The Power Quality Compensation Strategy for Power Distribution System Based on Hybrid Parallel Active Power Filters

Transcription

1 Leonardo Electronc Journal of Practces and Technologes ISSN Issue 6, January-June p. 89- The Power Qualty Compensaton Strategy for Power Dstrbuton System Based on Hybrd Parallel Actve Power Flters Rachd DEHINI, Benachaba CHELLALI, Brahm BERBAOUI, Brahm FERDI, Boumedène ALLAOUA Faculty of the scences and technology, Department of Technology, Bechar Unversty B.P 47 BECHAR (8), Algera. E-mal: yahoo.fr ( Correspondng author: Phone: ) Abstract In ths paper, the man am s to confront the performance of shunt actve power flter (SAPF) and the shunt hybrd actve power flter (SHAPF) to acheve flexblty and relablty of the flter devces. Both of the two devces used the classcal proportonal-ntegral controller for pulse generaton to trgger the nventers MOSFET s. In the adopted hybrd actve flter there s a passve power flter wth hgh power ratng to flter the low order harmones and one actve flter wth low power ratng to flter the other hgh order harmones. In order to nvestgate the effectveness of (SHAPF), the studes have been accomplshed usng smulaton wth the MATLAB-SIMULINK. The results show That (SHAPF) s more effectve than (SAPF), and has lower cost. Keywords Shunt actve power flter; Passve power flter; Nonlnear loads, Hybrd actve flter. 89

2 The Power Qualty Compensaton Strategy for Power Dstrbuton System Based on Hybrd Parallel Actve Power Flters Rachd DEHINI, Benachaba CHELLALI, Brahm BERBAOUI, Brahm FERDI, Boumedène ALLAOUA Introducton Due to prolferaton of power electronc equpment and nonlnear loads n power dstrbuton systems, the problem of harmonc contamnaton and treatment take on great sgnfcance.these harmoncs nterfere wth senstve electronc equpment and cause undesred power losses n electrcal equpment [-3]. In order to solve and to regulate the permanent power qualty problem ntroduce by ths Current harmoncs generated by nonlnear loads such as swtchng power factor correcton converter, converter for varable speed AC motor drves and HVDC systems, the resonance passve flters (RPF) have been used; whch are smple and low cost. However, the use of passve flter has many dsadvantages, such as large sze, tunng and rsk of resonance problems whch decrease more the flexblty and relablty of the flter devces Owng to the rapd mprovement n power semconductor devce technology that makes hgh-speed, hgh-power swtchng devces such as power MOSFETs, MCTs, IGBTs, IGCTS, IEGTs etc. usable for the harmonc compensaton modern power electronc technology, Actve power flter (APF) have been consdered as an effectve soluton for ths ssue, t has been wdely used. One of the most popular actve flters s the Shunt Actve Power Flter (SAPF) [6-]. SAPF have been researched and developed, that they have gradually been recognzed as a workable soluton to the problems created by non-lnear loads, unfortunately, because of the hgh cost operaton, the (SAPF) s not a cost-effectve soluton. The dsadvantages of (RPF) and (SAPF) orentate the researchers toward shunt hybrd actve power flter (SHAPF), consequently (SHAPF) has become more attractve []. The (SHAPF) nvolve a (RPF) connected n parallel wth (SAPF), ths soluton allows the use of (SAPF) n the large power system avodng the expensve ntal cost and mproves the compensaton performance of passve flter remarkably. In ths paper, a (SHAPF) s presented both to acheve harmonc currents mtgaton and to compensate reactve power n an ndustral power dstrbuton.ths flter devce s analyzed by estmatng the effect of (RPF) jon and dsjon on ts compensaton performance. In the adopted hybrd actve flter there s a passve power flter wth hgh power ratng to flter the low order harmones the 5th, 7th harmonc current and one actve flter wth low power ratng to flter the other hgh order harmones. 9

3 Leonardo Electronc Journal of Practces and Technologes ISSN Issue 6, January-June p. 89- The functonng of (SAPF) s to sense the load currents and extracts the harmonc component of the load current to produce a reference current c a block dagram of the system s llustrated n Fg.. The reference current conssts of the harmonc components of the load current whch the actve flter must supply. Ths reference current s fed through a controller and then the swtchng sgnal s generated to swtch the power swtchng devces of the actve flter such that the actve flter wll ndeed produce the harmoncs requred by the load. Fnally, the AC supply wll only need to provde the fundamental component for the load, resultng n a low harmonc snusodal supply. Fgure. Schematc dagram of shunt (SHAPF) Reference Source Current Generaton In order to determne harmonc and reactve component of load current, reference source current generaton s needed. Thus, reference flter current can be obtaned when t s subtracted from total load current. For better flter performance, generaton of reference source current should be done properly. For ths purpose several methods such as pq-theory, dq-transformaton, multplcaton wth sne functon and Fourer transform have been 9

4 The Power Qualty Compensaton Strategy for Power Dstrbuton System Based on Hybrd Parallel Actve Power Flters Rachd DEHINI, Benachaba CHELLALI, Brahm BERBAOUI, Brahm FERDI, Boumedène ALLAOUA ntroduced n lterature [3]. In ths paper the nstantaneous reactve power theory method s used for extracton of reference. Ths concept bascally conssts of a varable transformaton from the a, b, c reference frame of the nstantaneous power, voltage and current sgnals to the, reference frame. The nstantaneous values of voltages and currents n the, coordnates can be obtaned from the followng equatons: va a v = [ ] A vb, [ ] v = A b v c c where A s the transformaton matrx and s equal to: () [ A ] = 3 3 Ths transformaton s vald f and only f v ( t ) + v ( t ) + v ( t ) and also f the a b c = voltages are balanced and snusodal. The nstantaneous actve and reactve powers n the coordnates are calculated wth the followng expressons: p( t q( t ) = v ( t ) ( t ) + v ( t ) ( t ) (3) ) = v ( t ) ( t ) + v ( t ) ( t ) (4) The values of p and q can be expressed From Eqs. (3) and (4) n terms of the dc components plus the ac components, that s: p = p + p~ (5) q = q + q ~ (6) where: p : s the dc component of the nstantaneous power p, and s related to the conventonal fundamental actve current. p~ : s the ac component of the nstantaneous power p, t does not have average value, and s related to the harmonc currents caused by the ac component of the nstantaneous real power. q : s the dc component of the magnary nstantaneous power q, and s related to the reactve power generated by the fundamental components of voltages and currents. q ~ : s the ac component of the nstantaneous magnary power q, and s related to the harmonc currents caused by the ac component of nstantaneous reactve power. () 9

5 Leonardo Electronc Journal of Practces and Technologes ISSN Issue 6, January-June p In order to compensate reactve power and current harmoncs generated by nonlnear loads, the reference sgnal of the shunt actve power flter must nclude the values of p ~ and q ~. In ths case the reference currents requred by the SAPF are calculated wth the followng expresson: + = L L c c q ~ p ~ v v v v v v (7) The fnal compensatng currents components n a, b, c reference frame are the followng: = c c cc cb ca (8) Fgure. Block dagram for the nstantaneous actve and reactve power DC Voltage Control The (SAPF) control strategy, nvolves not only the producton of currents whether to elmnate the undesred harmoncs or to compensate reactve power. But also to recharge the capactor value requested VDC voltage n order to ensure sutable transt of powers to supply the nverter. The storage capacty C absorbs the power fluctuatons caused by the compensaton of the reactve power, the presence of harmoncs, the actve power control and

6 The Power Qualty Compensaton Strategy for Power Dstrbuton System Based on Hybrd Parallel Actve Power Flters Rachd DEHINI, Benachaba CHELLALI, Brahm BERBAOUI, Brahm FERDI, Boumedène ALLAOUA also by the losses of the converter. The average voltage across the capactor termnals must be kept at a constant value. The regulaton of ths voltage s made by absorbng or provdng actve power on the electrcal network. The correcton of ths voltage must be done by addng the fundamental actve current n the reference current of (SPAF)[3]. To realze these objectves, a proportonal ntegral (PI) voltage feedback control as shown n Fg. 3, s added to regulate the capactor dc voltage of the (SAPF). In ths crcut, the actual dc capactor voltage s detected and compared wth the reference value, and the error s amplfed then s added to the p~ L, the output of hgh-pass flter n Fg.. Therefore, actve power lowng nto the capactor wll be changed and the dc voltage cab be controlled. PI Fgure 3. Control of DC Voltage usng conventonal PI controller (CPI) Results The performance of the (SHAPF) was examned through smulatons. The system model was mplanted n Matlab / Smulnk envronment. The (SAPF) was desgned to compensate harmoncs caused by nonlnear loads when the network s small relatve to the load (Ssc / SL = ). The system model parameters are shown n Table I. Table. System parameters Actve Flter Parameters Supply phase voltage U V Supply frequency fs 5 Hz Flter nductor Lf.7 mh Dc lnk capactor Cf mf Smoothng nductor Lsmooth 7 µh A three-phase dode rectfer wth an RL load was used as a harmonc producng load. The load (resstance was /3 Ω and the nductance 6 mh.) 94

7 Leonardo Electronc Journal of Practces and Technologes ISSN Issue 6, January-June p. 89- In second place, two resonant passve flters tuned up to the frequency 5Hz (h5) and 35Hz (h7) are smultaneously connected n parallel wth (FAP) n load sde at.4s. Both resonant passve flters have the followng characterstcs: Table. Passve flters characterstcs Descrpton Resonant passve flter (h5) Resonance frequency 5Hz (h5) Reactve power suppled Var 6 Qualty Factor resonant passve flter (H7) Resonance Frequency 35Hz (H7) Reactve power suppled Var Qualty Factor ILa Mag (% of Fundamental) 5 5 Fundamental (5Hz) = 67.4, THD= 6.85% Harmonc order Mag (% of Fundamental) (c) Fundamental (5Hz) = 67.8, THD= 6.% Harmonc order Fgure 4. (a.) Smulated phase-a the load current waveforms Isa(A).(b.) Harmonc spectrum of load current Phase a, wth (SAPF).(c.) Harmonc spectrum of load current Phase a, wth (SHAPF) 95

8 The Power Qualty Compensaton Strategy for Power Dstrbuton System Based on Hybrd Parallel Actve Power Flters Rachd DEHINI, Benachaba CHELLALI, Brahm BERBAOUI, Brahm FERDI, Boumedène ALLAOUA Isa Mag (% of Fundamental) Fundamental (5Hz) = 7.4, THD=.% Harmonc order Mag (% of Fundamental).5..5 (c) Fundamental (5Hz) = 68., THD=.6% Harmonc order Fgure 5. (a.) Smulated phase-a the supply current waveforms Isa.(b.) Harmonc spectrum of supply current Phase a, wth (SAPF).(c.) Harmonc spectrum of supply current Phase a, wth (SHAPF) 4 3 Vsa(V) - Mag (% of Fundamental) x -3 Fundamental (5Hz) = 3, THD=.9% Harmonc order Mag (% of Fundamental) (c) Fundamental (5Hz) = 3, THD=.74% Harmonc order Fgure 6. (a.3) Smulated phase-a the supply voltage waveforms Vsa(A).(b.3) Harmonc spectrum of supply voltage Phase a, wth (SAPF).(c.3) Harmonc spectrum of supply voltage Phase a, wth (SHAPF) 96

9 Leonardo Electronc Journal of Practces and Technologes ISSN Issue 6, January-June p x Sf SL 5 4 S(VA) 5 4 (Sf/SL)% Fgure 7. (SAPF) apparent power (Sf) and (Load) apparent power (SL). The percentage of (SAPF) apparent power compared to (Load) apparent power Inj(A) Inj(A) (Peak) Inj = 88.56,( 35.5 rms) (Peak) Inj =58.,(9.33 rms) Fgure 8. (a.4) Smulated phase-a the njected current waveforms Inja (A) wth (SAPF).(b.5) Smulated phase-a the njected current waveforms Inja (A) wth (SHAPF) 5 IF IF Fgure 9. Smulated phase-a the passve flter current waveforms F5 wth (SHAPF). Smulated phase-a the passve flter current waveforms F7 wth (SHAPF) 97

10 The Power Qualty Compensaton Strategy for Power Dstrbuton System Based on Hybrd Parallel Actve Power Flters Rachd DEHINI, Benachaba CHELLALI, Brahm BERBAOUI, Brahm FERDI, Boumedène ALLAOUA 4. Impdance(ohms) 3 Impedance(ohms) Frequency (Hz) Frequence(Hz) Fgure. network mpedance wth (5h, 7h, h, 3h, and 7h hgh-pass).network mpedance wth (SAPF)and resonant passve flter (5h,7h) Dscussons The RPF (h5 + h7) has further mproved the functonng of the (SAPF) and declned further ts power. Accordng to fgures 6. and 6.(c), there s a remarkable mprovement THD V (from.9% to.74%). Accordng to fgures 5. and 5. (c), there s a remarkable mprovement THD I (from.% to.6%). The 5th and 7th harmoncs are not completely elmnated but they are strongly attenuated (Fg. 5. and 5. (c)). Accordng to fgures 7. and 7., the percentage of (SAPF) apparent power (SF) compared to (Load) apparent power (SL) has declned from 8.93% to 5.75%) and has become very reasonable. Accordng to smulaton results obtaned n ths work, we can say that the (RPF) can be an effectve soluton for the compensaton of harmonc currents for low and means power network (relatve to the load) wth a rsk of parallel resonance, fgures. and.. The (SAPF) presents the deal soluton for currents harmoncs compensaton regardless of the power network, but ths soluton s costly. The (SHAPF) justfed ts use by reducng the apparent power of the used (SAPF) and mprovng ts operaton especally f the network s low or medum power. 98

11 Leonardo Electronc Journal of Practces and Technologes ISSN Issue 6, January-June p. 89- Conclusons The paper presents the development of flexblty and relablty of the flter devce by comng together the advantages of resonance passve flters (RPF) and Shunt Actve Power Flter (SAPF) for leavng behnd ther drawbacks. A (SHAPF) s adopted n order to acheve the harmoncs and reactve power compensaton. The well adjusted (SHAPF) conssts of passve flter wth larger rated power s used to flter the low order harmoncs and one actve flter wth low power ratng to flter the other hgh order harmones. Measured up to (SAPF), the (SHAPF) can decrease the power ratng of actve part. Both the compensaton performance and the parallel resonance dampng can be mproved by the later compared wth resonance passve flters (RPF) used only and (SAPF). From the comparatve analyss, hybrd flter s effectve and economc for solvng harmoncs problems n large capacty nonlnear load. References. X Z., Fang Z., Ru D., Wanjun L., Pengbo Z., Zhaoan W., Development of a Parallel Hybrd Power Flter wth Respectve Harmonc Compensaton Method, IEEE, 6, p Rahman S., Hamad A., Mendalek N., Al-Haddad K., A New Control Technque for Three-Phase Shunt Hybrd Power Flter, IEEE, Wu J., He N., Xu D., A KV Shunt Hybrd Actve Flter for a Power Dstrbuton System, IEEE, 8, p Xaohua T., Yue W., Xao Z., Webn S., Yng T., Zhaoan W., An Overall Optmzaton Strategy for Novel Hybrd Parallel Actve Power Flters Based on Genetc Algorthm, IEEE, 6, p Abdelmadjd C., Jean-Paul G., Fateh K., Laurent R., On the Desgn of Shunt Actve Flter for Improvng Power Qualty, IEEE, Tavakol B.M., Pashajavd E., An effcent procedure to desgn passve LCL-flters for actve power flters, Elsever, 8, p

12 The Power Qualty Compensaton Strategy for Power Dstrbuton System Based on Hybrd Parallel Actve Power Flters Rachd DEHINI, Benachaba CHELLALI, Brahm BERBAOUI, Brahm FERDI, Boumedène ALLAOUA 7. Adel M.A., Davd A.T., A Three-phase Hybrd Seres PassveBhunt Actve Flter System, IEEE, 999, p He N., Wu J., Xu D., A Novel Shunt Hybrd Power Flter for Suppressng Harmoncs, IEEE ISIE 6, July 9-, 6, Montreal, Quebec, Canada, pp. 55-6, Salem R., Kamal A., Had Y. K., A comparatve study of shunt hybrd and shunt actve power flters for sngle-phase applcatons: Smulaton and expermental valdaton, Publshed by Elsever, 6, pp Huann K.C., Bor R.L., Ka Y., Kuan W.W., Hybrd Actve Power Flter for power qualty compensaton, IEEE, 5, p Y N.G., Juan Z., Jan C., Xng D.J., Optmal Desgn of Passve Power Flters Based on Knowledge-based Chaotc Evolutonary Algorthm, IEEE, 8, p Taruna J., Shalendra J., Ganga A., Comparson of Topologes of Hybrd Actve Power Flter, IET-UK Internatonal Conference on Informaton and Communcaton Technology n Electrcal Scences (ICTES 7), Dec. -, pp , Hurng L.J., Jnn C.W., Yao J.C., Ya T.F., A Novel Shunt Hybrd Power Flter for Suppressng Harmoncs, IEEE Transactons On Power Delvery, 5, (), p Ruxang F., Mn S., An L., Zhkang S., Confguraton of A Novel Hybrd Actve Power Flter and ts control method, IEEE, 9.