Introduction With the gradual development of China's urban network transformation, the market demand for urban distribution automation/management systems is increasing. The introduction of Geographic Information System (GIS) in Distribution Management System (DMS) is the current development direction of DMS, and it is also an inevitable choice for the distribution industry.
The main purpose of the DMS integrated design is to provide a simple, intuitive and unified operating environment for power users to realize the interaction between different data streams (including device geographic graphic data, network topology data, static file data, dynamic real-time data, etc.). And sharing, users need to achieve a single input and maintenance, multiple sharing and use. It must be emphasized that the DMS data storage scheme, internal topology representation, internal data flow, and internal function implementation are transparent to the user. The DMS integrated design must first be based on the characteristics of the data flow in the power management system, from the data structure. The development of the design can provide powerful support for the realization of integrated functions. In short, the key to integration is the unified data modeling, network topology mapping technology, and open standard functional interfaces.
This article attempts to combine the author's years of work experience and personal experience in the DMS field around the distribution automation master station system (including the SCADA subsystem for power distribution, power distribution fault diagnosis and restoration, distribution network application software (DAS) subsystems, and distribution automation The imagery (AM) / equipment management (FM) / GIS application subsystems) in-depth discussion of many issues involved in integrated design. In order to discuss the convenience of the problem, the relevant contents of the following specific GIS platform involved in this article are described as Smallworld as an example.
Functional positioning of each subsystem The distribution automation master station system can usually be divided into distribution SCADS subsystem, distribution fault diagnosis and restoration and distribution network application software (DAS) subsystem, distribution AM/FM/GIS application subsystem The distribution SCADA subsystem is the basis for real-time applications in DAS subsystems and distribution AM/FM/GIS application subsystems, providing real-time data sources for DAS and FM, and providing platform support in system design.
The task of distribution AM/FM/GIS system mainly focuses on graphic display control, equipment management, static off-line analysis, work management, and other data and information for other systems. The system is mainly targeted at the power supply bureaus or the power production departments, providing basic data platforms and information services for front-line employees and managers of production and operations.
The SCADA system completes the basic grid data acquisition and monitoring control functions. The main station SCADA includes data acquisition, communication services, data processing, online event/accident handling, security management, dispatcher operations, report, print management, database maintenance, screen configuration (screen management and maintenance), human-machine interface (screen display Basic functions such as operations and operations, accident recall, network and process management, and additional functions such as Web services and dispatcher training simulation (DTS) require high security, reliability, real-time performance, and powerful data processing capabilities.
The DAS subsystem can perform computer processing of various functions of the distribution network application software and collect fault information collected by multiple feeder terminal equipment (FTU), determine the nature of the fault, and accurately locate faults and isolate them. The system's fault detection, fault location, fault isolation and non-fault zone power restoration control can be divided into three levels: 1 based on the power distribution terminal based fault detection, fault location, fault isolation and non-failure zone restoration of power supply; 2 The Data Terminal Equipment (DTU)/Establishment of the electronic station is the unit's fault location, fault isolation, and restoration of power in non-faulty areas. 3 The master station is the high-level global control of the management center.
The integrated design of the distribution automation automation master station system must first be integrated design from the database, and the object identifier must be unified. The number or name in the switch preferably takes the same field name in the respective table and defines the same data type. When establishing various device data tables or SCADA/DAS parameter tables, full consideration should be given to the requirements of various applications on the power object data attributes while considering the reduction of data redundancy. In the GIS maintenance program, the graphics and SCADA/DAS formats in AM/FM/GIS are seamlessly transferred and the topology is seamlessly migrated, thus avoiding duplicate entries of graphics and inconsistencies that may be caused when the two systems are maintained.
It is worth noting that each distribution network has its own particularities, such as geographical environment, scope and scale, management model, user nature, etc. This often requires the developer to formulate the best distribution for the distribution network according to the specific situation. Electric automation model.
The data involved in the integrated plan of integrated data sources include the following:
a. Equipment account data: Input and maintenance by GIS.
b. Real-time data collection: The SCADA system collects and constructs real-time libraries, which can be transmitted to GIS for display.
c. Power grid topology data: The SCADA system and GIS usually have different topological expressions. The topology connection relationship of the SCADA system can be manually input, or can be converted by the GIS according to the topological representation format of the SCADA system according to its graphical topology (ie, the graphical topology. To the transformation of the line topology), the transition can also be made through the "intermediate format". This "intermediate format" is expressed by a set of graphical topologies defined by the developer. The specific form may be a plain text file, an XML file, or the like. Of course, the developer usually also needs to provide a program to convert (import/export) the intermediate format accordingly.
d. Equipment electrical parameters: GIS is manually input when performing analog analysis operation (analog); in real time, it is directly corresponding to SCADA real-time acquisition.
In the distribution master station system, information sharing between AM/FM/GIS and SCADA/DAS includes data transfer and display, conversion of different graphic formats, and mapping of topological relationships. In order to facilitate the two-way exchange of data flow between GIS and SCADA system (including GIS to take real-time numbers from SCADA system, send remote commands to SCADA system, and SCADA system query equipment account information saved in GIS, etc.), in the data structure At the beginning of the design, it is necessary to establish a "uniform identification of equipment objects." Specifically, the unified identification of equipment objects is the coding of the same electric power object in the GIS and the SCADA system, that is, the one-to-one correspondence between the GIS and the electric power equipment objects in the SCADA system can be established by uniformly identifying the equipment objects.
Taking Smallworld as a GIS platform as an example, it is necessary to use the API function provided by the main distribution station system and the inter-process data communication mechanism (such as ACP or TICS) provided by Smallworld to write a real-time running program responsible for AM/FM/GIS and Real-time data and control information interaction between SCADA/DAS applications. On the GIS screen, the display of the operational status of the distribution network (for example, the state of the switch, the state of the electrified lines, the size of the telemetry, etc.), and the display of faults in the distribution network are realized. This requires the real-time SCADA system and GIS to define a unified identification of device objects (ie, keywords of a unified database table) to ensure the uniqueness of information exchange between different systems.
The three integrated graphic organization 3.1 whether to save the internal map of the station on the GIS side (using GIS graphic format)
Smallworld can use the hypernode mechanism to complete the tracking from one world to another through programming, ie, it can easily perform topological tracking from outside the station to inside the station or outside the station to the outside of the station. This is one of the reasons for choosing Smallworld as a distribution GIS platform. Simply put, a super node is a special object that has two geometrical figures that belong to different worlds respectively. It uses the internal encapsulation method to complete the topology migration in low-level migration, that is, to map the geometry in a world to It exists on the geometry of another world and keeps the topology analysis program going.
The conclusion is: If it is necessary to achieve tracking inside and outside the station, the GIS terminal (in the Smallworld system) needs to save the internal map of the station (such as the one-time connection diagram in the station). A wiring diagram in the station needs to be completed before the SCADA system is put into operation. Therefore, the SCADA graphics format can be considered for converting to the Smallworld system.
3.2 Whether to save the entire electrical system at the GIS end (using GIS graphic format)
From the perspective of technology realization, adopting the GIS graphic format in Smallworld requires not only the preservation of geographical layout patterns, but also the preservation of the entire electrical system map. It is entirely possible to realize the GIS graphics. There are separate graphical representations along the layout and electrical system, but there is only one set of data for the equipment account, that is, one set of private technology equipment attribute data corresponds to a plurality of geometrical patterns belonging to different worlds.
This scheme makes the power distribution master station system appear in two graphic formats of the power system full picture, that is, the GIS graphics format of the electrical system and the SCADA drawing format of the entire power system. Obviously, in order to enable the user to input graphics once, to avoid duplicate entries of the graphics and the inconsistencies that may be caused when the two systems are maintained, these two graphics formats are all between the entire power system and between the geographic layout and the entire power system. There is a graphical conversion problem, which greatly increases the complexity of the system.
In addition, due to the differences in the topological connection between the full-scale electrical system of the Smallworld graphic format and the SCADA drawing format, the former directly expresses the topological relationship between the power line and the device through the graphical connectivity. People often use topology tables that are not transparent to developers to express this topology relationship. Therefore, there are also certain difficulties in implementation.
In summary, it is not recommended to use the GIS graphic format to save the entire power system map at the GIS end.
3.3 Overall diagram of the electrical system (one-time external wiring diagram) Whether or not the GIS graphic format is used Although the GIS system is essentially a graphic system, it can express geographical feature graphics with large data volumes, complex structures, and large coverage, including horizontal planes. Vertical electrical diagram, but it is recommended not to do so. This is because the dispatcher interface (MMI) displays the electrical maps that can be expressed using a specific vendor's drafting package format (eg, the power distribution SCADA drafting format). Relatively speaking, these specific vendor-provided graphical formats are often better than those provided by the GIS platform. The graphic format is simple, but it is more practical for expressing horizontal and vertical electricity system diagrams.
In addition, in order to complete the advanced analysis of the power system, it is necessary to maintain a topology table that stores the connection relationship between the power components and the developer, and the characteristics of the Smallworld graphics are to directly express the topology between the power lines and the devices through the connectivity of the graphics. Relationships, advanced analysis algorithms for power systems cannot harness the inherent connectivity of this Smallworld graphics.
In summary, it is proposed to separate the selection of GIS platform from the unified selection of distribution automation system platform. Do not use the GIS graphics system to express horizontal and vertical electricity system diagrams. However, because some GIS graphic formats (for example, shape format) are open to the outside or can be easily converted by some graphic conversion tools, a GIS graphic format (for example, shape) can still be considered when performing graphic conversion. Format) as an intermediate format. It is worth noting that the transformation of the geographic layout pattern to the electrical system (SCADA graphic format) in the GIS system can be incrementally converted according to user requirements, while allowing the user to edit and adjust the position of the graphics in the conversion result.
3.4 Expression of topological relationships between power devices The topology in the Smallworld graphics format is directly expressed by the connectivity of the graphics, ie, when the two geometries do not overlap or coincident in their graphics position, according to Smallworld. The topology analysis mechanism will find that the topology of the objects to which these two geometries belong is impossible.
When expressing the topological connection relationship between power lines and devices, the SCADA drawing format graphics are often implemented through a topology table that expresses the connection relationship between power lines and devices according to front and rear connection devices. In fact, the graphic position of the SCADA drawing format is separate from the topological relationship of the power object to which the graphic belongs, even if the graphic of the SCADA drawing format is not connected at its graphic position (ie, no overlapping or overlapping relationship occurs), as long as the topology table is Show that the two are connected devices before and after, then in the DAS still think that the two power devices are connected.
In Smallworld, when it is necessary to understand the connection relationship between power lines and devices, the topology analysis method of Smallworld can be used to complete the topology tracing of Smallworld graphics. In fact, there is no (or no need at all) to connect the devices before and after to express the topology of the power line and the connection relationship between the devices. This is because the topological relationship between the power lines and the devices in Smallworld is through the graphical Connected to express.
In short, there is no so-called topology table in Smallworld that expresses the connection relationship between power lines and devices. It expresses topology connections through graphic positions and implements topology tracing through the system-provided topology tracing mechanism. In SCADA/DAS, it must be used through The topological table that is not transparent to the developer expresses the topological relationship of the device. In fact, the topological relationship between the graphic position and the power object to which the graphic belongs is separated. The topology table is filled and maintained by the user according to the topological relationship of the actual power device. of. Because of this, it is necessary to generate the network topology data required for advanced application analysis based on the graphical network topology 5 established in the GIS map, which avoids the inconsistency and duplication of the graphics and SCADA/DAS graphics in the GIS.
Four conclusions DMS is a distributed, modular, and extensible open integrated management system that meets the modernization management requirements of distribution systems. It consists of an integrated basic platform and a number of relatively independent application subsystems that run the platform. The basic platform can not only provide data and graphics support for other advanced application systems, but also provide open information service support for various powerful applications.
The integration of graphic and data information description on the distribution network will completely solve the situation in which static drawings and data relationships are separated, and at the same time it also solves the problem of data consistency in various applications in DMS. However, the graphical conversion scheme between the geographical distribution layout of the distribution network in the distribution AM/FM/GIS system and the dispatcher's use of the electricity system remains to be further discussed based on the actual situation. However, the general principle is to ensure that the power grid graphs and attribute data are entered, maintained, and used in multiple locations to avoid data inconsistencies.
The integrated design must also consider the relationship between the distribution network and user information, build the data base of the operation and coordination, and interface design with other non-parallel simultaneous implementation systems to ensure the system's scalability and openness. It is worth noting that each distribution network has its own particularities (such as geographical environment, scope and scale, management mode, user nature, etc.), which requires that the DMS applicable to the distribution network be optimized according to these specific conditions. mode.
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