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IEEE Transactions on Power Systems, Vol. 13,No. 4, November 31998 1205PowerGraf: An Educational Software Package for Power Systems Analysis andDesign

Jian Y ang, Student Member, IEEE Max D Anderson, Senior M ember, IEEEUniversity of hlissouri - RollaRolla,MO 155409-0040A bstract -- The purpose of PowerGrdf i s to present agraphical user interface (GUI) and a convenient tool forbuilding one-line diagrams displaying data. The GU I is openand friendly for power systems design, analysis and control,because a picture provides a better illustration of cause andeffect relationships than a tabul ar printout does. Basicelements such as buses, lines and transformers are given suchthat the power system topology is easily drawn with this tool,and the system parameters are entered on the picture andchecked visually. This enables the power system topology andthe system data to be shown on one picture page. Theadvantages of these graphics are that users can view lineoverloads, low voltage problems, and outages on theoverall(tota1) system. I n addition, i t is possible to see the

impact of contingencies on the system. To date, PowerGraf 3.0together with an instructional demo has been used to teachpower systems courses in E lectrical Engineering Department atthe University of Missouri-Rolla (UM-Rolla). I t is alsoavail able on the Computer Learning Center network to helpstudents design their own optimal power systems.Index Terms -- Educational Software Package, ToolBook,GU I, One-line Di agram, Power Systems Analysis and Design.

I . INTRODUCTIONSeveral programs have been developed to help usersvisualize power system operation['-' I. Overbye['"' hasdeveloped Power World, which uses animation to show

power flows, voltages and other parameters over time.Mahadev and C hr i~ti e[~-~'ith a similar purpose, are using"task adaptive visualization" methods. L ine widths andcolorsareused to show line load changes. Circles are usedto show generator limits. Both have made large existing;power systems easier to visualize.The objectives of this project are the development ofeducational facilities for a course in power systemsengineering with an integrated laboratory. It wi ll be used forPE-290-PWRS-0-12-1997 A paper recommended and approved bythe IEEE Power Engineering Education Committeeof the IEEE PowerEngineering Society for publication in the IEEE Transactions on PowerSystems. Manuscript submitted J uly 28, 1997; made available forprinting December12, 1997.

course problem solving, design projects and self-teachiingexcises as well as demonstrations and tutorials.T o~lB ook[ '~-'~]as been selected as the platform for thispackage because of its capability and user friendliness. Inaddition ToolBook is being used by first and second yearengineering students as part of the Basic EngineeringSoftware for Teaching (BEST) curricula in Dynamics,Statistics and Circuits at UM -Rolla. Hence, these studentswill be familiar with using ToolBook applications beforethey take power systems courses.ToolBook isa software construction set that can be meldtodevelop Windows applications. A ToolBook application hasall the features of Windows applications -- a graphical userinterface, event driven programming, and the abilib tointeract with other Windows applications -- but doesn'trequire the time and efforts of using languages such as C,C++, Pascal, or FORTRA N.ToolBook applications can be created for almost anypurpose, especially applications that benefit from a graphicaluser interface. Examples of applications created withToolBook include: (1) hypermedia applications such as on-line encyclopedias, (2) interactive training applications, (3)tutorials, (4) database applications, and (5) gameapplications.ToolBook is an interactive environment for both creatingand running applications. ToolBook's drawing tools areused to create the visual interface of an application such asgraphics, buttons, and fields. To define the behavior ofelements in the application, ToolBook's programminglanguage, OpenScript, is used. For example, anything thathappens when a user clicks a button in the application can bedefined by OpenScript.Many applications, that require a graphical output anddata entry by the user, can be made to run under ToolBook.ToolBook handles all the tasks of communicating withWindows to display elements onscreen, detect mouse cllicks,and kcystrokes. Because ToolBook is used both to developand to run applications, an application can be revised at anytime to change the information it contains, the way it isorganized, or the tasks it performs.ToolBook uses the metaphor of a book as the basis for theapplication. This organization allows users to create and usesophisticated techniques such as hyperlinking and animationas part of their applications. ToolBook is also an Object-Oriented environment; all the visual elements of theapplication -- button, fields, graphics,viewers, andeven the

0885-8950/98,/$10.00 0 1997IEEE


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1206pages and backgrounds -- are objects. Each object has a setof properties that define the object's appearance andbehavior.Applications are developed in ToolBook's Author level,which is the mode that includes drawing and programmingtools. New books can be created, objects can ;be created andmodified on pages, and programs can be written inOpenscript. Conversely, users run applications atToolBook's Reader level, a mode that includes everythingneeded to run the application, but no development tools.Users can navigate to particular pages and add pages; type,edit, and format text in fields; print; and r~inOpenscriptprograms. ToolBook will interface with most programswritten in FORTRAN, Pascal, C or C++ for which thesource code is available or for which the input and outputdata formats are known to the users.

11 CONSTRUCTION AND INFORMA TION FLOWDIAGRAM OF POWERGRAFPowerGraf is developed under the multimedia ToolBookenvironment. It is mainly an open and friendly graphicaluser interface for power systems analysis and design Itsmain features include: (1) One line diagram of pon.ersystems can be drawn very easily. (2) Multimediaapplications can be added to this interface very convenientl>-.(3) Power flow and other power applications programmedwith most languages can be added to this interface withoutdifficulty. The construction and information flow ofPowerGraf is shown in Figure 1

PowerGraf I-

Fig. 1. Constructionand information flowof PowerGraf.111. COMPUTING REQUIREMENTS AND USER STEPSFOR POWERGRAFA Windows environment is needed. A PC wilh 16MB ofRAM and 16MB of free disk space is desired. A Pentium 90or better is recommended because of the long run times.

User steps needed to draii a one-line diagram Fiith dataincluded1 Enter PonerGraf and select the "A uthor" mod2 Asingle generator and bus are shonn in Figure 2 This pimrepaolrides an eas) starting point for draming the 1-linediagram Bus number "1" is defined as the swing bus (This

causes no loss in generality because the buses can alna s berenumbered )

InputEditor

#Fig 3 The completed layout of a7- ~USower system23

The main tools available are the "Element" menu andthe "Tool Palette" In the "Author" modeOn the Input Editor page, select the "Element" menuanal choose the "A dd" command to add a bus a line or atransformer Go to the Background fi rst Place theautomatically created bus or transformer ataproper place, ordraw a new line and place the correct line number on itThen go back to Foreground Move the automaticallycreated field to the corresponding newly added element


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1207opened, press F3 to go to the "Reader" mode.2. Enter the power system parameters in the correspondinginput fields on the Input Editor page.3. A fter all the input data have been entered correctly, savethe study in the 'Reader" mode. PowerGraf will give thestudy an extension .psa as a default. A completed input fo'r astudy is shown in Figure 4.

Finally go to the Bus Output Viewer and Line Output Viewerpages to make sure that their fields are all placed correctly.4. Repeat step 3 until the expected one-line diagram hasbeen completed. If it is necessary to modify the layout,please remember to use the "Element" menu to "remove" or"renumber" the existing elements. Otherwise, PowerGrafcannot memorize the modified data correctly.5. Give the system one-line diagram or layout a name andsave it. PowerGraf wil l give the layout an extension .tbk as adefault. A completed layout is shown in Figure 3.If an existing diagram needs to be modified, it can beopened at Step 1. Steps2 - 5should be followed to make thenecessary changes and corrections, and the layout stored as a*.tbk file.Input data editingIn PowerGraf, input data together with theircorresponding one-line diagram make a study. Studiesprovide the sets of data for power simulations. Data arestored in *.psa files in the "studies" sub directory of thePowerGraf directory. Editing, saving, and loading of studiescan only be done in the "Reader" mode.

1.From the "A uthor" mode, where a layout is created or

Runningapower f low programPowerGraf provides linkages to an existing power flowprogram. After the desired one-line diagram has beencreated and all input data have been entered and saved, apower flow study can begin. This is done by selecting the"Power Flow" from the "Run" menu. A power flow programcan only be run in the "Reader" mode. This will save thestudy again, so all changes since the last save will be used.Users will be asked to name the run. This allows the users tokeep track of which run is which when the output files areprinted. The output can now be viewed by either seleci.ing"V iew Output Fi le" from the "File" menu or "View Bus/L,ineOutput" from the "Options" menu. Examples of bus and lineoutputs are given in Figures5and6 respectively.

Fig. 4. The


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1208

e Edit Opt ions Bun Element I e x t page Help

Fig 5 Bus output of the 7-bus power system

Fig. 6. I

~ ~File Edit Options Bun Element Iext Page Yelp

n e utput of the7-bus power system


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1;!09IV. ON-LINE HELP, INSTRUCTIONAL DEM O ANDWWW-BASED USER MANUA L

On-line Help FilesThe help fi le can be viewed in two different ways. First, itis a PGV3HELP.DOC f ile, which can be opened usingMicrosoft Word. From here it can be printed or edited. Itcan also be accessed using the "Index" command from the"Help" menu. This command will run the bookPGV 3HEL P,TBK , which loads its information fromPGV3HELP.TXT,I nstructional DemoAn instructional demo can be run from PowerGraf usingthe "Demo" command from the "Help" menu. This wil l runthe book PGDEM O.TBK . The demo containsa showcase ofvarious methods for solving a 2-machine 6-bus power systemproblem.A low voltage and line overload problem was solved bydesigning the least cost compensation method using: (1)Reallocation of generation, (2) Adding capacitor banks, (3)Adding transformers, and (4) Adding (or/and removing)transmission lines. Finally an optimal design was found.The complete scenarios show the user the overall effect onthe power system of each of the compensation methods.Parameter values are shown on the same picture with powersystem configuration. The main menu of this on-lineinstructional demo is shown in Figure 7.

Fig. 7. Main menuoftheon-l ine nstructional demo.WWW-based user manual and on-line demoeven more conveniently, aWWW-based user manual wascreated as shown in Figure8. Its URL is:

In order to help students print or read the user manual

htt p: / / www um. edu/ - yangPowerGrafRJ serManua1.tmlA similar WWW-based on-l ine instructional demo is also

available at:http://www.umr.edu/-yang/PowerGraf/Demo.html

Fig8 WWW-baseduser manual of PowerGraf

V. CONCLUSIONA convenient tool PowerGraf 3.0 for completing powersystem studies/designs is presented. Power systemparameters are entered on a picture and checked visually.Output is displayed with the picture to show users bettercause/effect relationships. PowerGraf 3O and aninstructional demo have been used to teach power systemscourses in Electrical Engineering Department at UM-Rcdla.They are also available in the computer learning cente:r tohelp students design optimal power systems.A more powerhl PowerGraf with better visualizationis still under development. We are ;alsoconsidering using M atlab for calculations because most of

the students are famil iar with it. In the meantime, with thederegulation of power systems, many new problem "^^^willappear. PowerGraf can be easily extended to include theseconcerns.ACKNOWLEDGMENTS

The authors wish to thank the Dean of Engineering, theEE Dept. Chair, and the Intelligent Systems Center forsupport of this project. Thanks are given to Dr. CharlesGross, Auburn University for providing the first power flowprogram used with ToolBook in this application.

REFERENCES[I ] T. J. Overbye, P. W. Sauer, C. M. Marzinzik, and G. Gross, "A User-Friendly Simulation Program for Teaching Power System Operations,"IEEE Transactions on Power Systems, vol. PWRS-10, pp. 1725-1733,

November, 1995
http://www.umr.edu/-yangPowerGrafRJserManua1http://www.umr/http://www.umr/http://www.umr.edu/-yangPowerGrafRJserManua1


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1210[2] T. J Overbye, R. P. K lump and J . D. Weber, "Development andApplication of a Power System Simulation Environment," 1996 MidwestSymposium on Circuits and Systems, Ames, 1.4, August 1996.[3] T . J . Overbye, G. Gross and P. W . Sauer, "Understanding Third PartyAccess Issues: A Simulation and Visualization Tool for NontechnicalProfessionals," 1996 Power Systems Computation Conference (PSCC),Dresden, Germany, pp.621-627, A ugust 1996.[4] T . J . Overbye, P. W. Sauer, G. Gross, M. J . Laufenberg and J . D. Weber.

" A simulation tool for analysis of alternative paradigms for the newelectricity business," Proc. 20th Hawaii I ntemational Conference onSystem Sciences, pp. V634-V640, Maui, HI , anuary 1997.[5] T . J. Overbye, G. Gross, M. J . Laufenberg and P. W Sauer, "VisualizingPower System Operations in the Restructured Environment." I EEEComputer Applications in Power," pp. 53-58, January 1997.[6] P. M. Mahadev, R. D. Christie, "Envisioning Power System Data: Conceptsand a prototype System State Representation," lEEE Transactions onPower Systems, Vol. 8,No. 3, August 1993.[7] R. D. Christie, "Toward a Higher Level of User Interaction in the EnergyManagement Task," Proceedings of the IEE E International Conference onSystems, Man and Cybernetics, San Antonio, TX , October 2-5, 1994.[8] P. M. Mahadev, R. D. Christie, "Case Study: V isualization of an ElectricPower Transmission System," Proceedings of Visualization 1994, October12-21, 1994, Washington D. C.[9] P. M. M ahadev, R. D. Christie, "Minimizing User Interaction in EnergyManagement Systems: Task Adaptive V isualization," IEEE Transactionson Power Systems, Vol . 11,No. 3,August 1996.[ IO ] J . A . Huang, F. D. Galiana, "A n Integrated Personal Computer GraphicsEnvironment for Power System Education, Analysis, and Design" IEEETransactions on Power Systems, Vol. 6,No. 3, August 1991[I 11A . Thiyagarajah, B. Carlson, J . Bann, M. Mirheydar, S. Mokhtari, "SeeingResults in a Full Graphics Environment," IEEE Computer A pplications inPower, July 1993.[I21 P. R . D 'h ou r and W. R. Block, "Modern User Interface RevolutionizesSupervisory Systems," lE EE Computer Applications in Power, J anuary1994.[131 K. Ghoshal, L . D. Douglas, "GUl Display Guidelines Driving WinningSCA DA Projects," IEEE Computer Applications in Power, April 1994.[14]G. P. de Azevedo, C . S. de Souza, B. Feijo, "Enhancing the Human-Computer Interface of Power System Applications," IEE E Transactions onPower Systems, Vol. 1 , No. 2, May 1996.[15]Too/ Book* ser M anual, Version 3.0, Asymetrix Corporation, 1994.[161OpenScrrpt Reference Manual , Asymetrix Corporation, 1994.[I 71 J ames D. Foley, A ndries Van Dam, Steven K. Feiner and John F. Hughes,Computer G raphics Pr inciples and Practice, Addison-Wesley PublishingCompany, ISBN 0-201-121 10-7, Second Edition, 1990.[I81 Blake, M . "GAPP: A Proposed Solution to the Parallel Flow Problem".Proc. 55th American Power Conference, Mar, 1993[I91 Koller, C ., T. Kolenda, "Significant Issues Facing the Interconnection ofIndependent Power Producers and the Util ity", Proc. Annual A mericanPower Conference, Vol.55,March 1993.[201Nadira, R., F.F. Wu, D.J. Maratukulam, E. Weber, C. Thomas, "BulkTransmission System Loss Analysis", IEEE T-PWR S. Vol. 8. no. 2. May,1993, pp 405-416.[2l l Russell, T., L. Mogridge, "Some Operational Issues Between lndependentGenerators and an Independent Grid", Proc. American Power Conference,March 1993.[221 Sandrin, P., L Dubost, L . Feltin, "Evaluation of Transfer Capabilitybetween Interconnected Utilities", Proc. 1 th Power Systems ComputationConference (PSCC), Avignon, August, 1993, pp 981-985.

[%3]Baldick. R. , E. Kahn, "T ransmcsicn Planning Issues in a CompetitiveEnlironment", IEEE T-PtVRS. 1.01, . no. 4, Nov, 1993, pp. 1497-1403.* ToolBook is a trademark of As)mstnx. 110-110th Ave. N E, Sui te 700,Belle\ ieu.WA 98004-5840

J ian Y ang received dual BS degrees in ElectricalEngineering and Computer Science in 1991 fromTsinghua University, Beijing, P. R. China. Hereceived his MS degree in Electrical Engineering in1994 from Tsinghua University. He joined thesystems development and planning department ofNorth China Electric Power Design Institute inBeij ing from June 1994 to June 1994.At present, he is LL Ph.D. candidate of ElectricalEngineering Department at UM-Rolla. He is anactive studentmember of lE EE and was elected tobe a member of Tau Beta Pi, a nationalengineering honor society, in April 1997

LMaxD. A nderson (M '67, SM '80) received theB S E E and M S E E degrees from OklahomaState University He attended NorthwecternUniversity for postgraduate studies and completedthe Ph D degree from Anzona State University in1967 After 13 years of engneering responsibilityin the aerospace industry, he joined the faculty ofUM -Rolla as Associate Professor He wasappointed Professor of E lectncal Engneenng in1982 He has served as Power Area Coordinatorfor 105ear5Dr Anderson's research interests lie in the areasof electnc utility systems design and operationSpecific \cork includcr \ irualization technology for energy control centers,dispatcher training and training simulators, econormc analysis and modeling,and enerE storage s> rtems His research activities havebeen supported by theNational Science Foundation, Electnc Power Research Institute, theIntemational L ead Zinc Research Organization, and the U S Department ofEnergy Dr Anderson has ober SO technical publications and he has had over$500,000 in recearch grants and contracts in the past five years1Dr Anderson is 3 senior member of IEEE He is an active member of theIEEXPES Poaer S) stem Engineenng C omt tee and the followingsubcommttees and uorking groups I ) Power System OperationsSubconmttee 2 1 Joint Control Center Working Group, 3) Working Group onOperator Training where he served as Chairman for 10 years and 4) FullGraiphics A orAing Group He has been responcible for paper cessions, panelses'ioni and vorkshops for these groups In additi on, he is a revlewer oftechnical paper5 for the IEEE-PES summer and winter meetings, andsubquen t publication in the IEEE transactions on Power Systems He is pastCharman of the Rolla Subsection of the IEEEHe I S a member of Tau Beta Pi, Eta Kappa Nu, Slgma Xi and a regsteredprofessional enpneer in the states of M issouri and Oklahoma, and the pro\inceof Ontano Canada

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