Standardized Modeling Method and System for Medium and Low Voltage Distribution Network Topology in Distribution Internet of Things

Abstract

This invention discloses a standardized modeling method and system for medium- and low-voltage distribution network topology in a distribution Internet of Things (IoT). The method includes: constructing a medium- and low-voltage distribution network topology connection model and models of medium- and low-voltage distribution network equipment participating in the topology; improving class inheritance and association relationships by extending existing class attribute variables or redesigning classes for subsequent construction of cloud-side low-voltage topology phase-by-phase connection models, edge-side local topology connection models, and topology information interaction; constructing a cloud-side low-voltage topology phase-by-phase connection model for global topology analysis on the cloud side; constructing an edge-side local topology connection model for local topology correction on the edge side; and establishing a cloud-edge collaborative distribution network topology information interaction model for topology information interaction between the cloud and the edge. This invention comprehensively considers the actual operating characteristics of the distribution network and cloud-edge collaborative interaction, realizing the establishment and analysis of medium- and low-voltage distribution network topology models for the distribution IoT, and can be effectively applied to the construction of actual distribution IoT.

Description

Technical Field

[0001] This invention belongs to the field of power distribution network technology and relates to a method and system for standardized modeling of the topology of medium and low voltage power distribution networks in the Internet of Things for power distribution. Background Technology

[0002] With the continuous advancement of intelligent power distribution network construction, guided by the application needs of the power distribution and consumption sector, the construction of the power distribution Internet of Things (IoT) integrates advanced information and communication technologies such as big data, cloud computing, IoT, mobile internet, and artificial intelligence into all aspects of the power distribution side, constructing a "cloud, network, edge, and terminal" architecture. Power distribution network topology is a complete description of power distribution network equipment, lines, and their connections, and is a crucial foundation for realizing intelligent applications in power distribution networks. Therefore, researching standardized modeling techniques for medium- and low-voltage power distribution network topology for the power distribution IoT has significant theoretical and practical value.

[0003] As the end point of the power system, the distribution network is characterized by its complex structure, vast network size, multiple branches, and numerous connections. With the advancement of the distribution Internet of Things (IoT) construction, building a unified distribution network information model for the IoT has become a fundamental step. Currently, research on distribution and consumption information integration technology both domestically and internationally is mainly based on the information exchange standards of the Distribution Information Modeling (CIM). However, research on how to establish a low-voltage distribution network topology model and drive the development of upper-layer applications for the distribution IoT through a unified information model is still in its early stages.

[0004] 1) Power distribution and utilization information integration technology

[0005] The International Electrotechnical Commission (IEC) has proposed two major standards, IEC 61970 and IEC 61968. The Common Information Model (CIM) is a crucial foundation of this standard framework. Various applications will use CIM as the standard to describe the power grid and exchange information based on it. In advanced applications of the CIM interface, topology analysis of the power network is one of the most fundamental aspects.

[0006] 2) Research and application of information models in the power distribution field

[0007] While some literature has widely applied CIM models to various application areas of power systems with good results, the application of CIM and its extended models in distribution systems is still relatively immature. The State Grid Corporation of China has developed SG-CIM based on these two major series of standards. Some scholars have proposed CIM-based distribution network models and used them for three-phase power flow calculations in distribution networks. Furthermore, some scholars have proposed CIM models for each generation unit of a microgrid and described the overall microgrid model using XML.

[0008] The current method for constructing CIM models of power distribution networks is as follows:

[0009] Step 1: Perform an overall analysis of the distribution network being modeled, clarify the topological relationships of the entire network, and typically divide the network into substations as the basic units to establish a topological framework;

[0010] Step 2: Classify the distribution network equipment, extract necessary parameters, and provide a detailed description;

[0011] Step 3: Use the device container class of the CIM model to connect the various devices on the distribution network to form the entire distribution network model with substations as units.

[0012] While the above research and applications can describe the topology connection model of the distribution network and complete basic application analysis, they still have the following limitations:

[0013] 1) Due to the incomplete research on the topology standardization model of low-voltage distribution networks and the complexity of equipment and information models, the existing SG-CIM model has not been extended to the application of topology models in low-voltage distribution networks.

[0014] 2) In the construction of distribution Internet of Things, the cloud-side model lacks models of various new intelligent power distribution terminals such as distribution transformer monitoring terminals and line monitoring terminals, and the edge-side model lacks object models and cloud-edge interaction models that conform to edge characteristics. Therefore, there is a lack of unified standard models in terms of cloud-edge interaction, topology change analysis, and information transmission.

[0015] 3) Since the local topology model information on the edge needs to be transmitted to the cloud side through unified standards and protocols to realize the topology modeling of the entire low-voltage distribution network, there is currently a lack of methods and protocols for defining topology interaction communication between the cloud and the edge. Summary of the Invention

[0016] This invention addresses the current lack of suitable low- and medium-voltage power grid topology models for distribution IoT by providing a standardized modeling method and system for low- and medium-voltage distribution network topology. It models low- and medium-voltage distribution network equipment, constructs a cloud-side low-voltage topology phase-by-phase connection model and a side-side local topology connection model for distribution IoT, and comprehensively considers the actual operating characteristics of the distribution network and cloud-side collaborative interaction. This enables the establishment and analysis of low- and medium-voltage distribution network topology models for distribution IoT, and can be effectively applied to the construction of actual distribution IoT.

[0017] Therefore, one technical solution adopted by the present invention is: a method for standardized modeling of the topology of medium and low voltage distribution networks in the distribution Internet of Things, which includes:

[0018] Step 1: Construct a medium- and low-voltage distribution network topology connection model and a medium- and low-voltage distribution network equipment model participating in the topology. Improve the inheritance and association relationships of classes by expanding the original class attribute variables or redesigning the classes. This will be used for the subsequent construction of the cloud-side low-voltage topology phase connection model, the edge-side local topology connection model, and topology information interaction.

[0019] Step 2: Construct a phase-separated connection model of the low-voltage topology on the cloud side and perform global topology analysis on the cloud side;

[0020] Step 3: Construct a local topology connection model for the edges and perform local topology corrections on the edges;

[0021] Step 4: Establish a cloud-edge collaborative power distribution network topology information interaction model and conduct cloud-edge topology information interaction.

[0022] Existing distribution network topology models and their application analyses have certain limitations in both low-voltage distribution networks and distribution IoT topology models. In particular, the State Grid SG-CIM model, based on the IEC 61970 / 61968 standards, remains incomplete in its application to low-voltage distribution network topology models. Most application research focuses on basic distribution network analysis, such as power flow calculation, network loss calculation, and topology modeling, while lacking models for intelligent distribution and consumption terminals in distribution IoT cloud-edge topology models, and there is no unified cloud-edge information interaction model.

[0023] This invention addresses the lack of suitable low- and medium-voltage power grid topology models for distribution IoT. It models low- and medium-voltage distribution network equipment, constructs a cloud-side topology extension phase connection model and a side-side local topology connection model for distribution IoT, and comprehensively considers the actual operation characteristics of the distribution network and cloud-side collaborative interaction. This enables the establishment and analysis of low- and medium-voltage distribution network topology models for distribution IoT, which can be effectively applied to the actual construction of distribution IoT, forming a unified topology connection analysis model.

[0024] Further, in step 1, the content of the medium and low voltage distribution network topology connection model is as follows: The CIM model describes the topology connection relationship of the power grid mainly in the following five categories: conductive devices, terminals, connection nodes, topology nodes, and topology islands; each conductive device has 0, 1, or more terminals, which connect the conductive device to other components; at connection nodes, the terminals of the conductive device are connected through zero impedance; measurements on a connection node are applicable to all terminals it contains; a topology node refers to a group of connection nodes connected together by closed switches in the current network state, mainly provided for network analysis applications; a topology island refers to an electrically connected subset of the network.

[0025] Furthermore, in step 1, the steps for constructing the medium- and low-voltage distribution network equipment model are as follows:

[0026] To address the common three-phase imbalance or single-phase operation issues in the actual operation of conductive equipment in medium and low voltage distribution networks, an extended class, Terminal, is used to uniquely identify the phase code of the connected conductive equipment; and a design class, Phase, is used to describe the phase of switching equipment, conductor segments, loads, and parallel compensators.

[0027] The PowerTransformer class, which inherits from the ConductingEquipment class, describes three-phase unbalanced networks and directly participates in topology modeling. The PowerTransformerEnd class, which inherits from the TransformerEnd class, describes the winding parameters of a three-phase transformer and is simply associated with the PowerTransformer class. The TransformerTankEnd class, which inherits from the TransformerEnd class, is designed so that the transformer has one or more TransformerTanks and describes the phase codes of the two TransformerTankEnds for each single phase.

[0028] To address the lack of a smart power distribution terminal model for the Internet of Things (IoT) in power distribution, the Breaker class is extended to include low-voltage residual current circuit breakers, smart residual current circuit breakers, smart molded case circuit breakers, and smart miniature circuit breakers. These classes inherit from the ProtectedSwitch class, and their extended attributes describe the JP cabinet or cable branch box ID to which the circuit breaker points, as well as the phase ID of each phase. The LowVoltageTeiminalUnit class is designed to include power distribution monitoring devices, feeder monitoring devices, and smart meters.

[0029] Furthermore, in step 2, the characteristics of the low-voltage distribution network topology and its operating status are considered to determine the dynamic change process of the topology under the SG-CIM model, and to establish a cloud-side low-voltage topology phase connection model under the SG-CIM model extension.

[0030] Furthermore, in step 2, the cloud-side low-voltage topology phase connection model, when the cloud-side low-voltage distribution network experiences a three-phase unbalanced operation in actual operation, when merging connection nodes, it is first necessary to confirm that the phases variable values ​​of the terminals around the connection node are the same, and then form topology nodes, divide subsystems, and form topology islands for analysis.

[0031] Furthermore, the specific process of performing global topology analysis on the cloud-side low-voltage topology phase connection model is as follows:

[0032] First, select the untraversed feeder connection node (ConnectivityNode) as the traversal node. Determine if the phase codes of the surrounding terminals are the same; otherwise, correct the incorrect connection node. Then, use a depth-first search method to traverse the connection node. Determine if the node already belongs to a topology node. If yes, continue using the depth-first search method to traverse the topology node. If no, start a single topology traversal from this node. Then, assign all traversed connection nodes to a new topology node. Determine if the new topology node is still connected to the new connection node. If yes, return to the step of using the depth-first search method to traverse the connection node. If no, continue to determine if there are any untraversed feeders. If yes, return to the initial step and start traversing the new feeder connection node again. If no, the cloud-side topology information has been obtained.

[0033] Furthermore, in step 3, the edge-side local topology connection model considers that the state changes of switching components often affect the topology structure in the edge-side local topology. Based on the completion of the global topology analysis on the cloud side, only the topology of the area involved in the displacement is locally modified to achieve rapid topology analysis.

[0034] Furthermore, in step 3, the specific working process of the side-side local topology connection model is as follows: When the side-side local topology switch element changes from closed to open, take the connection nodes at both ends of the switch and determine whether the two connection nodes belong to the same topology node. If not, merge the two topology nodes; if so, do not process them. When the side-side local topology switch element changes from open to closed, take the connection nodes on one side of the switch element and traverse them. Determine whether the connection nodes on the opposite side of the switch have been traversed. If so, stop traversing and do not process them. If not, form a new topology node and assign all visited topology nodes to the new topology node, and delete the visited topology nodes from the original topology nodes. Finally, determine whether each switch element has been processed. If not, return to the initial processing step; if so, end the processing.

[0035] Furthermore, the aforementioned power distribution network topology information interaction model includes a cloud master station information model and an edge node information model; the cloud master station information model includes primary and secondary equipment information, configuration information, power grid topology information, measurement information, and service information, while the edge node information model includes equipment topology information, measurement information, and equipment management information; the edge node information model transmits information to the cloud master station information model in the CIM model format using the MQTT protocol.

[0036] Another technical solution adopted in this invention is: a standardized modeling system for the topology of medium and low voltage distribution networks in the Internet of Things for distribution, which includes:

[0037] Construction unit of medium and low voltage distribution network topology connection model and equipment model: Construct medium and low voltage distribution network topology connection model and medium and low voltage distribution network equipment model participating in the topology. Improve the inheritance and association relationship of classes by expanding the original class attribute variables or redesigning classes. Used for the subsequent construction of cloud-side low voltage topology phase connection model, edge-side local topology connection model and topology information interaction.

[0038] Building unit of cloud-side low-voltage topology phase connection model: Construct cloud-side low-voltage topology phase connection model and perform global topology analysis on the cloud side;

[0039] Construction unit of edge-side local topology connection model: Construct edge-side local topology connection model and perform local topology correction on the edges;

[0040] Topology Information Interaction Unit: Establishes a cloud-edge collaborative distribution network topology information interaction model to conduct cloud-edge topology information interaction.

[0041] The beneficial effects of this invention are as follows: Addressing the incomplete standardization of medium and low voltage distribution network topology models in the SG-CIM model, this invention proposes a cloud-side low voltage distribution network topology modeling method based on the SG-CIM model extension, a local topology modeling method oriented towards the edge side, and a topology interaction model and method oriented towards cloud-edge collaboration. It establishes a medium and low voltage distribution network topology model adapted to the distribution Internet of Things (IoT), which forms the basis for realizing "plug-and-play" identification, interaction, explanation, and integration of underlying information descriptions for devices, achieving comprehensive integration of business flows and data flows across various systems. Attached Figure Description

[0042] Figure 1 This is a structural diagram of the low-voltage distribution network topology connection model in this invention;

[0043] Figure 2 This is a flowchart of the row global topology analysis of the cloud-side low-voltage topology phase connection model of the present invention;

[0044] Figure 3 This is a flowchart illustrating the local topology correction of the edges in the edge-side local topology connection model of the present invention. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0046] Example 1

[0047] This embodiment provides a method for standardized modeling of the topology of medium and low voltage distribution networks in the Internet of Things (IoT) for distribution networks. The steps are as follows:

[0048] Step 1: Construct a medium- and low-voltage distribution network topology connection model and a medium- and low-voltage distribution network equipment model participating in the topology. Improve the inheritance and association relationships of the classes by expanding the original class attribute variables or redesigning the classes. This will be used for the subsequent construction of the cloud-side low-voltage topology phase connection model, the edge-side local topology connection model, and topology information interaction.

[0049] The CIM model lacks models of distribution IoT smart terminals and low-voltage distribution network topology extension phase models. Therefore, to fully describe the topology model of medium and low voltage distribution networks, it is necessary to first construct a medium and low voltage distribution network topology connection model and models of medium and low voltage distribution network equipment participating in the topology.

[0050] Step 1.1: Construct a topology connection model for medium and low voltage distribution networks

[0051] The content of the medium and low voltage distribution network topology connection model is as follows: The CIM model describes the network topology connection relationship mainly involving the following five categories: Conducting Equipment, Terminal, Connectivity Node, Topological Node, and Topological Island. Each conducting equipment has 0, 1, or multiple terminals, which connect the conducting equipment to other components; at the connecting node, the terminals of the conducting equipment are connected through zero impedance; measurements on a connecting node are applicable to all terminals it contains; a topological node refers to a group of connecting nodes connected together by closed switches in the current network state, mainly provided for network analysis applications; a topological island refers to an electrically connected subset of the network. Figure 1 This is a structural diagram of a medium- and low-voltage power distribution network topology connection model.

[0052] Step 1.2: Construct a model of medium and low voltage power distribution network equipment

[0053] The steps for constructing a model of medium- and low-voltage power distribution network equipment are as follows:

[0054] In actual operation, conductive equipment in medium and low voltage distribution networks commonly experiences three-phase imbalance or single-phase operation. Therefore, this invention extends the Terminal class to uniquely identify the phase code of the connected conductive equipment. The phase enumeration list is shown in Table 1. A Phase class, a phase-separated phase model, is designed to describe the phase-separated phases of switching equipment, conductor segments, loads, and parallel compensators. The attributes of each extended class are shown in Tables 2 and 3.

[0055] Table 1. Phase Encoding Enumeration List

[0056]

[0057] Table 2 Attributes of Terminal

[0058] name property Data types TerminalID TerminalID string phases PhaseCode string

[0059] Table 3. Properties of Phases

[0060] name property Data types PhaseID PhaseID string PhasesKind SinglePhase Kind string

[0061] This invention extends the class PowerTransformer, which inherits from the class ConductingEquipment, to describe three-phase unbalanced networks and directly participate in topology modeling. It also extends the class PowerTransformerEnd, which describes the winding parameters of a three-phase transformer, inheriting from the class TransformerEnd and simply associated with the class PowerTransformer. Furthermore, it designs the class TransformerTankEnd, which inherits from TransformerEnd. A transformer has one or more TransformerTanks, describing the phase codes of the two TransformerTankEnds for each single phase. The attributes of the various extended classes related to distribution transformers are shown in Tables 4 to 6.

[0062] Table 4 Properties of PowerTransformer

[0063] name property Data types vectorGroup vectorGroup string[0..1]

[0064] Table 5 Properties of Transformer Winding PowerTransformerEnd

[0065] name property Data types b Susceptance string b0 Susceptance string g Conductance string g0 Conductance string PowerTransformerID PowerTransformerID string TerminalID TerminalID string

[0066] Table 6 Properties of TransformerTankEnd Windings

[0067] name property Data types phases PhaseCode string

[0068] To address the lack of a smart power distribution terminal model for the Internet of Things (IoT) in power distribution, this invention extends the `Breaker` class, including low-voltage residual current circuit breakers (RCCBs), smart residual current circuit breakers (RCCBs), smart molded case circuit breakers (MCCBs), and smart miniature circuit breakers (MCBs), which inherit from the `ProtectedSwitch` class. The extended attributes describe the JP cabinet or cable branch box ID and the phase ID of the circuit breaker. A `LowVoltageTeiminalUnit` class is also designed, including low-voltage monitoring terminals such as distribution monitoring units (DTUs), feeder monitoring units (FTUs), and smart meters. The attributes of each extended class are shown in Tables 7 and 8.

[0069] Table 7 Attributes of the Smart Circuit Breaker

[0070] name property Data types BreakerID BreakerID string CabinetID CabinetID string PhasesKind SinglePhase Kind string

[0071] Table 8. Attributes of Low Voltage Terminal Unit

[0072]

[0073] Step 2: Construct a phase-separated connection model of the low-voltage topology on the cloud side and perform global topology analysis on the cloud side.

[0074] "Cloud" refers to the cloud-based master station platform. All feeders originating from the same master station are treated as a single object, and newly input CIM power grid data is processed to form a topology diagram of the entire network. Considering the characteristics of the low-voltage distribution network topology and its operational status, the dynamic change process of the topology under the SG-CIM model is determined, and a cloud-side low-voltage topology phase-by-phase connection model is established under the extended SG-CIM model.

[0075] When a three-phase unbalanced operation occurs in the cloud-side low-voltage distribution network during actual operation, when merging connection nodes, it is necessary to first confirm that the phases variable values ​​of the terminals around the connection node are the same, and then form topological nodes, divide subsystems, and form topological islands for analysis.

[0076] The specific process of performing global topology analysis on the above cloud-side low-voltage topology phase connection model is as follows: Figure 2 As shown:

[0077] First, select the untraversed feeder connection node (ConnectivityNode) as the traversal node. Determine if the phase codes of the surrounding terminals are the same; otherwise, correct the incorrect connection node. Then, use a depth-first search method to traverse the connection node. Determine if the node already belongs to a topology node. If yes, continue using the depth-first search method to traverse the topology node. If no, start a single topology traversal from this node. Then, assign all traversed connection nodes to a new topology node. Determine if the new topology node is still connected to the new connection node. If yes, return to the step of using the depth-first search method to traverse the connection node. If no, continue to determine if there are any untraversed feeders. If yes, return to the initial step and start traversing the new feeder connection node again. If no, the cloud-side topology information has been obtained.

[0078] Step 3: Construct a local topology connection model for the edges and perform local topology corrections on the edges.

[0079] The "edge" refers to the user terminal side. In practical applications, switching components often change position. This alters the system's topology, but only in a localized area. Based on the completed global topology analysis on the cloud side, there's no need to reanalyze the entire network topology; instead, only the area affected by the changing component needs topology correction for rapid topology analysis.

[0080] The specific process of local correction of the edge-side local topology connection model is as follows: Figure 3 As shown: When a local topology switch element on the side changes from closed to open, the connection nodes at both ends of the switch are taken, and it is determined whether the two connection nodes belong to the same topology node. If not, the two topology nodes are merged; if so, no processing is performed. When a local topology switch element on the side changes from open to closed, the connection nodes on one side of the switch element are traversed, and it is determined whether the connection nodes on the opposite side of the switch are traversed. If so, the traversal stops and no processing is performed; if not, a new topology node is formed, and all visited topology nodes need to be assigned to the new topology node, and the visited topology nodes are deleted from the original topology node. Finally, it is determined whether each switch element has been processed. If not, the process returns to the initial processing step; if so, the processing ends.

[0081] Step 4: Establish a cloud-edge collaborative power distribution network topology information interaction model and conduct cloud-edge topology information interaction.

[0082] The cloud-edge collaborative remote communication protocol adopts standard device management, configuration, command, and data reporting interfaces. The aforementioned distribution network topology information interaction model includes a cloud master station information model and an edge node information model. The cloud master station information model includes primary and secondary equipment information, configuration information, power grid topology information, measurement information, and service information. The edge node information model includes equipment topology information, measurement information, and equipment management information. The edge node information model transmits information to the cloud master station information model according to the CIM model format using the MQTT protocol, which can meet the requirements of rapid development, plug-and-play functionality, and efficient transmission in the design and data exchange of the distribution IoT platform.

[0083] Example 2

[0084] This embodiment provides a standardized modeling system for the topology of medium and low voltage distribution networks in the Internet of Things for distribution. It consists of a construction unit for the topology connection model and equipment model of medium and low voltage distribution networks, a construction unit for the phase connection model of cloud-side low voltage topology, a construction unit for the local topology connection model of edge side, and a topology information interaction unit.

[0085] Construction unit of medium and low voltage distribution network topology connection model and equipment model: Construct medium and low voltage distribution network topology connection model and medium and low voltage distribution network equipment model participating in the topology. Improve the inheritance and association relationship of classes by expanding the original class attribute variables or redesigning classes. Used for the subsequent construction of cloud-side low voltage topology phase connection model, edge-side local topology connection model and topology information interaction.

[0086] Building unit of cloud-side low-voltage topology phase connection model: Construct cloud-side low-voltage topology phase connection model and perform global topology analysis on the cloud side;

[0087] Construction unit of edge-side local topology connection model: Construct edge-side local topology connection model and perform local topology correction on the edges;

[0088] Topology Information Interaction Unit: Establishes a cloud-edge collaborative distribution network topology information interaction model to conduct cloud-edge topology information interaction.

[0089] In the construction unit of the medium and low voltage distribution network topology connection model and equipment model, the content of the medium and low voltage distribution network topology connection model is as follows: The description of the power grid topology connection relationship in the CIM model mainly involves the following five categories: conductive devices, terminals, connection nodes, topology nodes, and topology islands; each conductive device has 0, 1, or more terminals, which connect the conductive device to other components; at connection nodes, the terminals of the conductive device are connected through zero impedance; the measurement on a connection node applies to all the terminals it contains; a topology node refers to a group of connection nodes connected together by closed switches in the current network state, mainly provided for network analysis applications; a topology island refers to an electrically connected subset of the network.

[0090] The steps for constructing the medium- and low-voltage distribution network equipment model in the aforementioned construction unit for the medium- and low-voltage distribution network topology connection model and equipment model are as follows:

[0091] To address the common three-phase imbalance or single-phase operation issues in the actual operation of conductive equipment in medium and low voltage distribution networks, an extended class, Terminal, is used to uniquely identify the phase code of the connected conductive equipment; and a design class, Phase, is used to describe the phase of switching equipment, conductor segments, loads, and parallel compensators.

[0092] The PowerTransformer class, which inherits from the ConductingEquipment class, describes three-phase unbalanced networks and directly participates in topology modeling. The PowerTransformerEnd class, which inherits from the TransformerEnd class, describes the winding parameters of a three-phase transformer and is simply associated with the PowerTransformer class. The TransformerTankEnd class, which inherits from the TransformerEnd class, is designed so that the transformer has one or more TransformerTanks and describes the phase codes of the two TransformerTankEnds for each single phase.

[0093] To address the lack of a smart power distribution terminal model for the Internet of Things (IoT) in power distribution, the Breaker class is extended to include low-voltage residual current circuit breakers, smart residual current circuit breakers, smart molded case circuit breakers, and smart miniature circuit breakers. These classes inherit from the ProtectedSwitch class, and their extended attributes describe the JP cabinet or cable branch box ID to which the circuit breaker points, as well as the phase ID of each phase. The LowVoltageTeiminalUnit class is designed to include power distribution monitoring devices, feeder monitoring devices, and smart meters.

[0094] In the construction unit of the cloud-side low-voltage topology phase connection model, the characteristics of the low-voltage distribution network topology structure and the characteristics of the operating state are considered, so as to determine the dynamic change process of the topology structure under the SG-CIM model and establish the cloud-side low-voltage topology phase connection model under the extension of the SG-CIM model.

[0095] The cloud-side low-voltage topology phase connection model, when the cloud-side low-voltage distribution network experiences a three-phase unbalanced operation in actual operation, when merging connection nodes, firstly, it is confirmed that the phases variable values ​​of the terminals around the connection node are the same, and then topology nodes are formed, subsystems are divided, and topology islands are formed for analysis.

[0096] The specific process of performing global topology analysis on the cloud-side low-voltage topology phase connection model is as follows:

[0097] First, select the untraversed feeder connection node (ConnectivityNode) as the traversal node. Determine if the phase codes of the surrounding terminals are the same; otherwise, correct the incorrect connection node. Then, use a depth-first search method to traverse the connection node. Determine if the node already belongs to a topology node. If yes, continue using the depth-first search method to traverse the topology node. If no, start a single topology traversal from this node. Then, assign all traversed connection nodes to a new topology node. Determine if the new topology node is still connected to the new connection node. If yes, return to the step of using the depth-first search method to traverse the connection node. If no, continue to determine if there are any untraversed feeders. If yes, return to the initial step and start traversing the new feeder connection node again. If no, the cloud-side topology information has been obtained.

[0098] In the construction unit of the edge-side local topology connection model, the edge-side local topology connection model considers that the state changes of switching components often affect the topology structure in the edge-side local topology. Based on the completion of the global topology analysis on the cloud side, it only performs local correction on the topology of the area involved in the displacement, so as to achieve rapid topology analysis.

[0099] The specific process of local modification of the edge-side local topology connection model is as follows: When the edge-side local topology switch element changes from closed to open, take the connection nodes at both ends of the switch and determine whether the two connection nodes belong to the same topology node. If not, merge the two topology nodes; if so, do not process. When the edge-side local topology switch element changes from open to closed, take the connection nodes on one side of the switch element and traverse them. Determine whether the connection nodes on the opposite side of the switch have been traversed. If so, stop traversing and do not process. If not, form a new topology node and assign all visited topology nodes to the new topology node, and delete the visited topology nodes from the original topology node. Finally, determine whether each switch element has been processed. If not, return to the initial processing step; if so, end the processing.

[0100] In the aforementioned topology information interaction unit, the distribution network topology information interaction model includes a cloud master station information model and an edge node information model. The cloud master station information model includes primary and secondary equipment information, configuration information, power grid topology information, measurement information, and service information. The edge node information model includes equipment topology information, measurement information, and equipment management information. The edge node information model transmits information to the cloud master station information model in the CIM model format using the MQTT protocol.

[0101] The above are merely embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of the present invention.

Claims

1. A method for standardized modeling of medium- and low-voltage distribution network topology in the distribution Internet of Things (IoT), characterized in that, include: Step 1: Construct a medium- and low-voltage distribution network topology connection model and a medium- and low-voltage distribution network equipment model participating in the topology. Improve the inheritance and association relationships of classes by expanding the original class attribute variables or redesigning the classes. This will be used for the subsequent construction of the cloud-side low-voltage topology phase connection model, the edge-side local topology connection model, and topology information interaction. Step 2: Construct a phase-separated connection model of the low-voltage topology on the cloud side and perform global topology analysis on the cloud side; Step 3: Construct a local topology connection model for the edges and perform local topology corrections on the edges; Step 4: Establish a cloud-edge collaborative distribution network topology information interaction model and conduct cloud-edge topology information interaction; In step 2, the characteristics of the low-voltage distribution network topology and its operating status are considered to determine the dynamic change process of the topology under the SG-CIM model and to establish a cloud-side low-voltage topology phase connection model under the SG-CIM model extension. Step 3, the edge-side local topology connection model, considers that the state changes of switching components often affect the topology structure in the edge-side local topology. Based on the completion of the cloud-side global topology analysis, only the topology of the area involved in the displacement is locally modified to achieve rapid topology analysis. In step 3, the specific process of local modification of the edge-side local topology connection model is as follows: When the edge-side local topology switch element changes from closed to open, take the connection nodes at both ends of the switch and determine whether the two connection nodes belong to the same topology node. If not, merge the two topology nodes; if so, do not process them. When the edge-side local topology switch element changes from open to closed, take the connection nodes on one side of the switch element and traverse them. Determine whether the connection nodes on the opposite side of the switch have been traversed. If so, stop traversing and do not process them. If not, form a new topology node and assign all visited topology nodes to the new topology node, and delete the visited topology nodes from the original topology nodes. Finally, determine whether each switch element has been processed. If not, return to the initial processing step; if so, end the processing.

2. The method for standardized modeling of medium and low voltage distribution network topology in the distribution Internet of Things according to claim 1, characterized in that, In step 1, the content of the medium and low voltage distribution network topology connection model is as follows: The CIM model describes the topology connection relationship of the power grid mainly in the following five categories: conductive devices, terminals, connection nodes, topology nodes, and topology islands; each conductive device has 0, 1, or more terminals, which connect the conductive device to other components; at connection nodes, the terminals of the conductive device are connected through zero impedance; measurements on a connection node are applicable to all terminals it contains; a topology node refers to a group of connection nodes connected together by closed switches in the current network state, mainly provided for network analysis applications; a topology island refers to an electrically connected subset of the network.

3. The method for standardized modeling of medium and low voltage distribution network topology in the distribution Internet of Things according to claim 1, characterized in that, In step 1, the steps for constructing the medium- and low-voltage distribution network equipment model are as follows: To address the common three-phase imbalance or single-phase operation issues in the actual operation of conductive equipment in medium and low voltage distribution networks, an extended class, Terminal, is used to uniquely identify the phase code of the connected conductive equipment; and a design class, Phase, is used to describe the phase of switching equipment, conductor segments, loads, and parallel compensators. The PowerTransformer class, which inherits from the ConductingEquipment class, describes three-phase unbalanced networks and directly participates in topology modeling. The PowerTransformerEnd class, which inherits from the TransformerEnd class, describes the winding parameters of a three-phase transformer and is simply associated with the PowerTransformer class. The TransformerTankEnd class, which inherits from the TransformerEnd class, is designed so that the transformer has one or more TransformerTanks and describes the phase codes of the two TransformerTankEnds for each single phase. To address the lack of a smart power distribution terminal model for the Internet of Things (IoT) in power distribution, the Breaker class is extended to include low-voltage residual current circuit breakers, smart residual current circuit breakers, smart molded case circuit breakers, and smart miniature circuit breakers. These classes inherit from the ProtectedSwitch class, and their extended attributes describe the JP cabinet or cable branch box ID to which the circuit breaker points, as well as the phase ID of each phase. The LowVoltageTeiminalUnit class is designed to include power distribution monitoring devices, feeder monitoring devices, and smart meters.

4. The method for standardized modeling of medium and low voltage distribution network topology in the distribution Internet of Things according to claim 1, characterized in that, Step 2, Cloud-side Low-voltage Topology Phase Connection Model: When the cloud-side low-voltage distribution network experiences three-phase unbalanced operation in actual operation, when merging connection nodes, it is necessary to first confirm that the phases variable values ​​of the terminals around the connection node are the same, and then form topology nodes, divide subsystems, and form topology islands for analysis.

5. The method for standardized modeling of medium and low voltage distribution network topology in the distribution Internet of Things according to claim 4, characterized in that, The specific process of performing global topology analysis on the cloud-side low-voltage topology phase connection model is as follows: First, select the untraversed feeder connection node (ConnectivityNode) as the traversal node. Determine if the phase codes of the surrounding terminals are the same; otherwise, correct the incorrect connection node. Then, use a depth-first search method to traverse the connection node. Determine if the node already belongs to a topology node. If yes, continue using the depth-first search method to traverse the topology node. If no, start a single topology traversal from this node. Then, assign all traversed connection nodes to a new topology node. Determine if the new topology node is still connected to the new connection node. If yes, return to the step of using the depth-first search method to traverse the connection node. If no, continue to determine if there are any untraversed feeders. If yes, return to the initial step and start traversing the new feeder connection node again. If no, the cloud-side topology information has been obtained.

6. The method for standardized modeling of medium and low voltage distribution network topology in the distribution Internet of Things according to claim 1, characterized in that, The aforementioned power distribution network topology information interaction model includes a cloud master station information model and an edge node information model; the cloud master station information model includes primary and secondary equipment information, configuration information, power grid topology information, measurement information, and service information, while the edge node information model includes equipment topology information, measurement information, and equipment management information; The edge node information model transmits information to the cloud master station information model in the CIM model format using the MQTT protocol.

7. A standardized modeling system for the topology of medium- and low-voltage distribution networks in a distribution Internet of Things (IoT), used to implement the standardized modeling method for the topology of medium- and low-voltage distribution networks in a distribution IoT as described in any one of claims 1-6, characterized in that, include: Construction unit of medium and low voltage distribution network topology connection model and equipment model: Construct medium and low voltage distribution network topology connection model and medium and low voltage distribution network equipment model participating in the topology. Improve the inheritance and association relationship of classes by expanding the original class attribute variables or redesigning classes. Used for the subsequent construction of cloud-side low voltage topology phase connection model, edge-side local topology connection model and topology information interaction. Building unit of cloud-side low-voltage topology phase connection model: Construct cloud-side low-voltage topology phase connection model and perform global topology analysis on the cloud side; Construction unit of edge-side local topology connection model: Construct edge-side local topology connection model and perform local topology correction on the edges; Topology Information Interaction Unit: Establishes a cloud-edge collaborative distribution network topology information interaction model to conduct cloud-edge topology information interaction.

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