ACTIVE AND REACTIVE POWER CONTROL AND QUALITY MANAGEMENT IN DG-GRID INTERFACED SYSTEMS

VOL. 4, NO. 3, MAY 29 ISSN 1819-668 26-29 Aian Reearh Publihing Network (ARPN). All right reerved. ACTIVE AND REACTIVE POWER CONTROL AND QUALITY MANAGEMENT IN DG-GRID INTERFACED SYSTEMS R. D. Patidar and S. P. Singh Department of Eletrial Engineering, Indian Intitute of Tehnology, Roorkee, India E-Mail: rdpatdee@iitr.ernet.in ABSTRACT The main fou of thi paper i to ontrol the ative power upplied by ditributed generation (DG) ytem while ompenating harmoni and reative urrent aued by the nonlinear load uing hunt ative power filter (APF). The APF ontrol i baed on load urrent ening for referene urrent etimation in a-b- referene frame. In order to get the grid urrent inuoidal and in-phae with the ditorted grid voltage, the poitive equene omponent of the grid voltage are omputed. The ative power tranfer i baed on phae angle between DC-AC onverter and grid voltage and reative power management i baed on magnitude of thee voltage. The extenive imulation of the tudy i arried out under MATLAB /Simulink environment to how the uefulne of the ontrol algorithm. Variou imulation reult are preented with integrated mode (forward and revere power flow) of operation of ditributed generation ytem interfaed with grid. Keyword: ative power filter, ditributed generation, harmoni, reative power, power quality. INTRODUCTION The riing onern on a more effiient ue of the energy i booting the interet in expanding eletri generating apaitie through the ue of ditributed energy generation (DEG) [1-2]. The main objetive of the ditributed generation ytem onneted with grid i to ontrol the power that the inverter injet into the grid. Aording to the grid demand the ontroller alo injeted the reative power. Ditributed generation (DG) enompae a wide range of prime mover tehnologie, uh a internal ombution (IC) engine, ga turbine, miro turbine, photovoltai, fuel ell and wind-power. Thee ditributed generator are haraterized mainly by their unplanned loation and by a low nominal power rating(le than 1 MW). The integrated DG along with grid ytem an olve many typial problem of onventional AC network uh a energy eurity, redue tranmiion and high voltage equipment ot et. owever, a mall DG ha ome ignifiant problem of frequeny and voltage variation when it i operated in tand-alone mode. Therefore, a mall DG hould be interonneted with the power ytem in order to maintain the frequeny and the voltage. AC-main Z S Linear load PS Sinuoidal voltage v Non-linear load Z L (Voltage drop) Ditorted urrent P L v L Load PCC Ditorted voltage Non-linear load Figure-1. armoni voltage ditortion at load PCC. Further tremendou proliferation of power eletroni load may produe different power quality problem uh a harmoni, unbalaning, exeive neutral urrent, et. [4]. Figure-1 repreent the harmoni voltage ditortion at point-of-ommon-oupling (PCC) due to harmoni urrent flowing through the ytem impedane. Thee power quality problem aue many advere effet like additional heating, amplifiation of harmoni due to preene of power fator orretion apaitor bank, redution of tranmiion ytem effiieny, overheating of ditribution tranformer, malfuntioning of eletroni equipment, puriou operation of iruit breaker and relay, error in meauring intrument, interferene with ommuniation and ontrol ignal et.[3-5]. Therefore, the power quality iue ha beome important nowaday. The DG-grid interfaed ytem with power eletroni help to improve the power quality problem at PCC. Figure-2 how a general purpoe blok diagram of DG-grid ytem with power eletroni interfae whih an be ubdivided into four major etion [7-1]. Thee inlude: the AC-DC onverter, DC-AC inverter, the output interfae and the ontroller module. The unidiretional arrow how the power flow path for the ditributed energy oure wherea the bidiretional arrow indiate the bidiretional power flow for the ditributed energy torage. The input onverter module an be either ued with alternating urrent (AC) or diret urrent (DC) DG ytem and i mot likely to be peifi for the type of energy oure or torage. The DC-AC inverter module i the mot generi of the module and onvert a DC oure to gridompatible AC power. The output interfae module filter the AC output of the inverter. The fourth major module i the monitoring and ontrol module that drive the entire interfae and ontain protetion for both the DG oure and the utility at the PCC. 81

VOL. 4, NO. 3, MAY 29 ISSN 1819-668 26-29 Aian Reearh Publihing Network (ARPN). All right reerved. Power Eletroni and Control Ditributed Energy Reoure PV, Wind, Miroturbine, Fuel Cell, IC Engine Battery, Flywheel Energy Storage AC-DC or DC-DC Converter Module DC-AC Converter Module Output Interfaed Module PCC Grid Sytem Loal Load Monitoring and Control Sytem Figure-2. General purpoe blok diagram of DG-grid ytem with power eletroni interfaed. Several tudie propoed an interonnetion ytem for DG with the power ytem through inverter beaue the inverter give veratile funtion for improving the performane of DG [6]-[12], [15]. Referene [11] and [12] have reported the field tet reult of ative filter intended for intallation on power ditribution ytem. Liang et al. [13] have preented a power ontrol method for a grid-onneted voltage oure inverter whih ahieve good (P, Q) deoupling and fat repone. owever, thi approah require knowledge of the value of power ytem equivalent impedane, whih i not viable. Illindala et al. [14] have preented a different power ontrol trategy baed on frequeny and voltage droop harateriti of power tranmiion, whih allow deoupling of P and Q at teady tate. Thi paper preent the ombined operation of APF and DG whih i onneted to a d-link energy torage ytem through retifier. The propoed APF ytem i apable for imultaneouly ompenating harmoni, reative urrent, and load imbalane and alo for injeting energy generated by DG ytem to grid. ACTIVE POWER FILTER The bai ompenation priniple of APF i explained with the help of Figure-3. Soure Current Pt () = P() t P() t S Lf Sl Q () t = S i Sinuoidal Soure R L i R m L m L C d V d R L i Shunt Ative Filter Load Current Compenating urrent P () t = p () t p () t C Lh Sl Q () t = q () t q () t C Lf Lh P () t = p () t p () t L Lf Lh Q () t = q () t q () t L Lf Lh Non-Linear Load Figure-3. Bai iruit topology of ative power filter. The intantaneou nonlinear load urrent an be repreented by [5]. il() t = Ih in( hωt φh) h = 1 (1) = I1in( ω t φ1) Ih in( hωt φh) h = 2 The intantaneou load power an be given a: pl() t = v() t il() t 2 = VI m 1in ( ωt)o( φ1) VI m 1in( ωt)o( ωt)in( φ1) (2) V in( ωt) I in( hωt φ ) m h h h= 2 = p () t p () t p () t Lf Lq Lh Where, I 1 i the peak value of the fundamental load urrent, I h i the peak value of the harmoni load urrent, Φ 1 and Φ h are the phae angle of the fundamental and harmoni omponent of the load urrent, repetively. In (2) the intantaneou power of nonlinear load i divided into three term. The firt term p Lf (t) i the intantaneou load fundamental power. The eond term p Lq (t) i intantaneou load fundamental quadrature (reative) power and the third term p Lh (t) i the intantaneou load harmoni power. A hunt APF i deigned to be onneted in parallel with the load, to detet it harmoni and reative urrent and to injet into the ytem a ompenating urrent, idential with the load harmoni and reative urrent. Therefore, intantaneou upply urrent i having only fundamental omponent whih i inphae with oure voltage v (t). PROPOSED SYSTEM DESCRIPTION The hemati diagram of the propoed ditributed generation grid interfae with power eletroni i.e. ative power filter i hown in Figure-4 Three-phae grid ytem of oure reitane R and indutane L per phae, upplying power to loal nonlinear load. A urrent ontrolled three-phae hunt ative power filter with energy torage apaitor C d i onneted in parallel with loal nonlinear load. The APF onit of an indutor L and a reitane R (equivalent reitane of the inverter lo, the indutane lo) per phae and a three-phae IGBT bridge urrent-ontrolled 82

VOL. 4, NO. 3, MAY 29 ISSN 1819-668 26-29 Aian Reearh Publihing Network (ARPN). All right reerved. voltage oure inverter (CC-VSI). A ontant peed DG unit i onneted to the d-link of APF through AC-DC onverter. A moothing indutor of impedane (R m jωl m ) per phae to avoid the pike in the grid urrent i alo onneted in erie with nonlinear load. The APF an ompenate the urrent harmoni, load power fator, and imbalane in the oure urrent, while the DG upplie power to the grid and loal load. Two interonneted mode other than ilanding mode are poible of the propoed DG-grid interfaed ytem. One i alled the forwarded interonneted mode in whih the DG and grid both will upplie power to loal load. And another i revere interonneted mode in whih DG will upplie power to loal load a per load requirement and ret of the power i injeted into the grid. In the ilanding mode the DG upplie power to the loal load only. TE PROPOSED CONTROL TECNIQUE The propoed APF ontrol truture of the DGgrid interonneted ytem i hown in Figure-5. Three major element of the propoed heme are the poitive equene detetor, referene urrent alulator and PWM ignal generator. The ontrol trategy i deigned for ontrolling the power in interonneted and the ilanding mode. The ytem work in forwarded interonneted mode when both the DG and the grid upplie power to the loal load. i a v La PCC ila Z a i b v Lb i Lb Z b 3-phae Grid Sytem Ditribution Generation Controller R L Ditributed Generation ontrol S 1 S 3 S 5 i S 5 CC-VSI S 3 S 1 L R ia ib v L i i L Z Linear Load Indution generator Tranformer S 4 S 6 S 2 AC-DC Converter C d V d S 2 S 6 S 4 DC-AC Converter R C L L R L Nonlinear Load Figure-4. Shemati diagram of the DG-Grid interfaed ytem with ative power filter. v La v Lb v L i La i Lb LowPaFilter Poitive Sequene Calulator LPF V m1 P L P dg in( ωt φ ) in( ω 12 φ1) in( ω 12 φ1 ) P t t 1 Optimal Control I m1 i a i b i i Lb i La i L i a i b i Gate Control Pule DC-AC Converter i L V dref PI Controller P lo 1 S PWM1 Control 2 Gate Control Pule AC-DC Converter Swith S at 1 APF alone Swith S at 2 APF with DG V d Figure-5. Propoed ontroller for ative and reative power ontrol in a DG-grid interfaed ytem. But it work in ilanding mode when the voltage interruption on grid our. One the voltage interruption i removed, the ytem operation tranfer from the ilanding mode to the interonneted mode. The ontrol of inverter involve the ontrol of ative power upplied by DG and reative power requirement of load in uh a way that reative power upplied by the main oure remain zero. The a-ide voltage of the ative power filter inverter (DC-AC module) are ontrolled both in magnitude and phae to ontrol the ative and reative power. In order to examine the ompenation mehanim let aume that ditribution generation ue a ontant peed indution generator and the grid voltage of vetor v (t) and load urrent of vetor i L (t) onit of a et of harmoni omponent h are expreed in (3) and (4) repetively, where = {1, 2, 3..N} and where N i the highet order of harmoni under onideration. vla = VLha in( hω t α ha ) h (3) vl () t = vlb = VLhb in( h( ω t 2 π /3) α hb ) h vl = VLh in( h( ω t 2 π / 3) α h ) h 83

VOL. 4, NO. 3, MAY 29 ISSN 1819-668 26-29 Aian Reearh Publihing Network (ARPN). All right reerved. ila = I Lha in( hω t α ha φha ) h il ( t) = ilb = I Lhb in( h( ω t 2 π / 3) α hb φhb ) h il = I Lh in( h( ω t 2 π /3) α h φh) h Where (V ha V hb V h ) and (I Lha, I Lhb, I Lh ) are the peak value of upply voltage and load urrent orreponding to h th order harmoni, (α ha α hb α h ) and (Φ ha, Φ hb, Φ h ) are the arbitrary a well a phae angle. Grid voltage are filtered uing the 5 th order low-pa filter (LPF) with a ut-off frequeny at 5 z. (4) and hene the grid will upport to meet the load ative power requirement. The grid urrent in the ae will be in-phae with the repetive grid voltage. I q I Lq φ L I I dg I p I Lp I L δ δ V V L IR I = I I, I = I, I = I, I =, I > I jωli p Lp p p Lq q q Lp p IR V jωli V dg AC Ditributed Generation DC V d DC V δ Grid Z = R jl AC C d Z = R jl V L Loal Load V δ Figure-6. Single line diagram of DG-grid interfaed ytem. The ingle line diagram of the DG-grid ytem repreenting a 3- phae, ymmetrial, balaned teady tate ytem i hown in Figure-6. The ative and reative power (P p, Q p ) tranfer between the inverter and the grid ytem are given by the (5)-(6). The ative power tranfer i the funtion of power angle δ and the reative power tranfer i the funtion of voltage magnitude differene between the inverter voltage and the grid voltage. P p VVin δ L = (5) ωl V Qq ( V V oδ L ) ωl = (6) Where V L and V C are the load and DC-AC onverter (AC ide) voltage and δ i the phae angle between them. The APF referene urrent i funtion of ative power flow between inverter and PCC. Figure-7-8 how the vetor diagram of ative power flow at unity power fator for forward and revere interonneted mode of operation. In whih I SP, I Lp, and I dg are the ative fundamental urrent of the grid, load and DG (a-ide of the inverter) repetively. And V, V L, and V are the voltage at grid, load and a ide of the DC-AC onverter. The Φ L i the load power fator angle and δ are the power angle between grid and load voltage and δ i the power angle between filter inverter and load voltage. I Lq and I q are the reative omponent of load and APF urrent repetively. Figure-7 how the vetor diagram of ative power flow at unity power fator in forward interonneted mode (DG and grid both upply power to loal load). In thi ae the load ative urrent i higher than the DG ative urrent Figure-7. Phaor diagram at unity power fator in forward interonneted mode. Figure-8 how the phaor diagram of ative power flow at unity power fator in revere interonneted mode in whih DG upply power to loal load and grid. The ative omponent of loal load urrent I Lp in thi ae i lower than the ative urrent omponent of DG and hene the DG will upply extra power to grid. The grid urrent in the ae will be 18 out of phae with the repetive grid voltage. I p I q I Lq φ L I Lp I L I I dg δ δ V IR jωl I V L I = I I, I = I, I = I, I =, I < I p Lp p p Lq q q Lp p V IR jωli Figure-8. Phaor diagram at unity power fator in revere interonneted mode. The propoed ompenation trategy of the hunt APF to maintain the deired oure urrent to be balaned, inuoidal, and in-phae with the fundamental omponent of oure voltage. The PCC voltage and load urrent are ued to obtain the average value of three-phae load ative power P lavg i omputed a: 1 P [ v(). ti() t v(). ti() t v(). ti() tdt ] T T = lavg (7) La La Lb Lb L L Where T i the time period of voltage and urrent waveform. Apart from the load ative power oure ha alo upplied the ative lo power P Sl of the inverter. The loe in the inverter are beaue of the withing lo in the devie, iron and opper loe in the iruit omponent, et. [5]-[6]. Thi lo omponent i obtained uing an energy PI ontroller a expreed a: P = ( ) ( ) Sl K V V K V V dt pe dref d ie dref d (8) The average value of ative power upplied by the grid P i alulated by (1) 84

VOL. 4, NO. 3, MAY 29 ISSN 1819-668 26-29 Aian Reearh Publihing Network (ARPN). All right reerved. P (9) P = P P S L l d g Where P L i the load ative power and P dg i the ative power upplied by DG. When P i poitive that mean the both grid and DG will upply power to the load. Converely if P i negative the DG upply power to load a per load requirement and ret of the power i upplied to grid. In order to get the balane urrent after ompenation under the ondition of unbalaned PCC voltage and load urrent it i required to determine the deired oure urrent magnitude I from the equential m1 intantaneou PCC voltage and real power omponent upplied by the oure. The ative power upplied by the oure an be written a, 3V I oφ Lm1 m1 = (1) S P 2 Where V i the peak value of three-phae poitive m1 equene omponent of the PCC (grid) voltage expreed a (11)? V 2 = V V } (11) 3 2 2 2 { V Lm1 La1 Lb1 L1 The peak value of the deired oure urrent after ompenation an be obtained a (12) I m1 2PS = (12) 3V oφ m1 For unity power fator operation the oφ =1.One the peak value of the deired oure urrent are obtained the intantaneou value of the deired oure urrent an be obtained by (13) i I in( ωt φ ) a m1 i () t = i I in( t 2 / 3 ) b = ω π φ m1 (13) i I in( ωt 2 π / 3 φ ) m1 The referene urrent are now ompared with load urrent to alulate ative and reative power ompenating urrent whih are ued to generate PWM pule to with the devie onneted in the inverter onfiguration. The APF ompenating urrent vetor an be expreed a: ia i a ila i() t = i b = i b i (14) Lb i i i L RESULTS AND DISCUSSIONS The performane of the propoed APF ontroller for DG-Grid interfaed ytem a per Figure 4 and 5 i imulated under MATLAB/Simulink environment. The APF performane i analyzed in forward and revere interonneted mode for power flow. The DG unit i onneted by withing-on the APF at.5 in both the ae and further load i hanged at o.25 and.5.the parameter ued for the imulation tudy are given in Appendix. A. Forward interonneted mode Figure 9 and 12 how the performane of DGgrid interfaed ytem for ative and reative power ontrol in forward interonneted mode. The In thi ae the ative power demand of load i more than DG apaity and hene grid and DG both will upply ative power to load. The ompenator i withed on at t =.5 and further load i hanged at t =.25 and t =.5. The grid, load and DG ative power in thi ae are hown in Figure-9. After withing-on the APF the oure or grid urrent beome inuoidal and in-phae with repetive voltage. It i aumed that DG and grid provide 1kW power to load during.5 < t <.25, 11.8kW during.25 < t <.5, and 12.2kW during t >.5 in whih DG will upply ontant 5kW power. The phae-wie grid voltage and urrent are hown in Figure- 1 in whih the gird urrent are in-phae with the repetive phae voltage prove that grid i upporting to meet out the load ative power demand along with DG. Three-phae grid voltage, load urrent, grid urrent, APF urrent are hown in Figure-11. The FFT of the grid urrent ignal alo ha been arried out a ample of FFT of the load and grid urrent are hown in Figure-12 in whih the TD in grid urrent after ompenation are redued from 23.28% to 1.25% well within the IEEE reommended limit. B. Revere interonneted mode In thi ae the load ative power demand (PL) i le than DG apaity (P dg ) and hene DG upply ative power to load a per load requirement and ret of the power i injeted into the grid ytem. The ompenator i withed on at t =.5 and further load i hanged at t =.25 and t =.5 a hown in Figure 13 and 16. The grid, load and DG ative power in thi ae are hown in Figure-13. It i aumed that out of 5kW power DG provide 1.1kW power to loal load during.5 < t <.25, 2.2kW during.25 < t <.5, and 3.3kW during t >.5. The ret of the power in the above mentioned duration are injeted into the grid. The three-phae grid voltage and urrent are phae-wie and together are hown in Figure-14 and Figure-15, repetively in whih the grid urrent are 18 out of phae with repetive phae voltage prove that DG ytem i injeting extra power into the grid. A ample of FFT of the load and grid urrent are hown in Figure-16 in whih the TD in grid urrent after ompenation are redued from 27.76% to.75% well within the IEEE reommended limit 85

VOL. 4, NO. 3, MAY 29 ISSN 1819-668 26-29 Aian Reearh Publihing Network (ARPN). All right reerved. 15 Soure or Grid ative power P 1 5 15.1.2.3.4.5.6.7 Load ative power P L 1 5 1.1.2.3.4.5.6.7 DG ative power P dg 5.1.2.3.4.5.6.7 Time() Figure-9. Grid, load and DG ative power in forward interonneted mode of operation. Volt & Amp Volt & Amp Volt & Amp 2 3 3-3 3-3 Phae 'a' voltage and urrent.1.2.3.4.5.6.7 Phae 'b' voltage and urrent.1.2.3.4.5.6.7 Phae '' voltage and urrent.1.2.3.4.5.6.7 Time() Figure-1. Phae a, b and grid voltage (aled by a fator of.1) and urrent in forward interonneted mode. Volt Amp Amp Amp 4 2-2 -4 4 2-2 -4 4 2-2 -4 4 2-2 -4 Three-phae grid or oure voltage.5.1.15.2.25.3 Three-phae load urent.5.1.15.2.25.3 Three-phae grid or oure urrent.5.1.15.2.25.3 three-phae ompenating urrent.5.1.15.2.25.3 Time() Figure-11. Three-phae grid voltage, load urrent, grid or oure urrent and filter ompenating urrent in forward mode. 86

VOL. 4, NO. 3, MAY 29 ISSN 1819-668 26-29 Aian Reearh Publihing Network (ARPN). All right reerved. Figure-12. FFT of a eleted ignal of load and grid urrent for phae-a in forward interonneted mode. 4 Soure or grid ative power P 2 4.1.2.3.4.5.6.7 Load ative power P L 2 1.1.2.3.4.5.6.7 DG ative power P dg 5.1.2.3.4.5.6.7 Time() Figure-13. Grid, load and DG ative power in revere interonneted mode of operation. Phae 'a' voltage and urrent Volt & Amp 2-2.1.2.3.4.5.6.7 Volt & Amp 2-2 Phae 'b' voltage and urrent.1.2.3.4.5.6.7 Phae '' voltage and urrent Volt & Amp 2-2.1.2.3.4.5.6.7 Time() Figure-14. Phae-a, b and grid voltage (aled by a fator of.1) and urrent in revere interonneted mode. 87

VOL. 4, NO. 3, MAY 29 ISSN 1819-668 26-29 Aian Reearh Publihing Network (ARPN). All right reerved. Volt 4 2-2 -4 1 Three-phae grid voltage.5.1.15.2.25.3 Three-phae load urrent Amp Amp -1 1-1 2.5.1.15.2.25.3 Three-hhae grid or oure urrent.5.1.15.2.25.3 Three-phae filter urrent Amp -2.5.1.15.2.25.3 Time() Figure-15. Three-phae grid voltage, load urrent, grid or oure urrent and filter ompenating urrent in forward mode. Figure-16. FFT of a eleted ignal of load and grid urrent for phae-a in revere interonneted mode. CONCLUSIONS Thi paper diue the appliation of ative power filter a an interfae between ditributed generation and grid. The propoed APF ytem i apable for injeting DG power to eletri grid while ompenating load power fator, harmoni and load balaning. The utility urrent are inuoidal and in-phae with their repetive voltage (forwarded mode) and inuoidal and 18 out of phae in (revere mode).the oure urrent TD after ompenation i well within the IEEE 519-1992 reommended limit. The propoed ontroller i alo uitable under unbalaned and ditorted grid voltage. Apart from thee the propoed ontrol trategy i uitable for ilanding mode of operation. The omputation of referene oure (grid) urrent in natural referene frame rather then tranformation redue the omputational burden. REFERENCES [1] T. Akermann, G. Anderon and L. Soder. 21. Ditributed generation: a definition, Eletri Power Sytem Reearh. 57: 195-24, 4/2. [2] T. Akerman, G. Anderon, and L. Soder. 2. Eletriity market regulation and their impat on ditributed network, in Pro. Eletri Utility Deregulation Retruturing Power Tehnologie. pp. 68-613. [3]. Fujita,. Akagi. 1998. The unified power quality onditioner: The integration of erie and hunt ative filter, IEEE Tranation on Power Eletroni. 13(2): 494-51. 88

VOL. 4, NO. 3, MAY 29 ISSN 1819-668 26-29 Aian Reearh Publihing Network (ARPN). All right reerved. [4] B. Singh, K. Al-addad and A. Chandra. 1999. A review of ative filter for power quality improvement. IEEE Tranation on Indutrial Eletroni. 46(5): 96-971. [5] R. D. Patidar, S. P. Singh, and J. D. Sharma. 28. armoni Elimination and Var Compenation for 3P3W and 3P4W Ditribution Sytem Uing Shunt Ative Filter, IASTED International Conferene on Power and Energy Sytem (PES-28), Baltimore, USA. April. Paper No. 617-85. [6]. Akagi. 1996. New trend in ative filter for power quality onditioning. IEEE Tranation on Indutry Appliation. 32(6): 312-1322. [7] A. Chandra, B. Singh, B. N. Singh, and K. Al- addad. 2. An improved ontrol algorithm of hunt ative filter for voltage regulation, harmoni elimination, power-fator orretion, and balaning of nonlinear load. IEEE Tranation on Power Eletroni. 15(3): 495-57. [14] J. Liang, T. C. Green, G. Wei, and Q. C. Zhong. 2. Evaluation of repetitive ontrol for power quality improvement of ditributed generation in Pro. 22 IEEE Power Eletroni Speialit Conferene, Cairn, Qld., Autralia. June. 4: 183-188. [15] M. Illindala and G. Venkataramanan. 22. Control of ditributed generation ytem to mitigate load and line imbalane. In Pro. 22 IEEE Power Eletroni Speialit Conferene, Cairn, Qld., Autralia. June. 4: 213-218. [16] S. V. R. Kumar and S. S. Nagaraju. 27. Simulation of D-STATCOM and DVR in power ytem, ARPN Journal of Engineering and Applied Siene. 2(3): June. [8] F. Blaabjerg, Z. Chen, and S.B. Kjaer. 24. Power Eletroni a Effiient Interfae in Dipered Power Generation Sytem. IEEE Tranation on Power Eletroni. 19(5): 1184-1194. [9] P.S. Senarma, K.R. Padiyar, V Ramanarayanan. 21. Analyi and performane evaluation of a ditribution Statom for ompenating voltage flutuation. IEEE Tranation on Power Delivery. 16(2): 259-264. [1] S. Barali, M. Ceraolo, P. Pelahi, and D. Poli. 22. Control tehnique of dipered generator to improve the ontinuity of eletriity upply, in Pro. IEEE Power Eng. So. Winter Meeting. 2: 789-794. [11] F. Blaabjerg, R. Teodoreu, M. Lierre, A.V. Timbu. 26. Overview of ontrol and grid ynhronization for ditributed power generation ytem. IEEE Tranation on Indutrial Eletroni. 53(5): Otober. [12] T. Tenma, T. Genji, K. Mizuki, and Y. Fujita. 1999. Suppreion performane analyi of ative filter by neural network ontrol with voltage detetion on ditribution network Tran. Int. Elet. Eng. Jpn. vol. 119-D, No. 5. pp. 713-719. [13] Y. Suaki, T. Matumura, T. Genji, J. Inoue, K. Yohioka, and M. Kohata. 2. Development and proof examination reult of ative filter for power ditribution ytem Tran. Int. Elet. Eng. Jpn. vol. 12-B. 5: 746-752. 89

VOL. 4, NO. 3, MAY 29 ISSN 1819-668 26-29 Aian Reearh Publihing Network (ARPN). All right reerved. APPENDIX Parameter Value Parameter Value V S 4V, 5z K p : K i.5 : 1 R.1Ω per phae Load for forward mode L.15m per phae.5 < t <.25.25 < t <.5 t >.5 R.1Ω per phae 1kW 11.8kW 12.2kW L 2.5m per phae Load for revere mode C d 22µF and.5 < t <.25.25 < t <.5 t >.5 L m 1. m per phae 1.1kW 2.2kW 3.3kW 9