Pper ID: EE0 Proceedings of INTERNTIONL ONFERENE ON OMPUTING, OMMUNITION ND ENERGY SYSTEMS (IES-6) In ssocition with IET, UK & Sponsored y TEQIP-II 29 th -30 th, Jn. 206 NLYSIS OF DISTNE RELY PERFORMNE IN PROTETION OF HIGH VOLTGE TRNSMISSION LINE.M. Purohit Deprtment of Electricl Engineering, MIT ollege of Engineering, Pune, Mhrshtr Stte. strct Growing demnd of electricl energy leds to the incresingly complex nture of electricl power systems. Protection of trnsmission lines plys crucil role in improving the reliility of power system s well s to restore the services of power utilities. s trnsmission lines re frequently sujected to vrious kinds of fults different protection schemes re evolved for the effective protection of trnsmission lines. Distnce protection is the most widely used protection system in cse of high voltge nd extr high voltge trnsmission lines. Understnding the opertion of distnce rely involves complex theories nd philosophies. The effective use of MTL/SIMULINK pckge helps in clerly understnding the ehviour of distnce rely in protecting the trnsmission lines under norml conditions.this pper focuses on modelling nd simultion of distnce rely using MTL/SIMULINK pckge.in this pper, distnce rely is connected to 230 kv interconnected system with 400kv trnsmission line. The simultion results illustrte the simple nd effective wy to study the rely protection in power system. Keyword- Power System; Distnce protection; pprent Impednce; MTL/SIMULINK; Grphicl User Interfce I. INTRODUTION Due to incresing popultion nd industriliztion electricl power demnd is continuously incresing nd lso due to integrtion of power grids electricl power systems re ecoming complex in nture nd configurtion. It is necessry to develop new techniques to tckle the chllenges of these complex power systems, especilly protection of power systems. Protection of trnsmission lines plys crucil role in improving the reliility of power system s well s to restore the services of power utilities.[][2]trnsmission lines re prone to vrious types of fults. They cn e clssified s phse nd ground fults, permnent fults, trnsient fults, semi trnsient fults nd simultneous fults.[3]phse fults nd ground fults re the fults involving more thn one phse with or without ground. Fults involving ny phse with ground re clled ground fults. Thus power system hs to tckle totl of ten types of phse nd ground fults. [-3] Permnent fults re creted y puncturing or reking insultors, reking conductors nd ojects flling on the ground conductor or other phse conductors. These fults re detected y relys nd trip V.N. Gohokr Deprtment of Electricl Engineering, ISSMS ollege of Engineering, Pune, Mhrshtr Stte. the circuit rekers which remins locked out. Trnsient fults re of short durtion nd re creted y trnsient over voltges. siclly, this fult is cused y flshover cross the insultion due to norml trnsient over voltges. Semi trnsient fults re creted y externl ojects such s tree rnch or rodent. In medium voltge lines multishot utomtic reclosure cn urn out the oject cusing fult, restoring the equipment nd improving supply reliility. Simultneous fults such s flshover fults to ground, cross country fults nd open conductor nd ground fults re the fults which occur either t sme or different loctions on doule circuit lines. There re vrious cuses for fults on trnsmission lines. If helthy insultion in the equipment is sujected to either trnsient overvoltge of smll time durtion due to switching nd lighting strokes, direct or indirect. This cuses filure of insultion, resulting in fult current or short circuit current. nother cuse of fults is insultion ging which my cuse rekdown even t norml power frequency voltge. If n externl oject, such s tree rnch, ird, kite string, rodent etc. spnning either two power conductors or power conductor nd ground cuses fult on trnsmission lines. Sttisticlly out 80% of fults re trnsient nd 20% re permnent.[-3]the mjority of L-G fults re trnsient or rcing fults. No relying scheme cn, y itself, detect whether fult is trnsient or permnent. So it is necessry to see tht lines re not disconnected unnecessrily nd lso shorter operting times for relys. This demnds utmost ccurcy nd reliility of protective systems. Due to dvent of computing nd communiction systems protective relys hve evolved relys from electromechnicl relys to the processor sed numericl relys. This hs resulted into more ccurte nd relile performnce of the protective relys over fster nd fster relys. This pper presents the modelling of distnce rely using MTL/ SIMULINK pckge. Sim Power system toolox is used for detiled modelling of distnce rely, trnsmission line, nd fult simultion. II. DISTNE RERY PROTETION SHEME FOR TRNSMISSION LINES Distnce protection is the most populr nd widely used protection in power networks s the min nd ckup protection of trnsmission lines due to its dvntges like suitility, simplicity, economy nd reliility. [-3]The mesured impednce t the relying point is the min principl RJRMPU INSTITUTE OF TEHNOLOGY
Proceedings of INTERNTIONL ONFERENE ON OMPUTING, OMMUNITION ND ENERGY SYSTEMS (IES-6) In ssocition with IET, UK & Sponsored y TEQIP-II 29 th -30 th, Jn. 206 Pper ID: EE0 of opertion distnce rely protection scheme. onventionl distnce rely consists of three mesuring units, cn e three seprte units or one unit for the first nd second zone with time dely nd second unit for the third zone. The first nd second unit ct s primry protection units wheres second nd third zone provides remote ck up protection for djcent lines. Distnce rely hs different types of chrcteristics depending upon its function nd principl used such s mho, polrised mho, offset mho, rectnce, nd dmittnce etc. [4] Mho type of distnce rely is used for simultion purpose in this scheme. Figure shows the chrcteristics of Mho distnce rely long with its protection zones which is generlly used for protection of high voltge nd extr high voltge long trnsmission lines.[3] Tle. FULT IMPEDNE MESUREMENT LGORITHM FOR VRIOUS TYPES OF FULT Type of Fult lgorithm or G or G or G or G G G (V/I) or(v/i) or(v/i) (V-V)/ (I-I) (V-V)/ (I-I) (V-V)/ (I-I) (V)/ (I+3koIo) (V)/ (I+3koIo) G (V)/ (I+3koIo) FigureMho Type Distnce hrcteristics Figure 2 Zones Setting Of Distnce Rely III. IMPEDNE MESUREMENT LGORITHM siclly fults in power system re clssified s symmetricl fults nd unsymmetricl fults. Three phse fult is the only symmetricl fult while ll other fults like line to line fult (LL), doule line to ground fult (DLG), nd single line to ground fult (SLG) lie under the ctegory of unsymmetricl fults. Distnce rely opertion is sed on mesuring the impednce etween fulty phses in cse of LL fult or etween fulty phse nd ground in cse of ground fult. Tle show the different lgorithm used to clculte the fult impednce for vrious types of fult tking plce in trnsmission lines. [4-0] Where:,, indictes fulty phses, G indictes ground fult. V, V, V indicte voltge phses I, I, I indicte current phses Z0 = line zero sequence impednce Z = line positive sequence impednce Ko= residul compenstion fctor where Ko= (Z0- Z)/ K Z.K cn e or 3 depending on rely design. Io= (Vs/ Zo + 2 Z) Where Vs is phse voltge during the phse to ground fult IV. DISTNE RELY MODELLING Opertion of the rely cn e relized in etter wy using softwre rely models. Modelling of the protective rely is powerful tool to understnd the opertion of the rely in n economicl nd effective wy. MTL/SIMULINK is powerful softwre pckge which hs n ility of modelling, simulting nd nlysing the performnce of vrious power system components like three phse lod, three phse trnsformer, circuit reker, trnsmission line prmeters etc. used for vrious nd/or D pplictions. Wide selection of lirries ville in SimPowerSystems toolox inside SIMULINK pckge helps in detiled simultion of protective rely. Vrious spects of digitl relying like signl conditioning, nlog to digitl conversion, filtering, phsor estimtion, implementing lgorithms nd finlly rely trip logic cn e simulted in n effective mnner using different generl nd specil purpose locks from the signl processing lock sets. This pper focuses on developing the model for distnce rely. Performnce of the developed rely is nlysed for single fed trnsmission line under norml s well s under fult condition. For fulty phse detection nd pprent impednce clcultion post fult three phse voltges nd current phsors re RJRMPU INSTITUTE OF TEHNOLOGY
Proceedings of INTERNTIONL ONFERENE ON OMPUTING, OMMUNITION ND ENERGY SYSTEMS (IES-6) In ssocition with IET, UK & Sponsored y TEQIP-II 29 th -30 th, Jn. 206 Pper ID: EE0 required. Low pss filter is used to extrct fundmentl components of three phse voltges nd currents ville from VT nd T respectively. These fundmentl components of three phse voltges nd currents re then given to the FFT lock which helps to extrct the mgnitudes nd phse ngle from these fundmentl phsors. FFT lock set is used to perform Fourier nlysis of the input signl over running window of one cycle of the fundmentl frequency of the input signl. These mgnitudes re then given to the Fult Mesurement lock for impednce clcultion of the fulty phse. The outputs of this lock re the mgnitudes of resistnce nd rectnce nd lso the mgnitudes nd phse ngles of impednce. ll these vlues re clculted for pre fult s well s for post fult condition. V. MODELS FOR MESURING PPRENT IMPEDNE Figure 3 nd Figure 4 represents the model developed using SIMULINK pckge for clcultion of single phse to ground nd doule phse to ground fult. [5] V Discrete, Ts = 5e-05 s. Figure5. Modelling Of Trnsmission Line nd Three powergui FI F2 F3 Three-Phse Series RL Lod 2 Divide c c c c c c c c c c hree-phse Source Three-PhseUS II Three-Phse Three-Phse US III Three-Phse Three-Phse US IV US I Three-Phse PI Section LinePI Section Line2 PI Section Line3PI Section Line4 PI Section Line5 PI Section Line i Z dd2 3. K0 Vs Product Z0 + 2. Z Divide Figure 3.pprent Impednce for SLG fult V 2 V Sutrct 3 Z i Divide 4 i Sutrct Figure 4.pprent Impednce for DLG fult Figure 6. Developing Of Distnce Rely Model urrent nd voltge wveforms otined from instrument trnsformers re scled down nd pssed through low pss filter which helps to eliminte the effects of noise nd unwnted component of frequencies. Ech nlog input signl is pplied to the smple nd hold circuit nd then it is conveyed to the nlog to Digitl converter. The effect of Quntizer is to quntize smooth signl into stir-step output. Discrete Fourier Trnsform is used to remove the dc-offset components. DFT computes the mgnitude nd phse t discrete frequencies of discrete time sequence. Figure 8.Fult Detection Model Phse to ground fult output (G fult) VI. SIMULTION PRMETERS The network used for study consists of one three phse power supply s power sttion. The power sttion is supplying 400kv trnsmission line. Three seprte trnsmission lines ech 00km, is designed to deliver the three phse lod t the end of the trnsmission line. The us rs re provided with n rrngement of voltge nd current mesurement. The rely model developed using SIMULINK is integrted with the power system model. Performnce of the distnce rely is nlysed under norml nd under fult condition. The prmeters of the Power System, Trnsmission Line nd Lod re listed in Tle II. RJRMPU INSTITUTE OF TEHNOLOGY
Proceedings of INTERNTIONL ONFERENE ON OMPUTING, OMMUNITION ND ENERGY SYSTEMS (IES-6) In ssocition with IET, UK & Sponsored y TEQIP-II 29 th -30 th, Jn. 206 Pper ID: EE0 Tle II. POWER SYSTEM, TRNSMISSION LINE ND LOD PRMETERS Power System, Trnsmission Line nd Lod Prmeters Vlue Unit Power System Power System Voltge Volt Phse ngle of phse 0 Degree Nominl frequency 60 Hertz 3 phse short circuit level t se voltge Source X/R rtio 7 - Trnsmission line Line Length(L), 00 Km T.L.=T.L.2= T.L.3 Positive sequence 0.065 Ω/ Km resistnce Zero sequence resistnce 0.2676 Ω/ Km Positive sequence 0.8679e -3 H/ Km inductnce Zero sequence inductnce 3.008e -3 H/ Km Positive sequence 2.7e -9 F/ Km cpcitnce Zero sequence cpcitnce 7.75e -9 F/ Km 3 Phse lod ctive Power 40,000,0 00 W Inductive Rective Power 0 Vr pcitive Rective Power 9,373,0 00 Vr VII. SIMULTION RESULTS Single line to Ground Fult (G Fult) Figure 0.urrentsignls s ppered fter nlogue to Digitl onverter Figure.Voltge signls s ppered fter DFT Model Figure 2.urrent signls s ppered fter DFT Model Figure 9.Voltge signls s ppered fter nlogue to Digitl onverter Figure 3.R-jX plot for fult t 70 km distnce RJRMPU INSTITUTE OF TEHNOLOGY
Pper ID: EE0 Proceedings of INTERNTIONL ONFERENE ON OMPUTING, OMMUNITION ND ENERGY SYSTEMS (IES-6) In ssocition with IET, UK & Sponsored y TEQIP-II 29 th -30 th, Jn. 206 Figure 4. R-jX plot for fult t 90 km distnce Using MTL/SIMULINK pckge MHO type distnce rely is developed. The performnce of the developed rely is tested for different fult conditions. Using fult impednce lgorithm rely is le to detect the correct type of fult. The developed rely lso hs ility to the fult in correct zone. Impednce plot correctly shows the opertion of the rely under different fult conditions. It is possile to oserve the performnce of distnce rely y chnging simultion prmeters like trnsmission line dt, lod dt, power system dt nd fult dt. The results of the performnce chrcteristics of distnce rely re shown for single line to ground fult nd for three phse to ground fult t vrious loctions on the trnsmission line. Thus use of rely model designing helps to expedite nd economise the process of developing nd testing new relys. For the future scope distnce rely model cn e developed for different chrcteristics nd microcontroller cn e used to improve its performnce under different fult conditions. Figure 5.R-jX plot for fult t 20 km distnce Three Phse to Ground Fult (G Fult Figure 6.R-jX plot for fult t 30 km distnce Figure 7.R-jX plot for fult t 30 km distnce V. ONLUSION REFERENES. nderson P.M., Power System Protection (IEEE Press, New York, 99). 2..R. Msons, The rt nd Science of Protective Relying, Person Puliction 3. Y.G. Pithnkr Trnsmission Network Protection Theory nd Prctice. Septemer 9, 997 y R Press Puliction 4.Muhd HfiziIdris, MohdSufi hmd, hmd Zidi dullh, Sury Hrdi, dptive Mho Type Distnce Relying Scheme with Fult Resistnce ompenstion 203 IEEE 7th Interntionl Power Engineering nd Optimiztion onference (PEOO203), Lngkwi, June 203. 5. Omr G. Mrehel, Hssn. Elfetori, dllh O. Hwl, Implementtion nd Evlution SIMULINK Model of Distnce Rely in MTL/ SIMULINK ISN: 978-0- 989305-3-0 203 SDIW 6 Network Protection & utomtion Guide - NEWEdition LSTOM. 7. dlmnm. dlrhem nd Hmid H Sherwli ModellingIEEE Symposium on Industril Electronics nd pplictions (ISIE 2009), Octoer 4-6, 2009, Kul Lumpur, Mlysi 8. L.. Wu,. W. Liu nd. S. hen, Modeling nd testing of digitl distnce rely using Mtl/Simulink, IEEE 2005 9. Rely Using Mtl/Simulink Grphicl User Interfce, Mlysin Technicl Universities onference on Engineering nd Technology, Novemer 202. 0. dlmnm. dlrhem nd Hmid H Sherwli, Modelingof numericl distnce relys using Mtl, IEEE Symposium on Industril Electronics nd pplictions (ISIE 2009), Octoer 4-6, 2009, Kul Lumpur, Mlysi. HdiSdt., Power system nlysis, 3rdEdition,PS Pulishing, ISN 0984543805, 9780984543809 RJRMPU INSTITUTE OF TEHNOLOGY
Proceedings of INTERNTIONL ONFERENE ON OMPUTING, OMMUNITION ND ENERGY SYSTEMS (IES-6) In ssocition with IET, UK & Sponsored y TEQIP-II 29 th -30 th, Jn. 206 Pper ID: EE0 2. The Mth Works, Inc., SimPowerSystemsuser s guide, Version 4.6, 2008. 3. The Mth Works, Inc., GUIDE quick strt, 2008. 4. Mr. NileshPngre nd Mr. R.S. Desi, Study of ImpednceRely Interntionl Journl of Engineering nd Technicl Reserch (IJETR) ISSN: 232-0869, volume-3, Issue-4, pril- 205 5. SIMULINK 4., Reference Mnul, Mth Works, IN.200 6. Kwish. Dnge, P.P. edekr, Numericl Distnce Protectionof Trnsmission Line Interntionl Journl of Engineering Reserch nd pplictions (IJER) ISSN: 2248-9622 Interntionl onference on Qulity Up-grdtion in Engineering, Science & Technology(I- QUEST- th pril 205) RJRMPU INSTITUTE OF TEHNOLOGY