Power distribution network modeling and information exchange method based on Internet of Things technology

Abstract

The invention discloses a power distribution network modeling and information exchange method based on the Internet of Things technology. The method comprises the following steps: establishing intelligent equipment and a distributed resource information model based on IEC61850; according to an IECCIM expansion principle, carrying out CIM model expansion of distributed resources on a master station side; the IECCIM model and the IEC61850 model are analyzed under certain conditions, a fusion scheme is formulated, and a fusion model is constructed under the principle that modification of an existing standard is reduced and description of the models by the two standards tends to be consistent; mapping data of the distributed energy information model and the power system information model according to the fusion model to realize data interaction between the distributed energy system and the power system; the IEC 61850 is researched to convert the IEC CIM into a main part of an IEC 61850 information model, and the problems that a traditional power grid communication protocol is non-object-oriented, poor in expansibility and incapable of switching equipment models are solved; and a consumption-oriented Internet of Things communication protocol is slightly insufficient in security and real-time performance, and cannot support real-time application of the micro-grid, and the like.

Description

Technical Field

[0001] The present invention relates to the field of substation safety technology, and in particular to a distribution network modeling and information exchange method based on Internet of Things technology. Background Art

[0002] The distributed resources of the distribution network mainly include photovoltaic power generation, wind power generation, energy storage systems, electric vehicles, and flexible adjustable loads. These resources are characterized by dispersion, small capacity, and diverse types. These distributed resources are connected to the distribution network in large quantities and run in parallel, which brings new challenges to the planning and operation of the distribution network.

[0003] Since each distributed resource is an independent system, and the internal communication mechanism of power equipment varies from manufacturer to manufacturer, although the existing technology uses standard communication interfaces to establish communication physical links and realize the interconnection of intelligent devices, However, in the context of large-scale grid-connected operation of distributed resources, it is difficult to ensure that the standards adopted by distributed resources and the power system are the same, resulting in different corresponding communication methods and data definitions, causing some distributed resources to be unable to be integrated with the power system. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide a distribution network modeling and information exchange method and system based on the Internet of Things technology, which can achieve effective and immediate communication of information between distributed resources and the power system by constructing a new information interaction mechanism.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a distribution network modeling and information exchange method based on the Internet of Things technology, the steps of which are: Step 1: Establish an intelligent device and distributed resource information model based on IEC61850; Step 2: Expand the CIM model of distributed resources on the master station side according to the expansion principle of IECCIM; Step 3: Analyze the modeling scope, modeling method of the same object, and definition of inter-class relationship between the IECCIM model and the IEC61850 model, formulate a fusion plan, and build a fusion model based on the principle of reducing changes to existing standards and making the description of the model in the two standards consistent; Step 4: Map the data of the distributed energy information model and the power system information model according to the fusion model to realize data interaction between the distributed energy system and the power system.

[0006] Furthermore, in step 1, the process of establishing the smart device (LED) model is as follows: 1) Define the model data class of IED according to IEC61850; 2) Make a complete description of the functions and principles of the actual spacer equipment; 3) Abstract the functions of IED, analyze the logical structure of the equipment based on object-oriented thinking, and replace the actual equipment with logical equipment; 4) Decouple the functions, select appropriate logical nodes for each function, set the data and data attributes contained in each logical node, find out the data flow between logical nodes, and further analyze it using the unified modeling language tool; 5) After completing the information model attributes of the IED, select the corresponding ACSI service from 7-2 of the IEC 61850 standard, specify the corresponding abstract communication service as the functional service of the information model for the attributes of the information model, and configure the ACSI control block attributes to form a complete information model.

[0007] Furthermore, in step 1, the process of establishing the distributed energy information model is as follows: For different devices, refer to the object-oriented modeling technology in the IEC 61850 standard for the hierarchical division, define the relevant nodes of each device, so as to build a model of each device, and then build a distributed energy information model.

[0008] Furthermore, in step 2, according to the CIM extension guidelines given in the IEC61970 standard, the existing classes are extended by adding attribute values ​​and properties, and new class extensions are added through inheritance or association. In addition, new packages can also be added as applications increase, with the goal of making the most of the existing CIM.

[0009] Furthermore, in step 3, the fusion scheme formulated is: 1) For the missing parts between IEC CIM and IEC 61850 models, add new models according to your own modeling style; 2) For some objects, there are corresponding model parts associated; 3) For some objects that are better described by the IEC 61850 model, take IEC 61850 as the standard and modify the corresponding model in IEC CIM according to the IEC CIM modeling style. Similarly, for some objects that are better described by the IEC CIM model, take IEC CIM as the standard and modify the corresponding model in IEC 61850 according to the IEC 61850 modeling style. 4) For parts that are not included in both the IEC CIM and IEC 61850 models, they need to be expanded at the same time and newly created according to their own modeling style; 5) For the missing parts of the enumeration, they need to be supplemented; 6) Map the distributed model based on IEC 61850 and the power system model based on IEC CIM on the IoT communication protocol, then associate the power topology model with the distributed energy unit to finally achieve data interaction.

[0010] Furthermore, in step 4, the mapping process is: 1) Map the request / response service, request / non-response service, distributed general substation events, and distributed sampling measurement value group setting control in IEC61850 ACSI services to DDS topics; 2) Based on the standardized service description language (IDL), the feeder group and substation in the IEC CIM container model are mapped to the DDS domain to build IED device communication.

[0011] Furthermore, the specific process of the IED device communication is as follows: 1) Define the domain name of the IED communication data space and determine the communication scope of the IED.

[0012] 2) Define the topic for IED to communicate in its communication data space.

[0013] 3) Create an IDL file to define the data structure to be communicated.

[0014] 4) Use software middleware that complies with the DDS communication specification to convert IDL to program development language.

[0015] 5) Modify the variable assignment and communication frequency of specific communication data as required.

[0016] 6) Design and modify QoS configuration files according to requirements and establish service quality strategies that meet IED requirements.

[0017] 7) Compile the code test executable file.

[0018] The beneficial effects of the present invention are: The present invention constructs a distributed energy information model based on IEC 61850, and expands the power system information model based on IEC 61850. By studying IEC 61850, IEC CIM is converted into the main part of the IEC 61850 information model. DDS, as the transport layer and upper layer protocol standard, meets the requirements of real-time, high elasticity and robustness for efficient information exchange. Finally, based on the standardized service description language (IDL), a mapping relationship is established between the data fields of the protocol and the model class attributes, so as to solve the problems that the traditional power grid communication protocol is non-object-oriented, has poor scalability and cannot exchange device models; and the consumer-oriented Internet of Things communication protocol is slightly insufficient in security and real-time performance and cannot support the real-time application of microgrids.

[0019] In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specifically cites preferred embodiments and describes them in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only five of the drawings in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a flowchart of the application method; Figure 2 It is a data class diagram of the smart device model based on IEC 61850; Figure 3 It is a diagram of distributed energy architecture; Figure 4 It is the structural diagram of model fusion; Figure 5 This is a diagram of the distributed coordinated control architecture. DETAILED DESCRIPTION

[0022] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. Preferred embodiments of the present invention are provided in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0023] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0024] See also Figure 1-5 , Figure 1 The present invention shows a distribution network modeling and information exchange method based on the Internet of Things technology, the steps of which are: Step S1, establishing an intelligent device and distributed resource information model based on IEC61850; Step S2: Expand the CIM model of distributed resources on the master station side according to the expansion principle of IECCIM; Step S3, analyzing the modeling scope, modeling method of the same object, and definition of inter-class relationship of the IECCIM model and the IEC61850 model, formulating a fusion plan, and building a fusion model based on the principle of reducing changes to existing standards and making the description of the model in the two standards consistent; Step S4: Map the data of the distributed energy information model and the power system information model according to the fusion model to realize data interaction between the distributed energy system and the power system.

[0025] In step S1, the process of establishing the smart device (LED) model is as follows: 1) Define the model data class of IED according to IEC61850; 2) Make a complete description of the functions and principles of the actual spacer equipment; 3) Abstract the functions of IED, analyze the logical structure of the equipment based on object-oriented thinking, and replace the actual equipment with logical equipment; 4) Decouple the functions, select appropriate logical nodes for each function, set the data and data attributes contained in each logical node, find out the data flow between logical nodes, and further analyze it using the unified modeling language tool; 5) After completing the information model attributes of the IED, select the corresponding ACSI service from 7-2 of the IEC 61850 standard, specify the corresponding abstract communication service as the functional service of the information model for the attributes of the information model, and configure the ACSI control block attributes to form a complete information model.

[0026] IEC 61850 defines the model data class of IED in four levels from top to bottom: Server, LD Logical Device, LN Logical Node, DO Data Object. Figure 2 shown.

[0027] The IED modeling rules of IEC 61850 are as follows: Modeling principles of physical devices: A physical device is an IED, which is modeled as a device object. A physical device should contain one or more server objects (generally one server object, when the physical device is a gateway, the device can contain multiple server objects). The server object should contain at least one LD object, and each LD object should contain 3 to n LN objects.

[0028] Server modeling principles: Server represents the externally visible behavior of a device. Each server should have at least one access point, which can communicate with substation-level devices and process-level devices. In a communication network, a server is a functional node that can provide data or allow other functional nodes to access its resources, and use different access points to communicate with devices at different levels.

[0029] Modeling principles of logical device (LD) objects: LD is a virtual device that aggregates related logical nodes and data. IEC 61850 does not specify how LD objects should be divided. Generally, some LN objects with common characteristics are aggregated together to form an LD model.

[0030] Modeling principles of logical nodes (LN): LN is the smallest unit used to exchange data functions. An LN represents a function in a physical device. Data and data attributes belonging to the same functional object should be placed in the same LN. Logical nodes exchange data through logical connections and then perform some specific operations.

[0031] Distributed energy (DER) architecture is divided into distributed energy units, distributed energy systems, local distributed energy systems, local power systems, power systems, etc. The distributed energy architecture is constructed based on the hierarchical characteristics of the electrical connections of the power system. Multiple groups of distributed energy units of the same type connected to the local bus through electrical connections can form a distributed energy system; multiple distributed energy systems are connected to the local power system through electrical connections, and connected loads can form a local distributed energy system; the local power system plus the local load are connected to the power system through an electrical connection.

[0032] The key factor in connecting DER to the grid is the DER system. A DER system consists of 1-n DER units, or any combination of DER units and systems. A DER is a single or a group of DERs of the same type. The interface for DER system communication is standard and universal. In order to integrate DER into the grid, the point of common connection (PCC) is modeled as a DER, and the capabilities at the PCC are described.

[0033] According to the distributed energy architecture, DER units are photovoltaic, cogeneration, fuel cells, energy storage devices and other power generation or storage units; distributed energy systems are composed of an independent or multiple groups of similar distributed energy units connected to the bus; the local power system is a local supply and sales power system composed of multiple groups of distributed energy systems and local loads, which can also be called the local distributed energy system. The power system is the transmission and distribution system of the public power grid.

[0034] Figure 4It is a schematic diagram of the logical devices and logical nodes required for DER system management. The logical nodes of the logical device classification of its hierarchical architecture are defined, including: logical nodes for power generation protection, logical nodes for electrical connection points of DER equipment, logical nodes for DER unit controllers, logical nodes for physical quantities of logical devices in distributed energy systems, and logical nodes for power system measurements. The logical devices of the DER system include: circuit breakers, DC converters, synchronizers, generator units, exciters, energy converters, energy storage devices, etc. Among them, energy converters are various devices that convert other energy into electrical energy, including: micro turbines, fuel cells, photovoltaic systems, wind turbines, generators, gas turbines, etc.; energy storage devices are devices that store energy converters, including batteries, pumped storage, superconducting magnetic energy storage, wind wheels, micro flywheels, etc.

[0035] Construct a hierarchical information model of DER. Each intelligent electronic device (IED) in DER contains one or more servers, each server itself contains one or more logical devices, logical devices contain logical nodes, logical nodes contain data objects, and data objects are named by common data classes (CDCs) composed of data attributes. And by adopting instantiated logical node classes (compatible logical node classes) and data classes (compatible data classes) to agree on the intelligent semantics of distributed energy, the effective modeling of DER logical devices is realized.

[0036] In step S1, the process of establishing the distributed energy information model is as follows: For different devices, refer to the object-oriented modeling technology in the IEC 61850 standard for the hierarchical division, define the relevant nodes of each device, so as to build a model of each device, and then build a distributed energy information model.

[0037] Based on the IEC 61850 standard, an object-oriented distributed energy information model of the distributed energy system is established. The object-oriented modeling method is a method that uses object-oriented information modeling concepts, such as entities, relationships, attributes, etc., and uses encapsulation, inheritance, polymorphism and other mechanisms to construct a method of simulating a real system. The distributed energy system includes a variety of equipment, which can be roughly divided into: switching equipment, protection equipment, measuring equipment, metering equipment, converter equipment (voltage conversion equipment, current conversion equipment, frequency conversion equipment and power regulation equipment) and energy storage equipment.

[0038] In step S2, according to the CIM extension guidelines given by the IEC61970 standard, the existing classes are extended by adding attribute values ​​and properties, and new class extensions are added through inheritance or association. In addition, new packages can also be added as applications increase, with the goal of making the most of the existing CIM.

[0039] The IEC61970 standard provides guidelines for CIM extension, which can be extended by adding attribute values ​​and properties to existing classes, adding new class extensions through inheritance or association, and adding new packages as applications increase, with the goal of making the most of the existing CIM. In fact, CIM extension is to consider three issues: whether to create new packages, which new classes to extend, and which existing class attributes and attribute values ​​to extend. The extended model of distributed energy can be extended directly in CIM-301 without adding new packages. The extension involves the wire package Wires in CIM-301, the two sub-packages of the power production package Production and the power generation dynamics package GenerationDynamics in the power generation package Generation, and the package Domaino.

[0040] Expand the distributed energy resources from the power system resource category to photovoltaic, energy storage, wind power and other related categories. In fact, we can expand different types of distributed energy through the different access modes of distributed energy, namely power electronics access and generator access.

[0041] The power electronics access category expands to include battery category, distributed photovoltaic category, inverter access to wind power category, etc. The generator access category expands to include photovoltaic power station category, wind power station category, and combined heat and power category.

[0042] In step S3, the fusion scheme formulated is: 1) For the missing parts between IEC CIM and IEC 61850 models, add new models according to your own modeling style; 2) For some objects, there are corresponding model parts associated; 3) For some objects that are better described by the IEC 61850 model, take IEC 61850 as the standard and modify the corresponding model in IEC CIM according to the IEC CIM modeling style. Similarly, for some objects that are better described by the IEC CIM model, take IEC CIM as the standard and modify the corresponding model in IEC 61850 according to the IEC 61850 modeling style. 4) For parts that are not included in both the IEC CIM and IEC 61850 models, they need to be expanded at the same time and newly created according to their own modeling style; 5) For the missing parts of the enumeration, they need to be supplemented; 6) Map the distributed model based on IEC 61850 and the power system model based on IEC CIM on the IoT communication protocol, then associate the power topology model with the distributed energy unit to finally achieve data interaction.

[0043] Model fusion is achieved by mapping the IEC CIM to the main part of the IEC 61850 information model - the Substation Configuration Model (SLC). The SCL Process / Line / Substation part is generated from the appropriate CIM subset or XML schema generated from the subset.

[0044] Table 1 IEC 61850 / CIM to DDS mapping specifications type Property name Mapping to DDS Objects illustrate ACSI Services Group setting control (e.g. request / response service, request / no response service, distributed general substation events, and distributed sampling measurements) DDS Topic Uses a subset of the 61850 / CIM model 61970 container model Feeder group / substation, etc. DDS Domain Reports and Logs Reports and Logs Journal In step S4, the mapping process is: 1) Map the request / response service, request / non-response service, distributed general substation events, and distributed sampling measurement value group setting control in IEC61850 ACSI services to DDS topics; 2) Based on the standardized service description language (IDL), the feeder group and substation in the IEC CIM container model are mapped to the DDS domain to build IED device communication.

[0045] Furthermore, the specific process of the IED device communication is as follows: 1) Define the domain name of the IED communication data space and determine the communication scope of the IED.

[0046] 2) Define the topic for IED to communicate in its communication data space.

[0047] 3) Create an IDL file to define the data structure to be communicated.

[0048] 4) Use software middleware that complies with the DDS communication specification to convert IDL to program development language.

[0049] 5) Modify the variable assignment and communication frequency of specific communication data as required.

[0050] 6) Design and modify QoS configuration files according to requirements and establish service quality strategies that meet IED requirements.

[0051] 7) Compile the code test executable file.

[0052] Support local distributed applications of microgrids, and solve the problems that traditional power grid communication protocols are non-object-oriented, have poor scalability, and cannot exchange device models; while consumer-grade IoT communication protocols are slightly insufficient in security and real-time performance, and cannot support real-time applications of microgrids.

[0053] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A distribution network modeling and information exchange method based on Internet of Things technology, the steps of which are: Step 1: Establish an intelligent device and distributed resource information model based on IEC61850; Step 2: Expand the CIM model of distributed resources on the master station side according to the expansion principle of IECCIM; Step 3: Analyze the modeling scope, modeling method of the same object, and definition of inter-class relationship between the IECCIM model and the IEC61850 model, formulate a fusion plan, and build a fusion model based on the principle of reducing changes to existing standards and making the description of the model in the two standards consistent; Step 4: Map the data of the distributed energy information model and the power system information model according to the fusion model to realize data interaction between the distributed energy system and the power system.

2. According to a distribution network modeling and information exchange method based on Internet of Things technology according to claim 1, it is characterized by: In step 1, the process of establishing the smart device (LED) model is as follows: 1) Define the model data class of IED according to IEC61850; 2) Make a complete description of the functions and principles of the actual spacer equipment; 3) Abstract the functions of IED, analyze the logical structure of the equipment based on object-oriented thinking, and replace the actual equipment with logical equipment; 4) Decouple the functions, select appropriate logical nodes for each function, set the data and data attributes contained in each logical node, find out the data flow between logical nodes, and further analyze it using the unified modeling language tool; 5) After completing the information model attributes of the IED, select the corresponding ACSI service from 7-2 of the IEC 61850 standard, specify the corresponding abstract communication service as the functional service of the information model for the attributes of the information model, and configure the ACSI control block attributes to form a complete information model.

3. The distribution network modeling and information exchange method based on Internet of Things technology according to claim 1 is characterized by: In step 1, the process of establishing the distributed energy information model is as follows: For different devices, refer to the object-oriented modeling technology in the IEC 61850 standard for the hierarchical division, define the relevant nodes of each device, so as to build a model of each device, and then build a distributed energy information model.

4. The distribution network modeling and information exchange method based on Internet of Things technology according to claim 1 is characterized by: In step 2, according to the CIM extension guidelines given by the IEC61970 standard, the existing classes are extended by adding attribute values ​​and properties, and new class extensions are added through inheritance or association. In addition, new packages can also be added as applications increase, with the goal of making the most of the existing CIM.

5. The distribution network modeling and information exchange method based on Internet of Things technology according to claim 1 is characterized by: In step 3, the fusion plan formulated is: 1) For the missing parts between IEC CIM and IEC 61850 models, add new models according to your own modeling style; 2) For some objects, there are corresponding model parts associated; 3) For some objects that are better described by the IEC 61850 model, take IEC 61850 as the standard and modify the corresponding model in IEC CIM according to the IEC CIM modeling style. Similarly, for some objects that are better described by the IEC CIM model, take IEC CIM as the standard and modify the corresponding model in IEC 61850 according to the IEC 61850 modeling style. 4) For parts that are not included in both the IEC CIM and IEC 61850 models, they need to be expanded at the same time and newly created according to their own modeling style; 5) For the missing parts of the enumeration, they need to be supplemented; 6) Map the distributed model based on IEC 61850 and the power system model based on IEC CIM on the IoT communication protocol, then associate the power topology model with the distributed energy unit to finally achieve data interaction.

6. The distribution network modeling and information exchange method based on Internet of Things technology according to claim 1 is characterized by: In step 4, the mapping process is: 1) Map the request / response service, request / non-response service, distributed general substation events, and distributed sampling measurement value group setting control in IEC61850 ACSI services to DDS topics; 2) Based on the standardized service description language (IDL), the feeder group and substation in the IEC CIM container model are mapped to the DDS domain to build IED device communication.

7. The distribution network modeling and information exchange method based on Internet of Things technology according to claim 4 is characterized by: The specific process of IED device communication is as follows: 1) Define the domain name of the IED communication data space and determine the communication scope of the IED; 2) Define the topic for IED to communicate in its communication data space; 3) Create an IDL file to define the data structure to be communicated; 4) Use software middleware that complies with DDS communication specifications to convert IDL into program development language; 5) Modify the variable assignment and communication frequency of specific communication data according to needs; 6) Design and modify QoS configuration files according to requirements and establish service quality strategies that meet IED requirements; 7) Compile the code test executable file.

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