A New Optimal Locating and Setting of UPFC for Congestion Management in Deregulated Electricity Market

Transcription

1 nternatonal Journal of cence and Advanced echnology ( olume 3 o ebruary A ew Optmal Locatng and ettng of UC for Congeston Management n Deregulated Electrcty Market M. Jooraban Z.mrsadegh M. ane A.Lashkar Ara Chamran unversty Chamran unversty Chamran unversty slamc azad unversty aculty of engneerng aculty of engneerng aculty of engneerng Dezful branch ran, Ahvaz ran, Ahvaz ran, Ahvaz ran, Dezful mooraban@scu.ac.r Zenab.mrsadeghee@gmal.com mohsen.sane@gmal.com Lashkarara@ust.ac.r Abstract Congeston management of transmsson lnes s one of the maor problems of deregulated power markets. One effcent soluton to releve congeston s the locatng AC devces. UC s one of AC devces that causes the loadablty enhancement n heavy power corrdors by controllng the power flow. he optmzaton method s numercally solved usng general algebrac modelng system (AM software. he soluton procedure uses from a nonlnear programmng (L and mxed-nteger nonlnear programmng (ML to solve the optmal locaton and AC settng that has been ncorporated n the optmal power-flow problem. o verfy and valdate the effectveness of the proposed method, t s appled to EEE 14-bus system and 4-bus Relablty est ystem (R, and the obtaned results have been presented and dscussed. (Abstract Keywords-Congeston management; O; LM; socal welfare; UC (key words. RODUCO (HEAD 1 he electrcty market wll not be able to operate n ts compettve eulbrum n congested systems. n economc terms, t wll lead to dead weght loss to the socety. n order to allevate congeston, some nexpensve generators have to reduce ther dspatch and some expensve generators, n congested zone, have to ncrease ther dspatch. hs can further lead to creaton of local market power and hnders the development of compettve envronment n electrcty trade [1]. o releve the congeston, O can use manly two types of technues, whch are as follows [, 3]: Cost free means:. Out-agng of congested lnes.. Operaton of transformer taps/phase shfters. Operaton of lexble AC transmsson systems (AC devces seres devces on-cost-free means:. Re-dspatch of generaton n a manner dfferent from the natural settlng pont of the market. ome generators back down whle others ncrease ther output. he effect of ths s that generators no longer operate at eual ncremental costs.. Curtalment of loads and the exercse of (not-costfree load nterrupton optons. Optmal locaton, approprate sze and settng of AC devces are mportant n the deregulated electrcty markets. On one hand, there s consderable rsk n the nvestment of AC devces because of the hgh cost of AC devces and the uncertan market transactons [4, 5]. A lot of researches are done to mplement AC devces n order to manage congeston of transmsson systems, and some methods based on Optmal ower low (O are presented to solve the problem and fnd the locatng and szng AC devces. ome methods based on senstvty analyss have been used to fnd optmal placement of AC devces for congeston management[6-8]. Although, these methods have good performance to locate AC, they may not capture the nonlnearty assocated wth the system. rorty lst method for CC allocaton n order to congeston management has been proposed based on the locatonal margnal prces (LMs [9]. Heurstc technues such as partcle swarm optmzaton (O and genetc algorthm, have been used to fnd optmal locatons of AC devces n order to mnmze the cost nstallaton and to mprove system loadablty [10-11]. n ths paper, a new approach s proposed for congeston management by optmal locaton of AC devces and evaluatng the mpact of optmal allocaton on the system operaton n order to mnmze nvestment cost of devces and mzaton the beneft. ML program s used to determne the optmal locaton and settng AC devces.. AC DECE AC MODEL AD CO UCO A. UC operaton and ts tatc Model (Headng Unfed ower low Controller concept was proposed n 1991 by yugy. As shown n gure 3, UC conssts of seres and parallel transformers, two voltage source converters, and a DC lnk [1]. 4

2 nternatonal Journal of cence and Advanced echnology ( olume 3 o ebruary gure. 1. chematc dagram of UC. gure.. Euvalent crcut of UC. Converter 1 provdes the real power demanded of converter at the common DC lnk termnal from the ac power system. hus the Converter 1 s capable to support the real power exchange resultng from the seres voltage necton. Also converter1 can generate or absorb controllable reactve power and provde ndependent shunt reactve compensaton for the lne. Converter s used to generate a voltage source at the fundamental freuency wth varable ampltude (0 and phase angle (0 φ π, whch s added to the AC transmsson lne by the seres connected boostng transformer. hs voltage source can be used for drect voltage control, seres compensaton, phase shfter, and ther combnatons [13]. UC can control all three effcent parameters of power flow.e. voltage, lne mpedance and phase angle by smultaneously or selectvely control the actve and reactve power. Modelng of AC devces evaluated based on the performance of dynamc or statc system. Where the locaton of AC devces s consdered n order to reduce congeston n the statc studes, generally the statc models of AC controllers have been used. ower necton model of AC controllers s an approprate model for studes of congeston management n statc applcatons [14, 15]. n ths model, a certan amount of actve and reactve power nected to the node. he euvalent crcut of UC placed n lne-k connected between bus- and bus- s shown n gure.. UC has three controllable parameters, namely, the magntude and the angle of nserted voltage and the magntude of the shunt transformer reactve current. Based on the basc prncple of UC and the vector dagram, the basc mathematcal relatons can be gven as:, Arg( Arg( Re[ ] Arg( Arg( and (1 he power flow euatons between bus- and bus- can be wrtten as: ( B ( ( B (3 By usng (1-(3 euatons, actve and reactve power flows n a lne wth UC can be wrtten as: ( g g b sn( ] g cos b [ g cos( [ g cos b sn sn cos( b cos( (4 sn( ] (b B [g sn(φ δ (b B cos(φ δ ] (g snδ b cosδ ( B b sn( b cos( sn b cos g g cos( s [ g s cos( b sn( ] [ g cos( b sn( ] s [ g sn( ( b B cos( ] s [ g sn( b cos( ] gure. 3. necton model of UC. (5 (6 (7 (8 (9 (10 (11 B. he UC nvestment Cost uncton Based on the emens A Database, the cost functon of UC that has been used n ths study s [16]: U$ C UC (1 k var Where s the operatng range of the UC devce n Mvar.he nvestment cost of the UC devce s consdered as U$. Although t must be unfed nto U$/Hour. ormally, the AC devces wll be nservce for many years. However, only a part of ts lfetme s employed to regulate the power flow. n ths paper, t s consdered a ten years perod to evaluate the cost functon. herefore the average values of the nvestment costs are calculated usng the followng euaton: 5

3 nternatonal Journal of cence and Advanced echnology ( olume 3 o ebruary C f CUC $ h (13 LOCAO AD Z O AC DECE A. O ormulaton O tool has been used n many pool based deregulated electrcty markets to calculate generaton dspatch and load schedule, to prce energy (nodal prcng or LM and to manage congeston n the system. he generally accepted obectve s mnmzaton generaton cost and mzaton consumer beneft treated as negatve cost, whle satsfyng the operatonal and securty related constrants. hs goal s usually called as socal welfare. n ths paper, the cost of AC devces s added to the socal welfare mzaton problem whch can be expressed as [9]: Mnmze : ( ( ( 1 1 C BD D Cost AC D he eualty constrans that consdered n the ower balance euaton are: (, D 0 for 1,... (, D 0 for 1,... (14 (15 (16 f UC s located n the lne between buses and, the power balance euatons n node and are gven as follow: (, 0 D (, 0 D (, 0 (, 0 D D he neualty constrans are assumed as followed: -ower generaton lmt: mn g mn g g g -Apparent lne flow lmt: (, g g -Bus voltage and lmts: mn (17 (18 (19 (0 (1 ( (3 (4 -UC control parameter lmts: mn mn 0 (5 (6 (7 Where s the number of generators, C ( s the bd curve of the generator, B s the beneft curve of th demand, and generaton at node, D ( D are the actve and reactve power D and reactve power loads at node, D and reactve power necton at node. are the actve and and are the actve mn g and g are mnmum and mum actve power generaton lmts of generatng unt at bus, and are mn g g mnmum and mum reactve of generatng unt at bus s the apparent power flow n transmsson lne, connectng between nodes and, and mn mum lmt of the apparent power, and are mnmum and mum voltage lmts at bus. s ts B. oluton technue he Lagrange functon of the optmzaton problem ncorporatng all the constrants n the obectve functon s presented as follow: L 1 1 ( ( C L ( ( ( ( ( ( ( ( D 1 D D B D 1 ( D C mn 1 1 mn mn mn ( mn mn ( ( ( UC mn ( ( mn mn mn mn mn (8 6

4 nternatonal Journal of cence and Advanced echnology ( olume 3 o ebruary Where p and are the Lagrange coeffcents assocated wth the eualty constrants and, L,, mn mn,,,, mn mn,,, mn, mn, (9 are the Lagrange coeffcents assocated wth the neualty constrants. he O soluton gves the values of these coeffcents along wth the dspatch result. Each Lagrange coeffcent has economc sgnfcance. he mportant one s the Lagrange coeffcent assocated wth the real power balance euatons. t s the real power spot prce or nodal prce or LM and can be used for prcng energy n electrcty markets [17]. LM s generally composed of three components, a margnal energy component (for all buses, a margnal loss component and a congeston component. or a case of real power spot prce at bus, consderng all constrants n the O, the decomposton of the nodal spot prce nto three components s as follows: L L L 1 (30 gure.4 Concept of socal welfare gure.5 shows that the nodal prce dfference between any two buses depend on the congeston throughout the network.. OLUO ALORHM he man obectve of ths paper s to determne the optmal locaton and the optmal parameters settng of UC n order to manage network congeston and to lower costs s to mze socal welfare. L, C, (31 Where, s the margnal energy component at the reference bus, C, L, s the congeston component. s the margnal loss component and gure.4 shows a graphcal representaton of a perfectly compettve electrcty market. Demand and supply of the market are represented by lnear functons, where the ntersecton of the curves determnes the eulbrum pont, characterzed by the market clearng uantty ( m as well as the market clearng prce (p m. he summaton of producers surplus ( and consumers surplus (C s known as socal welfare. As socal welfare n a perfectly compettve market s at mum, any complcaton n an economc or techncal sense wll subseuently decrease welfare. gure.4 depcts a related stuaton takng nto account transmsson congeston. Due to network congeston n the uas-eulbrum pont two prces exst: one related to the consumers wllngness to pay (p d and one gven by the margnal cost of producton (p g. Hence, the market operator collects a rent, whch s known as the so-called congeston rent (CR. he trangular left to the congeston rent represents the deadweght loss (DW. he deadweght loss s ncurred by the fact that less energy can be traded leadng to a loss of welfare n general [18]. gure 5: ocal Welfare and transmsson congeston he proposed algorthm conssts he L and ML optmzaton problems are modeled n AM.4 software and solved usng O and DCO solvers, respectvely [19]. L program s used to solve ACO problem and ML s appled to determne the optmal locaton of AC devces. he proposed approach algorthm can be descrbed as follows: tep1. Read the power system data (generatons, loads, transmsson lnes, cost and beneft coeffcent tep. Run AC O wthout applcaton of AC devces, calculate load flows, LMs n the system, socal welfare and generaton pattern of unts. tep3. Run AC O wth applcaton of AC devces, calculate LMs and the power flows of all lnes n the system, socal welfare and generaton pattern of unts. tep4. he best locaton of AC devces s where that produces the mum socal welfare. f the suggested locaton s where that transformer s nstalled on t, so ths locaton wll be neglected and the next locaton s selected. he lowchart of the proposed algorthm s llustrated n gure.6. 7

5 nternatonal Journal of cence and Advanced echnology ( olume 3 o ebruary CAE UDE he proposed algorthm s mplemented n AM.4 software. n order to show the effectveness of the proposed approach, t s appled on the EEE 14-buses and EEE 4-buses Relablty est ystem. he results of applyng the proposed technue for each sample system are shown n three cases. Case1: Wthout applcaton of UC and wthout thermal constrant. Case: Wthout applcaton of UC and wth thermal constrant. Case3: Wth applcaton of UC and thermal constrant. A. EEE 14-Bus est ystem he network data for EEE 14-Bus system s avalable n [0]. he cost and beneft coeffcents for generators and loads have been modfed and the capacty of the ne1- decreased from 34 MA to 10 MA. able 1 shows the obectve functon for cases 1 to 3. Accordng to the table 1, after applcaton of UC n a proper locaton, the socal welfare of the network has ncreased from ($/h to ($/h, that shows ($/h savng. ABLE. Optmal Locaton REUL OMAL CHARACRC OR EEE 4-BU R YEM nvestment cost($/h UC ze(ma AR Read power system data... Run AC O wthout applcaton of AC devces YE Congeston =1 O ABLE. Obectve uncton REUL BAED O O OR EEE 14-BU YEM Case1 Case Case YE Dose the lne- nclude transformer ABLE. REUL OMAL CHARACRC OR EEE 14-BU YEM o lace AC on th lne Optmal Locaton nvestment cost($/h UC ze(ma Calculate obectve and store the value ABLE. Obectve uncton REUL BAED O O OR EEE 4-BU R YEM Case1 Case Case =+1 he obtaned results of runnng the optmzaton program and locatng the UC ncludng the optmal characterstcs of UC, the nvestment cost ($/h and UC sze are shown n table. Also, the LM values for all buses, and the generaton pattern of all unts wth and wthout UC, are shown n gures.7 and 8 respectvely. As can be seen of these fgures, n the presence of UC, the obtaned LM values for all buses are close to each other as well as they have been decreased. optmal locaton and the optmal parameters settng of AC O gure6. lowchart of the proposed algorthm 8

6 nternatonal Journal of cence and Advanced echnology ( olume 3 o ebruary gure.7 he LM values, wth and wthout UC for EEE 14-bus system gure. 9.he LM values, wth and wthout UC for EEE 4-bus system gure. 8 he pattern generaton of unts, wth and wthout UC for EEE 14-bus system B. EEE 4-Bus Relablty est ystem he network data for EEE 4-Bus R s avalable n [0]. he data for the generators can be found n [1]. he only modfcaton wth respect to the network data lsted n [0] conssts of the reducton of the capactes of the lnes 11 13, and 15 4 from 500 MA to 175 MA, 60 MA, and 175 MA, respectvely based upon []. able 3 shows obectve functon values for all three cases. Accordng to the table 3, after applcaton of UC n a proper locaton, the socal welfare of the network has ncreased from ($/h to ($/h, that shows about ($/h savng. he obtaned results of runnng the optmzaton program and locatng the UC ncludng the optmal characterstcs of UC, the nvestment cost ($/h and UC sze are shown n table 4. Also, the LM values for all buses, and the generaton pattern of all unts wth and wthout UC, are shown n gures.9 and 10 respectvely. As can be seen of these fgures, n the presence of UC, the obtaned LM values for all buses are close to each other as well as they have been decreased. gure. 10.he pattern generaton of unts, wth and wthout UC for EEE 4-bus system. COCLUO n ths paper, a new mathematcal program s proposed for the AC controller allocaton. he proposed program suggests the optmal locaton of the UC and ts settng to optmze the socal welfare and relef congeston. he obtaned results ndcate the sgnfcant reducton of prces, as well as some suffcent changes n the generators dspatches by ncreasng t for nexpensve and reducng t for expensve generators. herefore, the UC nstallaton has the economcal advantages n addton to ts ablty for the congeston management. REERECE [1].L. Joskow, J. role, ransmsson rghts and market power on electrc power networks, RAD J. Econ. ol. 31, pp , 000. [] A.K.Davd, Dspatch methodologes for open access transmsson systems, EEE ransactons on ower ystems, ol. 13, o. 1, pp 4653, eb [3] Harry ngh, han You, and Alex apalexopalos, ransmsson congeston management n compettve electrcty market, EEE ransactons on ower ystems, ol. 13, o., pp , May [4] A. ode-yome,. Mthulananthan, Comparson of hunt capactor, C and ACOM n statc voltage stablty margn enhancement, nt. J. Electr.Eng. Educ, vol. 41, o., 004. [5].C. rvastava, R.K. erma, mpact of AC devces on transmsson prcng n a deregulated electrcty market, n: roceedng of nternatonal Conference on Electrc Utlty Deregulaton and Restructurng and ower echnologes 000 (DR 000, Cty Unversty, London, pp , Aprl 4 7,

7 nternatonal Journal of cence and Advanced echnology ( olume 3 o ebruary [6].. ngh and A.K. Davd, Congeston Management by Optmsng AC Devce Locaton, nternatonal Conference on Electrc Utlty Deregulaton and Restructurng and ower echnologes 000, Cty Unversty, London, pp.3-8, 4-7 Aprl 000. [7] J. Brosda, E. Handschn, ellow, Congeston Management Methods wth a pecal Consderaton of AC-Devces, EEE orto ower ech Conference, loth -13'h eptember, 001. [8] J. Brosda, E. Handschn, ellow, A. L'Abbate, C. Leder, M. rovato, sualzaton for a Correctve Cong,eston Management based on AC Devces, EEE Bologna owerech Conference, taly, June 3-6, 003. [9] aresh Acharya,. Mthulananthan, Locatng seres AC devces for congeston managementn deregulated electrcty markets, Electrc ower ystem Management, Energy eld of tudy, Asan nsttute of echnology,.o. Box 4, Klongluang, athumthan 110, pp , 006. [10] Rony eto Wbowo, aoto Yorno, Mehd Eghbal, Yoshfum Zoka, and Yutaka asak, AC Devces Allocaton Wth Control Coordnaton Consderng Congeston Relef and oltage tablty EEE RAACO O OWER YEM, ol. 6, o. 4, pp , OEMBER 011. [11] Kesh Reddy ad Reddy, arayana rasad adhy and R.. atel, Congeston Management n Deregulated ower ystem usng AC Devces, n proceedng of power nda conference EEE,006. [1] L. yugy, A unfed power flow control concept for flexble ac transmsson systems, n roc. nt. Conf. AC DC ower ransm, pp. 19 6, 17-0ep1991. [13] K.. erma and H. O. upta, enor, mpact on Real and Reactve ower rcng n Open ower Market Usng Unfed ower low Controller EEE RAACO O OWER YEM, vol.1, no.1, pp , ebruary006. [14] Y. Xa, Y.H. ong, Y.Z. un, ower flow control approach to power systems wth embedded AC devces, EEE rans. ower yst. ol.17,no.4, pp , 00. [15] C. Lehmkoster, ecurty constraned optmal power flow for an economcal operaton of AC devces n lberalzed energy market, EEE rans.ower Del. ol.17, no., 00. [16] K. Habur, and D. Oleary, AC - flexable AC transmsson systems, or cost effectve and relable transmsson of electrcal energy, a report revewed by World Bank. [17].L. Alvarado, Controllng ower ystems wth rce gnals, Decson upport yst., vol. 40, pp , 005. [18] hlo KrauseEvaluatng, Congeston Management chemes n Lberalzed Electrcty Markets Applyng Agent-based Computatonal Economcs, hess for Dr of techncal scences, wss ederal nsttute of technology Zurch, 007. [19] eneral Algebrac Modelng ystem (AM [Onlne]. Aval-able: [0] R. D. Zmerman, C. E. Murllo-anchez and D. am, MAOWER- A MALAB power system smulaton package, erson 3, avalable at: [1] Lna.arces, Antono J.Coneo,Rauel arca-bertrand and Ruben Romero, A Blevel Approach to ransmsson Expanson lannng Wthn a Market Envronment, EEE RAACO O OWER YEM, vol.4, no.3, AUU 009. [] Relablty est ystem ask orrce, he EEE relablty test system- 1996, EEE rans. ower yst., vol. 14, no. 3, pp , Aug [3] J. M. Arroyo. D. alana Energy and reserve prcng n securty and network-constraned electrcty markets EEE rans. ower yst., vol.0, no., pp , May M.Jooraban receved the B.c. degree n electrcal engneerng from Amercan, n 198 and the M.c. degree n electrcal engneerng from Amercan, n 1984 and and the h.d. degree n electrcal engneerng from England, n he s an Assocate rofessor n the Electrcal Engneerng Department, Chamran Unversty of Ahvaz, ran. Hs research nterests are reactve power control, power system dynamcs, and stablty and control and flexble ac transmsson systems devces. rofessor ooraban s a member of the EEE ower and Energy ocety and ocety of Electrcal and Electroncs Engneers AEEE. Z.Mrsadegh receved the B.. degree n electrcal engneerng from Bu.Alsna Unversty, Hamedan, ran, n 006. he s currently a tudent of Mc n electrcal engneerng from hahd Chamran Unversty, Ahvaz, ran. M. ane receved the B.c. degree n electrcal engneerng from erdos Mashhad Unversty,Mashhad, ran, n 1989 and M.c. degrees n electrcal engneerng from arbat Modarres Unversty, ehran, ran, n 199 and the h.d. degree n electrcal engneerng from the trathclyde Unversty, lasgow, UK, n 004. he s an Assocate rofessor n the Electrcal Engneerng Department, Chamran Unversty of Ahvaz, ran. Hs current research nterests nclude analyss, operaton and control of power sys- tems, and Hgh voltage technology, pulsed power technology and ts applcatons. A.Lashkar.Ara was born n ehran, ran, n He receved the B.c degree n electrcal engneerng from the slamc Azad Unversty, Dezful Branch, Dezful, ran, n 1995, the M.c degree n electrcal engneerng from the Unversty of Mazandaran, Babol, ran, n 001, and the h.d. degree n electrcal engneerng from ran Unversty of cence and echnology (U, ehran, ran, n 011. Currently, he s a faculty member of slamc Azad Unversty. Hs current research nterests nclude analyss, operaton and control of power systems, and flexble ac transmsson system controllers. Dr. Ara s a member of the EEE ower and Energy ocety. 10