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Dynamic Security Assessment (DSA) is based on analysis of transient stability, voltage stability, small-signal stability, which gives evaluation on multi-contingency and preventive measures or optimization strategies. PSASP Dynamic Security Assessment (PDSA) Graph-Data integration platform is studied in this paper, which supports not only graph configuration, auto-consistent graph and data, drawing of geographical and single-line substation diagrams, but also online system monitor, offline analysis, visualization etc. Three run-states and two frameworks are summarized in the platform. Abundant two-dimensional and efficient three-dimensional visualization is also discussed. The platform of Graph-Data integration in this paper is used in Electric Power Dispatching Centre of State Grid and Guangdong province and so on.
Keywords—Dynamic Security Assessment; PSASP; Graph-Data support integration platform; visualization; PDSA
I. INTRODUCTION
SASP Dynamic Security Assessment (PDSA) system has been developed has been developed in China Electric Power Research Institute, which is composed of PSASP Distributed Computation platform, Dynamic Data platform and Graph-Data integration platform. Based on above platforms, power system analysis including transient stability, voltage stability, small-signal stability is integrated and gives evaluation on multi-contingency and preventive measures or optimization strategies. This paper focuses on Graph-Data integration platform of DSA system that can provide friendly Man-Machine interactive platform and support all kinds of functions of PDSA system. By the platform, maintaining PDSA system and showing visual assessment results is carried out.
The support platform based on Graph-Data integration technology is widely used in many systems, such as power system analysis, EMS/DMS, DTS and so on. The support platform of PDSA is supports not only graph configuration, auto-consistent graph and data, drawing of geographical and single-line substation diagrams, but also online system monitor, offline analysis, visualization etc. This paper
Kang jiandong is with China Electric Power Research Institute, (e-mail: [email protected]).
Li Yalou is with China Electric Power Research Institute, (e-mail: [email protected]).
Mu Lianshun is with China Electric Power Research Institute, (e-mail: [email protected]).
summarizes three run-states which include Online-Run state, Online-Study, Offline-Study and main functions on three states are discussed. Further, the main functions on three run-states are studied and realized and described in TABLE I. The platform of Graph-Data integration supports graph configuration technology, which can maintain consistency of graph and data and show analysis result on Single-line and geographical diagrams rapidly. Data Management can manage online data across-the-board, and online data analysis is based on it. In visualization, Rapid contouring method on OpenGL is given and three dimensional surface based on contour background is carried out.
Fig. 1. PDSA overall structure
II. PSASPGRAPH-DATA INTEGRATION PLATFORM
The so-called graph-data integration is to establish power system equipments models and power grid topology automatically along with power system diagrams drawing. Integration makes graph correspond with data, which reduces system maintenance difficulty. Power system graph-data integration system is the base of power system analysis, design, control and monitor visualization.
PSASP Graph-Data integration platform supports graph configuration, hot-spot technique, one suit of data – multi-views, etc. All kinds of applications of PSASP are integrated in the platform, such as drawing single-line diagram and geographical position diagram, creating and maintaining data of power system, displaying analysis result and so on.
The main method and technology of graph-data integration is as follows:
Architecture of one suit of data – multi-views
Study and Realization of Dynamic Security
Assessment system Graph-Data Integration
Platform
Kang Jiandong, Li Yalou, Mu Lianshun, Electric Power Research Institute, China, Qinghe, Beijing,
100192 China
P
All data in areas are integrated into one suit, and single-line diagram, single-line substation diagram and geographical position diagram are all based on it. The corresponding relation between graph and data depends on key information, including name of equipment, serial number of equipment, node name etc., which exist in both of them.
Automatic topology analysis
Topology analysis is only based on basic data in database, and independent of graph.
Along with graph-drawing , data are generated
Hot-spot technique provides flexible and rapid graph-drawing; meanwhile, the corresponding data is created or maintained.
Graph configuration
Graph configuration provides abundant graph symbols. Based on them users can draw their own symbols, no need for PSASP’s programmers to do extra coding. Safety data architecture
Layered protection for data is provided in platform. Interface of online data
A. Development tools
In order to adapt graph-data integration platform to various operation systems, Qt is chosen as C++ development tool and MySQL is chosen as basic database.
Qt features
Cross-platform: Microsoft Windows, Linux, UNIX, Solaris, Sun OS etc.
Object-oriented, nice reusability Abundant API
2D/3D modules, supporting OpenGL Efficient graph management mechanism MySQL features
Cross-platform: Microsoft Windows, Linux, UNIX etc. Strong inquiry ability
Multi-thread programmed kernel Large-scale database
High Reliabilityreliability B. Database structure
The relational database of PDSA graph-data platform is divided four types. These are power system elements and common parameters database, calculation database,
calculation result database and user-defined module database. In order to meet fast calculation and get online data, a real-time database called fasted is selected. The relationship of databases is shown in Fig.2.
Fig. 2. Relationship of databases
C. Automatic drawing of single-line substation
Automatic drawing of single-line substation diagrams can reduce the difficulty in system maintenance and solve the key questions (viz. integrality, order and rapidness) of auto-drawing. The main idea of the approach is: first, summarizing substation template from diagrams, which corresponds to one basic branch unit (i.e., one in-line and one out-line); then extending the unit to generate all lines according to the defined template. The PSASP Graph-Data integration platform guarantees the integrality of graph and data.
Typical templates include single-bus connection, double-bus connection, double-double-bus connection with bypass branch, 3/2 connection and so on, which have been defined by PSASP graph tool. In template, the element type should be defined. After the number of in/out-lines and the distance between in/out-lines are given, more in-lines or out-lines of the certain voltage level of the substation are generated. Because all elements in template are drawn orderly, the layout of all extended elements in diagrams is more reasonable and orderly. If data of power equipment have been given in database, template type can be judged through topology (DFS- Depth-first search) method. Based on Graph-Data integration platform of PSASP, elements on graph generated by template are associated with data in database.
III. STUDY AND REALIZATION OF FRAMEWORK Different from PSASP graph-data integration platform in section II, PDSA graph-data platform needs new functions. On online-run state, new features of framework are put forward:
1. It can display geographical diagrams and single-line substation diagrams in the same framework, not in two different frameworks.
2. It can display security assessment results and assistant decision results intuitively and clearly.
3. Layout of GUI framework should be compact, menu should be concise.
4. It can meet online system requirements, assessment results refresh more rapidly.
5. Man-machine operation should be simply.
On online-study state, the framework has some features such as power system diagram edit, history data download, fault list edit, parallel computing submission and computing results browse, so dynamic security assessment status should
be added in the framework. All analysis and assessment results can be shown by type of diagrams or tables.
On offline-study state, besides features of online-study state, the framework has features of projects manger, offline and online data maintenance and so on.
It is summarized that online-run and online-study can use one framework because of their similar functions. Offline-study uses the framework reconstructed from PSASP former framework. In PSASP framework, singe-line diagrams and geographical diagrams in different framework, but new online-run and online-study framework needs integrate them.
Three states in two frameworks are proposed. Two frameworks are online framework (run and online-study) and offline framework. Three states functions are described in TABLE I.
TABLE I
THREE STATES OF PDSA GRAPH-DATA INTEGRATION PLATFORM
State Main functions
Online-Run A. Displaying load flow results on geographical diagram and single-line
substation diagram
B. Displaying dynamic security analysis results clearly
C. Displaying assistant decision results rapidly and exactly
Online-Study A. Providing analysis of online data by parallel computing platform
Offline-Study A. Managing online and offline data and graph B. Editing geographical diagram and
single-line substation diagram
C. Providing analysis of offline data by parallel computing platform
A. Online framework
Main windows of online framework are shown in Fig.3. Diagrams window: geographical diagram, single-line substation diagram, dynamic tables, stability limit Schematic diagram, index graph etc.
Warning window: warning detail information Security assessment and assistant decision results
window
Warning light: security assessment warning tip light
Fig. 3. Main windows of online framework
B. Offline framework
Main windows of online framework are shown in Fig.4. Project manager window: geographical diagram and
single-line substation index window
Computing status switch window: switch between different computing status
Information feedback window: man-machine center
Fig. 4. Main windows of offline framework
C. Main functions of PDSA graph-data integration platform Main modules are studied and summarized and
corresponding functions are given in TABLE II.
TABLE II
MAIN MODULE OF PDSA GRAPH-DATA INTEGRATION PLATFORM
Module Main functions
Graph-Data integration
Editing power grid diagrams and data, auto-drawing, results display Data manager Online and offline Data and model manger:
edit, storage, control Study state
control
Communication with parallel computing platform, analysis results callback and display Visualization Two-dimensional and three-dimensional
visualization of data and results
IV. VISULIZATIONOFPDSAGRAPH-DATA PLATFROM
Effective power system operation requires engineers and operator to analyze amounts of multivariate data.
Visualization technologies have been shown to greatly help people understand system situation and ideas exactly and rapidly. These technologies help engineers reduce some errors and accidents. Using power system visualization, all data is presented in geographical diagram or single-line diagram. In PDSA graph-data platform, visualization is shown by geographical diagram, which includes two dimensional and three dimensional types which can used for both offline and online frameworks of PDSA.
A. Two dimensional visualization
Animated arrows: Animated arrow provides an intuitive understanding of power flow in a transmission system network. The size, color and orientation indicate the magnitude of power flow on transmission lines. Dynamic line overload pie charts: Dynamic line load
factor pie charts are used to assess to location and indicates line flow as a percentage of the line. Pie charts can display or not by display percent setting.
Computing status switch toolbar Project manager window Information feedback window Diagram window
Security assessment and assistant decision results window
Warning window
Fig. 5. Animated arrows and dynamic pie charts
2D contouring: 2D contouring shows the magnitude of substation voltage or line power. 2D contouring technology is mature, but in PDSA platform, a new method called OpenGL rectangle contouring is put forward. Main idea of the method is to decrease calculation. The whole diagram is divided to m rows and n columns, then m* n rectangles are formed. If each rectangle colored only once, efficiency is improved. OpenGL can give more real effect for each rectangle than single color in it. If m or n is set 200, 2D contouring effect is acceptable.
Fig. 6. 2D contouring in PDSA platform
Curve Browser: Curve browser is developed as a common power system curve browser. It can display all kinds of curves of transient stability, voltage stability, small-signal stability analysis. In Fig.7, two group generators are displayed in curve browser.
Fig. 7. Small-signal curve with two groups
Dynamic efficient tables: it can display dynamic data by tables. Dynamic table supports field name map, colored celled display etc.
B. Three dimensional visualization
Three-dimensional visualization has proven helpful when trying to visualize the interrelationships of several pieces of data simultaneously. The visualizations of PDSA base on the existing two-dimensional geographical diagrams used in power systems. Those concerned with power systems are familiar with this environment, making the jump to three-dimensions easier.
Three-Dimensional Displays: A third visualization
technique that has been examined is the use of interactive 3-D displays that use real-time computer graphics in such a way to make the user believe it is part of a virtual domain. The ability to extend objects in the z direction is a potential advantage of using 3D space since it permits the visual display of additional information by making the height of the object potentially proportional to some numeric value or variable.
3D surface contouring features of PDSA: 3D surface contouring of PDSA provides efficient refresh mechanism and rapid interactive response. Users can move canvas, zoom in or out and rotate diagram view through mouse operation. The peak standing above substation describes voltage of the substation. Certainly, the other parameters of power system can be shown through 3D surface contouring. Similarly, 3D histogram has also been implemented in PDSA graph-data integration platform.
Fig. 8. 3D contouring in PDSA platform
V. APPLICATIOINS
The platform of graph-data integration of PDSA is well used Electric Power Dispatching Centre of State Grid, Electric Power Dispatching Centre of Guangdong province etc. Below functions and features are applied well.
Monitoring system real-time run status and giving accurate assessment and assistant decision information Analyzing on real-time data on online-study and
offline-study state
Seamless exchange interface of single-line substation diagrams, such as SVG, G language
Efficient 2D and 3D contouring
Graph and data maintenance conveniently VI. CONCLUSIONS
Graph-data integration platform of PSASP Dynamic Security Assessment (PDSA) system is studied in this paper. It is implemented by writer and colleagues. The graph-data
platform framework is proposed. Main function modules are summarized. The visualization of power system elevates operation and decision efficiency.
With the rapid development of smart grid, it is a tendency to build feature-rich and flexible graph-data integration platform. Visualization will be further developed because of the evolution of computer science.
VII. REFERENCES
[1] Wu Zhongxi and Zhou Xiaoxin, "Power System Analysis Software Package (PSASP)-An Integrated Power System Analysis Tool,"
International Conference on Power System Technology, 1998. vol.1 pp.7-11
[2] Wu Zhongxi “China Electric Power Research Institute, Power System
Analysis Software Package PSASP) User‘s Manual”,1993.(in Chinese) [3] YS.Ong,H B .Gooia ndC .K.Chan ,“Algorithms for automatic generation
of one-line diagrams”
[4] Shao Lidong, Wu Wenchuan, Zhang Boming, “A CIM-BASED INTERACTIVE GRAPHICS SYSTEM FOR EMS/DMS,” Automation of Electric Power Systems, 2003 Vol.20
[5] Ashish Vashisht and K.S.Swarup, “Visualization for Power Systems Operation for Economic Energy Interchange in Power Pools,” IEEE Indicon 2005 Conference, Chennai, India, 11-13 Dec.2005
[6] Raymond P.Klump, James D.Weber, “Real-Time Data Retrieval and New Visualization Techniques and Energy Industry”, Proceedings of the 35th Hawaii International Conference on System Sciences, 2002 [7] YAN Jian-feng, YU Zhi-hong, TIAN Fang, ZHOU Xiao-xin ,“Dynamic
Security Assessment & Early Warning System of Power System”, Proceedings of the CSEE, Vol.28 No.34 Dec. 5, 2008
[8] Chen Zhenzhen, Zhang Jinhua, “Design and Implementation of GUI software for Real-time Electro-Magnetic Transient Simulation based on PC cluster”, 2004 International Conference on Power System Technology - POWERCON 2004, Singapore, 21-24 November 2004
VIII. BIOGRAPHIES
Kang Jiandong graduated from China Agricultural University in 2001, received his M.S. degree in Computer Science and Technology from China Electric Research Institute (CEPRI) in 2009. He has been engaged in research work at CEPRI since 2001. His special fields of interest include Graph-Data supported platform of power system and power system simulation.
Li Yalou was born in October, 1974. He graduated from Huazhong University of Science and Technology in 1997, received his M.S. degree and Ph.D. in Electrical Engineering from the Electric Research Institute of China in 2000 and in 2003 separately. His current research fields include real time power system simulation and power system analysis software.
