through differentiated communication protocols, supporting cross-layer transmission and collaborative control of fault information and shortening fault location time to seconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 This is a structural block diagram of a hierarchical distribution network system in a preferred embodiment of the present invention; Figure 2 for Figure 1 The diagram of the hierarchical distribution network system and substation busbar connection is shown; Figure 3 This is a structural block diagram of a hierarchical self-healing system in a preferred embodiment of the present invention; Figure 4 Flowchart of a multi-level coordinated load transfer control method in a preferred embodiment of the present invention; Figure 5 This is a flow chart of a method for building a hierarchical distribution network in a preferred embodiment of the present invention; Figure 6 This is the topography of a grid area in Linfen's central urban area before renovation; Figure 7 for Figure 6 Topography after transformation.

[0024] Explanation of the reference numerals in the specification: 10 - main layer, 20 - secondary layer, 30 - user layer. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0026] Example 1:

[0027] Reference Figure 1 and Figure 2 As shown, an embodiment of the present invention discloses a layered distribution network system, including a backbone layer 10, a secondary backbone layer 20 and a user layer 30, wherein the backbone layer includes three or four switch stations, and all the switch stations included in the backbone layer are connected by cables to form a closed ring network structure; wherein the total number of power supply paths of the closed ring network structure is equal to twice the number of the switch stations; the secondary backbone layer includes a plurality of segments formed by dividing the power supply lines, each of the segments is interconnected through a ring network cabinet, and each of the segments is respectively connected to a different backbone layer switch station to form a single ring network or a double ring network structure; the user layer includes a distribution room, which is equipped with a dual power access device, and the dual power access device includes a first access point and a second access point, the first access point is connected to the secondary backbone layer ring network cabinet, and the second access point is connected to the backbone layer switch station.

[0028] In specific application scenarios, the backbone layer includes three or four switch stations, preferably four: the first switch station KG1, the second switch station KG2, the third switch station KG3, and the fourth switch station KG4. The four switch stations KG1, KG2, KG3, and KG4 are connected in a "well" quadrilateral pattern, forming a closed ring network structure. For example, the first switch station KG1 is connected to the second switch station KG2 via a first cable (KG1-KG2) and to the fourth switch station KG4 via a second cable (KG1-KG4). The second switch station KG2 is connected to the third switch station KG3 via a third cable (KG2-KG3). The third switch station KG3 is connected to the fourth switch station KG4 via a fourth cable (KG3-KG4). Two independent cables are laid between KG1 and KG2, KG2 and KG3, KG3 and KG4, and KG1 and KG4, respectively, for a total of 4 × 2 = 8 paths. The closed ring network structure enables a single bay to carry multi-directional power supply tasks (for example, a switch station can supply power to two ring network directions at the same time), and the bay resource reuse rate is increased by more than 40%, breaking through the exclusive occupation of the bay by the traditional single ring network / radial structure.

[0029] When networking, the busbars of the four switch stations KG1, KG2, KG3, and KG4 are respectively connected to the four sections of substation busbars. Among them, the four sections of substation busbars can come from two substations, three substations, or four substations. When corresponding to four substations, the busbars of the four switch stations KG1, KG2, KG3, and KG4 are respectively connected to the four sections of busbars of the four substations.

[0030] The multiple switch stations on the backbone layer form a closed ring network structure through cables, and only a small number of substation outgoing lines are needed to cover multiple switch stations, releasing interval resources and reducing the shortage of link interval resources. In addition, when a substation fails, the load is quickly transferred through the closed ring network structure on the backbone layer, and users do not suffer power outages, achieving full stop and full rotation.

[0031] The secondary trunk layer includes a plurality of segments formed by the division of the power supply line, each of the segments is interconnected through a ring network cabinet, and each of the segments is respectively connected to a different trunk layer switch station, forming a single ring network or a double ring network structure. For example, each power supply line is divided into two segments A and B, the head end of segment A is connected to the switch station KG1, and the head end of segment B is connected to the switch station KG2; if each power supply line is divided into three segments A, B, and C, the head end of segment A is connected to the switch station KG1, the head end of segment B is connected to the switch station KG2, and the head end of segment C is connected to the switch station KG1. The single ring network connects each segment to two different trunk layer switch stations through a ring network cabinet, forming a single closed-loop structure, ensuring that power can be supplied through the switch station on the other side when any segment fails. The double ring network is two independent closed loops, and the segmented lines of each closed loop are still connected to two different trunk layer switch stations, but the overall double ring network structure is jointly supported by four trunk layer switch stations. For example, Ring 1: Segments A, B, and C connect to switch stations KG1 and KG2 (connection method is the same as above); Ring 2: Segments D, E, and F connect to switch stations KG3 and KG4. The two rings are interconnected by tie switches (or ring main units), creating higher redundancy and maintaining power transfer even in the event of an N-2 failure. In a dual-ring network structure, a single-segment line failure can be transferred via the same ring or across rings, reducing the risk of group load loss.

[0032] The power supply lines of the secondary trunk layer do not need to directly occupy the substation interval, but are transferred through the main trunk layer, thereby further releasing interval resources; in addition, through segmented control, the fault impact range is reduced to the secondary trunk layer ring network, reducing group load losses.

[0033] The following is a comparison of the prior art where three segments are connected to three different switch stations and the embodiment of the present invention where three segments are connected to two different switch stations: In the existing technology, three sections are connected to three different switch stations: the three sections A, B, and C are connected to switch stations KG1, KG2, and KG3 respectively. When switch station KG1 fails, section A loses power, and sections B and C are not affected, but they need to occupy 3 intervals and 3 independent corridors.

[0034] In the implementation scheme of the present invention, three segments are connected to two different switch stations, which meets the requirement of multiplexing non-adjacent segments into the same station (or multiplexing the same switch station with interval segments). Segment A is connected to switch station KG1, segment B is connected to switch station KG2, and segment C is connected to switch station KG1. When switch station KG1 fails, segment A and segment C are interconnected through the ring network cabinet and transferred to switch station KG2. All three segments are powered by switch station KG2. Segments A, B, and C are not affected, there is no power outage for users, and only two intervals are required.

[0035] Therefore, the hierarchical power supply network according to the embodiment of the present invention reduces the spacing requirement while ensuring power supply reliability.

[0036] The user layer is configured with dual power access equipment. The first access point of the dual power access equipment is connected to the secondary trunk layer ring network cabinet as the main power supply, and the second access point is connected to the trunk layer switch station as the backup power supply. The dual power supplies serve as backup for each other. When the main power supply fails, the backup power supply is automatically switched on, and the switching time is shorter than the tolerance threshold of the user's sensitive equipment (such as milliseconds). It is particularly suitable for scenarios such as hospitals and data centers that have extremely high requirements for power supply continuity.

[0037] In summary, the layered distribution network system described in the embodiment of the present invention is a backbone layer composed of switch stations that performs global load transfer, realizes full stop and full transfer, and releases interval resources; multiple segments divided by the power supply lines are connected to the secondary backbone layer formed by different backbone switch stations through ring network cabinets to perform local load transfer, thereby reducing networking losses; the dual power supplies at the user layer serve as backup power for each other to realize uninterrupted power supply to users; triple redundancy is formed in the backbone layer (ring network), secondary backbone layer (multiple transfer paths), and user layer (dual power supplies + load classification), and the core load power supply can still be guaranteed under system N-2 failure.

[0038] On the other hand, data interaction is achieved between the backbone layer, secondary backbone layer and user layer through differentiated communication protocols. Specifically, the backbone layer switch station is directly connected to the substation dispatching system based on a dual-ring optical fiber channel, and the channel switching delay of the dual-ring optical fiber channel is ≤10ms; the secondary backbone layer ring network cabinet interacts with the main station based on the wireless communication gateway, the working frequency band is 470-510MHz, the transmission power is ≤14dBm, and the transmission delay of the interaction with the main station is ≤50ms; the user layer interacts with the secondary backbone layer ring network cabinet based on the Internet of Things terminal.

[0039] In specific application scenarios, backbone switchyards, as high-voltage nodes, require highly reliable, low-latency communications. Direct fiber connections are used to meet differential protection requirements. Dual-ring fiber channels are two independent fiber communication loops. Physical path separation and logical hot standby ensure that if either loop fails, communication automatically switches to the backup loop, guaranteeing zero-interruption data transmission. Fiber channels directly connect to the dispatching system's communication interface (such as an SDH optical terminal or switch), bypassing intermediate forwarding nodes. This reduces transmission hops and latency. Ring main units are deployed in dispersed locations, enabling wireless communication without the high cost of laying fiber, while also enabling bandwidth that supports sub-second command transmission. Differentiated communication at each layer provides infrastructure support for self-healing collaboration through cross-layer data exchange.

[0040] In summary, the hierarchical distribution network system described in the embodiment of the present invention, through the hierarchical decoupling topological architecture design and cross-level differentiated communication collaboration, directly breaks through the interval and corridor resource bottlenecks of the traditional distribution network without relying on complex control equipment. At the same time, it provides infrastructure support for self-healing collaboration through cross-level data interaction, forming a distribution network system that is both resource-saving and highly reliable in power supply.

[0041] Specifically, the cross-sectional area of ​​the cable is ≥400mm². It should be noted here that the cross-sectional area of ​​the cable ≥400mm² is not a simple parameter selection, but rather a comprehensive improvement in transmission efficiency, reliability, economy, and system scalability through the deep coupling of physical characteristics with the requirements of the layered distribution network system. The specific application effects are as follows: Cables with a cross-sectional area ≥400mm² can carry a current ≥800A (copper core, ambient temperature 30°C) under rated conditions, allowing a single circuit to simultaneously meet the power supply requirements of dual power paths; for example, when the main layer switch station KG1 fails, the secondary trunk layer segments (such as A and C) are transferred to KG2 through the ring network cabinet interconnection cable (cross-sectional area ≥400mm²), avoiding secondary power outages due to cable overload. In the case of line N-1 failure, the cable load rate is ≤70%, meeting the redundancy design requirements of "GB 50217-2018". The low impedance characteristics of large-cross-sectional area cables (R≤0.075Ω / km) can reduce cross-layer transmission losses between the main layer and the secondary layer, supporting efficient energy scheduling under the "hierarchical decoupling" architecture.

[0042] As a further improvement of the embodiment of the present invention, the layered distribution network system further includes a layered self-healing system. Figure 3As shown, the layered self-healing system includes an optical differential protection device and a backup protection device configured in the backbone layer; wherein, after the optical differential protection device detects a fault, it sends a locking signal to the backup protection device, and the backup protection device performs load transfer after receiving the locking signal; a wireless communication module configured in the secondary backbone layer, the wireless communication module communicates with the main station based on the LoRKG1WKG1N protocol or the 4G communication protocol, and uploads the load data and fault information of the ring network cabinet to the main station, and the main station generates the optimal transfer path based on topology analysis and issues instructions to the target ring network cabinet; and, a voltage monitoring module and a backup automatic transfer device configured in the user layer; wherein, the voltage monitoring module monitors the power supply data on the user side in real time; when the voltage on the user side drops beyond the threshold, the backup automatic transfer device is triggered to switch to the backup power supply; wherein, the priorities of the backup automatic transfer device, the backup protection device and the self-healing control of the secondary backbone layer master station are level I, level II and level III, respectively.

[0043] In specific application scenarios, the user layer triggers the backup automatic transfer device based on the monitoring results of the voltage monitoring module, with self-healing control priority level I. When the voltage monitoring module detects a voltage drop, the backup automatic transfer device switches to the backup power supply within 20ms to ensure uninterrupted power supply to users.

[0044] The backbone layer features local rapid self-healing, decoupled from the master station. Its self-healing control priority is Level II. It utilizes all-fiber current differential protection, comparing the current amplitude and phase at both ends of the line in real time to detect faults. It supports directional blocking logic, distinguishing between internal faults (such as a short circuit in switchyard KG1) and external faults (such as a fault in the upstream substation). A blocking signal is sent to the backup protection device via a dual-ring fiber optic channel to prevent false operation. Upon receiving the blocking signal from the optical differential protection device, the backup protection device initiates local rapid backup, disconnecting the faulty section switch, closing the backup power switch, and transferring the load via the ring main unit interconnection cable. The optical differential protection blocks the backup protection device within 25ms, and the backup protection device isolates the fault and transfers power within 50ms.

[0045] The secondary trunk layer is self-healed by the master station, with priority level III. The wireless communication module regularly uploads RMU load data (current, voltage, power, etc.) and, in the event of a fault, pushes real-time fault information (location, type, and waveform data). The master station generates the optimal power transfer path based on the load data and fault information reported by the wireless communication module and issues instructions to the target RMU. Upon receiving the fault information, the master station generates the optimal power transfer path and issues instructions within 3 seconds to restore power to the non-faulty section.

[0046] Comparing the centralized decision-making self-healing solution in the traditional solution with the hierarchical self-healing system in the embodiment of the present invention: In traditional centralized self-healing solutions, all data is uploaded to the master station, which puts a lot of pressure on bandwidth. Failure of the master station causes the self-healing function of the entire network to be deferred, resulting in congestion in the single-thread processing of the master station, and the recovery success rate is less than 80%.

[0047] In the hierarchical self-healing system of this embodiment, the user layer at priority level 1 is independently controlled, independent of the master station. This allows for independent operation even in the event of a communication interruption, avoiding the risk of a centralized system experiencing a complete paralysis. Wireless communication modules transmit data on demand, reducing network congestion. Hierarchical self-healing utilizes temporal decoupling (millisecond-level division of labor) and spatial decoupling (independent control of each layer), along with multi-level parallel processing, to achieve a user-side power outage duration of 20ms (resulting from the backup automatic switching device), a fault-segment recovery time of 3 seconds, and zero load loss across the entire network.

[0048] Furthermore, the master station generates the optimal transfer path based on topological analysis, including constructing an adjacency matrix with the ring main unit as the node and the line impedance as the weight; generating a candidate path set from the fault point to the backup power supply based on the Dijkstra algorithm; arranging the candidate path set in ascending order of impedance to obtain a candidate path set ; Based on the candidate path set Obtain a shortest impedance path; verify the shortest impedance path according to the following verification conditions: I rated ≥max(1.2I max , I fault ); If the shortest impedance path meets the verification condition, the shortest impedance path is the optimal transfer path; if not, the suboptimal path verification is started; wherein, I rated The real-time current carrying capacity of the line with the shortest impedance path; I max is the historical maximum load; I fault is the instantaneous load before the fault.

[0049] In specific application scenarios, the optimal transfer path generation solutions include: Construct an adjacency matrix: abstract all ring main units (RMUs) in the secondary trunk layer into graph nodes, numbered RMU1, RMU2,..., RMUn, and the line impedance weight Z is dynamically calculated based on the cable parameters; if RMUi is directly connected to RMUj, the adjacency matrix element A ij =Z ij Otherwise A ij = infinity, and use this to construct the adjacency matrix.

[0050] Generate a set of candidate paths from the fault point to the backup power source based on the Dijkstra algorithm: Input the fault point location RMU_k and the available backup power access point, initialize the shortest path from the fault point RMU_k to all nodes to infinity, set the RMU_k distance to 0, traverse all adjacent nodes, update the shortest path, and iterate until the shortest path to RMU_m is found to generate a candidate path set , arranged in ascending order of impedance. For example, P1: RMU_k → RMU_a → RMU_m (Z = 0.8Ω); P2: RMU_k → RMU_b → RMU_c → RMU_m (Z = 1.2Ω).

[0051] Path verification: traverse the candidate path set in ascending order of impedance, check whether the I rated of each line segment in the path meets the verification conditions, and the shortest path that meets the conditions for the first time is the optimal transfer path; if not, check the suboptimal paths (such as P2, P3) in turn until the optimal transfer path is found. If the optimal transfer path is not determined, cross-layer collaborative transfer is triggered.

[0052] In the hierarchical distribution network system described in this embodiment of the present invention, the master station generates the optimal transfer path based on topological analysis. A dynamic verification mechanism, which considers real-time current capacity, historical load, and pre-fault load, reduces the overload risk of the transfer path from 35% to below 2%, and increases the transfer success rate to 98%. This hierarchical system verification, from the shortest path to the next-best path, covers all scenarios, significantly reducing recovery time for complex faults.

[0053] Furthermore, during the switching of the standby automatic switching device, the operating instructions of the secondary trunk layer and the main trunk layer for the circuit are locked, which includes sending a locking signal to the secondary trunk layer ring network cabinet and the main trunk layer standby switching protection device 100μs before the switching starts; the locking signal is released after the switching is completed and the voltage is restored to the rated value ±5% for a set time; after the locking signal is released, a status recovery instruction is sent to the secondary trunk layer ring network cabinet for the secondary trunk layer master station to synchronously update the topology data.

[0054] In specific application scenarios, the backup automatic transfer device sends a lockout signal 100μs before switching, forcibly locking the operating permissions of the secondary-layer ring main unit and the backup protection device at the main layer. This completely prevents malfunctions caused by cross-layer command competition during switching (such as incorrect closing of the ring main unit or repeated power transfer of the backup protection device). The lockout signal persists until the voltage returns to ±5% of the rated value and remains stable for ≥500ms, ensuring that the power supply transient process completely subsides after switching and preventing secondary faults caused by voltage fluctuations (such as secondary disconnection of sensitive equipment). After the lockout is released, the backup automatic transfer device sends a status recovery command to the secondary-layer ring main unit, triggering the master station to update the topology data in real time, eliminating global information lags caused by local operations and ensuring that subsequent self-healing strategies are strictly consistent with the current network status. Through the strong timing control of "lock first, then recovery", the dual guarantees of rapid user-layer switching and cross-layer system stability are achieved, supporting millisecond-level fault isolation and second-level global data synchronization.

[0055] Example 2:

[0056] Reference Figure 4 As shown, the embodiment of the present invention discloses a multi-level coordinated load transfer control method, which is executed based on the hierarchical distribution network system. The load transfer control method includes: When the backbone layer detects a complete outage of the substation, load transfer is performed based on the backup protection device within the closed loop network structure; If the main layer fails to transfer power, the wireless communication module of the secondary layer is triggered to send a cross-layer transfer request to the master station. The master station generates a cross-layer transfer path based on topology analysis and controls the opening and closing of the secondary layer ring network cabinet according to the cross-layer transfer path. If the secondary main layer fails to transfer power, the backup automatic transfer device of the user layer is triggered to switch to the backup power supply based on the voltage monitoring result; wherein, a pre-switching instruction is sent to the backup automatic transfer device of the user layer to make it enter the backup power supply hot standby state; non-critical user loads are cut off, and the power supply capacity of critical users is prioritized.

[0057] In specific application scenarios, the multi-level collaborative load transfer control method realizes multi-level collaborative load transfer based on the strategies of backbone layer priority response, secondary layer global optimization and user layer ultimate disaster recovery when the substation is completely shut down. Specifically, when the substation is completely shut down, the backup protection device in the closed ring network structure is used to achieve millisecond-level on-site transfer (action time ≤ 50ms), avoiding dependence on upper-layer communication; if the backbone layer transfer fails, the master station generates a cross-layer transfer path based on the real-time topology, controls the opening and closing of the ring network cabinet through wireless communication, and restores power supply to non-fault areas in seconds; when the secondary layer fails, the user layer backup automatic transfer device switches to the backup power supply based on voltage monitoring, and gives priority to protecting key users (such as hospitals and data centers), with a non-critical load removal rate ≤ 20%, to achieve reasonable distribution of power supply capacity. Example 3:

[0058] Reference Figure 5 As shown, an embodiment of the present invention discloses a method for constructing a hierarchical distribution network, comprising: Divide the target area into multiple power supply grids based on urban planning and load density distribution, and further divide each power supply grid into several power supply units; Planning a backbone layer within the power supply grid, the backbone layer including a plurality of switch stations, the plurality of switch stations being connected by cables to form a closed ring network structure; Planning a secondary trunk layer within the power supply unit, the secondary trunk layer includes multiple segments formed by dividing the power supply line, each of the segments is interconnected through a ring main unit, and each of the segments is connected to a different trunk layer switch station, forming a single ring network or a double ring network structure; A user layer is deployed on the user side, the user layer includes a power distribution room, the power distribution room is equipped with a dual power access device, the dual power access device includes a first access point and a second access point, the first access point is connected to the secondary trunk layer ring network cabinet, and the second access point is connected to the trunk layer switch station; A hierarchical communication system is configured, including the main layer switch station equipped with an optical fiber communication terminal, which is directly connected to the substation dispatching system; the secondary layer ring network cabinet is equipped with a wireless communication gateway to interact with the master station; the user layer power distribution room is equipped with an Internet of Things terminal to communicate with the secondary layer ring network cabinet; A layered self-healing system is configured, including the installation of optical differential protection devices and backup protection devices in the main layer switch station; the integration of wireless communication modules in the secondary layer ring network cabinet; and the configuration of backup automatic switching devices and voltage monitoring modules in the user layer distribution room.

[0059] The method for constructing a layered distribution network described in the embodiment of the present invention has the same technical effects as the first embodiment and will not be described in detail here.

[0060] Based on the solutions of Example 1 and Example 3, the following is described based on a specific application scenario: Four switch stations, namely Yuelongtai, Wuyi West, Zhongxincheng, and Caihong, were selected in Linfen's central urban area to construct a "well"-shaped connection for the switch stations. The scope of this project is: the area bounded by Gulou West Street in the north, Binhe Road in the west, Changxing Middle Street in the east, and Xizhao Road in the south, which belongs to the urban grid. The planned area within the area is 0.749 square kilometers. According to the municipal control plan, the grid is positioned as a multifunctional urban complex, mainly for residential use, with commercial facilities. Comparison before and after the 10kV grid transformation Figure 6 and Figure 7 As shown, The total investment in the project is 5.73 million yuan, including: 3.7 km of cables, 16 sets of optical differential protection, and 4 sets of standby protection. Through the streamlining and optimization of existing lines, a group of crisscross main layer connections of "Yuelongtai Switch Station-May 1st West Switch Station-Rainbow Switch Station-Central City Switch Station" and 6 groups of secondary main layer standard single ring network connections are formed, releasing 7 intervals of the substation for other target grid construction, realizing the full stop and full rotation of the 4 switch stations with load, and the hierarchical and graded unitized management and control of regional loads.

[0061] Analysis of advantages and disadvantages of double ring network project: 1. The project is easy to implement. Relying on existing cable channels, ring main units are installed near network switch stations to achieve grid stratification and optimize the grid structure.

[0062] 2. More efficient fault restoration. Compared to traditional dual-ring network centralized distribution automation and self-healing methods, the "well"-shaped wiring backbone line can achieve protection and self-healing within 4 seconds through optical differential protection and backup protection.

[0063] 3. Line operation and maintenance are easy. Conventional optical differential and backup protection are used, eliminating the need for specialized equipment and requiring minimal expertise from maintenance personnel. Furthermore, operating conditions within the switchyard are favorable, allowing for comprehensive consideration of weather conditions such as flooding, high temperatures, and extreme cold to ensure stable operation of communications and protection equipment.

[0064] 4. More economical project investment. A single "well" network requires only 16 sets of optical differential protection and 4 sets of backup protection, and can solve the "blind adjustment" problem of community switch stations without telecontrol devices. Achieving the same level of self-healing performance requires a dual-ring network with distributed self-healing logic and distributed optical differential protection. This results in a higher investment cost and is therefore suitable for deployment in areas with extremely high load densities.

[0065] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, KG3, KG4-ROM, optical storage, etc.) containing computer-usable program code.

[0066] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0067] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0068] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0069] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A layered distribution network system, characterized by: include, A backbone layer includes three or four switch stations, all of which are connected by cables to form a closed ring network structure; wherein the total number of power supply paths in the closed ring network structure is equal to twice the number of the switch stations; The secondary trunk layer includes multiple segments formed by dividing the power supply lines. Each of the segments is interconnected through a ring network cabinet, and each of the segments is connected to a different trunk layer switch station to form a single ring network or a double ring network structure; The user layer includes a power distribution room, wherein the power distribution room is equipped with a dual power access device, wherein the dual power access device includes a first access point and a second access point, wherein the first access point is connected to the secondary trunk layer ring network cabinet, and the second access point is connected to the trunk layer switch station; Among them, data interaction is achieved between the backbone layer, secondary backbone layer and user layer through differentiated communication protocols.

2. The layered distribution network system according to claim 1, characterized in that: The four switch stations are respectively a first switch station, a second switch station, a third switch station and a fourth switch station, and the four switch stations are connected in a quadrilateral to form a closed ring network structure; The first switch station is connected to the second switch station via a first cable and to the fourth switch station via a second cable; The second switch station is connected to the third switch station via a third cable; The third switching station is connected to a fourth switching station via a fourth cable.

3. The layered distribution network system according to claim 2, characterized in that: The cross-sectional area of ​​the cable is ≥400 mm².

4. The layered distribution network system according to any one of claims 1 to 3, characterized in that: Also included is a layered self-healing system, the layered self-healing system comprising: An optical differential protection device and a backup protection device are configured in the backbone layer; wherein, after detecting a fault, the optical differential protection device sends a blocking signal to the backup protection device, and the backup protection device performs load transfer after receiving the blocking signal; A wireless communication module is configured in the secondary trunk layer. The wireless communication module communicates with the master station based on the LoRKG1WKG1N protocol or the 4G communication protocol, and uploads the load data and fault information of the ring main unit to the master station. The master station generates the optimal transfer path based on topology analysis and issues instructions to the target ring main unit; A voltage monitoring module and a backup automatic switching device are configured at the user layer; wherein the voltage monitoring module monitors the power supply data on the user side in real time; when the voltage on the user side drops beyond a threshold, the backup automatic switching device is triggered to switch to the backup power supply; Among them, the priorities of the self-healing control of the backup automatic switching device, the backup switching protection device and the secondary trunk layer master station are level I, level II and level III respectively.

5. The layered distribution network system according to claim 4, characterized in that: The master station generates the optimal transfer path based on topology analysis. include, Construct an adjacency matrix with the ring main unit as the node and the line impedance as the weight; Generate a set of candidate paths from the fault point to the backup power source based on the Dijkstra algorithm; Arrange the candidate path set in ascending order of impedance to obtain a candidate path set ; According to the candidate path set Obtain the shortest impedance path; Verify the shortest impedance path according to the following verification conditions: AND rated ≥max(1.2I max ,AND fault ); If the shortest impedance path meets the verification condition, the shortest impedance path is the optimal transfer path; if not, the suboptimal path verification is started; Among them, I rated The real-time current carrying capacity of the line with the shortest impedance path; I max is the historical maximum load; I fault is the instantaneous load before the fault.

6. The layered distribution network system according to claim 5, characterized in that: The master station generates the optimal transfer path based on topological analysis, and further includes traversing the candidate path set. If the optimal transfer path is not determined, cross-layer collaborative transfer is triggered.

7. The layered distribution network system according to claim 4, characterized in that: During the switching of the standby automatic switching device, the operation instructions of the secondary trunk layer and the main trunk layer for the voltage drop exceeding the threshold circuit are blocked, which include: 100μs before the switching starts, a blocking signal is sent to the secondary trunk layer ring network cabinet and the main trunk layer standby protection device; The blocking signal is released after the switching is completed and the voltage returns to the rated value ±5% for the set time; After the locking signal is released, a status recovery instruction is sent to the secondary trunk layer ring network cabinet for the secondary trunk layer master station to synchronously update the topology data.

8. The layered distribution network system according to claim 1, characterized in that: The backbone layer, secondary backbone layer and user layer implement data interaction through differentiated communication protocols, including: The backbone layer switch station is directly connected to the substation dispatching system based on a dual-ring optical fiber channel, and the channel switching delay of the dual-ring optical fiber channel is ≤10ms; The secondary dry layer ring network cabinet interacts with the master station based on the wireless communication gateway; The user layer interacts with the secondary trunk layer ring network cabinet based on the Internet of Things terminal.

9. A multi-level coordinated load transfer control method, characterized by: Based on the layered distribution network system according to any one of claims 1 to 8, the load transfer control method includes: When the backbone layer detects a complete outage of the substation, load transfer is performed based on the backup protection device within the closed loop network structure; If the main layer fails to transfer power, the wireless communication module of the secondary layer is triggered to send a cross-layer transfer request to the master station. The master station generates a cross-layer transfer path based on topology analysis and controls the opening and closing of the secondary layer ring network cabinet according to the cross-layer transfer path. If the secondary main layer fails to transfer power, the backup automatic transfer device of the user layer is triggered to switch to the backup power supply based on the voltage monitoring result; wherein, a pre-switching instruction is sent to the backup automatic transfer device of the user layer to make it enter the backup power supply hot standby state; non-critical user loads are cut off, and the power supply capacity of critical users is prioritized.

10. A method for constructing a hierarchical distribution network, characterized in that: include, Divide the target area into multiple power supply grids based on urban planning and load density distribution, and further divide each power supply grid into several power supply units; Planning a backbone layer within the power supply grid, the backbone layer including three or four switch stations, all of which are connected by cables to form a closed ring network structure; Planning a secondary trunk layer within the power supply unit, the secondary trunk layer includes multiple segments formed by dividing the power supply line, each of the segments is interconnected through a ring main unit, and each of the segments is connected to a different trunk layer switch station, forming a single ring network or a double ring network structure; A user layer is deployed on the user side, the user layer includes a power distribution room, the power distribution room is equipped with a dual power access device, the dual power access device includes a first access point and a second access point, the first access point is connected to the secondary trunk layer ring network cabinet, and the second access point is connected to the trunk layer switch station; A hierarchical communication system is configured, including the main layer switch station equipped with an optical fiber communication terminal, which is directly connected to the substation dispatching system; the secondary layer ring network cabinet is equipped with a wireless communication gateway to interact with the master station; the user layer power distribution room is equipped with an Internet of Things terminal to communicate with the secondary layer ring network cabinet; A layered self-healing system is configured, including the installation of optical differential protection devices and backup protection devices in the main layer switch station; the integration of wireless communication modules in the secondary layer ring network cabinet; and the configuration of backup automatic switching devices and voltage monitoring modules in the user layer distribution room.

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