Optimum allocation of Renewable DG sources and Synchronous capacitor simultaneously using PSO

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1 Optimum allocatio of Reewable DG sources ad Sychroous acitor simultaeously usig PSO R.Sivasagari Associate Professor, Electrical ad Electroics Egieerig, AAA College of Egieerig ad Techology, Sivakasi, Tamil Nadu, Idia. Dr. N. Kamaraj Professor ad Head, Electrical ad Electroics Egieerig, Thiagarajar College of Egieerig, Madurai, Tamil Nadu, Idia. Abstract Due to the cotiuous icrease of load demad i the restructured power system eviromet, the distributed geeratio is istalled i the distributio system by the utilities or customers. The improper placemet ad sizig of distributed geeratio may icrease the losses i the etwork ad also lead to power quality problems ad voltage collapse i severe cases. Owig to the depletio of fossil fuels, the reewable eergy based DGs such as solar photovoltaic ad wid have more attractio. I this paper, the optimal placemet ad sizig of reewable eergy based DG sources ad their combiatio for real reductio i the distributio etwork are discussed. To have the optimal solutio, particle swarm optimizatio method is used. This work uses the two stage methodology. I the first step the Distributed Geeratio sittig idex(dgsi) framed by combiig Loss deviatio idex ad the voltage sesitivity idex is used to determie the DG locatio ad i the secod stage the PSO is used to determie the optimal size of DGs ad for miimizatio of real power loss. The proposed methodology is tested o stadard IEEE 33 bus systems for istallatio of differet types of reewable DG sources with sychroous acitor. The performaces of various reewable DG sources idividually ad their combied placemet with sychroous acitor are evaluated ad the results are compared. The results prove the efficiecy of this two phase methodology ad show the effect of types of DG sources ad their combied placemet with the sychroous acitor i loss reductio ad voltage profile improvemet of the distributio system. From the results it is also iferred that the combied placemet of the reewable eergy DG system ad Sychroous acitors reduces the istallatio cost of DG for per uit loss reductio with the icreased loss reductio acity. Keywords: Distributed Geeratio, Particle swarm optimizatio, Radial Distributio system, Loss reductio, Voltage profile Itroductio Due to the rise i eergy crisis ad cocer of gree impacts, the etire world s attetio turs towards the alterative resources as a suitable substitute to the covetioal depletig fossil sources of eergy. The reewable eergy resources of solar ad wid are the most essetial resources foud plety of ature totally free of cost without ay dagerous effects. Hece, i the restructured power system eviromet the reewable DG sources play a major role i the lie loss reductio, ehaced voltage profile, reductio of greehouse gas emissios, improved etwork acity, reliability ehacemet ad cogestio maagemet. [1, 2]. But i order to maximize the beefits of DG sources, the size, locatio ad type of DG should be optimum.[3].the impact of DG sources also depeds o the etwork topology of the power system. The optimal placemet ad sizig of DG i order to improve the parameters such as loss reductio, voltage profile, power quality, ad loadability was discussed by may authors previously [4-11]. Some of the authors solved the optimal placemet problem by aalytical approach ad some of them used evolutioary computig ad itelliget techiques. To solve the optimal placemet problem of DG, oly the real power source DGs were cosidered i most of these approaches. I this paper both the real ad reactive power source of DGs are cosidered. The particle swarm optimizatio techique is used with the two stage methodology. I the first stage a combiatioal idex (i.e) Distributed Geeratio Sittig Idex is framed by combiig the voltage deviatio idex ad real ad reactive idices [12] is used to determie the optimum locatio. The optimum locatio is foud out such that the DGSI value is least at that locatio after the isertio of selected types of DG. The size of DG to determie DGSI is selected as 25% of total feeder acity. After determiig the optimum locatio, the optimum size of DG is searched out such that it produces miimum real i the distributio system. The purpose for choosig PSO as a optimizatio algorithm i this work is that i PSO, there is either race betwee particles or self-adaptatio of the calculated parameters. The progressio towards the optimum solutio is directed by the movemet equatio. For the large iterative problem of the time cosumig ature, the PSO has the fast covergece ability towards the solutio. [13]. Problem Formulatio To obtai the maximum beefit from the DG istallatio, the type,site ad size of DG should be optimum. [3]. The forward-backward sweep algorithm is used to solve the power flow problem of RDS. The target of the optimizatio problem is F = miimise P LOSS (1) 2781

2 I (1) the P LOSS is give as P LOSS = N N i=1 j=1 A ij (P i P j + Q i Q j ) + B ij (P i P j + Q i Q j ) (2) Where A ij = R ij cos(δ i δ j ) ad B V i V ij = R ij si(δ i δ j ) j V i V j Here at the bus i ad j,the real power ijectio is termed as P i ad P j,the reactive power as Q i ad Q j,per uit voltage as V i ad V jad the voltage agle as δ iad δ jcorrespodigly. The lie resistace betwee the i th ad j th bus is termed as R ij. For the isertio of reewable eergy DG i the system,p i i equatio (2) ca be writte as P i = P DGi P Di (3) Q i = Q DGi Q Di (4) Where P DGiad Q DGiare real ad reactive power geeratio of DG. The reewable eergy DG sources are classified accordig to their ature of real ad reactive power ijectio i the radial distributio system. Accordig to the types of reewable eergy sources they are modeled as i the table I. Reewable Eergy DG techology Solar Photo Table 1: model of reewable eergy sources Power of DG PDG power of DG QDG P DGi 0 voltaic cells(spv) Gas turbie(gt) P DGi = S DGi cos φ Q DGi = S DGi si φ Wid farm(wf) P DGi Q DGi = ( (P DGi ) 2 ) This optimizatio problem (1) is subjected to followig power balace, voltage, geeratio ad sychroous acitor ratig costraits. N N P slack + i=1 P DGi = P L + P Di i=1 (5) V i mi V i V i max (6) Here V i mi =0.9 ad V i max =1.05 S mi max DGi S DGi S DGi (7) Where S DG is the MVA ratig of DG. S mi DGi = 0.25 MVA ad S max DGi = 4 MVA Bus 2< positio of DG<bus S C mi S C S C max (8) Where S C is the MVAR ratig of sychroous acitors. S C mi = 0.25 MVAR ad S C max = 4 MVAR P1 P2 (9) The locatio of DG ad sychroous acitors should ot be i the same locatio. Methodology I this work, the optimum locatios for the isertio of DG ad sychroous acitors are determied by usig DGSI based rakig methodology. To determie the DGSI at each bus the DG size of 25% total feeder acity is iserted. The value of P DG ad Q DG deped o the type of DG to be iserted i the system. The power factor of type II DG is cosidered as 0.9 i this paper. P LDGi Q LDGi DGSI i = W 1 BVSI i + W 2 + W P 3 (10) LWODG Q LWODG Where W 1 + W 2 + W 3 = 1 Whe DG is liked at bus i, BVSI for bus i is described as [14] BVSI i = k=1 (1 V k ) 2 (11) Where V kis the voltage at k th ode ad is the umber of odes ad k=1, 2,,. P LDGi ad P LWODG are with ad without istallatio of DG Q LDGi ad Q LWODG are with ad without istallatio of DG The bus with least value of DGSI is selected for the isertio of DG. The the PSO algorithm is used to determie the optimum size of DG. The load data is updated with optimum size of DG ad the sychroous acitor of size 1MVAR is iserted at each bus to determie the optimum locatio of sychroous acitor usig DGSI. After determiig the optimum locatio for sychroous acitor ad DG, the PSO algorithm is applied to determie the optimum size of DG ad sychroous acitors for their simultaeous placemet i the RDS with the iitial load data. The PSO-based approach for fidig sizes of DGs at selected locatios to miimize the real is as follows: i. Geerate a iitial populatio of particles with radom velocity ad positios i the solutio space radomly. ii. iii. Iitialize k=0 as the iteratio couter For every particle if the bus voltage, load balace, geeratio ad sychroous acitor costraits are withi the limits, compute the total real P LOSS. Else, that particle is ifeasible. iv. Compare the idividual best ad its objective value for each particle. If the objective is lesser tha Pbest, fix this value as the curret Pbest, ad record the resultat particle positio. v. Select the particle related with the miimum distict best Pbest of all particles, ad set that value as overall best Gbest. vi. Update the positio ad velocity of particles usig equatios (12) ad (13) respectively. v k+1 id = wv k id + c 1 rad (Pbest id s k id ) + vii. viii. c 2 rad (gbest d s id k ) (12) s id k+1 = s id k + v id k+1 (13) Calculate the New fitess values with this ew positio of particles. If the ew fitess value for a particle is better tha the precedig Pbest value, the substitute that particle with ew Pbest. Likewise, fid the gbest value from the latest Pbest values. Icremet k ad check whether k has reached maximum if ot, go to step (iii). 2782

3 ix. Prit the result of Gbest particles as optimum sizes of DG ad sychroous acitor i the cadidate locatios. Here the DGSI based rakig method is used to idetify the locatios for placemet of DG ad sychroous acitors ad the PSO algorithm is used for sizig of DG ad sychroous acitors. The o of iteratio chose for this problem is 50.The value of c 1=2 ad c 2=2.Populatio of swarm particles is 20. Results ad Discussio I this paper, to select the optimum locatio of DG ad sychroous acitors the DGSI based rakig is used. By usig this method the size of DG required to miimize the loss gets reduced with the icreased voltage profile. For the placemet of sigle reewable eergy DG the algorithm is ru ad the fidigs are tabulated. The table II shows the optimum placemet results of various DG sources aloe i the RDS. The table III displays the result of loss reductio by the placemet of sychroous acitors aloe i the etwork. If the sychroous acitors are placed at optimum locatio, the it reduces the real ad reactive es appreciably. of DG ad sychroous acitors for their simultaeous placemet i distributio etwork ad the results are tabulated. From the compariso of table II, III ad V, it is kow that the simultaeous placemet of DG ad sychroous acitor reduces the loss drastically compared to the placemet of DG aloe. The sychroous acitor improves the loss reductio acity of WF DG more tha its placemet aloe. By the isertio of WF DG aloe i the radial distributio system the loss reductio ad voltage profile improvemet acity are very poor. But whe it is combied with the sychroous acitor the voltage profile improves comparatively greater as i Figure 1. By comparig the Figure 2.adFigure 3.,it is see that the simultaeous placemet of DG ad sychroous acitor placemet improves the voltage profile comparatively more tha their stadaloe placemet. Table 2: results for optimum placemet of various reewable dg sources aloe i ieee 33 rds DG locatio Type of DG Optimal size of DG power of DG i MW power of DG i MVAR KW KVAR Without Base DG case 30 SPV GT Wid Figure 1: Voltage profile improvemet for the isertio of WFDG with ad without Sychroous acitor Table 3: results for optimum placemet of sychroous acitor aloe i ieee 33 rds DG Type of DG locatio Optimal size of sychroous acitor i MVAR KW KVAR Without Base case DG 30 Sychroous acitor From the table II, it is iferred that the GT produces high real reductio with icreased voltage profile. Due to the reactive power compesatio provided by GT techology, it produces the best result. Hece, to provide reactive power compesatio, the sychroous acitors are itroduced i the system. The sychroous acitors are assumed as a reactive power geerator i this work. After updatig the load data accordig to the DG techology adopted, agai the DGSI is determied to fid the locatio for sychroous acitors. The the PSO algorithm is used to determie the optimum size Figure 2: Voltage profile improvemet with the isertio of DG ad Sychroous acitor aloe Figure 3: Voltage profile improvemet with the simultaeous placemet of DG ad Sychroous acitor The istallatio costs of various reewable eergy DG sources are as i Table IV ad the cost of sychroous acitor is $700/KVA.[15] 2783

4 Table 4 Reewable eergy Istallatio cost Equipmet life DG Techology $/KVA i years Solar Photo voltaic cells(spv) Gas turbie(gt) Wid farm(wf) From the sizes of DGs as i table III ad V the uit cost required for istallatio of DGs are foud out. The results show that the simultaeous placemet of the sychroous acitor ad DGs reduces the istallatio cost required for per KW loss reductio better tha the stadaloe placemet of DGs. From the table II, it is well kow that the GT techology has icreased the loss reductio acity compared to other reewable DG techology. But the equipmet life for Gas turbie DG techology is less compared to SPV ad WF techology eve its cost is least compared to SPV ad WF. The ruig cost ad operatio cost of GT DG is more compared to other reewable techology due to fuel requiremet ad its trasportatio. The loss reductio acity of SPV ad WF techology icreases comparatively equal to the GT techology with the simultaeous placemet of sychroous acitors with these DGs. The istallatio cost is also gettig reduced with the itroductio of sychroous acitors i the distributio system with these DGs. For SPV ad WF DG techology, there are o fuel requiremets ad pollutio cause. Hece, i ecoomic ad evirometal poit of view, istead of selectig GT DG, it is recommeded to choose SPV or WT DG with the simultaeous placemet of sychroous acitor i the distributio system. The percetage of loss reductio is also improved with the simultaeous placemet of sychroous acitors. Table 5: results for simultaeous placemet of reewable eergy dg techology ad sy. Capacitor i ieee33 rds Locatio Type Optimal size of DG/Sychroous acitor At P1 At P1 At P2 At P2 PDG QDG MW MVA power R of DG i MVA R power loss KW power loss KVAR P1 P2 At P1 At P2 power of DG /Sy. acitor i MVAR WODG Base case SPV Sy GT Sy WF Sy Sy. SPV Sy. GT Sy. WF Table 6: istallatio cost for per kw loss reductio ad % of loss reductio for isertio of dg ad sychroous acitor Type of DG Locatio Istallatio cost of DG i $ perkw loss savigs % of real reductio Case 1: With DG oly SPV 30 88, GT 30 25, Wid 8 75, Case 2:With Sychroous acitor oly Sy.acitor 30 14, Case 3:With both DG ad Sychroous acitor SPV, 30,29 64, Sy. acitor GT, 30,29 25, Sy.acitor WF, Sy.acitor 8,30 34, Sy.acitor, 30,12 50, SPV Sy.acitor, 30,12 19, GT Sy. acitor, 30,29 7, WF % of reactive reductio Coclusio This paper has preseted the DGSI based rakig for determiig the optimum locatios of DG ad sychroous acitors ad the PSO techique is applied to fid the optimum size of DG ad sychroous acitor for simultaeous placemet. The projected method is tested o IEEE 33 radial distributio system. The result shows that the projected method has sigificatly reduced the power system losses ad icreased the voltage profile. The percetage of loss reductio ad the voltage profile improvemet i the RDS deped o the type of DG techology, locatio ad size of DG. The reductio of istallatio cost ad percetage of loss reductio proves the eed of simultaeous allocatio of sychroous acitors with reewable DG sources. The result shows that the combied placemet of SPV or WF DG techology with the sychroous acitors reduces the istallatio cost ad the real ad reactive es remarkably. Thus, this result supports techically the eed for developmet i SPV ad WF DG sources so that to make a clea ad gree eviromet. Ackowledgmet The authors would like to express their sicere ad the heartfelt thaks to the Pricipal ad Maagemet of AAA College of Egieerig ad Techology ad Thiagarajar College of Egieerig ad Techology for their Costat support ad ecouragemet towards the success of this research work. 2784

5 Refereces [1] W. El-hattam, M.M.A. Salma, Distributio Geeratio techologies, Defiitio ad Beefits, Electrical Power system Research 2004.Vol. 71, pp , [2] H. Zareipour, K. Bhattacharya ad C. A. Caizares, Distributed Geeratio: Curret status ad challeges, IEEE proceedig of NAPS, Feb 2004.pp 1-8. [3] Caisheg Wag ad M.H. Nehrir, Aalytical Approaches for optimal placemet of Distributed geeratio sources i power systems IEEE Trasactio o power system,2004. vol.19,pp [4] H. Hedayati, S. A. Nabaviiaki, ad Adel Akbarimajd A Method for Placemet of DG Uits i Distributio Networks, IEEE trasactios o power Delivery, Vol. 23, No. 3, Jul 2008.PP [5] M. Wag et al., A ovel method for distributed geeratio ad acitor placemet cosiderig voltage profiles., IEEE power ad eergy geeral meetig, July 2011,pp 1-6. [6] Deepedra, S., Deveder, S. ad Verma, K.S. GA Based Optimal Sizig Ad Placemet Of Distributed Geeratio For Loss Miimizatio Proceedigs of World Academy of Sciece, Egieerig ad Techology,2007,Vol. 26, Pp [7] Padma Lalitha M., M.veera Reddy V.C., Usha V. ad Sivarami Reddy N., Applicatio of Fuzzy ad PSO For DG Placemet for miimum loss i Radial Distributio system. ARPN Joural of Egieerig ad Applied scieces, April 2010; Vol.5, No.4: pp [8] Maafi H., Ghadimi N., Ojaroudi M. ad Farhadi P., Optimal Placemet of Distributed Geeratios i Radial Distributio Systems Usig Various PSO ad DE Algorithms. ELEKTRONIKA IR ELEKTROTECHNIKA, ISSN , 2013, VOL.19, NO.10,.pp [9] Buayai K., Optimal Multi-type DGs Placemet i Primary Distributio System by NSGA-II. Research Joural of Applied Scieces, Egieerig ad Techology 2012;Vol. 4(19): pp [10] M. Ladjavardi et. al., Geetically Optimized Fuzzy Placemet ad Sizig of Capacitor Baks i Distorted Distributio Networks, IEEE Trasactios o Power Delivery, Ja 2008,Vol. 23, No. 1, PP [11] Sudipta Ghosh, S.P. Ghoshal, ad Saradidu Ghosh, Optimal sizig ad placemet of distributed geeratio i a etwork system, Electrical Power ad Eergy Systems 32(2010) PP [12] R.Sivasagari ad N.Kamaraj., Performace assessmet of Distributed Geeratio techologies i radial distributio system Rev. Téc. Ig. Uiv. Zulia. Vol. 38, NO 3, , 2015 [13] M. H. Moradi, M. Abedii, A combiatio of geetic algorithm ad particle swarm optimizatio for optimal DG locatio ad sizig i distributio systems, Electrical Power ad Eergy Systems, vol. 34,pp , [14] Subramayam J.V.B. Ad Radhakrisa C., Distributed Geeratio placemet ad sizig i the ubalaced radial distributio system. World Academy of Sciece, Egieerig ad Techology, Iteratioal Joural of Electrical, Computer, Eergetic, Electroic ad Commuicatio Egieerig, 2009; Vol: 3, No: 4, pp [15] K. Buayai, Optimal Multi-type DGs Placemet i Primary Distributio System by NSGA-II Research Joural of Applied Scieces, Egieerig ad Techology 4(19): October 2012, pp About the Author: Dr. N. Kamaraj is the Head of the Departmet ad Professor i Electrical ad Electroics Egieerig Departmet, Thiagarajar College of Egieerig, Madurai, Tamiladu, Idia. He obtaied B.E. degree i Electrical ad Electroics Egieerig ad M.E. degree i Power System Egieerig from Madurai Kamaraj Uiversity i the year 1988 ad 1994 respectively. He obtaied Ph.D.Degree i the Power System Assessmet i the year 2003 from Madurai Kamaraj Uiversity. Curretly he is headig the departmet of Electrical ad Electroics Egieerig i Thiagarajar College of Egieerig. His research areas iclude Security Assessmet usig Neural Network, Fuzzy logic ad Geetic Algorithm. He has published 36 papers i the Iteratioal jourals ad preseted 65 papers i the Iteratioal cofereces. He is the recipiet of Merit award from IEEE Computer Society for CSIDC 2003 as best advisor for the team cotested i CSIDC. Also he has received Gold medal ad Corps subject award from Istitutio of Egieers (Idia) for the year R. Sivasagari is a Associate Professor i Electrical ad Electroics Egieerig Departmet, AAA College of Egieerig ad Techology,Sivakasi, Tamiladu, Idia.She Obtaied B.E. degree i Electrical ad Electroics Egieerig ad M.E. degree i Power System Egieerig i the year 2000 ad 2007 respectively from Aa uivrsity.she has 15 years of teachig experiece.curretly she is the research scholar uder Aa uiversity. 2785