International Review of Electrical Engineering (IREE)

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1 Inernaional Review of Elecrical Engineering (IREE) Conens Aspecs Regarding he Conrolled Swiching of he Circui Breakers by M. Adam, A. Baraboi, C. Pancu, A. Plesca Prioriizaion Procedure for he Power ransmission Lines and ransformers Revializaion by D. Bajs, G. Majsrovic, I. Medic Operaion of Saic Compensaor wih ime-opimal Curren Conroller by A. Božiček, B. Blažič, I. Papič Idenificaion of Dominan Flicker Source in Muli Side Supplied Power Sysems by A. Dasfan, M. R. Mirzayi Using Disribued Energy Resources o Supply Reacive Power for Dynamic Volage Regulaion by Y. Xu, F. Li, H. Li, D.. Rizy, J. D. Kueck An Adapive Precise One End Faul Locaion in ransmission Lines Based on Hybrid Complex Leas Error Squares Algorihm and Adapive Arificial Neural Neworks by I. Sadinezhad, M. Joorabian Soluions for Power Qualiy Using he Advanced UPFC - Conrol Sraegy and Case Sudy by K. Sedraoui, F. Fnaiech, K. Al-Haddad Sizing Opimizaion of a Sand-Alone Hybrid Power Supply Uni: Wind/PV Sysem wih Baery Sorage by R. Belfkira, G. Baraka, C. Nichia A New Sof Swiching Isolaed Buck-Boos PWM Converer by M. Delshad, H. Farzanehfard Applying Novel Sof Swiching o Synchronously Recified Buck Converers by K. I. Hwu Average Modeling and Carrier-Based Conrol Sraegies Applied o a hree-phase Four-Leg Shun Acive Power Filer by H. Y. Kanaan, I. Mougharbel, K. Al-Haddad A New Sof Swiching Bridgeless PFC wihou any Exra Swich by M. Mahdavi, H. Farzanehfard Comparison Overview of four AC/DC Fron-Sage Converers Including an Original Self-Commuaed Recifier for On-board Aircraf EHA by F. Richardeau, H. Pique Opimal SHE-PWM echnique for hree-level Volage Source Converer Conrol by M. S. A. Dahidah, V. G. Agelidis Modeling of High Frequency Resonan Inverer Sysem in Phasor Domain for Fas Simulaion and Conrol Design by Z. Ye, P. K. Jain, P. C. Sen Sliding Mode Muliscalar Conrol of Inducion Moor by M. Morawiec, A. Lewicki, Z. Krzeminski Hybrid Boundary Elemen wih Permeances Nework Mehods for Modeling Permanen Magne Moors in Auomoive Applicaions by S. ouai, R. Ibiouen, A. Djerdir, J. A. Farooq, A. Miraoui, O. ouhami Nonlinear Feedback Conrol of Bearingless Slice Moors by H. Grabner, W. Amrhein, S. Silber Miscellaneous Operaions of Variable Speed Wind urbine Driven Permanen Magne Synchronous Generaor by S. M. Muyeen, R. akahashi,. Muraa, J. amura Wavele-Based ADC esing Auomaion Using LabView by C. M. Akujuobi, E. Awada An Ulra Wide uning Range VCO wih Acive unable Inducors by M. Mehrabian, A. Nabavi

2 Inernaional Review of Elecrical Engineering (I.R.E.E.), Vol. 3, N. 5 Sepember-Ocober 2008 Using Disribued Energy Resources o Supply Reacive Power for Dynamic Volage Regulaion Y. Xu 1, F. Li 2, H. Li 2, D.. Rizy 1, J. D. Kueck 1 Absrac Disribued energy (DE) resources are power sources locaed near load ceners and equipped wih power elecronics converers o inerface wih he grid, herefore i is feasible for DE o provide reacive power (along wih acive power) locally for dynamic volage regulaion. In his paper, a synchronous condenser and a DE source wih an inverer inerface are implemened in parallel in a disribuion sysem o regulae he local volage. Developed volage conrol schemes for he inverer and he synchronous condenser are presened. Experimenal resuls show ha boh he inverer and he synchronous condenser can regulae he local volage insananeously alhough he dynamic response of he inverer is much faser han he synchronous condenser. In a sysem wih muliple DEs performing local volage regulaion, he ineracion of muliple DE a differen locaions under differen load levels may have an impac o he conrol parameer seing for each individual DE conrol sysem. Fuure research is needed o find ou he ineracion of DEs o idenify he opimal conrol parameer seings wih he consideraion of many facors such as sysem configuraion, load variaion, and so on. Copyrigh 2008 Praise Worhy Prize S.r.l. - All righs reserved. Keywords: Disribued Energy Resources, Insananeous Power heory, PI Conrol, Power Elecronic Inerface, Volage Regulaion I. Inroducion here are a wide range of ancillary services in he disribuion sysem ha can be supplied by disribued energy (DE) resources [1]-[9], among which volage regulaion has drawn much ineres because of he reacive power shorage and ranspor problems in power sysems [5]-[9]. Previously, ohers have repored ha he power elecronics inerface beween he DE and he uiliy can provide several reacive power services [10]-[12]. he insallaion of DE and he provision of volage regulaion from DE can have a beneficial impac on ransmission capaciy and sabiliy by supplying reacive power a he disribuion level [13],[14]. he oal insalled DE capaciy for insallaions smaller han 5 MW in he U.S. is 195,251 MW, among which he reacive-power-capable DE is presenly esimaed a around 10% of he oal insallaions [15]. If DE resources were designed o provide reacive power when hey were purchased, his amoun could easily be 90% of he oal insallaions. In order o be a reacive power supplier, a fuel cell or phoovolaic insallaion would need an inverer capable of operaing a non-uniy power facor, and an engine generaor would need a cluch beween he engine and generaor. he generaors are ypically capable of operaing a 0.8 o 0.9 power facor. 200,000 MW of DE hus equipped could provide nearly 100,000 o 150,000 MVar of reacive power. his amoun of dynamic reacive power insalled near loads would have a dramaic effec in reducing disribuion losses, increasing circui capaciy, improving power qualiy, and expanding he margin o volage collapse. he power and curren raings of he power elecronics inerface are required o be larger o provide boh acive power and reacive power insead of only acive power, while he DE raings remain he same. If he power facor is 0.9, 0.48 MVar reacive power is provided from a 1 MW DE, i.e., he reacive power is 48% of he acive power. he power and curren raings (i.e., capial coss) of he power elecronics inerface is only required o be 11.1% larger han he no reacive power service case. If he DE can run a 0.8 power facor, 0.75 MVar reacive power can be supplied from a 1 MW DE, and he power and curren raings is only increased by 25%. he reacive power capabiliy is significan comparing o he addiional coss. II. Sysem Configuraion Some DE requires a power elecronics inverer inerface o connec o he uiliy, while ohers do no. A ypical DE wih a power elecronics inverer inerface is conneced in parallel wih respec o he load o provide volage regulaion, as shown in Fig. 1. Manuscrip received and revised Sepember 2008, acceped Ocober 2008 Copyrigh 2008 Praise Worhy Prize S.r.l. - All righs reserved 795

3 Y. Xu, F. Li, H. Li, D.. Rizy, J. D. Kueck Fig. 1. Parallel connecion of a DE wih power elecronics inverer inerface Fig. 2. Configuraion of DECC laboraory a ORNL he inerface, including he inverer, he DC link capacior wih a volage V dc, and he coupling inducor L c, is referred o as he compensaor because volage regulaion from DE is he main opic of his paper. he compensaor is conneced in parallel a he poin of common coupling (PCC), and he PCC volage is denoed as v. By generaing or consuming reacive power, he compensaor regulaes he PCC volage v. he compensaor curren i c only conains reacive power componen. A synchronous condenser does no need any power elecronics inerface o connec o he uiliy. he synchronous condenser supplies reacive power during over-exciaion o boos volage, and absorbs reacive power during under-exciaion o lower volage. By conrolling he exciaion volage, and consequenly changing he reacive power i provides or consumes, he synchronous condenser regulaes he sysem volage. he Disribued Energy and Communicaion Cener (DECC) a Oak Ridge Naional Laboraory (ORNL) is conducing research and esing on dynamic volage regulaion using DE and muliple DE conrol schemes. Fig. 2 shows he configuraion of DECC wih inerconneced exernal primary disribuion feeders and ransmission sysems. Wih he insallaion of muliple DE in he disribuion sysem, he conrol and operaion of DE is differen depending on he sysem configuraion. wo sysem configuraions of he compensaor (inverer) and he synchronous condenser are sudied in his paper, which are shown in Figs. 3 and 4. In Fig. 3, he wo devices are conneced on wo differen circuis from a 2.4 kv subsaion. he synchronous condenser is conneced o he 480 V Panel A wih local loads hrough ransformer 1, and he compensaor is conneced o he 480 V Panel B wih local loads hrough ransformer 2. In Fig. 4, boh he synchronous condenser and he compensaor are conneced o Panel A. Fig. 3. Parallel connecion of he wo DE on differen panels Fig. 4. Parallel connecion of he wo DE on he same panel he elecrical disance beween he compensaor and he synchronous condenser in Fig. 4 is less han he case in Fig. 3, and herefore differen volage regulaion mehods are used. III. Insananeous Power heory An insananeous nonacive (i.e., reacive) power heory [16] is adoped in his paper for he real-ime calculaion and conrol of DE volage regulaion. In he heory, definiions of insananeous acive curren, insananeous reacive curren, average acive power, average reacive power, apparen acive power, and Copyrigh 2008 Praise Worhy Prize S.r.l. - All righs reserved Inernaional Review of Elecrical Engineering, Vol. 3, n

4 Y. Xu, F. Li, H. Li, D.. Rizy, J. D. Kueck apparen reacive power are defined. Only he definiions ha are relaed o he calculaion and conrol in his paper are presened in his secion. he full descripion of he heory is presened in [16]. In all he following equaions, he lower case indicaes ime. All he definiions are funcions of ime. For a hree-phase volage vecor v() and curren vecor i() (vecors for volage and curren will be denoed in bold): () = v (),v (),v () v a b c (1) () = i (),i (),i () i a b c (2) he insananeous power p() and he average power P() over he averaging inerval [- c, ] are defined by (3) and (4): () ()() () () 3 p v i v i (3) = = k k = 1 1 P() = p( τ ) dτ (4) c he averaging inerval c can be chosen arbirarily from zero o infiniy, and for differen c values, he resuling acive curren and reacive curren will have differen characerisics. In a periodic sysem wih period, c is normally chosen as inegral muliples of /2 o eliminae curren harmonics. he insananeous acive curren i a () and insananeous reacive curren i n () are defined by, respecively: 2 p c () () P ia () = v p() (5) V n () = ( ) ( ) i i i (6) he volage v p () is he reference volage, which is chosen based on he characerisics of he sysem and he desired compensaion resuls. V p () is he roo-meansquare (rms) value of he reference volage v p (), i.e.: 1 Vp () = ( τ ) ( τ) dτ vp v p c c a k (7) he rms values of he volage v() and he curren i() are: = 1 () v ( ) v ( ) V c c τ τ dτ (8) = 1 () i ( ) i ( ) I c c τ τ dτ (9) As poined ou in [16], he above generalized definiion from (1) o (9) exends he radiional definiion of insananeous nonacive power from hreephase, balanced, and sinusoidal sysems o oher cases. his unique feaure makes i easy o be applied in modern disribuion sysems in which here are challenges like single-phase, non-sinusoidal, unbalanced, and non-periodic waveforms. herefore, i is suiable for real-ime conrol in a real-world sysem and provides advanages for he design of conrol schemes, which will be discussed in he nex secion. IV. Conrol Mehods Mos of he volage flucuaions in he power sysem are because of a shorage or surplus of reacive power. Capacior banks are widely used in power sysems for volage regulaion. However, capacior banks are swiched on or off, and are no a coninuously variable real-ime source of reacive power. Moreover, he reacive power supplied by capacior banks decreases as he sysem volage decreases (by volage squared) when reacive power is mos needed. herefore, capacior banks fail o provide sufficien reacive power when i is mos needed during severe volage excursions. DE wih a power elecronics converer can provide dynamic volage regulaion service. he volage is conrolled according o a volage schedule ha could be supplied and updaed by he local uiliy o coordinae wih he needed uiliy suppor and o change in configuraion and condiions. Under his volage schedule mehod, he local volage would be beer regulaed, i.e., suppored during low volage, such as a sag due o a faul or moor sar, and reduced during an overvolage, such as excessive fixed capaciance during ligh load. he concerns of feeding excessive curren o a faul or exceeding he raing of a circui breaker or confusing proecive relaying will be addressed by selecing he appropriae conrol seings for he DE based on he disribuion sysem ype and proecive relaying configuraion. Developmen of he engineering guidelines for he selecing he seings would ensure rouble free, reliable DE insallaions. A volage regulaion mehod is developed based on he sysem configuraion in Fig. 1. he conrol diagram is shown in Fig. 5. he PCC volage is measured and he rms value is calculaed. he rms value is compared o he volage reference V, and he error is fed o a proporional-inegral (PI) conroller. he reference compensaor oupu volage v c is he reference o generae pulse-widh modulaion (PWM) signals o drive he inverer. he oupu volage of he compensaor is conrolled so ha i is in phase wih he PCC volage and he magniude of he compensaor Copyrigh 2008 Praise Worhy Prize S.r.l. - All righs reserved Inernaional Review of Elecrical Engineering, Vol. 3, n

5 Y. Xu, F. Li, H. Li, D.. Rizy, J. D. Kueck oupu volage is conrolled so ha he PCC volage is regulaed a a given level V. he value of V could be supplied by he local uiliy s volage schedule. he conrol scheme is shown in (10): ( () ()) 1 + KP1 V V + v () () c = v (10) KI1 ( V () V () ) d 0 In a hree-phase sysem, a volage or a curren is balanced if he magniudes of he hree phases are equal, and he phase-angles beween consecuive phases are also equal. Mos of he volage unbalance in power sysems is because of he magniude inequaliies, and only his case is considered in he paper. In his conrol mehod, he rms value of volage in each phase is conrolled independenly; herefore he unbalance in he PCC volage can be correced by he compensaor. he volage regulaion mehod of he synchronous condenser is designed based on he configuraion in Fig. 2 and he conrol diagram is shown in Fig. 6. he synchronous condenser, which is used in he experimens, does no generae or consume any reacive power when he exciaion volage is 85 V. Reacive power is generaed or consumed by conrolling he exciaion volage o be higher or lower han 85 V, and herefore he sysem volage v s is regulaed o follow he uiliy s volage schedule. he conrol scheme is shown in (11): v exciaion () = () () ( ) K V V P2 sysem sysem ( () ()) + K V V d+ 85 I 2 sysem sysem 0 (11) In he ORNL DECC laboraory, he compensaor and he synchronous condenser are currenly conneced o differen panels and subsequenly differen disribuion circuis as shown in Fig. 3. hus, he elecrical disance of he wo devices is large so ha he conrols of he wo devices are independen, as shown in Figs. 5 and 6. However, when hey are conneced o he same panel as shown in Fig. 4, hey are close o each oher and conrol he same panel volage so ha hey mus be conrolled ogeher. he inegraed conrol diagram is shown in Fig. 7 for his case. he compensaor response ime is much shorer han he synchronous condenser, herefore when he wo devices are operaing ogeher, he compensaor is responsible for he fas and small changes in he volage while he synchronous condenser is responsible for he slower and larger changes. Fig. 5. Conrol diagram for compensaor volage regulaion Fig. 6. Conrol diagram for synchronous condenser volage regulaion Fig. 7. Inegraed conrol of he compensaor and he synchronous condenser he reference volage for he synchronous condenser (v exciaion_reference in Fig. 7) is only changed if he required compensaor curren exceeds he pre-se curren limi and hus reaches he limi of is capabiliy. V. Dynamic Volage Regulaion he parallel volage regulaion sysem is implemened in a DE sysem on he local disribuion sysem a Oak Ridge Naional Laboraory. he simplified sysem diagram is shown in Fig. 3. he synchronous condenser and he compensaor are operaed simulaneously o regulae Panel A volage (referred o as sysem volage in Fig. 8) and Panel B volage (referred o as PCC volage in Fig. 9). he synchronous condenser can supply around 300 kvar of maximum reacive power, while he compensaor can provide abou 45 kvar maximum. In he synchronous condenser volage regulaion, he sysem volage was V before he regulaion. he reference volage is se o be 480 V (he red line in Fig. 8(a)), and he regulaed volage is shown as he blue waveform in Fig. 8(a), which racks he reference volage wih an error wihin ±0.1 V. he hree-phase synchronous condenser curren waveforms are shown in Fig. 8(b) ogeher wih he phase a volage o show he phase angle beween he volage and he curren. he phase a curren is leading he phase a volage by abou 90º, which shows ha he synchronous condenser is Copyrigh 2008 Praise Worhy Prize S.r.l. - All righs reserved Inernaional Review of Elecrical Engineering, Vol. 3, n

6 Y. Xu, F. Li, H. Li, D.. Rizy, J. D. Kueck supplying reacive power. he spikes in he curren waveforms are because of he elecromagneic inerference (EMI) in he curren measuremen. he dynamic response of he synchronous condenser is shown in Figs. 8(c) and 8(d). he reference volage is increased from 480 V o 482 V (he red waveform in Fig. 8(c), and decreased from 483 V o 478 V (he red waveform in Fig. 8(d)), respecively. he corresponding sysem volage waveforms are he blue waveforms in Figs. 8(c) and 8(d), respecively. he synchronous condenser can regulae he sysem volage o a reference level a seady sae and dynamically by conrolling he amoun of reacive power generaed (o raise volage) or consumed (o lower volage) by he synchronous condenser. In he compensaor volage regulaion, he PCC volage was V before regulaion. he reference volage is se a V (he red line in Fig. 9(a)) insead of he raed value 480 V, which is because of he curren limi of he inverer which permis a smaller range of volage regulaion. he regulaed volage is shown as he blue waveform in Fig. 9(a). he hreephase compensaor curren waveforms are shown in Fig. 9(b) ogeher wih he phase a volage o show he phase angle beween he volage and he curren. he phase a curren is leading he phase a volage by abou 90º, which shows ha he compensaor is generaing reacive power. he ripple in he compensaor oupu curren is parly filered by he coupling inducor (Lc in Fig. 1), so ha he curren waveforms are fundamenal sinusoids wih some harmonics. Larger coupling inducors could reduce he ripple o a lower level, bu his would require higher DC link volage o he inverer. he dynamic response of he compensaor is shown in Figs. 9(c) and 9(d). he reference volage is increased from V o V (he red waveform in Fig. 9(c)), and decreased from V o V (he red waveform in Fig. 9(d)), respecively. he corresponding PCC volage waveforms are he blue waveforms in Figs. 9(c) and 9(d), respecively. he compensaor can regulae he sysem volage o a reference level a seady sae and dynamically by conrolling he amoun of reacive power generaed or consumed by he compensaor. he parallel operaion of he synchronous condenser and he inverer on he same panel (Fig. 4) was simulaed, and he resuls are shown in Fig. 10. he reference of he rms line-o-neural volage is se a 275 V from = 1 s o = 1.5 s, and hen a 277 V from = 1.5 s o = 2.5 s, as shown by he red waveform in Fig. 10(a). he blue waveform is he Panel A volage. A seady sae, i follows he reference volage, and a ransien sae, he dynamic response is less han 0.2 s. he compensaor curren limi is se a 90 A according o he curren raing of he inverer. If he compensaor curren is below 90 A, he reference volage for he synchronous condenser remains he same value, and he compensaor responds o all he changes in he volage. Copyrigh 2008 Praise Worhy Prize S.r.l. - All righs reserved If he required compensaor curren is above 90 A, as shown in Fig. 10(b )because of he sudden volage reference change a = 1.5 s, a shor period of curren over 90 A is allowed for he compensaor so ha he sysem can have a faser dynamic response. Fig. 8(a) Fig. 8(b) Fig. 8(c) Fig. 8(d) Figs. 8. Experimenal resuls of synchronous condenser volage conrol: (a) Rms line-o-line volage, (b) Synchronous condenser curren, (c) Volage increase conrol, (d) Volage decrease conrol Fig. 9(a) Inernaional Review of Elecrical Engineering, Vol. 3, n

7 Y. Xu, F. Li, H. Li, D.. Rizy, J. D. Kueck Fig. 10(c) Fig. 9(b) Figs. 10. Resuls of parallel operaion on he same panel: (a) rms lineo-neural volage, (b) Compensaor curren,(c) Synchronous condenser curren Fig. 9(c) here are wo advanages o conrolling he synchronous condenser and he compensaor on he same volage panel: he wo devices share he reacive power requiremen for volage regulaion; herefore he volage regulaion capabiliy is improved; he devices of differen characerisics are operaed in parallel ogeher, and hese characerisics are combined ogeher o achieve faser overall sysem dynamic response, and o reduce he capial and operaing coss a he same ime. VI. Fig. 9(d) Figs. 9. Experimenal resuls of compensaor volage conrol: (a) rms line-o-line volage, (b) Compensaor curren, (c) Volage increase conrol, (d) Volage decrease conrol Afer his shor curren overshoo, he compensaor curren is conrolled below 90 A. A he same ime, he synchronous condenser increases he reacive power oupu which is required by he sysem o increase he panel A volage according o he increased reference volage. Ineracion of Muliple DEs he fuure disribuion sysem should have muliple DEs conneced [17]. I is sill unclear abou he exac ineracion of muliple DEs regarding differen locaions, load levels, conrol parameers, ec. o explore he ineracion of muliple DEs, a series of simulaion has been performed as an iniial aemp o explore his ineresing area. wo DEs, DE1 and DE2 are placed a Bus 2 and 5, respecively, in a es sysem shown in Fig. 11, which is more complicaed han he field experimen configuraion a DECC. Here, Bus 5 is away from he source (subsaion), so i is subjec o he bigges volage drop and idenified as he weak bus. Fig. 11. he one-line diagram of a sample disribuion sysem wih wo DEs conneced Fig. 10(a) Fig. 10(b) Fig. 12 shows he volage a Bus 5 under wo differen scenarios: DE1 placed a differen buses (Bus 2 and Bus 1, respecively) while DE2 is always placed a Bus 5. I should be noed ha he volage references are raised o mimic he siuaion ha a volage regulaion is needed o boos he volage under a sudden disurbance. From Fig. 12, i is apparen ha he volage regulaion speed is faser when DE1 is closer o he weak bus han he case ha DE1 is placed far away from he load. Copyrigh 2008 Praise Worhy Prize S.r.l. - All righs reserved Inernaional Review of Elecrical Engineering, Vol. 3, n

8 Y. Xu, F. Li, H. Li, D.. Rizy, J. D. Kueck Fig. 13 shows he impac of differen load levels o volage regulaing DEs. In Fig. 13(a), local volage regulaion a Bus 2 and 5 are shown when he load a Bus 3 is low. As shown in he figures, even if he same conrol parameers and he final volage references are mainained, i will be sluggish for DE1 o bring is local volage o he desired reference value while i is ineresing o observe a sligh overshoo for DE2 o bring is local volage o he reference value. Fuure research is needed o find ou he ineracion of DEs o idenify he opimal conrol parameer seings wih he consideraion of many facors such as sysem configuraion, load variaion, and so on. Fig. 12. Volages a he weak bus (Bus 5) wih wo DEs insalled (DE2 is always a he weak bus) Fig. 13(a) VII. Conclusions and Fuure Works his paper presens he recen research, developmen and demonsraion hrough simulaion and experimen abou he possible uilizaion of he dynamic Var capabiliy from DE o regulae local volage a he cusomer side. I applies a generalized definiion, exended from radiional definiions, of insananeous nonacive power such ha i works in a real-world disribuion sysem ha may have single-phase, nonsinusoidal, unbalanced, and non-periodic waveforms. DE, if equipped wih he proposed PI conrol based on he insananeous nonacive power heory and he new power elecronic converers, has fas dynamic response o effecively compensae volage sags and oher sudden changes in he sysem. his is shown wih simulaion and experimen resuls. Simulaion resul also shows he ineracion of muliple DE a differen locaions or under differen load levels may have an impac o he conrol parameer seing for each individual DE conrol sysem. his leads o possible furher research direcions. I is will be also necessary o invesigae he correlaion of volage changes wih respec o he elecrical disance beween differen DE in a larger sysem. Also, i needs furher sudy o idenify an approach o uilize muliple DE o regulae volage in a decenralized approach wih minimum communicaion o achieve he bes ransien performance in volage regulaion. Acknowledgemen he auhors would like o hank Oak Ridge Naional Laboraory for financial suppor in par o complee his research work. Fig. 13(b) Figs. 13. Volages a Buses 2 and 5 under low load and high load a Bus 3: (a) Low Load a Bus 3; (b) High Load a Bus 3 References [1] J. B. Campbell,. J. King, B. Ozpineci, D.. Rizy, L. M. olber, Y. Xu, X. Yu, Ancillary services provided from DER, Oak Ridge Naional Laboraory Repor, ORNL/M-2005/263. [2] S. Li, K. omsovic,. Hiyama, Load following funcions using disribued energy resources, IEEE Power Engineering Sociey Summer Meeing, Copyrigh 2008 Praise Worhy Prize S.r.l. - All righs reserved Inernaional Review of Elecrical Engineering, Vol. 3, n

9 Y. Xu, F. Li, H. Li, D.. Rizy, J. D. Kueck [3] J. Driesen, G. Deconinck, W. D haeseleer, R. Belmans, Acive User Paricipaion in Energy Markes hrough Acivaion of Disribued Energy Resources, IEEE Power Engineering Sociey General Meeing, [4]. Niknam, M. Nayeripour, J. Olamaei, A. Arefi, An Efficien Hybrid Evoluionary Opimizaion Algorihm for Daily Vol/Var Conrol a Disribuion Sysem Including DGs, Inernaional Review of Elecrical Engineering, vol. 3, n. 3, June [5] D. N. Gaonkar, P. C. Rao, R. N. Pael, Hybrid mehod for volage regulaion of disribuion sysem wih maximum uilizaion of conneced disribued generaion source, IEEE Power India Conference, [6] C.M. Hird, H. Leie, N. Jenkins, H. Li, Nework volage conroller for disribued generaion, IEE Proceedings on Generaion, ransmission and Disribuion, vol. 151, n. 2, pp , March [7] Johan Morren, Sjoerd W.H. de Haan, J.A. Ferreira, Conribuion of DG unis o volage conrol: Acive and reacive power limiaions, IEEE Power ech Conference, [8] M. H. J. Bollen,A. Sannino, Volage conrol wih inverer-based disribued generaion, IEEE ransacions on Power Delivery, vol. 20, n.1, pp , January, [9] Simon R. Wall, Performance of inverer inerfaced disribued generaion, IEEE ransmission and Disribuion Conference and Exposiion, [10] B. Meyer, Y. Bamberger, I. Bel, Elecricie de France and inegraion of disribued energy resources, IEEE Power Engineering Sociey General Meeing, [11] B. Kroposki, C. Pink, R. DeBlasio, H. homas, M. Simoes, P. K. Sen, Benefis of power elecronic inerfaces for disribued energy sysems, IEEE Power Engineering Sociey General Meeing., [12] D. Feng, Z. Chen, Sysem conrol of power elecronics inerfaced disribuion generaion unis, IEEE 5h Inernaional Power Elecronics and Moion Conrol Conference, [13] R.. Guromson, Modeling disribued energy resource dynamics on he ransmission sysem, IEEE ransacions on Power Sysems, vol. 17, n. 4, pp , November [14] J.Driesen, R.Belmans, Disribued generaion: challenged and possible soluions, IEEE Power Engineering Sociey General Meeing, [15] Fangxing Li, Wenjuan Zhang, L. M. olber, J. D. Kueck, D.. Rizy, Assessmen of he Economic Benefis from Reacive Power Compensaion, Proceeding of he IEEE Power Sysems Conference and Exposiion (PSCE) 2006, pp , Ocober 29 - November 1, 2006, Alana, GA. [16] Yan Xu, L. M. olber, F. Z. Peng, J. N. Chiasson, J. Chen, Compensaion-Based Non-Acive Power Definiion, IEEE Power Elecronics Leers, vol. 1, n. 2, June 2003, pp [17] M. A. Kashem, Gerard Ledwich, Muliple disribued generaor for disribuion feeder volage suppor, IEEE ransacion on Energy Conversion, vol. 20, n. 3, Sepember 2005, pp engineer for four and a half years. His curren ineress include energy marke, reacive power, and disribued energy resources. Dr. Li is a regisered Professional Engineer in he sae of Norh Carolina. Huijuan Li (S 07) is presenly a Ph.D. suden in elecrical engineering a he Universiy of ennessee. She received her B.S.E.E. and M.S.E.E. in elecrical engineering from Norh China Elecrical Power Universiy, China in 1999 and 2002 respecively. She previously worked as a research engineer a Shanghai Sieyuan Elecrical Company in China on he field of ungrounded neural disribuion sysems. D. om Rizy (SM 87) is a senior research power sysems engineer a Oak Ridge Naional Laboraory (ORNL) in he Engineering Science and echnology Division. His curren ineres and aciviies focus on new conrols for disribued energy resources (DER) and applicaions for synchro-phasor measuremens. He is a cofounder of he Disribuion Energy Communicaions and Conrol Laboraory (DECC) a ORNL for esing dynamic volage regulaion conrols using DER. He has over 29 years experience in power sysems R&D and received his MSEE and BSEE from Virginia ech and he Universiy of Virginia, respecively. His is a co-recipien of he IEEE Prize Paper Award (1990) for Adapive Relaying Conceps for Improved Performance and a chaper auhor of he book on he Ahens Auomaion and Conrol Experimen, a large-scale disribuion auomaion projec conduced in he 80s by DOE, VA and EPRI. John D. Kueck (M 75, SM 00) earned a BS in Physics from Purdue Universiy and an MS in Elecrical Engineering - Power Sysems, from Ohio Sae Universiy. Over he firs 20 years of his career, Mr. Kueck worked in he design and operaion of fossil fuel and nuclear generaing saions. From 1992 o presen, Mr. Kueck has been a researcher a he Oak Ridge Naional Laboraory. His major ineres is he local supply of reacive power from disribued energy resources as a reliabiliy service. 1 Oak Ridge Naional Laboraory 2 he Universiy of ennessee Auhors informaion Yan Xu (S 02, M 06) received her Ph.D. in elecrical engineering a he Universiy of ennessee in She is a pos docoral research member a Oak Ridge Naional Laboraory. She received he BS degree from Shanghai Jiaoong Universiy, China in 1995 and he MS degree from Norh China Elecric Power Universiy, China in Her research ineress include power elecronics applicaions in power sysems and disribued energy resources. Fangxing (Fran) Li (M 01, SM 05) received he Ph.D. degree from Virginia ech in He has been an Assisan Professor a he Universiy of ennessee (U), Knoxville, N and an adjunc researcher a ORNL since Augus Prior o joining U, he worked a ABB, Raleigh, NC, as a senior and hen a principal R&D Copyrigh 2008 Praise Worhy Prize S.r.l. - All righs reserved Inernaional Review of Elecrical Engineering, Vol. 3, n

10 Inernaional Review of Elecrical Engineering (IREE) Auhors pag. pag. Adam M. 759 Li H. 795 Agelidis V. G. 874 Mahdavi M. 858 Akujuobi C. M. 922 Majsrovic G. 768 Al-Haddad K. 811, 844 Medic I. 768 Amrhein W. 906 Mehrabian M. 931 Awada E. 922 Miraoui A. 900 Bajs D. 768 Mirzayi M. R. 788 Baraboi A. 759 Morawiec M. 892 Baraka G. 820 Mougharbel I. 844 Belfkira R. 820 Muraa. 912 Blažič B. 779 Muyeen S. M. 912 Božiček A. 779 Nabavi A. 931 Dahidah M. S. A. 874 Nichia C. 820 Dasfan A. 788 Pancu C. 759 Delshad M. 829 Papič I. 779 Djerdir A. 900 Pique H. 864 Farooq J. A. 900 Plesca A. 759 Farzanehfard H. 829, 858 Richardeau F. 864 Fnaiech F. 811 Rizy D Grabner H. 906 Sadinezhad I. 803 Hwu K. I. 837 Sedraoui K. 811 Ibiouen R. 900 Sen P. C. 881 Jain P. K. 881 Silber S. 906 Joorabian M. 803 akahashi R. 912 Kanaan H. Y. 844 amura J. 912 Krzeminski Z. 892 ouai S. 900 Kueck J. D. 795 ouhami O. 900 Lewicki A. 892 Xu Y. 795 Li F. 795 Ye Z. 881