Vol. 2, No. 4, pril 2013, PP: 131-137, ville online www.ijretr.org Reserch rticle VOLTGE SG MITIGTION IN LV ND HV PLTFORM USING SMES SED DVR S. Deep 1, Mrs. K. Eskki shenglog 2 1.M.E Scholr,,EEE Deprtment,Fx-Engineering ollege,thirunelveli, 2. M.E,(Ph-D)ssoc.Professor,Eee Deprtment, Fx-Engineering ollege,thirunelveli, E-mil: dyndhrmik@gmil.com,logupilli@yhoo.co.in STRT DVR cn e effectively provides fine solution to power qulity relted concerns. s per the PQ issues sg is the mostly hppen prolem. y the Superconducting mgnetic energy storge (SMES) technology sed DVR the sg is mitigted nd rel power is restored nd thus wstge is overcome, providing protection to consumers from grid voltge fluctutions. This pper nlyses the opertion principle of the SMES linked DVR technology nd its design sed on simple PI nd voltge feed forwrd control. Using MTL /SIMULINK, the model of the SMES sed DVR ws plotted nd the dynmic response of the DVR on voltge sg is evluted in trnsmission system of nonliner lods y inserting fult nd for low voltge pltform with n synchronous drive using MTL/SIMULINK simultion nd the simultion tests re performed to evlute the system performnce. opyright IJRETR, ll right reserved. Keywords: DVR, technology, power system, voltge INTRODUTION Now dy s power systems hve een experiencing drstic chnges nd disturnces in electric power genertion, trnsmission, distriution, nd end-user fcilities. ontinuous electric lod growth nd higher power trnsfer in wide interconnected network leds to complicted, security lck power system opertion. In ddition, certin fctors such s technicl, economicl, environmentl nd governmentl regultion constrins put limittion on power system plnning nd opertion. Power system engineers dy y dy fcing so mny risks nd chllenges over the PQ concern solutions nd re 131
Vol. 2, No. 4, pril 2013, PP: 131-137, ville online www.ijretr.org seeking solutions to overcome nd opertee the system in more flexilee nd controllle mnner. So role of energy storge devices ply vitl roles. s Energy storge ppers to e eneficil to utilities since it cn decouple the instntneous lncing etween the demnd nd the supply. Thereforee it llows the incresed sset utiliztion, fcilittes the penetrtion of renewle sources nd improves the flexiility, reliility nd efficiency of the grid. Here we re more concern with short term response energy devices like Flywheel nd super cpcitor nd re hving less power rting nd energy rting so they cnnot use for higher power ppliction. So in order to overcome this deficiency SMES hs een used to improve performnce of power system s it is hving high power rting with mx efficiency thn ny other energy storge devices. Recent development nd dvnces on oth superconducting nd power electronics technology hve mde the ppliction of SMES (superconducting mgnetic energy storge) systems vile choice to ring solutions to some of the prolems experienced in power systems.. In This pper, proposes superconducting mgnetic energy storge unit s the energy storge unit of the DVR. In section II, the configurtionn of SMES is nlyzed. In section III, the dynmic response of the SMES sed DVR on voltge sg is evluted in trnsmission system of nonliner lods y inserting fult nd for low voltge pltform with n synchronous drive using MTL simultion ONFIGURTION OF DVR DVR is sophisticted custom power device tht serilly injects dynmiclly y controlled voltge Vinj(t) to the us voltge y mens of injection trnsformer s depicted in Figure1. The mplitudes of the injected phse voltges re controlled so s to erdicte ny of the detrimentl effects of us fult to the lod voltge VL(t). This mens tht if ny detrimentl fult occurs then the differentil voltge get rise in thee feeder will e compensted y n equivlent voltge generted y the converter circuit nd is injected on the medium voltge level through the injection trnsformer. The DVR works independently, provides tht the whole system remins connected to the supply grid. The, resonle fct ehind it is due to the components infinite impedence ecuse of tht the zero sequence prt of disturnce will not pss through the step down trnsformer. For most of the time the DVR is in nothing to do sttus except us voltge monitoring. This mens it does not inject ny us voltge (Vinj(t)= 0)independent off the lod current. When ever ny sg occurs v DVR is supplied s the difference of v presg nd v sg y DVR in the form of ctive power with help of D energy storge nd required rectivee power is generted internlly without nyy mens dc storge. n equivlent circuit digrm of the DVR nd the principle of series injection for sg compenstion is depicted in Figure 1. Figure 1: DVR configurtion in line SMES UNIT In SMES unit super conducting coil is used which genertes mgnetic field y the flow of D current,where the energy is stored,nd is long lsting compre to other short term energy storge units. SMES consists of super conducting 132
Vol. 2, No. 4, pril 2013, PP: 131-137, ville online www.ijretr.org mgnetic energy storge unit, cpcitor nk, voltge source inverter (VSI), low pss filter nd voltge injection trnsformer. SMES system consists of min system nd its su-systems. Where the superconducting coil is the prime importnt section of SMES system, which is plced in cryostt or dewr consistingg of vcuum vessel nd liquid vessel.the liquid vessel which keeps the system temperture y providing proper cooling set up ss cryogenic system is lso keeps the temperture elow the criticl temperture. n c/dc PS is used minly for two purposes: 1.To convert electricl energy from dc to c. 2.To provide proper chrging nd dischrging of the coil. Finlly, trnsformer which provides the power system connectionn nd coordintion nd therey the PS operting voltge will reduce to n cceptle levels. lthough SMES system hving fine efficiency,reduced positive cost y less fuel consumption, nd fst response cpility. INTEGRTION OF SMES WITH DVR The sic structure of DVR sed on SMES is shown in Fig.2 Figure 2 : SMES sed DVR configurtion ONTROLLER SETION Voltge sg is creted t lod terminls y three phse fult s shown in Fig.4. Lod voltge is converted into per unit quntity nd is pssed through sequence nlyzer. The mgnitude is then compred with reference voltge (Vref) through which error signl is fed to PI controller. This voltge is then fed to triggering circuit. Pulse width modultedd (PWM) control techniquee is pplied for inverter switching so s to produce three phse 50 Hz sinusoidl voltge t the lod terminls. hopping frequency is in the rnge of few KHz. The PI controller processes the error signl nd genertess the required ngle δ to drive the error to zero. n dvntge of proportionl plus integrl controller is tht integrl term cuses thee stedy-stte error to e zero for step input. PI controller input is n ctuting signl which is the difference etween the Vref nd Vin. The output of error detector is Vref - Vin. (f) 133
Vol. 2, No. 4, pril 2013, PP: 131-137, ville online www.ijretr.org Vref equl to 1 p.u. voltge Vin voltge in p.u. t the lod terminls. The controllerr output when compred t PWM signl genertor results in the desired firing sequence. Figure 3 : voltge feed forwrd controller Fig. 3 shows the Simulink model of DVR control. Trnsformtion of supply voltge from c frme to dqo frme nd input to the functionn lock is to detect voltge sg. If Vd is in etween 0.985pu to 1pu,mkes the function output closes the circuit reker,nd is connected in prllel with DVR, there y DVRR get ypssed.. If Vd vlue lesser thn 0.985pu,then suddenly function output opens the three-phse to mitigte sg or fluctution s perr the injected voltge reference. This reference signl reker. DVR is connected serilly through ooster trnsformer to the power system nd injects voltge is derived y compring supply voltge with reference voltge in dq0 frme. long with the phse informtion of the supply voltge from phse-locked loop, will converts the difference too c frme.pll lso helps in the synchroniztion of signl lso. Discrete, Ts = 5e-006 s. Source 2 2 c2 3 3 c3 Trnsformer (Three Windings)1 T Serie es RL rnch1 Series RL rnch4 c Trnsformer (Two Windings) Thre1 c Trnsformer (Two Windings)1 Series RL rnch3 c T1 c c V-I Mesurement Th Series Mg c Phse 3-P hree-phse s RL rnch2 Te Scope 2 2 2 1 1 1 DVR c Figure 4: 3 Mtl circuit of SMES sed DVR 134
Vol. 2, No. 4, pril 2013, PP: 131-137, ville online www.ijretr.org Figure 5: 3 phse fult mitigtion with SMES sed DVR Figure 6: 3 phse PU voltge without SMES sed Figure 7 : PU voltge t 3 Φ Fult t lod with DVR 135
Vol. 2, No. 4, pril 2013, PP: 131-137, ville online www.ijretr.org Figure 8: simultion outputt of IM lod without DVR Figure 9: Mtl circuit in IM lod using DVR Figure 10 : Simultion outpu of sg compenstion in IM lod y DVRR 136
Vol. 2, No. 4, pril 2013, PP: 131-137, ville online www.ijretr.org When suddenly n voltge drop occurs, utomticlly speed dips occur nd there y torque reduces,it ffects motor chrcteristics.so if we use DVR,the voltge sg cn e compensted,there y speed-torque compenstion cn e improved. ONLUSION This pper hs presented DVR system with SMES sed on the V-source inverter for high voltge trnsmission system nd low voltge pltform with induction motor lod.in trnsmission system the fult is inserted nd how it compenstes while DVR is connecting serilly is explined with corresponding outputs.in low voltge pltform,,the unlnces occurs s sg when n induction motor suddenly strts re studied nd mitigted,there y its torque speed chrcteristics cn e improved. The operting principle, nlysis nd the Sg compenstions of DVR re presented. Overll we cn concludes, the V-source inverter DVR system hs severl unique dvntges tht re very desirle for mny DVR pplictions,since it cn produce ny desired output c voltge, even greter thn the line voltge nd cn provide ride through without ny dditionl circuits nd energy storge while sg occurs. lso cn le to reduces in-rush nd hrmonic current. The voltge source technology is pplied to the entire spectrum of power conversion.the Simultion results prove tht the SMES cn e useful lterntive D source for the DVR. REFERENES [1] ysen (s) rsoy, Electromgnetic Trnsient nd Dynmic Modeling nd Simultion of Sttom-SMES ompenstor in Power System. [2] Rosli Omr. ; Nsrudin d Rhim, " Modeling nd Simultion for Voltge sgs/swells Mitigtion using Dynmic voltge Restorer(DVR)", UPE'08. pp:464-470. [3] Detiled Modeling of Superconducting Mgnetic Energy Storge (SMES) System IEEE Tsk ForceFTS nd ustom-power ontrollers, T&D om [4]. Dynmic Voltge Restorer Using Multilevel scded Inverter nd pcitors s Energy Sources [5] Soleimn Gleshi, Hosein Imn Eini The DVR-, Novel Structure for Mitigting Lrge Voltge Sgs nd Swells using Voltge Re-injection :M.. Sntoyo ny Student M. IEEE, E. L. Moreno Goyti, J.R. Rodríguez 2011 [6] Voltge sg mitigtion in offshore oil rig power system using smes sed DVR Di Wu,. S. hng Deprtment of Electricl nd omputer Engineering, Ntionl University of Singpore, 4, Engineering Drive 3, Singpore 117576 137