Optimal Placement of Unified Power Quality Conditioner using Ant Lion Optimization Method

Transcription

1 Research India Publicaions. hp:// Opimal Placemen of Unified Power Qualiy Condiioner using An Lion Opimizaion Mehod M. Laxmidevi Ramanaiah 1 and Dr. M. Damodar Reddy 2 Research Scholar 1, Deparmen of E.E.E, Sri Venkaeswara Universiy, Tirupai, Andhra Pradesh, India. Professor 2, Deparmen of E.E.E., Sri Venkaeswara Universiy, Tirupai, Andhra Pradesh, India. 1 ORCID: Absrac This paper acquains us wih he problem of Unified Power Qualiy Condiioner () placemen in radial disribuion sysems. The objecive of placemen is o reduce he real power losses and improve he volage profile. The problem is formulaed as a nonlinear single objecive problem. The volage compensaion is done by injecing acive and reacive power wih he aid of series compensaor of. The shun compensaor provides he required load reacive power along wih he series compensaor. The opimal placemen of is unraveled using he laes opimizaion mehod known as An Lion Opimizaion (ALO) mehod. The proposed mehod is esed using sandard disribuion sysems. Keywords: An Lion Opimizaion; disribuion sysems; reacive power compensaion; Unified Power Qualiy Condiioner. INTRODUCTION The inroducion of compuer conrolled devices in he disribuion sysem has deerioraed he qualiy of power supply. The inegraion of renewable energy sources in he form of Disribued generaion unis a he cusomer end has worsened he problem of power qualiy. The exising power qualiy improving equipmens are no reliable o ackle muliple issues. Hence i is necessary o develop devices which can handle muliple issues of power qualiy. This requiremen has led o he inegraion of series and shun compensaing devices. [1]-[3] is one such device which can solve curren and volage relaed problems simulaneously. is a versaile device. There are differen classificaions of based on he srucure, supply, ec. Based on volage compensaion capabiliy, he ypes of available s are -P, -Q and -S. In -P, he series par of injecs acive power. The raing of he DVR is low as i requires minimum volage injecion by he series compensaor. The shun compensaor, DSTATCOM, is used for all curren-based compensaion wih uniy power facor a he load end. In -Q, he series compensaor of he injecs only reacive power. The shun compensaor is conneced across he consumer s load end as he righ shun and is used for all curren-based compensaion a he load end. In -S, he series compensaor of he injecs real and reacive power wih he minimum VA raing. The shun compensaor is used for all curren-based compensaion. In -S boh he compensaors are uilized for reacive power compensaion. The concep of opimum operaion of is evidenly visible in case of -S. The digial signal processor-based experimenal sudy [4] based on opimal uilizaion of is proposed by Khadkikar e.al. The direcion of research for placemen in a large disribuion sysem uilizing he concep of opimal uilizaion of boh he series and shun compensaors is eviden in [5]-[8]. S. A. Taher e.al [5] has deailed he problem of allocaion in he disribuion sysem wih he differenial evoluion algorihm. M. Bouebel e.al [6] has solved he placemen problem by using Paricle Swarm Opimizaion based Hybrid Differenial Evoluion (PSO- HDE) mehod. S. Ganguly e.al [7] has adoped Paricle Swarm Opimizaion (PSO) mehod for solving placemen problem. is modeled in he load flow mehod [8] and he bus which is having minimum power loss is adoped for placemen. The disadvanage wih his mehod is for large disribuion sysem finding he loss a each and every bus is ime consuming. Hence, in his paper a new opimizaion mehod known as An Lion Opimizaion mehod is implemened o solve he placemen problem. The volage injeced by he series compensaor and he reacive power injeced by he shun compensaor is incorporaed in he load flow mehod. The losses in he radial disribuion sysem and volages are found by using he load flow mehod described. model realized in he load flow mehod is presened. A brief descripion of ALO algorihm and is implemenaion o find he opimal locaion and raing of is given. The conclusion from he resuls are presened. 3708

2 Research India Publicaions. hp:// LOAD FLOW METHOD Load flow is a significan ool o evaluae he performance of he sysem parameers well in advance. The Newon Raphson mehod is he mos powerful load flow mehod. Bu he compuaional complexiy is ineviable. The oher mehods available in he disribuion sysem are idenifying he nodes beyond branches [9], formaion of bus-injecion o branchcurren (BIBC) and branch-curren o bus-volage (BCBV) marices [10]. The load flow seps involved are finding he load currens, developmen of BIBC marix and Forward sweep. Finding he load currens: Consider real and reacive load on he radial disribuion sysem as P L and Q L, volage a he load bus as V. The load curren I L a he m h bus is calculaed as given in equaion (1) I L (m) = ( P L (m)+jq L (m) ) (1) V(m) Developmen of BIBC marix: This sep involves building BIBC marix. The marix dimension is [n х n]. Here n is he number of branches. The elemen in he marix is one if here exiss a pah from he source o he load else he elemen is zero. BIBC marix relaes he load curren wih he branch curren. The relaed equaion is given in equaion (2) [I b ] = [BIBC] [I L ] (2) Forward sweep: This sep involves finding he volage drop across he i h branch and he new node volages. The relaed equaions are given by equaion (3) and (4) ΔV(i) = I b (i). Z b (i) (3) V L (i) = V s (i) I b (i). Z b (i) (4) The difference beween he new and old volages is calculaed. If he error is less han olerance, hen he load flow seps is repeaed else he load flow is said o be converged. The real and reacive power losses for n number of branches wih branch resisance R b and branch reacance X b in a disribuion sysem are given by (5) and (6) respecively. P Loss = i=1:n I b (i) 2 R b (i) (5) and so on. Shun compensaor solves load reacive power compensaion, curren harmonics, and imbalance and so on. The concepual srucure of is shown in Fig 1. A. Modeling of Figure 1: srucure The volage compensaion can be done by using acive power as well as reacive power. Here he series compensaor is modeled as a volage source injecing acive as well as reacive power and shun compensaor is modeled as he source of reacive power. The series compensaor injecs volage in series wih he line nearer o he receiving end bus and he shun compensaor provides reacive power. Figure 2: Phasor diagram for series volage injecion The new load bus volage V L obained afer adding he volage V se injeced by he series compensaor a he load bus V L is calculaed as given in equaion (7) V L δ = V L + V se (7) Q Loss = i=1:n I b (i) 2 X b (i) (6) The mainly includes a series and a shun compensaor conneced back o back by a DC link capacior. Series compensaor connecs grid-side wih series ransformer. Shun compensaor connecs load-side wih inducance. Series compensaor solves grid-side volage qualiy problems, including volage sags, swells, inerrupions, and imbalance The complex power injeced by he series compensaor is obained as follows: S se = V se. I b (8) Calculae he shun compensaing curren I c [11]. The reacive power injeced by he shun compensaing device is given by equaion (9) Q sh = V L I c (9) 3709

3 Research India Publicaions. hp:// ANT LION OPTIMIZATION METHOD The ALO algorihm [12] is moivaed from he huning performance of anlions. The main phases of huning include random walk of ans, building raps, enrapmen of ans in raps, caching preys, and re-building raps. i. Random walks: This phase models he ans movemen. The movemen of ans in naure is seleced as a random walk since heir search for food is sochasic in naure. ii. Trapping in anlions pis: This phase models he effec of anlions raps on random walks of ans. iii. Building rap: In order o model he anlion huning capabiliy, a roulee wheel is employed. The ALO algorihm is obligaed o develop a roulee wheel operaor for choosing anlions based on heir finess during opimizaion. This mehod offers a higher probabiliy o he fier anlions for grasping ans. iv. Sliding ans owards anlions: Anlion shoos sand ouwards he cener of he pi so ha he an slips in he rap and does no escape he rap. v. Caching prey and re-building he pi: An anlion improves is chance of caching new prey by updaing is posiion o he newes posiion of he huned an. vi. Eliism: Eliism is an imporan characerisic which allows mainaining he bes soluion obained a any sage of he opimizaion process. The bes anlion achieved in each of he ieraion is saved and considered as elie. A. Algorihm o find he opimal locaion and raing of in radial disribuion sysem Sep 1: Iniializaion of he anlions and ans: Generae he posiions of anlions and ans randomly. The posiions of anlions and ans are locaions and real and imaginary par of he volage injeced by he series compensaor. Sep 2: Finess Evaluaion: By compensaing he volage a he corresponding locaion by using equaion (7) and reacive power by using equaion (9), run he load flow. Find he finess values. Here he finess funcion is defined by equaion (5). Discard he anlions which violae he consrain which saes ha he volage a he desired locaion should no exceed 1 p.u. Sor he anlions finess and he bes anlion is assumed as he elie. Sep 3: Se he ieraion coun o 2. Sep 4: Sliding ans owards anlions phase: Choose an anlion wih he help of he Roulee wheel. Consider w as a consan based on he curren ieraion, as he curren ieraion number, T as he maximum number of ieraions, he raio I is given by equaion (12). c, d define he random walks of ans in a hyper-sphere around he seleced anlion. Updae c and d using equaion (10) and (11) c = c I d = d I I = 10 w T (10) (11) (12) Sep 5: Random walks phase: Consider he movemen of ans as a sochasic funcion r(), a i and b i as he minimum and maximum of random walk for he i h variable, c i and d i as he minimum and maximum of i h variable for h ieraion. Creae random walks using equaion (14) and normalize he random walks using he equaion (15) r() = 1 if random > 0.5 r() = 0 if random < 0.5 (13) X() = [0, cumsum(2r( 1 ) 1), cumsum(2r( 2 ) 1,.. cumsum(2r( T ) 1] (14) X i = (X i a i ) (d i c i ) b i ai + c i (15) Sep 6: Consider R A as he random walk around he anlion seleced by he roulee wheel, R E as he random walk around he elie. Updae he posiion of i h an for h ieraion using equaion (16) An i = R A +R E 2 (16) Sep 7: Check wheher he newly generaed ans are wihin he limis. Run he load flow by compensaing he volage and reacive power a he desired locaion using equaion (7) and equaion (9). Find he finess of ans. Sep 8: Caching prey and re-building he pi: Updae he posiion of seleced j h anlion if posiion of i h an finess is beer han anlion finess Anlion j = An i if f(an i ) < f(anlion j ) (17) Sep 9: Updae elie if an anlion becomes fier han he elie. Sep 10: Check for convergence. If he soluion does no converge, hen repea he seps from 4 o

4 Research India Publicaions. hp:// Sep 11: The elie gives he locaion and complex volage. Prin he resuls for real and reacive power injeced by he series compensaor and reacive power injeced by he shun compensaor. RESULTS The sandard disribuion sysems used o validae he proposed approach are 33 and 69 bus radial disribuion sysems. A. 33 Bus Sysem: The daa of he sysem is acquired from [13]. The nework configuraion of he sysem is shown in Fig. 3.The base volage is kv. The real and reacive load of he sysem is 3715 kw and 2300 kvar respecively. I has 33 buses and 32 branches. 21 ou of 33 buses of he disribuion sysem have under volage problem. The resuls of insallaion are deailed in Table I. The shun compensaion required afer placemen is kvar. The minimum volage has increased from p.u. o p.u. a 18 h node. The reducion in real power loss is 39.1%. Comparaive resuls for 33 bus sysem are presened in Table II. The comparaive resuls indicae ha he proposed mehod has significan reducion of 39.1% in real power losses as compared wih Differenial Evoluion and he mehod available in [8]. Table II. Comparaive Resuls of 33 bus sysem 33 Bus sysem Descripion [5] [8] Proposed Mehod Opimal Locaion Real Power Loss (kw) Minimum volage (p.u.) Real power loss reducion (%) The volage profile wihou and wih consideraion of is shown in Fig 4. Figure 3: Nework configuraion of 33 bus sysem Table I: Resuls of 33 bus sysem Sr No. Descripion 33 Bus sysem Wihou Wih 1 Locaion Toal real power loss (kw) Toal reacive power loss (kvar) Volage injeced (p.u.) i 5 Injeced real power by series compensaor (kw) 6 Injeced reacive power by series compensaor (kvar) 7 Injeced reacive power by shun compensaor (kvar) 8 Minimum volage (p.u.) 18 9 Nodes wih under volage problem Figure 4: Volage Profile for 33 bus sysem wihou and wih consideraion of B. 69 Bus Sysem: The daa of he sysem is obained from [14]. The nework configuraion of he sysem is shown in Fig.5.The base volage is kv. The oal load on he sysem is kw and kvar. I has 69 buses and 68 branches. 3711

5 Research India Publicaions. hp:// Figure 5: Nework configuraion of 69 bus sysem 9 nodes ou of 69 nodes of disribuion sysem (13.04%) have under volage problem. The resuls of insallaion for 69 bus radial disribuion sysem are deailed in Table III. The volage profile wihou and wih consideraion of is shown in Fig 6. Sr No. Table III. Resuls of 69 bus sysem 69 Bus sysem Descripion Wihou 1 Locaion Wih Toal real power loss (kw) Toal reacive power loss (kvar) Volage injeced (p.u.) i - Injeced Real power by series compensaor (kw) Injeced reacive power - 0 by series compensaor (kvar) Injeced reacive power by shun compensaor (kvar) Minimum volage (p.u.) bus 61 Nodes wih under volage 9 2 problem The shun compensaion required afer placemen is kvar. The minimum volage has increased from p.u. a 65 h node o p.u. a 61 s node. The reducion in real power loss is 52.19%. Figure 6: Volage Profile for 69 bus sysem wihou and wih consideraion of The comparaive resuls of 69 bus sysem are presened in Table IV. The proposed mehod is compared wih Differenial Evoluion mehod, Paricle Swarm Opimizaion mehod, hybrid mehod and he mehod in [8].The proposed mehod has significan reducion of 52.19% in real power losses. Descripion Table IV. Comparaive Resuls of 69 bus sysem [5] 69 Bus sysem [6] [8] [7] Proposed mehod Opimal Locaion Real Power Loss (kw) Minimum volage (p.u.) Real power loss reducion (%) CONCLUSION The opimal locaion and raing for he Unified Power Qualiy Condiioner are deermined using An Lion Opimizaion. The salien oucomes are: The series compensaor akes par in reacive power compensaion by injecing he volage a he receiving end of he bus in he seady sae. Resuls indicae ha here is a significan reducion in power losses and subsanial improvemen in volage profile. The effeciveness of An Lion Opimizaion mehod is validaed using sandard radial disribuion sysems. 3712

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