Optimum Allocation of Distributed Generations Based on Evolutionary Programming for Loss Reduction and Voltage Profile Correction

Transcription

1 ISSN : (Onlne) ISSN : (rnt) Optmum Allocaton of Dstrbuted Generatons Based on Evolutonary rogrammng for Reducton and Voltage rofle Correcton 1 Mohammad Saleh Male, 2 Soodabeh Soleyman 1,2 Dept.of Electrcal Engneerng, Scence And Research Branch, Islamc Azad Unversty, Tehran, Iran Abstract Ths artcle presents an optmal placement method n order to szng and sttng of dstrbuted generaton n IEEE 33 bus test system. The algorthm for optmzaton n ths paper s Evolutonary rogrammng. The proposed objectve functon consders actve power losses of the system and the voltage profle n nomnal load of system. In order to use of E algorthm, at frst, placement problem s wrtten as an optmzaton problem whch ncludes the objectve functon and constrants, and then to acheve the most desrable results, Evolutonary rogrammng (E) method s appled to solve the problem. Hgh performance of the proposed algorthm n menton system s verfed by smulatons n MATLAB software and n order to llustrate of feasblty of proposed method ths optmzaton n three cases one unt, Two unts, and Three unts- wll accomplsh. Keywords Dstrbuted Generaton, lacement, Evolutonary programmng, Optmzaton. I. Introducton Now days dstrbuted or decentralzed generaton unts connected to local dstrbuton systems, almost are not dspatchable by a central operator, but they can have ntrcately effect on the power-flow, voltage profle, stablty and qualty of power supply for customers and electrcty suppler s [1]. The output power of Major of Dstrbuted Generatons (s) such as wnd turbne and fuel cells depends on the condton of weather and can not forecast orgnally. The concern about the lmtaton of fossl fuels and also rsng conscousness of envronmental protecton, cause the nstallaton of s ncrease annually. Growng of Dstrbuted Generaton can be has nfluence n voltage profle, stablty, power loses at power system both n dstrbuton and transmsson sde. In order to mprovement of power system stuaton such as correcton of voltage profle, addton of stablty, decrease of loses power and etc, t s necessary that the nstallaton of s n power system become systematcally [2]. In some papers, the optmum locaton and sze of a sngle unt s determned [3, 4].whle n others the optmum locatons and szes of multple unts are determned [5,6]. In [7], a mxed nteger lnear program was proposed to determne of optmum locaton. A TS search method to fnd the optmal soluton of ther problem was explaned n [8], but the TS s known to be tme consumng algorthm also t s may be trapped n a local mnmum. In order to mnmzaton of real power losses of power system n ref [9], a SO algorthm was developed to specfy the optmum sze and locaton of a sngle unt. The problem was converted to an optmzaton program and the real power loss of the system was the only aspect consdered n ths study n order to determne of optmally locaton and sze of only one unt. In ref [10], a deferent scenaro were nvestgated for determne of optmum locaton of dstrbuted generaton n order to modfy of voltage profle and mnmze the nvestment rsk. A Genetc Algorthm (GA) based method wth optmal power flow (OF) calculatons were formulated n order to mnmze the cost of actve and reactve power generaton for determne of best sze and locaton of s n power system. GA s a tme consumng technque but t could reach global or near global solutons. In [11], In order to mnmze lne losses of power system an analytcal technque to determne the optmum locaton-sze par of a unt was suggested. The placement of one unt wth specfc sze n [12] was explaned. In ths paper mult objectve functon such as power lne losses, modfy of voltage profle, lne loadng capacty and short crcut level were consdered. -V curves n ref [13] have been used for analyzng voltage stablty n electrc power system to determne the optmum sze and locaton of multple unts to mnmze the system losses under lmts of the voltage at each node of the system. In ths paper, Evolutonary rogrammng (E) whch s capable of fndng global or near global optmum soluton s used for optmal sze and ste of Dstrbuted Generaton n 33-bus of IEEE test system wth te lne that present n [14]. Objectve functons are gathered to form a mult objectve optmzaton problem. The objectve functon s formed by combnng on real power losses and voltage profle of the menton system. In next secton, the problem formulaton contan of objectve functon and constrans s explan. Secton III represents the E algorthm n order to solve the optmzaton problem. The test system used to verfy the effectveness of the proposed technque descrbe n secton IV that explores the effectveness of the proposed technque appled on smulaton test system, Secton V concludes the paper. The smulaton test systems were smulated n MATLAB software. II. roblem formulaton A. Objectve functons formulaton The objectve functon combned from two components. One part s Real ower (RL) that s 70 percent of menton objectve functon and Voltage rofle Improvement (VI) that combned 30 percent of objectve functon. - Real ower formulaton (RL): Buses voltage, lne currents and real power loss n system lnes calculates from the output results of power-flow whch s used of Newton-Raphson n ths paper. If v s th bus voltage and vj s jth bus voltage that specfy from power flow results, the lne current between th and jth buses s gven by: (1) In t e r n a t o n a l Jo u r n a l o f Co m p u t e r Sc e n c e & Te c h n o l o g y 7

2 Where Zj s the mpedance between th and jth buses, the transmsson power between the th and jth buses and vce versa calculated by: (3) The real actve loss between th and jth buses s defned as: Total loss power n power system s defned by: N N Total = = 1 j=, j loss Where, N s the number buses of power system and RL s gven by: RL = Total n o mn a l (6) Where,s the real power loss n nomnal condton of study system. -Voltage rofle Improvement (VI): One of the avals of optmzes locaton and sze of the s the mprovement n voltage profle. Ths ndex penalzes the sze-locaton par whch gves hgher voltage devatons from the nomnal value (Vnom). In ths way, closer the ndex to zero better s the network performance. The VI can be defned as: n Vnom V VI = max = 2 Vnom (7) The Mult Objectve Functon (MOF) n ths paper n order to acheve the performance calculaton of dstrbuton systems for sze and locaton s gven by: MOF = s 1RL + s 2VI (8) Where and consder n ths paper 0.7 and 0.3 respectvely. (2) (4) (5) ISSN : (Onlne) ISSN : (rnt) solve the above optmzaton problem and search for optmal or near optmal set of problem. Typcal ranges of the optmzed parameters are [ ] MW for and [ ] for voltage of buses. III. Evolutonary rogrammng Algorthm In ths optmzaton method lke the other methodes the ntal ponts are selected n the stochastc manner as shown n the flowchart of the fg. 1. As t can be seen from the fg., after selectng these ponts, for each of them the power flow wll accomblshed and the objectve functon wll calculated. therefore, ths pont are checked n the constrants and any of them whch are not wthn ths vable soluton zone should be elmnated and for the ponts wthn ths area the value of the objectve functon should be determned, and n the next state, partcles are moved wthn ths area and f the omted partcles are more, new partcles wll be regenerated and ths process s contnued untl the selecton of the optmum pont [15]. B. constrans formulaton The mult objectve functon (8) s mnmzed subjected to varous operatonal constrants to satsfy the electrcal requrements for dstrbuton network. These constrants are the followng. 1. ower-conservaton Lmts The algebrac sum of all ncomng and outgong power ncludng lne losses over the whole dstrbuton network and power generated from unt should be equal to zero. n (9) Gen + D G = 1 D total = 0 2. Dstrbuton Lne Capacty Lmts ower flow through any dstrbuton lne must not exceed the thermal capacty of the lne. 8 Internatonal Journal of Computer Scence & Technology (10) 3. Voltage Lmts the voltage lmts depend on the voltage regulaton lmts should be satsfed. V mn V V max (11) Ths paper employs Evolutonary rogrammng technque to Fg. 1 :Optmzaton flowchart n E artcles changes are done accordng to the Gauss normal dstrbuton. These changes are expressed n Eq (12). Whch, x s the th partcle poston n the current state, s the poston of the partcle n the next stage. s the Gauss normal dstrbuton, and s s a weghted functon obtaned from Eq (13). b s the movement coeffcent,here t s equal to 1, g s the offset value adjusted n zero, and F(x) s the value of objectve functon for the partcle n the prevous stage whch s affect the next movements [16]. (12) (13) In ths optmzaton problem, the number of partcles and the number of teratons are selected 30 and 50, respectvely. Dmenson of the partcles wll vary for each condton.

3 ISSN : (Onlne) ISSN : (rnt) IV. Case Study and lacement Results In the case study presented n ths secton, we nvestgate how placement affects system power loss reducton and voltage profle enhancement. The placement of only a sngle, two s and Three s are consdered. To demonstrate the utlty of the proposed placement algorthm, a 33-bus test system wth te lnes that present n ref [14] and shown n fg. 2. s consdered and the system detals are gven n Table 1. Fg. 2: IEEE 33 bus study system wth te lnes n ref [14] Table 1: lnes, actve and reactve power detals n study system wbranch Nom Sen. node Rec. node Actve ower of Rec.node KW Reactve ower of Rec.node KVAr Resstance ohms Reactance ohms * * * * * At Frst, we assume that one unt whch ts sze varyng between 25KW-10MW wll placement n menton network. The results of ths study s shown n table 2 and fg. 3, Table 2 shows that the power loss of the network wth and wthout. Wth comparng of power loss n two cases that s obvous the placement can be has effect n power loss n whole menton network. fg. 2 llustrate buses voltage n two cases. Wth attenton to ths fg., the voltage profle wth unt s better than wthout and almost unt can be affect to all of buses voltage. Table 2: results of szng and sttng wth a sngle unt Number of Sze Ste Wthout KW KW Fg. 3: voltage profle of study system wth a sngle unt and wthout In other case, two unts that sze of them between 25KW- 10MW too, consdered n order to locaton n mentoned system. Results of ths case present n table 3 and fg. 4. In ths fg. the voltage profle of three cases (wthout, one and Two unts szng and sttng) are presented. As can be seen, that s obvous the two placement results n lne power losses and voltage profle s better than one unt and wthout n study system. In t e r n a t o n a l Jo u r n a l o f Co m p u t e r Sc e n c e & Te c h n o l o g y 9

4 Table 3: results of szng and sttng wth two unts-sngle and wthout Number of Sze Ste Wthout KW One KW Two s KW Fg. 4: voltage profle of study system wth two unts - sngle unt and wthout In the next study, we assume that three unts n order to optmal placement are consdered. The result of ths study n represented power system. The results of lne power loss that present n table 4 depct n ths case ths power loss become less than other cases and n fg. 5 the voltage profle s shows. The voltage profle n ths case s better than prevous cases. Table 4: results of szng and sttng wth three unts-two unts-sngle and wthout Number of Wthout One Two s Three s Sze Ste 10 Internatonal Journal of Computer Scence & Technology KW KW KW KW ISSN : (Onlne) ISSN : (rnt) Fg. 5 : voltage profle of study system wth three unts- two unts - sngle unt and wthout V. Concluson In ths paper, a dfferent approach based on Evolutonary rogrammng n order to Multobjectve optmzaton analyss, ncludng one, two and three unts, for sze-ste plannng of dstrbuted generaton n dstrbuton system was presented. In solvng ths problem, at frst problem was wrtten n the form of the optmzaton problem whch ts objectve functon was defned and wrtten n tme doman and then the problem has been solved usng E. The proposed optmzaton algorthm was appled to the 33-bus test system wth te lnes. The results clarfed the effcency of ths algorthm for mprovement of voltage profle and reducton of power losses n study system. References [1] H.Hedayat, S.A.Nabavnak, A.Akbarmajd, A method for placement of unts n dstrbuton networks, IEEE Trans. on ower Delvery, 23, (3), pp , 2008 [2] V.V. Thong, J. Dresen, R. Belmans, Transmsson system operaton concerns wth hgh penetraton level of dstrbuted generaton, n roc. of Inter. Unverstes ower Engneerng Conference, Brghton, pp , 2007 [3] Y.A. Katsganns,.S. Georglaks,"Optmal szng of small solated hybrd power systems usng tabu search", Journal of Optoelectroncs and Advanced Materals, 10, (5), pp [4] M.A.Kashem, D.T.Le, M.Negnevtsky, G.Ledwch, Dstrbuted generaton for mnmzaton of power losses n dstrbuton systems, n IEEE ower Eng. Socety General Meetng, pp [5] W. El-Khattam, Y.G.Hegazy, M.M.A.Salama, An ntegrated dstrbuted generaton optmzaton model for dstrbuton system plannng, IEEE Trans. on ower Systems, 20, (2), pp [6] R.K.Sngh, S.K.Goswam, Optmum allocaton of dstrbuted generatons based on nodal prcng for proft, loss reducton and voltage mprovement ncludng voltage rse ssue, Int. Journal of Electrc ower and energy Systems, 32, pp [7] A.keane, M.O Malley, Optmal dstrbuted generaton plant mx wth novel loss adjustment factors, IEEE ower Eng. Socety General Meetng, pp [8] Y.A. Katsganns,.S. Georglaks, Optmal szng of small solated hybrd power systems usng tabu search, Journal of Optoelectroncs and Advanced Materals, 10, (5), pp [9] M..Laltha, V.C.V. Reddy, V.Usha, Optmal lacement for Mnmum Real ower n Radal Dstrbuton Systems Usng SO, Journal of Theoretcal and Appled Informaton Technology, 2010, pp [10] W. El-Khattam, Y.G.Hegazy and M.M.A.Salama, An ntegrated dstrbuted generaton optmzaton model for dstrbuton system plannng, IEEE Trans. on ower Systems, 20, (2), pp [11] T.Gozel, M.H.Hocaoglu, An analytcal method for the szng and stng of dstrbuted generators n radal systems, Int. Journal of Electrc ower System Research, 2009, 79, pp

5 ISSN : (Onlne) ISSN : (rnt) [12] L.F.Ochoa, A.adlha-Feltrn, G..harrson, Evaluatng dstrbuted generaton mpacts wth a multobjectve ndex, IEEE Trans. on ower Delvery, 21, (3), pp [13] R.K.Sngh, S.K.Goswam, Optmum allocaton of dstrbuted generatons based on nodal prcng for proft, loss reducton and voltage mprovement ncludng voltage rse ssue, Int. Journal of Electrc ower and energy Systems, 32, pp [14] M. A. Kashem, V. Ganapathy, G. B. Jasmon, M. I. Buhar,"A Novel Method for Mnmzaton n Dstrbuton s, Internatonal Conference on Electrc Utlty",Deregulaton and Restructurng and ower Technologes 2000, London, pp , 4-7 Aprl 2000 [15] C.W. So, K.K. L,"Overcurrent relay coordnaton by evolutonary programmng", Electr. ower Syst. Res. 53,pp ,2000. [16] C.W. So, K.K. L, "Tme coordnaton method for power system protecton by evolutonary algorthm", IEEE Trans. Ind. Appl, pp , October Mohammad Saleh maleh was born n sar- Iran n 1985, and receved the B.Sc. degree n electrcal engneerng from the Alabad Unversty, Golestan, Iran, n he s workng toward hs M.S degree n electrcal engneerng at Islamc Azad Unversty Scence and Research branch-tehran, Iran. Hs areas of nterest n research are power system stablty, electrcal power systems, network plannng and optmzaton, and dstrbuted generaton. Soodabeh Soleyman receved the M.S. and h.d. degrees n the Electrcal Engneerng Department of Sharf Unversty of Technology, Tehran, Iran n 2005 and 2007 respectvely. Snce 2002, she has been at Scence and Research Branch, Islamc Azad Unversty. Her man research nterests are n the areas of electrc power systems protecton and operaton, market power montorng, optmzaton and electrcty market ssues. She has publshed up to 60 research papers on the nternatonal conferences and journals. In t e r n a t o n a l Jo u r n a l o f Co m p u t e r Sc e n c e & Te c h n o l o g y 11