Flow Based Activation of Reserves in the Nordic Power System

Transcription

1 Flow Based Actvaton of Reserves n the Nordc ower System Hossen Farahmand, Seyed Mohammad Al Hossen, erard. Doorman. Member, IEEE, and Olav Bjarte Fosso, Senor Member, IEEE Abstract-- In the Nordc market, manually actvated tertary control based on bds for upward and downward regulaton s used for system balancng. Although a system wde mert order lst s used, the resultng regulaton s suboptmal because of the congeston and the effect of losses, whch are not taken nto account. Ths paper proposes an algorthm for the dspatch of regulaton resources based on an ncremental DC optmal power flow formulaton. The results of ths model are compared wth today s practce for some cases of up- and downward regulaton, and a potental for cost reducton s observed. However, the method requres Automatc eneraton Control that s not n use n the system, although t s presently evaluated. Also prcng of regulaton s an ssue, because ocaton Margnal rces probably are unacceptable to market partcpants. Index Terms-- Nordc regulatng market, Incremental DC- OF, ocaton Margnal rcng (M), Congeston management, Margnal losses. T I. INTRODUCTION O mantan the operatonal securty of a power system t s necessary to keep a contnuous balance between generaton and demand. Thus the operatonal requrements of a power system comprse such ssues as mantanng suffcent operatonal reserves, dstrbutng these reserves between subsystems and the actvaton of the reserves n such a way as to ensure the contnuous secure operaton of the system. The operatonal reserves are used to compensate for devatons from the forecasts and varatons n the electrcty consumpton, and to lmt the mpact of operatonal dsturbances n the producton and transmsson system. In a European context, these reserves are normally dvded between prmary, secondary and tertary reserves []. rmary control uses the prmary reserves to mantan the balance between generaton and demand n the network usng turbne speed governors. Secondary control s a centralzed automatc functon to regulate the generaton n a control area based on secondary reserves to mantan the exchange between control areas and to keep the frequency between the desgnated lmts. Secondary control s appled by changng the setponts of selected generators. Tertary control s appled by manual or automatc changes n generator setponts. rmary and secondary reserves are dvded between control The authors are wth the Department of Electrc ower Engneerng, Norwegan Unversty of Scence and Technology (NTNU), Trondhem NO- 749, Norway. Emal: Hossen.Farahmand@elkraft.ntnu.no, Seyed.Hossen@elkraft.ntnu.no erard.doorman@elkraft.ntnu.no, Olav.Fosso@elkraft.ntnu.no areas by ENTSO-E gudelnes. For tertary only recommendatons are gven. In the Nordc system, secondary reserves usng Automatc eneraton Control are presently not n use (the excepton s West Denmark, whch s a part of the Central European synchronous system). Imbalance regulaton s performed usng so called Fast Reserves, that are manually actvated and that must be fully actvated wthn 5 mnutes. The TSOs receve bds for upward or downward regulaton from market partcpants who are wllng to rase or lower ther producton or consumpton. A bd for upward regulaton ndcates how much the player asks to be pad to sell a certan volume of regulatng power correspondng to ncreased producton or reduced consumpton. A bd for downward regulaton ndcates how much the player s prepared to pay to buy a certan quantty of regulatng power correspondng to reduced producton or ncreased consumpton [4]. In January 2007, the European Commsson publshed ts Energy Sector Inqury, whch stressed the fact that balancng energy and reserve markets are hghly concentrated, and pontng to the fact that the nadequate ntegraton of balancng markets s a key mpedment to the development of a sngle European electrcty market [2]. In the Nordc area the TSOs have snce 2002 submtted all ther natonal bds to a common Nordc regulaton lst. The lst s avalable to all Nordc TSOs n a common nformaton system NOIS (Nordc Operatonal Informaton System). These resources are thus traded on a sngle-buyer market, where the TSOs act jontly as buyer n procurng resources for the balance regulaton. Ths market s called the regulatng power market (RM) n the Nordc regon [4]. Recently, steps have been taken to further harmonze the balancng market rules n the area [3]. Accordng to the market rules, upward regulaton wll be done by usng the cheapest bd on the common Nordc lst, unless ths causes congeston. Wth the ntegraton of balancng markets over several control areas, t becomes more complcated to assess whch regulatons wll cause congeston, because congeston s generally more prevalent between than wthn control areas. Also, n the case of larger cooperatng balancng areas t becomes more mportant to take nto account the effect of transmsson losses. These ssues become even more prevalent f the HVDC connectons to the European contnent are gong to be used for balancng n the future. Increased ntegraton of wnd s another factor that can create larger devatons at specfc locatons. In general, the lowest prce bds are not necessarly those that mnmze the total cost of regulaton /0/$ IEEE

2 2 These consderatons suggest the use of a framework based on Optmal ower Flow (OF), whch would mplctly assess both concerns. However, such an approach would rase questons about the payment for and prcng of balancng. resently the spot market s splt n several prce areas wth dfferent prces n the case of congeston. Also RM prces wll dffer f congeston between areas nfluences the use of balancng resources. Wthn each area the RM prce s set by the margnal actvated bd. Ths margnal prce s pad to all actvated resources and also pad for all mbalances, resultng n revenue neutralty for the TSO f there s no congeston. The use of OF would mplctly result n ocaton Margnal rces (M) n the RM, whch would be a major change n the market rules. On the other hand, also other prcng mechansms could be used. In ths paper we wll present the problem formulaton for an OF based framework for the Nordc Regulaton ower Market. We wll argue for the use of Incremental DC Optmal ower Flow ncludng margnal losses. Subsequently we wll descrbe some major characterstc of the Nordc system, as well as the aggregate model used for the present analyss. Results of some relevant smulatons wll be presented and compared wth today s practce. Fnally we wll dscuss the results as well as some possble prcng mechansms. II. ROBEM FORMUATION AND SOUTION METHODOOY In the present Nordc Regulatng ower Market requred reserves are manually actvated by the operators of the system based exclusvely on the common Nordc mert order lst of regulatng reserve bds. If there s no congeston wthn the system, the regulatng prce s dentcal for the all subsystems. However, n the case of congeston, some of the regulatng bds wll be dsregarded, and the regulatng prce for the congested area wll become hgher (n the case of upward regulaton) or lower (n the case of downward regulaton) than the other parts of the system to match the transferred power and avalable capacty on the te-lnes. For the tme beng Norway s splt nto three and Denmark nto two area prces whlst the area prce n Fnland and Sweden s equal n the whole country. The congeston wthn each area s releved by a counter trade procedure where the TSO buys and sells at both ends of the congested lne to releve the congeston. Snce the costs of congeston and losses are not consdered explctly n the dspatch of reserves, the resultng solutons are dfferent from the optmal dspatch of the reserve. An alternatve methodology to consder these costs n the reserve dspatch s to use Optmal ower Flow for the calculaton of ocaton Margnal rcng (M) to mnmze the total operatng cost. An AC based OF represents the most accurate methodology for calculatng the Ms. Apart from beng computatonally expensve, the AC-OF s dffcult to mplement n the current regulatng market n the Nordc area. Snce the Ms are determned based on the gradent of objectve functon, they are very senstve to small devatons. Ths would requre many small control actons, whch makes t dffcult to mplement. An alternatve to the AC-OF formulaton s to formulate the problem as a DC-OF, focusng exclusvely on real power constrants n the lnearzed form. The results of the DC-OF problem can be nterpreted n a more meanngful way than the AC-OF n an electrcty market context. As s well-known, the major approxmaton n a DC power flow s to neglect the lne resstance and reactve power, and to assume a flat voltage profle n all nodes (all voltage magntudes wll be equal to.0 p.u.). A quadratc cost curve can be represented wth pecewse-lnear curves to be able to formulate the DC power flow as an problem. enerally the DC-OF can be expressed as [5]: N Mn F = c subject to: = N N 0 = = = N kl kl mn kl, max = mn max for =,2, K, N Δf a ( Δ Δ ) Δ f for kl =,2, K, M N N M c number of generators number of loads number of transmsson lnes generated actve power at bus (MW) () margnal generaton cost at bus ( /MWh) actve power consumpton at bus (MW) kl kl Δfmax, Δ f maxmum and mnmum transmsson lmt mn of lne kl respectvely (MW) a ower Transfer Dstrbuton Factor (TDF) kl, at lne kl regardng power changes at bus max mn, maxmum and mnmum generaton output at bus respectvely (MW) A. DC-OF ncludng margnal losses The problem wth the standard DC formulaton () s that the losses are neglected. However, as dscussed n the ntroducton, takng nto account losses was one of our man consderatons. To consder the losses n the DC-OF, a margnal loss or ncremental loss factor s calculated. Mathematcally t can be wrtten as: loss ρ = (2) loss ncremental total actve losses of the system ncremental power at bus The total actve losses are equal to the sum of the losses for each transmsson lne: M 2 oss = Rj I (3) j I j R j j = flow on transmsson lne j (A) resstance of transmsson lne j (Ω)

3 3 The margnal loss factor s equal to the change n system losses accordng to a change n the power njected or wthdrawn at bus. An alternatve approach s to defne a hub or a reference bus, whch can be the slack bus n the system. An ncrease n generaton n bus by Δ wll result n a decrease n the hub bus producton by Δ ref that s equal to the ncrease of the total actve losses of the system mnus the ncrease n generaton at bus. Ths can be expressed as: Δ ref =Δloss Δ (4) In a lossless system, Δ would be equal to the negatve of Δ ref whereas the flows on the system are changed as a result of the two generators adjustment. Ths change n flow causes a change n losses. When losses are consdered, Δ ref s necessarly not equal to Δ. Wth ths assumpton the delvery factor (β) as the rato of negatve change n reference bus can be wrtten as [5]: Δref β = (5) Δ Substtutng (4) n (5) wll result n the margnal loss factor: ( Δ Δloss ) Δloss β = = (6) Δ Δ or usng (2): ρ = β (7) Dependng on the sgn of the change n losses, the margnal loss factor can be postve or negatve. Includng ths factor n the cost functon of a generator wll reflect the requred cost of the losses arsng from generator contrbuton to the power flow. In a market wth ocaton Margnal rces, ths margnal loss factor would be reflected n the nodal prces. The Ms can be calculated as [6]. C λ = λref + + (8) λ M at bus ( /MWh) λ reference bus energy prce ( /MWh) ref margnal cost of losses ( /MWh) C margnal cost of congeston ( /MWh) C s the dual value of the transmsson lne constrants n () whch can be postve or negatve dependng on the flow drecton. Snce the flow on each transmsson lne s the lnear combnaton of the contrbuton of all producers and consumers, a superposton theorem can be appled. Then the margnal loss between a producer and a consumer pont s equal to the margnal loss between the producer and the hub mnus the margnal loss between the consumer and the hub. The lnear combnaton of the margnal losses dvded by the total load represents the margnal loss for the aggregate load. Ths can be wrtten as: N K k = tot = N K k = k margnal loss between aggregate load and tot hub pont K margnal loss between load K and hub pont K load at bus K (MW) Ths factor can be employed n (8) to account for the margnal loss of generator feedng a set of loads at dfferent ponts of the system. In order to calculate the losses wthn a DC-OF an teratve process s employed where frst results from DC-OF are consdered as ntal results to estmate losses. The allocated loss on each transmsson lne s calculated based on (3). Half of the losses s added at each end of the lne [7] as shown n Fg.. oss j ne j = R I oss j 2 2 j j oss j Fg.. oss represented as loads at both ends of transmsson lne Then these estmated losses wll be used to obtan a new dspatch. Ths process s repeated untl the results between two teratons are wthn a certan tolerance. The results from ths teratve process and an AC-OF are very smlar whle the DC-OF s faster [7]. B. IDC-OF consderng margnal losses A regulatng market deals wth the real-tme reserve dspatch to keep the balance between producton and consumpton, caused by e.g. devatons between forecast and actual demand or generaton outages. In real tme, the bass for the calculatons would be the actual stuaton n the system as ndcated by the state estmator. However, n a model approach the bass can be an assumed day ahead spot market dspatch. Subsequently an ncremental optmzaton approach s used to mnmze the cost of compensatng for devatons from the ntal market balance. Upward generator downward generator = u d = ~ ~ ~ max = max = max max = - mn max =0 mn = mn = 0 = - Bus mn - Fg. 2. enerators represented n IDC-OF (9) mn We wll use an Incremental DC-OF (IDC-OF) formulaton that takes nto account grd congeston and

4 4 margnal losses when determnng the optmal dspatch of regulaton resources. Fg. 2 llustrates how each generator contrbutng n real tme reserve dspatch s modelled as a fxed negatve load representng the spot dspatch (- ) and two hypothetcal generators representng upward and downward regulaton respectvely. The IDC-OF model can be formulated as [8]: subject to: N N ) u u ) d d = = Mn F = c Δ + c Δ N N u d Δ Δ = dev + oss = = N kl u d kl mn kl, max = u max 0 Δ for =,2, K, N mn d Δ 0 for =,2, K, N Δf a ( Δ Δ ) Δ f for kl =,2, K, M (0) u d Δ, Δ upward and downward ncremental generaton at bus respectvely (MW) u d c ), c ) upward and downward margnal generaton cost at bus respectvely, ncludng margnal losses ( /MWh) dev real-tme devaton (MW) commtted generaton capacty at bus I (MW) The total actve system losses (MW) oss III. NORDIC OWER SYSTEM & SST MODE The Nordc area ncludes Sweden, Norway, Fnland and Denmark. West Denmark s a part of the synchronous Central European system, whle the remander consttutes a separate synchronous system (the former Nordel system), cf. Fg.3. Fg. 3. The Nordc countres The system had a peak demand of 6 W and annual generaton of 44 TWh n 2008 [9]. Table I shows how annual generaton was dvded between countres and generaton technologes n TABE I. SHARE OF ANNUA ENERATION IN 2008 BY ENERATION TYE IN THE NORDIC OWER SYSTEM [9] Type Denmark Fnland Norway Sweden Nordc Hydropower Nuclear ower Other thermal power Wnd power The table llustrates the domnatng poston of hydropower. The favourable characterstcs of hydropower n general and the hghly storable Norwegan hydropower specfcally, make ths technology a perfect canddate for the provson of regulatng servces. Ths property wll become more and more requred wth an ncreasng ntegraton of wnd power n the Nordc system as well as the Central European system. However, ncreased use of hydropower for regulaton purposes ncreases the need for a more effcent use n the context of system regulaton. There are a number of HVDC cables between the Nordc area and the Central European power system, cf. Table II. TABE II. HVDC CABE CONNECTION BETWEEN NORDIC AND UCTE OWER SYSTEM [9] Countres/ Cable name Rated voltage Transmsson Capacty [kv] From a To b Sweden-oland (Sweol) Sweden-ermany (Baltc) c 600 c Denmark East-ermany (Kontek) Sweden- Denmark West (KontSkan) Norway- Denmark West (Skagerrak) 250/ Norway-The Netherlands (NorNed) a Transmsson capacty from the frst country n Countres name lst b Transmsson capacty to the frst country n Countres name lst c Due to lmtaton n ermany the transmsson capacty s 460 MW from ermany and 390 MW to ermany. In addton to the cable nterconnectons shown n the table, several new ones are beng consdered. Ths creates an ncreasng opportunty to utlze Norwegan hydropower for balancng purposes n Central Europe. As explaned before, tertary reserve n the Nordc power system s actvated manually, where the cheapest regulatng bd s selected from a common mert order lst rrespectve of natonalty, provded there s no congeston problem n the grd. In the case of congeston to an area some of the regulatng bds wll be dsregarded and regulatng prces wll be dfferent from other areas [4]. Manual actvaton of reserve based on human operator experence has worked satsfactory n the Nordc system so far, although followng the large (net) load ncreases durng the mornng hours sometmes s challengng. Ths s caused by the fact the daly exchange wth the Central European system has the characterstcs of a pumped storage scheme, where Norwegan hydropower s exported durng the daytme, whle cheap thermal low load power s mported durng the nght.

5 5 An ncreasng exchange of both peak and balancng power ntroduces the need for a more sophstcated methodology for dspatch of actvated reserves. It may also become necessary to ntroduce automatcally actvated secondary reserves. The proposed IDC-OF based model for the RM can be used as a kernel to solve these challenges. IV. SIMUATION & RESUTS ANAYSIS In ths secton we wll compare the results of usng the proposed model for balancng n the Nordc system wth the present practce. Smulaton of the balancng market must be started wth a day ahead system dspatch, whch s establshed n two steps:. Calculaton of the market dspatch, based on a zonal model wth 6 nodes n the Nordc system (Western Denmark s consdered part of the Central European system n the model). Ths results n dfferent zonal prces whenever there s congeston between zones. 2. The zonal dspatch may result n congeston wthn zones. In the market such congeston s releved by counter trade as explaned n Secton I. In the model ths s approxmated by usng a DC-OF model. Ths may result n dfferent margnal costs at dfferent buses wthn the same zone. To establsh the base case stuaton (step ), we use the ower System Smulaton Tools (SST) developed under the Tradewnd project [0]. Ths model s based on DC-OF and ncludes a representaton of the European grd wth the man physcal characterstcs of the European system at an aggregate level, ncludng the HVDC connecton between the Nordc and Central European system and tme-varyng parameters such as wnd, load, and hydro nflows. The mpedances of the model are adjusted n such a way that the results most closely correspond to a detaled model. The results of the model wll be the optmum dspatch of generators and the optmum flow on the HVDC connecton, gven the zonal representaton of the Nordc system. The model smulates the flow based market couplng wthn the whole contnental Europe takng nto account wnd power producton scenaros. To releve ntra-zonal congeston (step 2), a more detaled model of the Nordc system s used, shown n Fg Fg. 4. The Nordc power system 700 Ths model has 4 buses wth generaton at 23 of them. At the generator buses a total of 35 generators are connected, because dfferent technologes are represented by dfferent generators wherever applcable. E.g. there are 6 generators connected to bus 7000 representng Fnland, each of them representng a specfc technology such as nuclear, hydro, gas, lgnte etc. For the smulaton of the Regulaton ower Market, we look at a typcal peak load day. Fg. 5 presents the forecasted Nordc load on the second Wednesday n February 200 [9]. As the fgure shows, there s a fast ncrease of the load from 59 to 63 W between hours 7 and 8. Between hours 9 and 20, there s a decrease of 000 MW. It should be noted that large changes on the nterconnectons wth the Central European system wll occur at the same tme, and that the Norwegan generaton system wll take up a large share of these changes, makng consderable requrements to the ablty of the control systems n the Norwegan system. The greatest devatons wth the day ahead dspatch plans therefore typcally occur durng these hours, and we therefore use the demand n hours 8 and 9 as the bass for our calculatons. Country oad Hours [h] Total oad Sweden Norway Fnland Denmark East Total Nordc oad Fg. 5. Forecast hourly load on the second Wednesday n February 200 An earler study modellng the need for regulaton power [2] estmated the expected devatons n the Nordc system. These were assumed to occur at the major load areas Oslo (bus-500) n the Norwegan and Stockholm (bus-3000) n the Swedsh power system and were taken as the bass for the subsequent analyses. A. Day ahead dspatch The generator bds were approxmated by assumed fuel costs and water values n the case of hydropower. The water values were obtaned by the results of smulatons wth the EMS model, a long term optmzaton model for systems wth large shares of hydropower [3]. Fg. 6 shows the resultng mert order lst, and also ndcates the total load of MW n hour 8 and MW n hour 9. Wthout congeston, there would be one system prce gven by the most expensve runnng generator on ths lst.

6 6 rce [ /MWh] Hour Energy [MWh] Hour-9 Fg. 6. Nordc mert order lst for hour 8 and 9 n the mornng However, congeston between the areas occurs, resultng n dfferent zonal prces as shown n Table III. TABE III. ZONA RICES IN HOUR 8 AND 9 [ /MWH] Area rce [ /MWh] Hour 8 Hour 9 SW (Sweden) NO (South of Norway) NO2 (Md Norway) NO3 (North of Norway) FI (Fnland) E-DK (Eastern Denmark) However, before we consder what happens n the Regulaton ower Market, t s necessary to do a redspatch to releve ntra-zonal congeston. Ths results n the dspatch and prces gven n Table IV. TABE IV. MARINA COSTS AFTER COUNTER TRADIN IN HOURS 8 AND 9 [ /MWH] Hour 8 Hour 9 Zone en. # power rce [ /MWh] power rce [ /MWh] SW NO NO NO FI E-DK Note that the dspatch for the zone SW (Sweden) s almost the same for both hours, because the load s very smlar and there s congeston to areas wth lower costs, cf. Table V. TABE V. OWER EXCHANE BETWEEN AREA RICIN From To Capacty ower exchange Hour 8 Hour 9 NO SW NO2 NO NO2 SW NO3 NO NO3 SW SW FI SW E-DK The grd losses are bought n the spot market by the respectve TSOs and pad for by the market partcpants through the grd tarffs. A weekly updated pont tarff s based on average losses durng day and nght perods respectvely, and can be vewed as a coarse approxmaton to M. B. Actvaton of reserves based on mert order lst We approach the present practce of regulaton by usng the cheapest generator on the Nordc mert order lst, whenever that s possble wthout causng congeston. The results are shown n the table below. Case # Devaton TABE VI. RESUTS OF MANUA REUATION Bus # en # roducton Regulaton rce [ /MWh] Cost [ ] C. Smulaton results usng IDC-OF model appled n the Nordc system We now use the algorthm descrbed n Secton II to fnd the optmal regulaton for each of the four cases. Table VII shows the dspatch of the actvated regulatng reserves. It can be seen from the table that nstead of large steps at one or two generators, the regulaton s spread wth partally small steps on several generators. To some extent ths s caused by congeston, but also by the fact that losses are taken nto account. As t s shown n the table, n the frst case the actvated reserve s lower than the devaton, whch means that ths dspatch pattern decreases the total system losses and the requred reserve wll become lower.

7 7 TABE VII..OTIMA REUATION RESUTS en. # Case Case 2 Case 3 Case Sum rces are lsted n Table VIII at the buses where the reserve resources have been actvated. TABE VIII. RICES AT ENERATION AND CONSUMTION BUSES [ /MWh] en. # Case Case 2 Case 3 Case The TSO s cost n dfferent cases s compared wth the current stuaton of the market based on mert order lst and presented n Table IX. TABE IX. TSO COSTS COMARISON IN THE DIFFERENT METHOD OF RESERVE ACTIVATION (IDC-OF AND MERIT ORDER IST) Case # TSO cost [ ] IDC-OF Mert order lst Dfference [ ] The results n the table ndcate that the IDC-OF algorthm wll dspatch the reserve more effcently than the mert order lst method and ths could result n sgnfcant cost reductons n the long-term runnng of the system. D. Dscusson In the present market soluton, the cost of losses and congeston s not explctly consdered n the market. Usng some examples of the regulaton of moderate devatons, t s shown that an optmzaton model usng an IDC-OF algorthm takng nto account the losses results n a lower cost of regulaton. Instead of usng one or a few generators for the regulaton, the optmal procedure n our examples uses four to sx generators n the optmal soluton. Two ssues must be dscussed n ths context. Frstly, wth today s manual dspatch of tertary reserves t would not be possble to change the setpont of many generators at the same tme. The proposed soluton would requre the use of secondary control based Automatc eneraton Control to be feasble. Ths s presently dscussed because system operaton wth the exstng procedures becomes more and more challengng. Secondly, there s the ssue of prcng n the Regulaton ower Market. Today all actvated generators get pad the margnal prce for regulaton n the actual hour, whle all Balance Responsble artes pay the same margnal prce for ther mbalances. There may be dfferent prces between the zones f congeston lmts the use of Regulaton ower on a system wde bass. The use of OF n the RM n prncple results n ocaton Margnal rces for Regulaton ower (but note that zonal prces n the day ahead market can stll be used). However market partcpants wll probably be reluctant to accept M because t ncreases the uncertanty they face. Other alternatves are possble, but they are n prncple sub optmal (because dfferent market partcpants face dfferent prces). Dfferences between prces pad to the provders of regulaton and prces pad for mbalances also affect the revenues and costs of the TSO, whch should be carefully analyzed. V. CONCUDIN REMARKS Regulaton of mbalances n the Nordc market today s done on the bass of a system wde mert order lst for up- or downward regulaton usng manual tertary control. Congeston s manly handled on the bass of operator experence. Because of ths and the fact that tertary control s used, regulaton s clearly not optmal, even though system wde mert order lst s used. Ths s partly because congeston s not handled n an optmal way, partly because large regulaton steps are taken on a few generators and partly because losses are not taken nto account. We propose a method based on Incremental DC-OF (IDC- OF), based on an optmal redspatch after a devaton. The model s tested on postve and negatve devatons occurrng n the load centres and the results show a decrease n costs. The mplementaton of the proposed method requres the ntroducton of secondary control usng Automatc eneraton Control, because the present manual tertary control cannot handle the many small adjustments that are result from the proposed method. It s also mportant to evaluate prcng optons, because the ntroducton of M n the Regulaton ower Market probably wll be unacceptable for market partcpants. Further work wll focus on the mplementaton of the method n a framework of Stepwse ower Flow to smulate the contnuous operaton of the market and to analyze the effect of the exchange of balancng servces wth Contnental Europe.

8 8 VI. REFERENCES [] olcy : oad-frequency Control and erformance-fnal verson, Operaton Handbook, olces, ENTSO-E, [Onlne]. Avalable on: [2] Inqury pursuant to Artcle 7 of Regulaton (EC) No /2003 nto the European gas and electrcty sectors (Fnal Report), COM(2006)85, 0 January 2007 [Onlne]. Avalable on: [3] Harmonsaton of Balance Regulaton n the Nordc Countres, Entsoe- Nordc-market-report, December 2008, [Onlne]. Avalable on: [4] Descrpton of Balance Regulaton n the Nordc Countres, entsoe- Nordc-market-report, March 2008, [Onlne]. Avalable on: [5] A. J. Wood and B. F. Wollenberg, ower eneraton Operaton and Control. New York: Wley, 996. [6]. u and A. Zoban, The mportance of margnal loss prcng n an RTO envronment, The Electrcty Journal, vol. 5, no. 8, pp Oct [7] F., R. Bo, DCOF-Based M smulaton: algorthm, comparson wth ACOF, and senstvty, IEEE Trans. ower Syst., Vol. 22, no. 4, pp , Nov [8] O. B. Fosso, Hydro schedulng wth transmsson transfer lmtatons n a lberalzed power market, TRA6890, SINTEF Energy Reaserch, November [9] Nordc Annual statstcs 2008 [Onlne], avalable [0] M. Korpås,. Warland, J. O.. Tande, K. Uhlen, K. urchala, and, S. Wagemans, rd modellng and power system data, TradeWnd report D3.2, Dec. 2007, [Onlne]. Avalable: [] B. H. Bakken, Techncal and economc aspects of operaton of thermal and hydro power system, h.d. dssertaton, Dept. Electrc ower Eng., Norwegan Unversty of Scence and Technology, Trondhem, Norway, 997. [2] Stefan Jaehnert, Hossen Farahmand, erard Doorman, Modellng of prces usng the volume n the Norwegan regulatng power market, presented at IEEE Bucharest owertech, 28 June 2 July 2009 [3] Ove Wolfgang, Arne Haugstad, Brger Mo, Anders jelsvk, Ivar Wangensteen, erard Doorman, Hydro reservor handlng n Norway before and after deregulaton, Energy, v 34, n 0, p , October management. From 992, he was wth SINTEF Energy Research, Trondhem, workng wth hydropower optmzaton and deregulaton ssues. resently, he s a rofessor n electrc power systems at NTNU. Olav Bjarte Fosso graduated from The Department of Electrcal Engneerng, the Norwegan nsttute of Technology, Trondhem, Norway wth the M.Sc. n 985, and receved hs h.d. n electrcal engneerng at the same nsttute n 989. From 989 to 2002 he has been wth SINTEF Energy Research except for an employment n 997/998 at owel (a company provdng decson support tools n a deregulated market envronment). A man responsblty at SINTEF Energy Research has been development of tools for analyss and decson support n transmsson and power producton systems. Snce March 2002, he holds a full-tme professor poston at the Norwegan Unversty of Scence and Technology (NTNU) and a part-tme poston at SINTEF Energy Research as Scentfc Advsor. VII. BIORAHIES Hossen Farahmand was born n Iran, on September 6, 979. He receved both B.Sc. and M.Sc. n electrcal engneerng n 2002 and 2005 respectvely. He s currently pursung the h.d. degree at the Department of Electrc ower Engneerng, Norwegan Unversty of Scence and Technology (NTNU), Trondhem, Norway. Hs area of research nterest s the ntegraton and operaton of multnatonal balancng markets. Seyed Mohammad Al Hossen was born n Iran, on August 04, 983. He receved both B.Sc. and M.Sc. n electrcal power engneerng n 2005 and 2008 respectvely. Currently he s pursung the h.d. degree n the area of power system analyses and transmsson plannng n a compettve envronment at the Department of Electrc ower Engneerng, Norwegan Unversty of Scence and Technology (NTNU), Trondhem, Norway. erard. Doorman (M 99) receved the M.Sc. degree n electrcal engneerng from the Norwegan Insttute of Technology (NTH), Trondhem, Norway, n 98 and the h.d. degree from the Norwegan Unversty of Scence and Technology (NTNU, formerly NTH) n He started hs career as a research scentst at EFI. ater, he worked wth a power company wth hydropower optmzaton and as a consultant, among others, wth demand-sde