INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING & TECHNOLOGY (IJEET)

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1 INTERNTINL JURNL F ELECTRICL ENINEERIN & TECHNLY (IJEET) Internatonal Journal of Electrcal Engneerng and Technology (IJEET), ISSN (rnt), ISSN (nlne) Volume 5, Issue 2, February (204), pp IEME ISSN (rnt) ISSN (nlne) Volume 5, Issue 2, February (204), pp IEME: Journal Impact Factor (204): (Calculated by ISI) IJEET I E M E ERFRMNCE IMRVEMENT F DISTRIBUTIN SYSTEM WITH MULTI DISTRIBUTED ENERTIN USIN RTICLE SWRM TIMIZTIN. Sobha Ran, Dr.. Lakshm Dev 2 ssoc.rofessor, Dept.E.E.E., N.B.K.R.I.S.T, Vdyanagar, ndhrapradesh 2 rofessor, Dept. E.E.E., S.V.Unversty College of Engneerng, Trupath BSTRCT Dstrbuted generators are benefcal n reducng losses effectvely n dstrbuton systems as compared to other methods of loss reducton. Szng and locaton of D sources places an mportant role n reducng losses n dstrbuton network. In ths paper both genetc algorthm and partcle swarm optmzaton methods are presented for optmal locaton and szng of D sources. The methodology s based on exact loss formula. The obectve of ths methodology s to calculate sze and to dentfy the correspondng optmum locaton for D placement for mnmzng the total power losses and to mprove voltage profle n prmary dstrbuton system. The proposed methodology s tested on IEEE-33 dstrbuton system and the results are compared. Keywords: Dstrbuted generaton (D), exact loss formula, enetc algorthm (), artcle swarm optmzaton (S), ower losses.. INTRDUCTIN Dstrbuton system provdes a fnal lnk between the hgh voltage transmsson and consumers. ower loss n a dstrbuton system s hgh because of low voltage and hence hgh current. ne of modern mportant technques n electrcal dstrbuton systems to reduce losses s to accommodate small scale decentralzed generatng unts known as dstrbuted generaton (D). The Ds are small scale power generaton technologes of low voltage type that provde electrcal power at a ste closer to consumpton centers. Developments of Ds wll brng new chances to tradtonal dstrbuton systems. pproprate sze and locaton of D play a sgnfcant role n mnmzng power losses n dstrbuton systems. Examples of D are desel generators, small hydro, wnd electrc systems, solar electrc systems, batteres, photo voltac and fuel systems. 44

2 Internatonal Journal of Electrcal Engneerng and Technology (IJEET), ISSN (rnt), ISSN (nlne) Volume 5, Issue 2, February (204), pp IEME In the present vast load growng electrcal system usage of D have more advantages lke reducton of transmsson and dstrbuton cost, electrcty prce, savng of fuel, lne loss reducton, better voltage profle, power qualty mprovement. D can be classfed nto four maor types based on ther termnal characterstcs n terms of real and reactve power delverng capablty as follows:. D capable of nectng actve power only. 2. D capable of nectng reactve power only. 3. D capable of nectng both actve and reactve power. 4. D capable of nectng actve power but consumng reactve power. hoto voltac, mcro turbnes, fuel cells whch are ntegrated to man grd wth the help of converters/ nverters are good examples of type. Synchronous compensators such as gas turbnes are examples for type2. D unts that are based on synchronous machne fall n type 3. Type 4 s manly nducton generators that are used n wnd farms. Ths paper s organzed as follows: Methodology s explaned n secton II, roblem formulaton s dscussed n secton III, Smulaton results are shown n secton IV. 2. METHDLY Techncal advances and avalablty of renewable energy sources have resulted n a constantly ncreasng penetraton of D ntegrated wth dstrbuton networks. For the connecton of new D nstallatons to the networks a varety of factors have to be taken nto account to ensure that the D doesn t adversely affect the operaton and power qualty of networks. In a large dstrbuton system network wth hgh power loss, t s dffcult to select a partcular bus from many buses so as to place a D unt for loss reducton. ower losses are present at every bus and dentfcaton of bus wth hghest ower loss s mportant because losses at that bus ncludes maorty of total losses n the system. Ths can be partally accomplshed by D unt placement n the network. If D sze exceeds certan value of lmt, power loss at that bus becomes negatve. Ths stuaton must be avoded. The benefcal effects of D manly depend on ts locaton and sze. Selecton of optmal locaton and sze of D s a necessary process to mantan relablty of exstng system effectvely before t s connected to grd. There are many approaches to determne the optmum szng and sttng of D unts n dstrbuton systems consderng overall system effcency, system relablty, voltage profle, load varaton, network losses. In some research the optmum locaton and sze of a sngle D unt s determned and n some others optmum locaton and szes of multple D unts are determned. In ths aper exact loss formula s used to determne the sze and locaton of Type- and Type-2 D. 3. RBLEM FRMULTIN The obectve of problem s to fnd the locaton of Ds and ts sze for type- and type-2 D to mnmze the real power losses and to mprove the voltage profle. ower loss n the system can be calculated by equaton (), gven the system operatng condton, L = n =, = [ α ( + Q Q ) + β ( Q Q )] () r r Where α = Cos( δ δ ) and β = Sn( δ δ ) V V V V 45

3 Internatonal Journal of Electrcal Engneerng and Technology (IJEET), ISSN (rnt), ISSN (nlne) Volume 5, Issue 2, February (204), pp IEME The obectve s to mnmze L subect to power balance constrants as per equaton(2) Σ D = Σ D + L (2) Voltage constrants: Vmn V Vmax Where L s real power loss n the system, D s real power generaton D at bus, D s power delvered at bus. Type- D For type- D, power factor s unty. The optmal sze of D at each bus for mnmzng losses s gven by equaton (3). D = D [ β Q + α n =, ( α Q β )] (3) Type-2 D For type-2 D, the optmal sze of D at each bus for mnmzng losses s gven by equaton (4) Q D = Q D + [ β α n =, ( Q α + β )] (4) The optmal szes at varous locatons have been calculated for dfferent types of D and the losses are calculated wth optmal szes for each case. The case wth mnmum losses s selected as optmal locaton for each type D. Ths paper uses and S for solvng problems of optmal sttng and szng of D. 3. enetc algorthm enetc algorthms () are a part of evolutonary computng whch s a rapdly growng area of artfcal ntellgence. begns wth a set of solutons (represented by chromosomes) called populaton. Soluton from one populaton are taken and used to form a new populaton. Ths s motvated by a hope that new populaton wll be better than old one. Solutons that are then selected to form new solutons (offsprng) accordng to ther ftness- the more sutable they are the more chances to reproduce. Ths s repeated untl some condton s satsfed. Smplcty of operaton and power of effect are advantages of approach. lgorthm. Read the system data, perform load flow, and generate ntal populaton sze. 2. Start teraton count ter= 3. Determne the szes of D unts at each canddate node by decodng the populaton. 4. lace the D unt at a canddate bus and run the load flow for each strng of populaton and fnd the losses. Wth the obtaned losses, calculate the ftness functon. Ftness=/total loss. 5. rrange the elements of the ftness functon n the descendng order and hence fnd the maxmum ft and average ft. 6. Fnd the error usng Error=(maxft) (average ft) If ths error s less than epslon, go to step 9. 46

4 Internatonal Journal of Electrcal Engneerng and Technology (IJEET), ISSN (rnt), ISSN (nlne) Volume 5, Issue 2, February (204), pp IEME 7. Carry out cross over and mutaton on the off sprngs and generate new populaton. Increment the teraton count. 8. If (ter<=termax) go to step If the problem s converged n termax teratons stop. 0. rnt the D unt ratng and power losses after compensaton. 3.2 artcle swarm optmzaton artcle swarm optmzaton s an algorthm capable of optmzng a nonlnear and mult dmensonal problem whch gves good solutons. The basc concept of algorthm s to create a swarm of partcles whch move n the space around them (the problem space) searchng for ther goal, the place whch best suts ther needs s gven by a ftness functon. Each partcle keeps track of ts coordnates n the soluton space whch are assocated wth best soluton (ftness) that has acheved so far by that partcle. Ths value s called personal best (pbest). nother best value s the best value obtaned so far by any partcle n the neghborhood of that partcle. Ths value s called gbest. The basc concept of S les n acceleratng each partcle toward ts pbest and gbest locatons wth a random weghted acceleraton. The modfcaton of the partcle s poston can be mathematcally modeled accordng the followng equaton: V k + = wv k +c rand ( ) x (pbest -s k ) + c 2 rand 2 ( ) x (gbest-s k ) (5) where, v k : velocty of agent at teraton k, w: weghtng functon, c : weghtng factor, rand: unformly dstrbuted random number between 0 and, s k : current poston of agent at teraton k, pbest : pbest of agent, gbest: gbest of the group. The followng weghtng functon s usually utlzed n (6) w = wmax-[(wmax-wmn) x ter]/maxiter (6) where wmax = ntal weght, wmn = fnal weght, maxiter = maxmum teraton number, ter = current teraton number. s k+ = s k + V k+ (7) lgorthm. Read the system data, perform load flow 2. Randomly generate an ntal populaton of partcles wth random postons and veloctes on dmensons n soluton space. 3. Intalze the swarm from the soluton space. 4. Evaluate ftness of ndvdual partcles. 5. Modfy gbest, pbest and velocty. 6. Move each partcle to a new poston. 7. o to step 3, and repeat untl convergence or a stoppng condton s satsfed. 47

5 Internatonal Journal of Electrcal Engneerng and Technology (IJEET), ISSN (rnt), ISSN (nlne) Volume 5, Issue 2, February (204), pp IEME 4. SIMULTIN The proposed algorthm s tested on IEEE-33 bus system. The orgnal total real power loss and reactve power loss n the system are found to be kw and kvar respectvely by conductng Backward-Forward load flow method. For parameters populaton sze=00, crossover probablty=0.7; the maxmum number of D s 3 for each type. ne type- D can reduce total real and reactve power loss by23.77 and respectvely. For three type- Ds they can further reduce the loss by compared to n type-2 D. The results are shown followng tables. Number of D D S Bus Number Table. Summary of results for type- D TL(kw) D sze (kw) TQL(kvar) Voltage(p.u) Wthout Wth % loss Wthout Wth %loss Wthout Wth % voltage D D reducton D D reducton D D ncrement D 3D S S Number of D D 2 D S S Bus Number TL(kw) Table 2: Summary of results for type-2 D D sze (kvar) TQL(kvar) Voltage(p.u) Wthout Wth % loss Wthout Wth %loss Wthout Wth % voltage D D reducton D D reducton D D ncrement D S

6 Internatonal Journal of Electrcal Engneerng and Technology (IJEET), ISSN (rnt), ISSN (nlne) Volume 5, Issue 2, February (204), pp IEME Smulaton results are shown n the followng fgures. wthout D wth D wth D S 5 Voltage n p.u BUS NUMBER Fg : Bus voltages for one Type- D 0.8 wthout D wth D wth D S 0.7 Lne Losses Branch Number Fg 2: Lne losses for one Type- D wthout D wth D wth D S 5 Voltage n p.u Bus Number Fg 3: Bus voltages for three Type-2 DS 49

7 Internatonal Journal of Electrcal Engneerng and Technology (IJEET), ISSN (rnt), ISSN (nlne) Volume 5, Issue 2, February (204), pp IEME 0.8 wthout D wth D wth D S 0.7 Loss n p.u Branch Number Fg 4: Lne losses for three Type-2 Ds 5. CNCLUSIN In ths paper both genetc algorthm and partcle swarm optmzaton methods are used for optmal placement of mult D sources. Exact loss formula s used to determne optmal sze and the locaton for both type- and type-2 Ds. The two types of Ds effectvely reduced the power loss and voltage profle s also mproved. REFERENCES []. M.H.Morad, M.bedn, combnaton of genetc algorthm and partcle swarm optmzaton for optmal D locaton and szng n dstrbuton system, Electrc power energy systems 34 (202) [2]..Sobha Ran, Dr..Lakshm Dev, Szng and placement of mult D usng exact loss formula,, Internatonal ournal of advanced research n electrcal electroncs and nstrumentaton engneerng, vol.2, ssue, Nov 203. [3]. Duong quoc Hung, Nadaraah Mthulananthan, Multple dstrbuted generatons n prmary dstrbuton networks for loss reducton, IEEE transactons on ndustral electroncs, vol.60, No.4, prl 3. [4]. W. El-hattam, M.M.. Salma, D technologes defnton and benefts, Electrcal power system research, vol.7, pp 9-28, [5]..M.El-Zonkoly, optmal placement of mult D unts ncludng dfferent load models usng partcle swarm optmzaton, Swarm and evolutonary computaton, (20) [6]. D. Zhu, R..Broad water, K.Tam, R. Segun, H. sgersson, Impact of D placement on relablty and effcency wth tme varyng loads, IEEE transactons on power systems 2() 2006, [7]. T.ozel, M.H.Hocaoglu, n analytcal method for the szng and sttng of dstrbuted generators n radal systems, Internatonal ournal of electrc power system research 79(2009) [8]. Dr.T.nanthapadmanabha, Maruth rasanna.h.., Veeresha... and Lkth Kumar. M. V, New Smplfed pproach for ptmum llocaton of a Dstrbuted eneraton Unt n the Dstrbuton Network for Voltage Improvement and Loss Mnmzaton, Internatonal Journal of Electrcal Engneerng & Technology (IJEET), Volume 4, Issue 2, 203, pp , ISSN rnt : , ISSN nlne: