The Implementation of a New Smart Scheme of Hotspot Monitoring in Smart Grid

Jing Zhang1,2, Ming Liang1,2, Yun Wang1,2, Helou Ma1,2

1RCIEPT, North China Electric Power University, Changping District,Beijing 102206, China 2ZHONGBO Info-Science (Beijing) Technology Co.Ltd., Haidian District, Beijing 100085, China

Email:zjtx@ncepu.edu.cn, lm@ncepu.edu.cn ,wangyf@ncepu.edu.cn, helou_ma@126.com

Abstract: A scheme of extracting DXF format graphic from traditional connection diagrams is presented by analyzing the main connection diagrams of power station and problems contained in device terminal moni-toring. Graphics extracted by this program enter PDXF2DAT conversion software connected with PointTem-per developed by ZhongBo (Beijing) can produce a fast user interface. Using this interface can realize moni-toring and early warning for each terminal, monitoring data and historical data can be available through the user interface or SQLite Database Browser Display. Finally, an example proved the feasibility of the moni-toring program. The implementation of this scheme provides a common graphical user interface and conven-ient system data extraction and maintenance platform for the power monitoring system.

Keywords: smart grid, DXF, user-interface, extracting graphics data.

1 Introduction

Since the United States proposed the concept of smart grid, all countries have had a practical definition on the basis of national situation, the Chinese State Grid com-bined with actual situation in our country proposed China's reunification strong intelligence network plan-ning. National Grid noted that the unity of our country strong and smart grid should based on strong grid, utiliz-ing extra-high-voltage as backbone and advanced tech-niques on information、communication and controlling to achieve the automation, information and interaction of power grid.

In short, the goal of our strong and smart grid is to improve the reliability 、self-healing capabilities and power quality, under the premise of satisfying the load requirements and ensuring the normal transmission and distribution and supply.

Nowadays, a large part of economic loss was caused by the conk. Therefore, online monitoring and early warning technology research and application becomes particularly important.

2 Monitoring technology and importance in power system

The safe operation of power system plays a vital role in the reliability of electricity supply industry , re-quirements for power station are also increasing. A variety of network / plant line monitoring stations and early warning systems are becoming increasingly impor-tant . In the process of running as the inevitable by me-chanical, heat, light and other environmental impacts, resulting performance of electrical equipments declining, even failure, directly or indirectly caused huge economic

losses. The main power wiring diagram is the base of ana-

lyzing power system which s widely used in various power system calculations. With the constant develop-ment of computer technology, computer graphics tech-nology has been gradually introducing to the power sys-tem analysis. Analysis of visual graphics are becoming more and more attractive. In the term of high intuition-ism and man-machine interaction. How to provide fast, convenient graphical interface has became the focus.

Power Station line monitoring and early warning systems need a good user interface and match the practi-cal main wiring diagram. There are still some problems in extracting main wiring diagram from power station. Firstly, there are excessive labels and definition in the main wiring diagram, which makes the drawing and ex-tracting verbose and they are useless for online monitor-ing system. Secondly, the general storage format for main wiring diagram is for DWG, which can not auto-matically convert into common data exchange file DXF, also the size of the common DXF file are so large to take up too much processor resources.

Thus, we provide a common graphical user inter-face and convenient database generation system to meet the power system online monitoring and early warning systems, which can remove the artificial burden of drawing and maintenance of the graphics.

3 Implementation of extracting DXF files

DXF(Drawing Exchange File) is the change format of AutoCAD. Compared with DWG, it is ASCII text file containing whole information of DWG and have a high speed in generating drawing. We can interchange draw-ing through changing DXF among different types of

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computers. DXF file consists of paired code and associated

code value which not only point the types of following value, but also match with them. DXF files are organized into paragraphs by using these matched group code and group values. Typically, a complete DXF file consists of the following components: 1) SECTION. It represents the beginning of a segment and can be applied before each segment. 2)Segment feature mark, including HEADER, which contains the map of general informa-tion, such as AutoCAD database version number, system variables, parameters and their values; CLASSED, which contains the application and the definition of class; TA-BLES, which contains definitions such as blocks, anno-tation, layer styles, coordinates, text fonts and other symbol table; BLOCKS, which contains the block name, location, proportion and other information; ENTITIES, which contains a variety of entities such as circle, line, arc position, thickness, color information; OBJECTS, contains the object definitions and related information. 3) OENDSEC which represents the end of a paragraph.4) OEOF which represents the end of the whole DXF file.

In practice, in order to extract entity information many items can be omitted in graphics DXF file, we can complete description of the corresponding geometry if only requiring the information of layers form, BLOCKS, and ENTITIES. We can sort out the four basic drawing unit: thin line, thick straight lines, small round, great circle by analyzing the structure of the main wiring dia-gram and online monitoring system. These basic units can be replaced by line drawing, square, octangle, hexa-gon replacement is 10 in the premise of meeting the re-quirements of graphic user interface. Pixel of color, line, line width, fill color and other parameters can be set freely, which are not included in data conversion areas. The substitute can make up all device graphics primitive in power station (including switches, busbars, transform-ers three times, twice transformers, circuit breakers, lines, generators and other primitives). Thus, we can customize main power wiring layer for extracting user interface data DXF files.

The dedicated AutoCAD drawing data file com-posed of five layers. Data exchange layer 0 is the back-ground layer, which has been used to place the main wiring diagram and as the background of other data ex-change layer. The layer does not participate in data ex-change. Data Exchange Layer 1 interface is used to draw the maximum window or frame Ratio of graphics data can formed following data conversation. Data exchange layer 2 is used to draw the background graphics of user interface, such as switches, busbars, transformers three times, twice transformers, circuit breakers, lines, genera-tors and so on. This layer mainly composed of straight line, square, hexagon, regular octagon, background graphics database can formed following data conversion processing. Data exchange layer 3 is used to draw the

monitoring terminal, terminal graphics and hotspots da-tabase can formed following the data conversion. Data exchange layer 4 is used to draw a special tag or label, tag graphics database can formed following data conver-sion processing. Data exchange layer 5 is used to draw the data concentrator and the management of each con-centrator and concentrator terminal region number. Hot spot data database can formed following data conversion. A required DXF file can be drawn following orders above.

4 Data extraction and generation of database of Power Graphics PDXF2DAT

PDXF2DAT based on VC + +6.0 integration envi-ronment using MFC libraries to implement power system DXG graphics data extraction, and thus providing a good platform for online power monitoring system.

4.1 About SQLite database

Embedded database SQLite is used in this design. SQLite database is in-process database engine with no database client and server. One of the biggest advantages is the lightweight, only using a dynamic library can we enjoy all of functions, and its size is very small, probably only three or four hundred K or so. SQLite is completely free , all of its source code can be downloaded from the official site, without any restrictions to use, without the need to purchase a separate database service, no server process, the configuration cost is zero, and its core en-gine does not rely on third parties. We use it without in-stallation, so that the deployment has obvious advantages. In addition to many other mainstream operating system, SQLite also support others, especially the embedded operating system, the entire database is stored in a single file, importing ,exporting and recovering is only to copy files with zero-maintenance difficulty.

4.2 Operating Interface and its use of PDXF2DAT

The figure is the user interface of PDXF2DAT de-signed in VC + +6.0 software development platform. The screen appears when starting PDXF2DAT. Firstly, we set the input file and output file, and then select the but-ton by data processing, then AutoCAD DXF files are began to generate, and put the extraction of data into database for monitoring

Connected with PointTemper developed by ZhongBo , user interface can generated, the following picture shows the user interface of a 110KV substation.

In this interface, the operating state indicates that the power system wiring and terminal location diagram, flashing yellow spots and red spots indicate the early warning and alarm terminals. “Warning message ”to look at “theRun Status”by the chart format showing the early warning and alarm information; "End query" to search and view the end of the database information by the way of chart. "Historical data" to search and view the

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historical database information by list. "Parameter" can view and modify the system / software operating pa-rameters. "Number of library tools" for database backup and database recovery; "Exit system" can be prompted to confirm exiting.

Figure 1. User interface of PDXF2DAT

Figure 2. The user interface of a 110KV substation

We Mainly introduce “warning message” interface，

the rest of the interfaces are similar. "Warning message" interface, enabling the follow-

ing functions: 1) The list of early warning information displays

contents of database realtemp.db and table UnitAlarm0.

2) Alarm information list displays contents of data-

base realtemp.db and table UnitAlarm2. 3) Alarm history list displays contents of database

RealState.db and table AlarmHistory (arranged by date descending select * from AlarmHistory order by Re-cordDate desc limit 30;）

4) Select the item of curve graph displayed, or dis-played in a list.

5) Select the three-phase comparison items, ap-pointed warning terminals are mainly shown and in the corresponding library to retrieve the phase with the group's other two cable terminal information to show together.

6) Terminal daily record: Terminal parameters and gradient of 12 points are placed on top of the graph by the form of a table or graph, Environmental parameters and gradient of 12 points are placed on top of the graph by the form of a table or graph. If the graph shows by curve, lines of color to take regular, left scale for the temperature / temperature, the right scale for the current / humidity, gradients were only shown four curves do not indicate the coordinates, but must indicate the maximum and minimum.

7) Terminal weekly record: Terminal parameters and gradient of 7*7 points are placed on top of the graph by the form of a table or graph, Environmental parame-ters and gradient of 7*7 points are placed on top of the graph by the form of a table or graph. If the graph shows by curve, lines of color to take regular, left scale for the temperature / temperature, the right scale for the current / humidity, gradients were only shown four curves do not indicate the coordinates, but must indicate the maximum and minimum.

In the specified folder, we get the output interface and output of database files, which can be opened by SQLite Database Browser, As shown below:

Figure 3. The output of database files

We can open the desirable database using this interface, clicking the button Database Structure can view the wir-ing diagram of the various data structure, Browse Data can browse all output data terminal, including all points and lines of temperature and humidity.

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5 Summary

The paper take tracking cutting edge technology theo-ries、combination of theory and practice and explore new applications as basic starting point, providing a con-venient and efficient solution for the electrical system of the graphic. Its greatest feature is its convenience and low cost of maintenance. When the Power engineering drawings needs to be changed or monitoring points changed, we only need to open the appropriate DXF file to edit or delete and updating in online monitoring sys-tem, which can ensure consistency between them. In addition, historical data can be viewed through interface and database, providing a good platform for safe and effective monitoring.

The implementation of the scheme provides a good human-machine interface for early warning system in network / line monitoring stations , meeting the actual monitoring requirements and remove the burden of hu-man edit and maintenance of drawing and graphics. Cur-rently, PDXF2DAT DXF graphics data extraction soft-ware has been put into use to the MC-011A temperature

and current monitoring and early warning systems de-veloped by ZhongBo Information Science Institute. PDXF2DAT provides good user interface for the moni-toring system for its fast, convenient data extraction ca-pabilities.

References

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[2] Liang Xuechun, Song Deming, AutoCAD Secondary Develop-ment Guide, Beijing, Tsinghua University Press.2001.

[3] Zhu Yongli, Liran, LiuYan. The automatical generation of main connection diagram of power station. Technology of power system and automation 2000, 12(1): 41-45.

[4] Wang Ziru, Ren Qingbo, Study of DXF data files interface based on VC++, Xiamen University of Technology, 2007(01):4.

[5] Li Yujian, Visua1C + + the Graphics chapter of programming practice and improvement, Beijing: China Railway Press, 2001.2.

[6] Beijing ZHONGBO Information Science Institute, IMC-011A monitoring and early warning systems of power cables and joints of the temperature and current, www.zbaist.cn, 2008.

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