Effect of simultaneous movement of multiple particles under electric field in a Single Phase Gas Insulated Bus duct

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1 Ranuva Nageswaa Rao Int Jounal of Engineeing Reseach an Applications ISSN : 48-96, Vol 4, Issue 1( Pat - ), Octobe 14, pp96-1 RESEARCH ARTICLE OPEN ACCESS Effect of simultaneous movement of multiple paticles une electic fiel in a Single Phase Gas Insulate Bus uct Ranuva Nageswaa Rao * D SS Tulasiam** *( G Naayanamma institue of technology & science,hyeaba, AP,INDIA) **( Dept of EEE,JNT univesity,hyeaba, AP,INDIA) amsankaa@gmailcom ABSTRACT % of failues in Gas Insulate Substations ae ue to the existence of vaious metallic contaminations in the fom of loose paticles These paticles may be fee to move in the electic fiel o may be fixe on the conuctos, thus enhancing local suface fiels In this pape a Single Phase Gas Insulate Bus uct with inne an oute iamete to mm an 1 mm is consiee In this pape multiple paticles ie thee paticle of iffeent sizes ae consiee These thee paticles ae assume to be est at a position Basic equations fo the movement of thee metallic paticles ae fomulate The motion of the thee paticles ae simulate fo iffeent voltages using MATLAB Effect of multiple paticles fo vaious electic fiels on paticle movement ae analyze an time of collisions of the paticle at fist time is etemine fo vaious voltages Paticles of coppe of 1 mm in length an mm aius, 1 mm length an 1 mm aius an 7 mm an aius ae consiee The esults show that the thee paticle collie at iffeent points epening on the paticles positions The simulation esults have been pesente an analyze Keywos multiple paticles, Gas Insulate Substations, Paticle Contamination, MATLAB I INTRODUCTION Sulphu hexafluoie is the electic powe inusty s pefee gas fo electical insulation an, especially fo ac quenching cuent inteuption equipment use in the tansmission an istibution of electical enegy Compesse Gas Insulate Substations (GIS) an Tansmission Lines (CGIT) consist basically of a conucto suppote on insulato insie an enclosue, which is fille with SF6 gas Basic components of the GIS bay ae cicuit beakes, isconnectos, eathing switches, bus ucts, cuent an voltage tansfomes, etc The inne live pats of GIS ae suppote by insulatos calle spaces, which ae mae of alumina fille epoxy mateial The GIS enclosue foms an electically integate, oune enclosue fo the entie substation Even though SF6 exhibits vey high ielectic stength, the withstan voltage of SF6 within the GIS is astically euce ue to the pesence of paticles o efects like Fee paticles on the inne suface of the enclosue, Potusion on the high voltage (HV) bus, Potusion on the inne suface of the enclosue an naow gaps between the space an the electoe ae ue to impefect casting an impefect mechanical stength, The pesence of contamination can theefoe be a poblem with gas-insulate substations opeating at high fiels [1]-[] Fee conucting paticles ae most angeous to GIS These fee conucting paticles may have any shape o size, may be spheical o filamentay (wie like) o in the fom of fine ust Paticles may be fee to move o may be fixe on to the sufaces wie like paticles mae of conucting mateial ae moe hamful an thei effects ae moe ponounce at highe gas pessues As given by the authos [-], the pesence of atmospheic ust containing conucting paticles, especially on the cathoe, euces the beakown voltage The pesent wok eals with consieing thee iffeent paticles on the inne suface of the bus uct at iffeent positions, an fomulating the basic equations fo the movement of these metallic paticles In this pape a Single Phase of Gas Insulate Bus uct with iamete of mm an enclose iamete of 1mm is consiee fo analysis Paticles of coppe of 1 mm in length an mm aius, 1 mm length an 1 mm aious an 7 mm an aious ae consiee fo simulation iwith MATLAB II IIMODELING OF GAS INSULATED BUS DUCT A typical hoizontal single-phase bus uct shown in Figue (a) has been consiee fo the analysis It consists of an inne conucto an an oute enclosue, fille with SF6 gas Paticles ae assume to be at est at some position on the 96 P a g e

2 Ranuva Nageswaa Rao Int Jounal of Engineeing Reseach an Applications ISSN : 48-96, Vol 4, Issue 1( Pat - ), Octobe 14, pp96-1 m m enclosue suface, until a voltage sufficient enough to lift the paticles an move in the fiel is applie Afte acquiing an appopiate chage in the fiel, the paticles lifts an begins to move in the iection of the fiel afte ovecoming the foces ue to its own weight an ag Fo paticles on bae electoes, seveal authos have suggeste expessions fo the estimation of chage on both vetical/hoizontal wies an spheical paticles The equations ae pimaily base on the wok of Felici[] Unestaning the ynamics of a metallic paticle is of vital impotance fo etemining the effect of metallic contamination in a Gas Insulate System (GIS) If the motion pattens of a metallic paticles ae known, the pobability of paticle colliing in coaxial gap an causing a flash ove can be estimate The lift-off fiel fo the paticles on the suface of an electoe can be estimate by solving the motion equation Conucting paticles in motion in an extenal electic fiel will be subjecte to a collective influence of seveal foces Fig (a) Typical single phase gas insulate bus The foces ae : - -Electostatic foce (Fe) - Gavitational foce (mg) - Dag foce (F) The motion equations fo the thee paticles ae given by y1 m1 Fe1 - m1g - F (1a) t y t y t Fe - mg - F Fe - mg - F (1b) (1c) whee m1,m,m = mass of the paticles y = isplacement in vetical iection Fe = Electostatic foce g = gavitational constant The chages acquie by a vetical wie paticles espectively in contact with a nake enclosue can be expesse as: l1 E(t) Q 1 ( a) l1 ln( ) 1 1 l E(t) Q ( b) l ln( ) 1 l E(t) Q ( c) l ln( ) 1 whee Q1 Q Q ae the chages on the paticles until the next impact with the enclosue, l1 l l ae the paticle length, 1 ae the paticle aii espectively, E(t) is the ambient electical fiel at t = t The chage caie by the paticle between two impacts has been consiee constant in the simulations The electic fiel in a coaxial electoe system at position of the paticles can be witten as: E ( t) Vm Sin t () - y(t) ln i ^ whee Vm Sin wt is the supply voltage on the inne electoe, is the enclosue aius, i is the inne conucto aius y(t) is the position of the paticle which is the vetical istance fom the suface of the enclosue towas the inne electoe The electostatic foce on each paticle is given by F Q E(t) ( 4a) e1 K 1 Fe K Q E(t) ( 4b) F Q E(t) ( 4c) e K Whee K is a coecto an is a facto less than unity Howeve, fo length-to-aius atios geate than the coection facto, K, is close to unity The ag foces ae given by: F 1 y1 6K (y) 66 g l1 y (a) F y 6K (y) 66 g l y (b) 97 P a g e

3 Ranuva Nageswaa Rao Int Jounal of Engineeing Reseach an Applications ISSN : 48-96, Vol 4, Issue 1( Pat - ), Octobe 14, pp96-1 F y 6K (y) 66 g l y (c) whee y is the velocity of the paticle, is the viscosity of the flui (SF6 : 1_1 6kg/m_s at C), 1 ae the paticle aius, is the gas ensity, l1 l l ae the paticle lengths, K(y) is a ag coefficient The influence of gas pessue on the ag foce is given by empiical fomula P P g whee ( 6) = ensity p = Pessue of the gas an 1 < p < 1mboxMPa The estitution coefficient fo coppe an aluminum paticles seem to be in the ange of 7 to 9:R = 8 implies that 8% of the incoming impulse of the paticle is peseve when it leaves the enclosue The motion equation (1a),(1b),(1c) using all foces can theefoe be expesse as l E(t ) V Sint my ( t) X - mg l ln( ) 1 [ - y(t)]ln ( ) i - y (t) 6 K (y) 66[ l y (t)] In the above equation, the paametes m,l, can be eplace by m1,l1,1 an motion of the paticle 1 can be obtaine similaly fo paicles an motions can be obtaine The above equation is a secon oe non-linea iffeential equation an in this pape, the equation ae solve using MATLAB by Runge- Kutta 4th Oe Metho III SIMULATION OF PARTICLE MOTION In oe to etemine the anom behavio of moving paticles, the calculation of movements in axial an aial iections was caie at evey time step using ectangula anom numbes The above simulation yiels the paticle movement in the aial an axial iections The anom movement can be aequately simulate by Monte-Calo metho In oe to etemine the anomness, it is assume that the paticle emanates fom its oiginal site at any angle less than φ, whee φ/ is half of the soli angle subtene with the vetical axis At evey step of movement, a new ectangula anom numbe is geneate between an 1an moifie to φ The angle thus assigne, fixes the position of paticle at the en of evey time step, an in tun g etemines the axial an aial positions The position in the next step is compute on the basis of equation of motion with new anom angles as escibe above Thee iffeent paticles on the inne suface of the bus uct ae consiee,paticles of coppe of 1 mm in length an mm aius, 1 mm length an 1 mm aius an 7 mm an aius ae consiee fo simulation IV RESULTS AND DISCUSSIONS Table 1 shows the aial movement of the paticles in a 1- Phase Gas Insulate Bus uct Figue 1 to Figue 4 shows the movement pattens of coppe paticles in Electic Fiel an with Monte Calo Technique fo applie voltages of 1 kv,1 KV,14 KV an kv espectively The paticle 1 has 1 mm in length an mm aius,paticle has 1 mm length an 1 mm aius an paticle has 7 mm an aius Figue to Figue 8 shows the collision of paticles in the bus ucts It is obseve that the thee paticle ae state at same position an pobability of collision at iffeent points also shown in figues to 8 It is seen that as the voltage vaies fom 1 kv to Kv maximum aial movement also vaies as shown in Table1 an also the paticles collie at iffeent intevals The collisions of the paticles fo the fist time both time an height of collision also shown in Table At this point of collisions (fom fig to 8 ) the paticle moves anomly an its velocity an iection also changes which gives the actual maximum aial isplacement woul be moe than the maximum aial isplacement when no collision takes place The axial movements of paticles an collision points ae shown in figues 9 to 1 fo the applie voltages of 1 KV,1 KV,14 KV, KV espectively Table:1 Raial movement of coppe paticles with Monte- Calo technique fo vaious voltages Voltage KV Max Raial Movement of paticle 1 Max Raial Movement of paticle Max Raial Movement of paticle P a g e

4 Ranuva Nageswaa Rao Int Jounal of Engineeing Reseach an Applications ISSN : 48-96, Vol 4, Issue 1( Pat - ), Octobe 14, pp96-1 Table: height an time of paticle collisions with Monte- Calo technique fo vaious voltages Voltage KV Time of paticle collision at fist time (sec ) Height of the paticle collisions at fist time 1 1mm length/ mm aius mm length/ mm aius Figue: RaialMovement fo Cu/ 14 KV / 76mm - mm 1 1mm length/ mm aius Figue:1 Raial Movement fo Cu/ 1 KV / 76mm - mm mm length/ mm aius Figue:4 RaialMovement fo Cu/ KV / 76mm - mm Figue: Raial Movement fo Cu/ 1 KV / 76mm - mm 99 P a g e

5 height of the paticle (mm) height of the paticle (mm) Ranuva Nageswaa Rao Int Jounal of Engineeing Reseach an Applications ISSN : 48-96, Vol 4, Issue 1( Pat - ), Octobe 14, pp mm length/ mm aius 198 1mm length/ mm aius Figue: Paticles collision fo Cu/ 1 KV / 76mm - mm mm length/ mm aius Figue:8 Paticles collision fo Cu/ KV / 76mm - mm 1 1mm length/ mm aius Figue:6Paticle collisiont fo Cu/ 1KV / 76mm - mm 1 1mm length/ mm aius hoizontal istance ( mm) Figue:9 Axial Movement fo Cu/ 1 KV / 76mm - mm 1mm length/ mm aius Figue:7Paticle collision fo Cu/ 14KV / 76mm - mm hoizontal istance ( mm) Figue:1 Axial Movement fo Cu/ 1 KV / 76mm - mm 1 P a g e

6 height of the paticle (mm) height of the paticle (mm) Ranuva Nageswaa Rao Int Jounal of Engineeing Reseach an Applications ISSN : 48-96, Vol 4, Issue 1( Pat - ), Octobe 14, pp96-1 1mm length/ mm aius VI ACKNOWLEDGMENT The authos ae thankful to the managements of GNaayanamma Institute of Technology an science,hyeaba an JNT Univesity, Hyeaba, fo poviing facilities an to publish this wok hoizontal istance ( mm) Figue:11 Axial Movement fo Cu/ 14 KV / 76mm - mm 1 1 1mm length/ mm aius hoizontal istance ( mm) Figue:1 Axial Movement fo Cu/ KV / 76mm - mm V CONCLUSION It is shown that the pobability of a flashove occus at smalle size of the paticle an at highe voltages but ue to the paticle collisions paticles move anomly an its velocity an iection also changes which leas to flash ove even at low voltages If the calculations, as escibe above, ae pefome at a iffeent voltage levels by consieing a single paticle at a time as no collisions takes place, max height of the paticle an chances of flash ove woul be low The esults obtaine fom the calculations show that aitional infomation about the paticles collision an time at which fist time collision takes place shoul be consiee to estimate the flash ove chances REFERENCES [1] L G Chistophoou, J K Olthoff, R J Van Bunt, SF6 an theelectic Powe Inusty, IEEE Electical Insulation Magazine,DEIS, 1997, pp [] AH Cookson, PC Bolin, HC Doepken, RE Wootton, CM Cooke an JG Tump, Recent Reseach in the Unite States on the Effect of Paticle Contamination Reucing the Beakown Voltage in Compesse Gas Insulate System, Int Conf On Lage High Voltage System; Pais, 1976 [] HAnis an KD Sivastava, Beakown Chaacteistics of Dielectic Coate Electoes in Sulphu Hexafluoie Gas with Paticle contamination, Sixth Inten Sympos High Voltage Engineeing, Pape No 6, New Oleans, LA, USA 1989 [4] J Amanath, B P Singh, C Rahakishna an S Kamakshiah, Detemination of paticle tajectoy in a Gas Insulate Busuct peicte by Monte-Calo technique, IEEE Conf Elect InsulDielect Phenomena (CEIDP), Texas, Austin, USA, 1991 Vol 1, pp 99-4,1991 [] N Felic Foces et chages e petits objects en contact avec une electoe affectee un champ electique Revue geneale e I electicite, 1996, [6] MRamya Piya, GVNagesh Kuma, Membe, IEEE, JAmanath an RPabha Devi Effect of Vaious Design Paametes ofgas Insulate Bus Duct in the Pefomance of Gas Insulate Sub-Stations 11 P a g e

Ranuva Nageswaa Rao Int Jounal of Engineeing Reseach an Applications ISSN : 48-96, Vol 4, Issue 1( Pat - ), Octobe 14, pp96-1 Biogaphy: Ranuva Nageswaa Rao He eceive the MTech egee in electical

High voltage Engineeing his inteesting aeas ae High voltage engineeing,powe system contol D SS Tulasiam He eceive his phd egee in High Voltage Engineeing, JNTU in 199 At pesent he is pofesso in

7 Ranuva Nageswaa Rao Int Jounal of Engineeing Reseach an Applications ISSN : 48-96, Vol 4, Issue 1( Pat - ), Octobe 14, pp96-1 Biogaphy: Ranuva Nageswaa Rao He eceive the MTech egee in electical an electonics engineeing fom Si venkateswaa Univesity college of Engineeing, Tiupathi, Anha Paesh, Inia in Cuetly he is an associate pofesso at GNITS, Hyeaba, INDIA he is oing Ph D in the aea of High voltage Engineeing his inteesting aeas ae High voltage engineeing,powe system contol D SS Tulasiam He eceive his phd egee in High Voltage Engineeing, JNTU in 199 At pesent he is pofesso in the epatment of Electical an electonics Engineeing, JNT univesity Hyeaba His eseach inteests ae insulation potection stuies of High Voltage Equipement, SR motos, SiC an powe semiconuctos 1 P a g e

Electric Potential and Gauss s Law, Configuration Energy Challenge Problem Solutions

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