DISTRIBUTION SYSTEMS RELIABILITY ANALYSIS PACKAGE USING MATLAB GRAPHICAL USER INTERFACE (GUI)

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1 Internatonal Journal on Techncal and Physcal Problems of Engneerng (IJTPE) Publshed by Internatonal Organzaton of IOTPE ISSN IJTPE Journal March 2012 Issue 10 Volume 4 Number 1 Pages DISTRIBUTION SYSTEMS RELIABILITY ANALYSIS PACKAGE USING MATLAB GRAPHICAL USER INTERFACE (GUI) H. Shayegh 1 Kh. Valpur 1 M. Haydar 1 H.A. Shayanfar 2 1. Techncal Engneerng Department, Unversty of Mohaghegh Ardabl, Ardabl, Iran, hshayegh@gmal.com 2. Center of Excellence for Power System Automaton and Operaton, Electrcal Engneerng Department, Iran Unversty of Scence and Technology, Tehran, Iran, hashayanfar@yahoo.com Abstract- Ths paper presents a software package whose am s to provde a tool to be used for relablty ndces analyss n radal dstrbuton system. It contans all the man elements found n practcal system. The software package employs the Graphcal User Interface (GUI) capabltes of Matlab. The man advantage of the proposed package s that the relablty ndces analyss can fnd n dfferent states for a dstrbuton network. Moreover ths software can plot relablty ndces n a fgure. Thus, t can be a useful tool for operator, manufacture and costumers n dstrbuton network. Keywords: Relablty Indces, Radal Dstrbuton System, Graphcal User Interface. I. INTRODUCTION The usage of computer smulatons n the classroom s ganng popularty for partcularly power engneerng educaton [1, 2]. It s apprecated that, most of the computer smulaton studes requre a GUI that makes user nteracton easer and more effectve when compared wth classcal text based methods [3]. A successful GUI not only asssts easy and effectve data preparaton process but also permts post processng of the results and most vtally permts the user to see everythng at once. The relablty ndces analyss s an mportant ssue n dstrbuton network plannng and operatonal studes. The relablty ndces that have been evaluated usng classcal concepts are the three prmary ones of average falure rate, average outage duraton and average annual unavalablty or average annual outage tme. Although the three prmary ndces are fundamentally mportant, they do not always gve a complete representaton of the system behavor and response. The addtonal ndces that are most commonly used are customer-orentated ndces and load-and energy- orentated ndces [4]. In ths paper, we descrbe an educatonal software package whch s called Relablty Dstrbuton Analyss Package (RDAP) and developed n Matlab s GUI. The package allows the student to acheve dstrbuton system relablty analyss usng dfferent protectve devce, loop swtches, lnes/cables and repar/replacement transformers. The paper s organzed as follows: Secton II descrbes Evaluaton technques for radal dstrbuton system; Secton III descrbes GUI n Matlab; Secton IV evaluates GUI package n a RBTS test system and Secton V summarzes the man pont and results of ths paper. II. EVALUATION TECHNIQUES A radal dstrbuton system conssts of a set of seres components, ncludng lnes, cables, dsconnects (or solators), bus bars, etc. A customer connected to any load pont of such a system requres all components between hmself and the supply pont to be operatng. The basc dstrbuton system relablty ndces are the three Load Pont (LP) ndces: (1) Average falure rate λ s ; (2) average outage duraton r s ; (3) annual outage duraton U s [4]. The prncple of seres systems can be appled drectly to these systems as follows: λ = λ (1) U s s = λ r (2) Us rs = (3) λs In order to measure the system s relablty, certan ndces are used. In ths secton some of most commonly used metrcs are descrbed. For any updates on the defntons gven below and for some of less commonly used ndces. Relablty ndces have two categores: System-wde ndces and customer ndces. The former s used to gve an nsght of the overall system performance whle the latter s more specfc and reflects what the ndvdual customer experences. These are also classfed dependng on the nterruptons dealt wth: sustaned or momentary. Thus, we have: rn SAIDI = (4) NT N SAIFI = (5) N T 80

2 Internatonal Journal on Techncal and Physcal Problems of Engneerng (IJTPE), Iss. 10, Vol. 4, No. 1, Mar rn SAIDI CAIDI = = N SAIFI (6) NT 8760 rn ASAI = NT 8760 (7) ENS = L U (8) where, N s the number of nterrupted customers for each nterrupton event durng the reportng perod, N T s the total number of customers served n the area. The customer-and load-orented ndces descrbed are very useful for assessng the severty of system falures n future relablty predcaton analyss. They can also be used, however, as a means of assessng the past performance of a system. In fact, at the present tme, they are probably more wdely used n ths respect than as measures of future performance. Assessment of system performance s a valuable procedure for three mportant reasons [4]: a) It establshes the chronologcal changes n system performance and therefore helps to dentfy weak areas and the need for renforcement. b) It creates exstng ndces whch serve as a gude for acceptable values n future relablty assessments. c) It facltates prevous predctons to be compared wth actual operatng experence. There are two basc approaches to conductng system relablty studes. The varous methods can be generally dvded nto the applcaton of analytcal models and approaches, and the use of Monte Carlo smulaton. The relablty assessments presented n ths paper were performed usng analytcal technques. The method adopted n the paper does a falure modes and effects analyss whch needs the dentfcaton of the dfferent component falures modes and the effects of these falure events on load pont and system success. It s assumed here that the component falure rates and outage tme are exponentally dstrbuted. Two sets of relablty ndces have been defned [5] for dstrbuton systems, namely the basc load pont ndces and the system performance ndces. The basc ndces are mportant from an ndvdual customer s pont of vew, but do not gve an overall apprecaton of the system performance. The overall dstrbuton system performance s obtaned by a weghted aggregaton of the ndvdual load pont ndces [10, 11]. The algorthm for calculaton relablty ndex for contngency j, when alternatve path by loop swtches s provded s gven by: 1. Consder a contngency j 2. Fnd the frst crcut breaker n the path toward feeder 3. Dsconnect faulty zone by ths CB 4. Fnd the frst sectonalzng swtch n the path toward feeder, If there sn t any sectonalzng swtch n the path, go to next step else go to Fnd all load ponts whch are deenergzed by CB trp and calculate, relablty ndex usng equatons for the repar tme requred to restore energy (t rep ) then go to step Fnd all load ponts whch are deenergzed by CB trp and calculate, relablty ndex equaton for swtchng tme of remote controlled sectonalzes (t sec ) 7. Dsconnect remote controlled sectonalzng swtch and connect CB and fnd new load ponts whch are deenergzed and calculate relablty ndex for the swtchng tme of loop swtch (t te ) to restore energy from alternatve path. 8. Connect loop swtch and determne relablty ndexes for repar tme requred for the remaned faulty zone. 9. Total relablty ndex for contngency j s the sum of three calculated n steps 6, 7, 8, and then go to step 1. Fgure 1 shows step by step swtchng ntervals of breaker, sectonalzes and loop swtch when a fault occurred between S 2 and S 3 [6]. III. GRAPHICAL USER INTERFACES A graphcal user nterface s a pctoral nterface to a program. A good GUI can make programs easer to use by provdng them wth a consstent appearance and wth ntutve controls lke pushbuttons, lst boxes, slders, menus, and so forth. The GUI should behave n an understandable and predctable manner, so that a user knows what to expect when he or she performs an acton. For example, when a mouse clck occurs on a pushbutton, the GUI should ntate the acton descrbed on the label of the button. CB Fault occurs between S2 CB trps S2 & S3 open CB closes S5 closes : Interrupton areas : Crcut Breaker : Close : Open S1 S3 S4 S5 S2 Contngency : Secton or Loop swtch : Close : Open Fgure 1. Process of swtchng ntervals to solate a fault A graphcal user nterface provdes the user wth a famlar envronment n whch to work. Ths envronment contans pushbuttons, toggle buttons lsts menus, text boxes, and so forth, all of whch are already famlar to the user, so that he or she can concentrate on usng the applcaton rather than on the mechancs nvolved n dong thngs. However, GUIs are harder for the 81

3 Internatonal Journal on Techncal and Physcal Problems of Engneerng (IJTPE), Iss. 10, Vol. 4, No. 1, Mar programmer because a GUI-based program must be prepared for mouse clcks (or possbly keyboard nput) for any GUI element at any tme. Such nputs are known as events, and a program that responds to events s sad to be event drven. The three prncple elements requred to create a Matlab Graphcal User Interface are [7]: 1. Components: Each tem on a Matlab GUI (pushbuttons, labels, edt boxes, etc.) s a graphcal component. The types of components nclude graphcal control (pushbuttons, edt boxes, lsts, slders, etc.), statc elements (frames and text strngs), menus, and axes. Graphcal controls and statc elements are created by the functon ucontrol, and menus are created by the functon umenu and ucontextmenu. Axes, whch are used to dsplay graphcal data, data, are created by functon axes. 2. Fgures: The components of a GUI must be arranged wthn a fgure, whch s a wndow on the computer screen. In the past, fgures have been created automatcally whenever we have plotted data. However, empty fgures can be created wth the functon fgure and can be used to hold any combnaton of components. 3. Callbacks: Fnally, there must be some way to perform an acton f a user clcks a mouse on a button or types nformaton on a keyboard. A mouse clck or a key press s an event, and the Matlab program must respond to each event f the program s to perform ts functon. For example, f a user clcks on a button, that event must cause the Matlab code that mplements the functon of the button to be executed. The code executed n response to an event s known as a callback. There must be a callback to mplement the functon of each graphcal component on the GUI. IV. SOFTWARE DESCRIPTION Developed package, called RDAP, conssts of one man wndow that allows user to solve relablty ndex for radal dstrbuton systems. All program routnes of the package use Matlab m-fles, verson 7.8. The man wndow, gven n Fgure 2, dvded nto three sectons called system data, protectve devces and relablty ndex results. The system data secton provdes user to nput the system relablty ndex and branch data. In system data, user enter nformaton depended to number secton, sendng node, recevng node, man or lateral secton, protectve devce (1=breaker, 2=recloser, 3=swtch and 4=fuse), exst transformer (1=s, 0=sn t), secton length, repar tme, swtchng tme, customer number, load and customer types. After enter data, user can by rado button defned lne or cable, repar or replacement transformer, te ponts moreover software can plot radal dstrbuton network, wth clckng on calculaton, software reply relablty ndex. Now user can see affect protectve devce. User can evaluate the followng cases n dstrbuton network [8]: 1. Case A: Dsconnects, fuses, alternate supply, transformer repar. 2. Case B: No dsconnects, no fuses, no alternate supply, transformer repar. 3. Case C: No dsconnects, fuses, no alternate supply and transformer repar. 4. Case D: Dsconnects, no fuses, alternate supply and transformer repar. 5. Case E: Dsconnects, fuses, alternate supply and 6. Case F: Dsconnects, no fuses, no alternate supply and transformer repar. Fgure 2. Man wndows for relablty dstrbuton network analyss 82

4 Internatonal Journal on Techncal and Physcal Problems of Engneerng (IJTPE), Iss. 10, Vol. 4, No. 1, Mar Case G: Dsconnects, fuses, no alternate supply, transformer repar. 8. Case H: Dsconnects, fuses, no alternate supply, 9. Case I: No dsconnects, no fuses, no alternate supply, 10. Case J: No dsconnects, fuses, no alternate supply, 11. Case K: Dsconnects, no fuses, alternate supply, 12. Case L: Dsconnects, no fuses, no alternate supply, V. TEST EXAMPLES Several dstrbuton networks can be used to llustrate the effectveness of the proposed package for calculaton relablty ndex such as RBTS [9] test network. The RBTS has 5 load bus bars (BUS2-BUS5). Two of these bus bars (BUS2 and BUS4) were selected and dstrbuton networks desgned for each. Fgure 3 and Fgure 4 show relablty ndces for RBTS BUS2 and RBTS BUS4, Moreover, Fgures 5 and 6 show SAIDI for RBTS BUS2 and RBTS BUS4. Fgure 3. Relablty Indces for RBTS BUS2 Fgure 4. SAIDI ndex for RBTS BUS2 Fgure 5. Relablty Indces for RBTS BUS4 83

5 Internatonal Journal on Techncal and Physcal Problems of Engneerng (IJTPE), Iss. 10, Vol. 4, No. 1, Mar Fgure 6. SAIDI ndex for RBTS BUS4 VI. CONCLUSIONS In ths paper, a software package called RDAP for dstrbuton relablty analyss at the graduate and undergraduate levels s developed. It s desgned n Matlab s GUI envronment and tested on RBTS (BUS2 and BUS4) test system. From the test examples, t s observed that the relablty ndexes soluton of the systems s same [8]. The package allows students to rapdly gan experence and knowledge for relablty ndexes n dstrbuton network. NOMENCLATURE λ: Average falure rate r: Average outage tme U: Average annual outage tme N: Number of customers L: Average load connected to load pont GUI: Graphcal user nterface SAIFI: System average nterrupton frequency SAIDI: System average nterrupton duraton CAIDI: Customer average nterrupton duraton ASAI: Average servce avalablty ENS: Energy not suppled RBTS: Roy Bllton test system REFERENCES [1] S. Muknahllpatna, S. Legowsk, S. Ula, J. Kopas, Power System Transent Stablty Analyss Software Tool for an Undergraduate Currculum, Computer Applcatons n Engneerng Educaton, Vol. 9, pp , [2] H.C. Ln, An Interactve Framework for Power System Harmoncs Measurement Usng Graphcal Programmng and the Internet, Computer Applcatons n Engneerng Educaton, Vol. 14, pp , [3] C. Depck, D.N. Assns, Graphcal User Interfaces n an Engneerng Educatonal Envronment, Computer Applcatons n Engneerng Educaton, Vol. 13, pp , [4] R. Bllnton, R.N. Allan, Relablty Evaluaton of Power System, New York, Plenum Press, Secton 7, [5] IEEE Standard-1366, IEEE Gude for Electrc Power Dstrbuton Relablty Indces, [6] A. Morad, M. Fotuh-Fruzabad, M. Rashd-nejad, A Relablty Cost/Worth Approach to Determne Optmum Swtchng Placement n Dstrbuton System, Proceedngs of the IEEE Asa and Pacfc Transmsson and Dstrbuton Conference and Exhbton, Dalan, Chna, pp. 1-7, [7] S.J. Chpman, Matlab Programmng for Engneers, Second Edton, [8] R. Bllnton, J. Aweya, G. Wacker, Value Based Relablty Evaluaton of Electrc Dstrbuton Systems, Proceedngs of IEEE Conference on Communcatons, Computers and Power n the Modern Envronment, pp , [9] R.N. Allan, R. Bllnton, I. Sjaref, L. Goel, A Relablty Test System for Educatonal Purposes Basc Dstrbuton System Data and Results, IEEE Transactons on Power Systems, Vol. 6, No. 2, pp , May [10] M.H. Aslnezhad, S.M. Sadeghzadeh, J. Olamae, Over Current Relays Protectve Coordnaton n Dstrbuton Systems n Presence of Dstrbuted Generaton, Internatonal Journal on Techncal and Physcal Problems of Engneerng (IJTPE), Issue 7, Vol. 3, No. 2, pp , June [11] H.A. Shayanfar, H. Shayegh, A. Jal, Takag- Sugeno Fuzzy Parallel Dstrbuton Compensaton Based Three-Area LFC Desgn, Internatonal Journal on Techncal and Physcal Problems of Engneerng (IJTPE), Issue 8, Vol. 3, No. 3, pp , September

6 Internatonal Journal on Techncal and Physcal Problems of Engneerng (IJTPE), Iss. 10, Vol. 4, No. 1, Mar BIOGRAPHIES Hossen Shayegh receved the B.Sc. and M.S.E. degrees n Electrcal and Control Engneerng n 1996 and 1998, respectvely. He receved hs Ph.D. degree n Electrcal Engneerng from Iran Unversty of Scence and Technology, Tehran, Iran n Currently, he s an Assocate Professor n Techncal Engneerng Department of Unversty of Mohaghegh Ardabl, Ardabl, Iran. Hs research nterests are n the applcaton of robust control, artfcal ntellgence and heurstc optmzaton methods to power system control desgn, operaton and plannng and power system restructurng. He s author and coauthor of sx books n electrcal engneerng area all n Fars, two book chapters n nternatonal publshers and more than 188 papers n nternatonal journals and conference proceedngs. Also, he collaborates wth several nternatonal journals as revewer boards and works as edtoral commttee of four nternatonal journals. He has served on several other commttees and panels n government, ndustry, and techncal conferences. He was selected as dstngushed researcher of the Unversty of Mohaghegh Ardabl several tmes n 2007, 2010 and He was elected as dstngushed researcher n engneerng feld n Ardabl provnce of Iran. Also, he s a member of Iranan Assocaton of Electrcal and Electronc Engneers (IAEEE) and IEEE. Currently, he s head of Ardabl Technology Incubaton Center (ATIC) at Unversty of Mohaghegh Ardabl snce Mojtaba Haydar receved the B.Sc. degree n Electrcal Engneerng from Shahd Rajae Tranng Teacher Unversty of Technology, Tehran, Iran n Currently, He s a M.S.E. student n Techncal Engneerng Department of the Unversty of Mohaghegh Ardabl, Ardabl, Iran. Hs areas of nterest n research are the applcaton of heurstc optmzaton to dstrbuton network protectve devces placement. Hedar Al Shayanfar receved the B.Sc. and M.S.E. degrees n Electrcal Engneerng n 1973 and 1979, respectvely. He receved hs Ph.D. degree n Electrcal Engneerng from Mchgan State Unversty, U.S.A., n Currently, he s a Full Professor n Electrcal Engneerng Department of Iran Unversty of Scence and Technology, Tehran, Iran. Hs research nterests are n the area of applcaton of artfcal ntellgence to power system control desgn, dynamc load modelng, power system observablty studes, voltage collapse, congeston management n a restructured power system, relablty mprovement n dstrbuton systems and reactve prcng n deregulated power systems. He has publshed more than 140 papers n nternatonal journals and 214 papers n conference proceedngs. He s a member of the Iranan Assocaton of Electrcal and Electronc Engneers and IEEE. Khall Valpur receved the B.Sc., M.S.E. and Ph.D. degrees n Electrcal Engneerng, respectvely. Currently, he s an Assstant Professor n Techncal Engneerng Department of Unversty of Mohaghegh Ardabl, Ardabl, Iran. Hs research nterests are n the power systems and electrc machnes desgn. 85