Digital Simulation of an Interline Dynamic Voltage Restorer for Voltage Compensation

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1 JOURNL OF ENGINEERING RESERH ND TEHNOLOGY, VOLUME 1, ISSUE 4, DEEMER 214 Digitl Simultion of n Interline Dynmi Voltge Restorer for Voltge ompenstion Dr.P.Ush Rni R.M.D.Engineering ollege, henni, pushrni71@yhoo.om strt The Dynmi Voltge Restorer (DVR) provides n dvned solution for ge sg/swell prolems. The gerestortion proess involves relpower injetion into the distriution system. The Interline DVR (IDVR) proposed in this pper provides wy to ompenste the ge sg/swell used in feeder. The IDVR onsists of severl DVRs onneted to different distriution feeders in the power system shring ommon energy storge, where one DVR in the IDVR system works in gesg/swell ompenstion mode while the other DVR in the IDVR system operte in powerflow ontrol mode. The modelling nd simultion of single phse IDVR system using Sinusoidl Pulse Width Modultion (SPWM) tehnique for ge sg nd swell onditions nd three phse IDVR using Spe Vetor Pulse width modultion (SVPWM) tehnique for ge sg ondition re presented. losed loop ontrol for ge sg nd swell for simple IDVR systems re modeled nd simulted using MTL softwre. The simultion results re presented to demonstrte the effetiveness of the proposed IDVR system.. Index Terms Interline Dynmi Voltge Restorer (IDVR), Interline Power Flow ontroller (IPF), Sinusoidl Pulse width modultion (SPWM), Spe Vetor Pulse width modultion (SVPWM), Totl Hrmoni Distortion (THD). I INTRODUTION The need of the eletril power is inresing nd simultneously the prolems while trnsmitting the power through the distriution system re lso inresing. Voltge flututions re onsidered s one of the most severe power qulity disturnes to e delt with. Even shortdurtion ge flutution ould use mlfuntion or filure of ontinuous proess. There re severl types of ge flutution tht n use the systems to mlfuntion, inluding surges nd spikes, sg, swell, hrmoni distortions, nd momentry disruptions. mong them, ge sg nd swell re the mjor powerqulity prolems. Voltge swell is the sudden inrese of ge to out more thn 11% mplitude of the supply ge, wheres the ge sg is the sudden derese of ge ton out 9% mplitude of supply ge. This is used due to the sudden redution or ddition of the lod ross tht prtiulr feeder. This hnge of ge is ompensted y injeting the ge in series with the supply from nother feeder t the time of disturnes using DVR. This IDVR system is presently one of the most osteffetive nd highly effiient method to mitigte ge sg/swell. The onept of Interline Dynmi Voltge Restorer (IDVR) where two or more ge restorers re onneted suh tht they shre ommon Dlink is similr to the Interline Power Flow ontroller (IPF) onept. In this pper, twoline IDVR system is explined whih employs two DVRs, onneted to ommon Dlink, is onneted to two different feeders originting from two grid susttions, nd ould e of the sme or different ge level. When one of the DVRs ompenstes for ge swell/sg produed, the other DVR in IDVR system opertes in powerflow ontrol mode. DVR priniples nd ge restortion methods t the point of ommon oupling re presented. The prolem of ge sgs nd swells nd its severe impt on sensitive lods re desried [1]. Voltge swell nd overge ompenstion prolems in diode ridge retifier supported trnsformerless oupled DVR, re disussed. The simultion nd experimentl results for unlned ge swell ompenstion re given [2]. The performne of DVR in mitigting ge sgs/ swells is demonstrted with the help of MTL. The DVR hndles oth lned nd unlned situtions [3]. The modeling nd simultion of IDVR is presented in pper [4] nd [6]. Pper [5] proposed new topology sed on the Z soure inverter for the DVR, in order to enhne the ge restortion property of the devie. The modeling spets of the DVR working ginst ge sgs y simultion in the PSD/EMTD hve een presented [7]. Modeling 13

2 Dr.P.Ush Rni/ Digitl Simultion of n Interline Dynmi Voltge Restorer for Voltge ompenstion (214) nd simultion of single phse IDVR using multiple PWM tehnique is presented [8] nd [1].The modeling nd simultion of single phse Z soure impedne sed DVR, IDVR using multiple PWM tehnique is presented [9] nd [13]. In this pper, modeling nd simultion of single phse IDVR with SPWM tehnique is used for ge sg nd swell ompenstion. II. PRINIPLE OF IDVR The IDVR system onsists of severl DVRs in different feeders, shring ommon Dlink. twoline IDVR system shown in Fig.1 employs two DVRs re onneted to two different feeders where one of the DVRs ompenstes for ge swell/sg produed, the other DVR in IDVR system opertes in powerflow ontrol mode. The ommon pitor onneted etween the two feeders t s the ommon D supply. nd simultion of single phse IDVR using multiple PWM tehnique is presented [8] nd [1].The modeling nd simultion of single phse Z soure impedne sed DVR, IDVR using multiple PWM tehnique is presented [9] nd [13]. In this pper, modeling nd simultion of single phse IDVR with SPWM tehnique is used for ge sg nd swell ompenstion. Voltge swell/sg in trnsmission system re likely to propgte to lrger eletril distne thn tht in distriution system. Due to these ftors, the two feeders of the IDVR system in Fig.1 re onsidered to e onneted to two different grid susttions. It is ssumed tht the ge distortion in Feeder 1 would hve lesser impt on Feeder 2. The lod ross eh feeder is onneted in series to the DVR, where V l1 nd V l2 re the ges ross the lod. The injetion of n pproprite ge needs ertin mount of rel nd retive power whih must e supplied y the DVR. Supply of rel power is met y mens of n energy storge fility onneted in the Dlink. Lrge pitors re used s soure of energy storge in most of the DVRs. Generlly, pitors re used to generte retive power in n power system. However, in D system, pitors n e used to store energy. When the energy is drwn from the energy storge pitors, the pitor terminl ge dereses. Hene, lrge pitors in the Dlink energy storge re needed to effetively mitigte ge swell of lrge depths nd long durtions. The pulse n e generted using vrious modultion tehniques. In this pper, the pulse for the swith is generted using SPWM. III. MODEL OF IDVR USING SPWM TEH NIQUE The simulink models of the losed loop ontrolled IDVR system with the H ridge inverter using SPWM tehnique for sg nd swell onditions re developed nd the simultion results re presented. The IDVR system with two ktok onneted DVR sttions ws implemented with losed loop ontrol of inverter swithes. Fig.2 shows the simulink model of the losed loop ontrolled IDVR. The retifierinverter system is shown s susystem. 3ohm 18mH i urrent Mesurement Sope2 2V v ohm 1mH v.2 to.5 4 ohm 4mH v.2 to.51 in1 Out1 in2 Susystem2 In1 onn1 in1 Fig.1 Shemti digrm of n IDVR 3ohm 18mH1 in2 Susystem1 onn2 The upstrem genertiontrnsmission system is pplied nd the two feeders n e onsidered s two independent soures. These two ge soures Vs1 nd Vs2 re onneted in series with the line impednes Zl1 nd Zl2 whih is inturn onneted to the uses 1 nd 2 s in Fig. 1. The DVR is onneted in series with the feeder nd the DVRs ross different feeders re onneted y ommon Dlink. 35 V Fig.2 Simultion iruit of IDVR ohm 1mH 14

3 Dr.P.Ush Rni/ Digitl Simultion of n Interline Dynmi Voltge Restorer for Voltge ompenstion (214) The susystem 1 onsists of full ridge inverter with filter. Susystem 2, shows the retifier output ge The SPWM ontrol tehnique is used to redue the hrmoni ontent in the output ge. The driving sine pulses for the swithes re shown in Fig Fig.4 () shows 32.6 % ge sg initited t 3ms nd it is kept until 6ms, with totl ge sg durtion of 3ms in low ge feeder 1. Fig.3 () nd () show the ge injeted y the DVR 2 nd the ompensted lod ge respetively. Due to the presene of the IDVR, the lod ge remins onstnt throughout the ge sg period. Fig.5 shows the ommon D link ge wveform. Fig.6 shows the FFT nlysis of the losed loop IDVR system for sg. The Totl Hrmoni Distortion (THD) vlue is 4.81% Fig.5 ommon D link ge for sg 2. Gte pulse 1, Gte pulse 3, Fig.3 Driving pulses of inverter swithes. unompensted ge Injeted ge ompensted ge 2 Fig.6 FFT nlysis of IDVR for sg Fig.7 () shows 44.1 % ge swell initited t 3ms nd it is kept until 6ms, with totl ge swell durtion of 3ms in low ge feeder 1. Fig.7 () nd () show the ge injeted y the DVR 2 nd the ompensted lod ge respetively. Due to the presene of the IDVR, the lod ge remins onstnt throughout the ge swell period. Fig.8 shows the ommon D link ge wveform. Fig.9 shows the FFT nlysis of the losed loop IDVR system for swell. The Totl Hrmoni Distortion (THD) vlue is.12% Fig.4 Response of IDVR to ge sg 15

4 Dr.P.Ush Rni/ Digitl Simultion of n Interline Dynmi Voltge Restorer for Voltge ompenstion (214). unompensted ge Injeted ge ompensted ge The proposed IDVR iruit with the Spe Vetor PWM is shown in Fig.1. Here, the error ge in the dqfrme is used to lulte the resultnt referene ge nd ngle α of the spe vetor eight setor frme work. Tle. 1 shows the prmeters used for simultion studies. The susystem 1 onsists of feeder 1 nd DVR 1 s shown in Fig.12. The DVR 1 onsists of n inverter, swithing time lultor nd swithing pulse genertor. The susystem 2 onsists of feeder 2 nd DVR 2. The DVR 2 hs n inverter, swithing time lultor nd swithing pulse genertor Fig.7 Response of IDVR to ge swell onn2 onn1 D Voltge Soure onn2 onn1 s Susystem Susystem Fig.8 ommon D link ge for swell Fig. 1 Simultion iruit of three phse IDVR Tle. 1 Prmeters of the two line IDVR Fig.9 FFT nlysis of IDVR for swell IV. IDVR USING SVPWM TEHNIQUE Supply ge feeder 1 24V Supply ge feeder 2 77V Soure Impedne (.1j3.142*e4)Ω Line impedne (for 1km) (1.6j.34)Ω Series trnsformer turns rtio 1:1 Injetion trnsformer rtio 1:1 D ge 26V Fixed Lod resistne 4Ω Fixed Lod indutne 6mH Filter indutne 1mH Filter pitne.177µf Line frequeny 5Hz rrier frequeny 123Hz 16

5 Dr.P.Ush Rni/ Digitl Simultion of n Interline Dynmi Voltge Restorer for Voltge ompenstion (214) v 1 onn1 2 onn Sope INVERTOR Sope2 V Port2 Gte Port1 Sope1 reker reker1 reker2 Port4 Port3 N V V Port5 > 1/3 onstnt sin os _to_dq Trnsformtion1 sin_os dq node 1 1 u 2 u 2 sqrt pi Swithing time lultor setor T1 T1 mg T2 lph T2 Timing T lph1 T Setor Tz Swithing pulse genertor Fig.14 Response of three phse IDVR to ge sg PID(s) N V sin_os dq _to_dq Trnsformtion Sope PID ontroller lph tn2 K MTL Fn MTL Funtion Sope Sopee Soped 18 Fig.12 Susystem 1 of three phse IDVR Fig.13 indites tht 27.42% ge sg is initited t 3ms nd it is kept until 8ms, with totl ge sg durtion of 5ms in the low ge feeder 1. Fig.14 () nd () show the ge injeted y the DVR2 nd the ompensted lod ge respetively. Due to the presene of the IDVR, the lod ge remins onstnt throughout the ge sg period. Fig.15 shows the FFT nlysis of the three phse IDVR with the SVPWM model. The THD of the SVPWM system is found to e.8 %. Fig.15 FFT nlysis of the three phse IDVR 4 unompensted ge (v) V. ONLUSION Time Fig.13 Voltge sg of three phse IDVR The modelling nd simultion of single phse IDVR system using SPWM tehnique for sg nd swell onditions re presented. The modelling nd simultion results of three phse IDVR using spe vetor PWM tehnique re lso presented. The model of single phse IDVR for 44.1% of the ge swell nd 32.6% of the ge sg is ompensted using losed loop ontrol. The model of three phse IDVR for 27.42% of the ge sg is ompensted using losed loop ontrol. The simultion results indite tht the implemented ontrol strtegy ompenstes ge sgs with high ury. The results show tht the ontrol tehnique is n improved method for ge sg nd swell ompenstion. 17

6 Dr.P.Ush Rni/ Digitl Simultion of n Interline Dynmi Voltge Restorer for Voltge ompenstion (214) REFERENES 1. helli enhi nd rhim Ferdi, Voltge Qulity Improvement Using DVR, Eletril Power Qulity nd Utiliztion, Journl Vol. XIV, No. 1, pp. 3945, hiseng Lm, Mnhung Wong nd YingDuo Hn, Voltge Swell nd Over ge ompenstion with Unidiretionl Power Flow ontrolled Dynmi Voltge Restorer, IEEE Trnstions on Power Delivery, Vol. 23, No. 4, pp , Pisn oonhim, nd Ndrjh Mithulnthn, Detiled nlysis of Lod Voltge ompenstion for Dynmi Voltge Restorer, Thmmst Interntionl Journl of Siene nd Tehnology, Vol. 11, No. 3, pp. 16, Mhind Vilthgmuw D., hoi S. S. nd Wijekoon H.M, Interline Dynmi Voltge Restorer: Novel nd Eonomil pproh for Multiline Power Qulity ompenstion, IEEE Trnstions on Industry pplitions, Vol. 4, No. 6, pp , Mhind Vilthgmuw D.,.J.Gnyke, P..Loh, Y.W.Li, Voltge sg ompenstion with Z soure inverter sed dynmi ge restorer, IEEE Industril Eletronis onferene, pp , Mhind Vilthgmuw D., hoi S. S. nd Wijekoon H.M, Novel Tehnique to ompenste Voltge Sgs in Multiline Distriution System The Interline Dynmi Voltge Restorer, IEEE Trnstions on Industril Eletronis, Vol.53, No.5, pp , Nguyen P. T. nd Tpn K. Sh, DVR ginst lned nd Unlned Voltge Sgs: Modelling nd Simultion, Proeedings of the IEEE Industril Eletronis onferene, pp. 16, Ush Rni P. nd Rm Reddy S, Digitl Simultion of n Interline Dynmi Voltge Restorer for Voltge ompenstion, Interntionl onferene on omputer, ommunition nd Eletril Tehnology IET, IEEE Xplore /11, pp , Ush Rni P. nd Rm Reddy S, Modeling nd Simultion ZSI sed DVR for ge ompenstion, Interntionl onferene on omputer, ommunition nd Eletril Tehnology IET, IEEE Xplore /11, pp. 996, Ush Rni P. nd Rm Reddy S, Voltge sg / swell ompenstion in n interline dynmi ge restorer, Interntionl onferene on Emerging Trends in Eletril nd omputer Tehnology, IETET, IEEE Xplore /11, pp , Ush Rni P. nd Rm Reddy S, Voltge sg / swell ompenstion using Zsoure inverter sed dynmi ge restorer, Interntionl onferene on Emerging Trends in Eletril nd omputer Tehnology IETET, IEEE Xplore /11, pp , Ush Rni P, Voltge Swell ompenstion in n Interline Dynmi Voltge Restorer, Journl of Sientifi nd Industril Reserh, Vol.73, No.1, pp.2932, Ush Rni P, Modelind nd simultion of MLI sed Interline Dynmi Voltge Restorer, ustrlin Journl of si nd pplied Sienes, Vol.8, No.2, pp , 214. P. Ush Rni is Professor in Eletril nd Eletronis Engineering Deprtment, R.M.D. Engineering ollege, henni, Indi. She reeived her.e. degree in Eletril & Eletronis Engineering from the Government ollege of Tehnology, oimtore, Indi, M.E. degree in Power Systems from ollege of Engineering, nn University, henni, Indi nd PhD in the re of Power Eletronis nd Drives from nn University, henni, Indi. She hs pulished over 26 tehnil ppers in interntionl nd ntionl journls / onferenes proeedings (IEEE Xplore5). She hs 17 yers of tehing experiene. Her erlier industril experiene ws with hemin ontrols, Pondiherry, Indi. Her reserh interests on pplition of Power Eletronis to Power Qulity prolems nd FTS. She is life memer of Indin Soiety for Tehnil edution nd memer if IEEE. 18