HVDC for Beginners
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HVDC
begies be
PIONEER PIONE ERING ING HVDC SINCE SINC E 1962 1962 ou ieie
Staord UK
FranCe
USa
Germany
19 6 2
19 6 8
19 8 9
Egish Eecic
GEC
GEC ash
1996
19 9 8
2004
alStom arEVa
CGEE - ash
GE
aEG (“Ge HVdC Wkig Wkig Gup”; aEG, aEG , BBC, Siees)
HVDC or beginners and beyond (C) Copyright AREVA T&D UK Limited, September 2009
PIONEER PIONE ERING ING HVDC SINCE SINC E 1962 1962 ou ieie
Staord UK
FranCe
USa
Germany
19 6 2
19 6 8
19 8 9
Egish Eecic
GEC
GEC ash
1996
19 9 8
2004
alStom arEVa
CGEE - ash
GE
aEG (“Ge HVdC Wkig Wkig Gup”; aEG, aEG , BBC, Siees)
HVDC or beginners and beyond (C) Copyright AREVA T&D UK Limited, September 2009
PREFACE this bke’s ces is iee gp i he vibe ieue bewee he ve bsic iuc ei gee vibe suppies he e ceic sis HVdC pesee i ex bks. this bke is heee ie hse wh wish gi bee uesig he cpex sses which e w ig ieg p pwe sissi i he w , e which wi icese. I ece es he echg HVdC sissi usig pwe siss kw s ‘Vge Suce Cvee’ (VSC) hs bee iuce i he ke. Whis shig se ci wih lie Cue Cvee (lCC) HVdC i es he schus ue he iececi he bees i c big he aC sse he echg ies i seve ws. I e vi cusi wih VSC echg his bke cuses lCC HVdC . the s hee chpes he bke pvie iuc veview he subjec lCC HVdC, cveig usge, usge , cguis bsic peig picipes. Chpe 4 cis e eie exii he i equipe HVdC cvee si chpe 5 iscusses he u his equipe wihi he cvee si. Chpes 6 7 eview he pei HVdC cvee is c. Chpe 8 pvies iuci ‘s ic chceisics’ iuces he ccep supepsii aC quiies he chceisics. a ip esig csiei csiei lCC HVdC schee ees he ecive pwe ig h HVdC cvee si s i ipses he ewk which i is cece his is eviewe i chpes 9 hugh 13.
Chpes 14 22 pvie expi he cuses, eecs iigi ehs eig cvee geee hics, bh aC dC. a e eie eview he c ciiies vibe s s lCC HVdC schee e iuce i chpe 23, whis chpes 24, 25 26 pvie e eie echic iscussi egig HVdC cvee vves, vve cig ses. as HVdC ceci wi ws be sigic eee wihi pwe sse is pece i es eibii, vibii sses e ip csieis hese cceps e iuce i chpes 27 28. Speci csiei hs s bee give hse i ius wh be i he psii hvig pepe specici HVdC cvee schee. Seci 29 pvies escipi he iiu suies pee s p u-ke HVdC pjec. aii, appeix is icue he e his bke which ieies he eee buge qui, h eee eeig he eiig equie uig cc. the use i he cei his bke hs ce egiees wihi arEVa t&d UK PES he I geu. a es e ie. Carl Barker
Chie Engineer, Systems
Chpe tie
1
InTrODUCTIOn TO HVDC
2
HVDC COnFIGUraTIOnS
3
WHaT IS HVDC?
4
a TOUr arOUnD THe SInGLe LIne DIaGram (SLD) OF One enD OF a HVDC BIPOLe COnVerTer
5
STaTIOn LayOUT
6
HOW DOeS a LIne COmmUTaTeD COnVerTer WOrK
7
COnTrOL OF a HVDC LInK
8
STaTIC CHaraCTerISTICS
9
reaCTIVe POWer In aC SySTemS
10
THe reaCTIVe POWer LOaD OF a COnVerTer
11
reaCTIVe POWer SOUrCeS WITHIn a COnVerTer STaTIOn
12
COnTrOLLInG COnVerTer reaCTIVe POWer
13
VOLTaGe STeP CHanGeS
14
eFFeCTS OF HarmOnICS In aC POWer SySTemS
15
SOUrCeS OF HarmOnICS In aC POWer SySTemS
16
HOW COnVerTerS CaUSe HarmOnICS
17
PULSe nUmB er anD HarmOnIC CanCeLLaTIOn
18
DC HarmOnICS
19
CHaraCTerISTIC anD nOn CHaraCTerISTIC HarmOnICS
20
HarmOnIC FILTer DeSIGn, TyPeS OF FILTerS
21
aC HarmOnIC PerFOrmanCe anD raTInG CaLCULaTIOnS
22
DC HarmOnIC PerFOrmanCe anD raTInG CaLCULaTIOnS
23
COnTrOL FaCILITIeS PrOVIDeD By HVDC SCHemeS
24
HVDC THyrISTOr VaLVeS
25
THyrISTOr VaLVe COOLInG CIrCUIT
26
HVDC COnVerTer TranSFOrmerS anD THeIr COnFIGUraTIOnS
27
reLIaBILITy anD aVaILaBILITy OF a HVDC COnVerTer
28
LOSSeS In a COnVerTer STaTIOn
29
COnTraCT STaGe STUDIeS FOr a HVDC COnTraCT
30
reFerenCeS
31
aPPenDIX – DaTa reQUIremenTS FOr a HVDC SCHeme
Pge
6 7 10 13 19 23 28 30 33 34 36 37 38 39 40 41 42 45 46 48 52 55 57 61 63 65 67 68 69 83 84
6 or BEGInnErS and BEyond HVDC
1 INTRODUCTION TO HVDC Eecic pwe is geee s eig cue (aC). I is s sie isibue s aC , p cei ci iusi ives pcesses, i is csue s aC. I cicusces, hweve, i is ecic echic vgeus iuce iec cue (dC) iks i he eecic supp sse. I picu siuis, i be he esibe eh pwe sissi. Whe w aC sses c be schize whe he isce b cbe is g sbe / ecic aC sissi, dC sissi is use. a e “cvee si” he aC is cvee dC, which is he sie sec cvee si, cvee bck aC, e i he eecic ewk. I “bck--bck” HVdC schees he w cvee sis e bugh ue he se , eucig he dC sissi egh ze. HVdC sissi ppicis i u b cegies schee usu ivves cbii w e hese. the cegies e: i) tsissi buk pwe whee aC wu be uecic, ipcicbe subjec evie esicis. ii) Iececi bewee sses which pee iee equecies, bewee schize ise sses which, hugh he hve he se i equec, c be pee eib i schis. iii) aii pwe iee wihu sigic icesig he sh cicui eve he eceivig aC sse. iv) Ipvee aC sse pece b he s ccue c HVdC pwe.
7 or BEGInnErS and BEyond HVDC
2 HVDC CONFIGURATIONS 2.1
Monopolar HVDC Systems
mp HVdC sses hve eihe gu eu eic eu. A Monopolar HVDC System with Ground Return
Figure 2.1: Monopolar HVDC System with Ground Return
csiss e e six-puse cvee uis i seies pe ech e, sige cuc eu hugh he eh se, s shw i igue 2.1. I c be cs-eecive sui HVdC cbe sissi / he s sge bip schee [1]. a ech e he ie, i equies eece ie gu se eece bui ciuus pei. A Monopolar HVDC System with Metallic Return
usu csiss e high-vge e eiuvge cuc s shw i igue 2.2. a p cgui is use eihe s he s sge bip schee, viig gu cues, whe csuci eece ies gu eeces esus i uecic sui ue sh isce high vue eh esisivi. 2.2 igue 2.2: mp HVdC Sse wih meic reu
Bipolar HVDC Systems
a Bip HVdC Sse csiss w pes, ech which icues e e weve-puse cvee uis, i seies pe. thee e w cucs, e wih psiive he he wih egive pi gu pwe fw i e ieci. pwe fw i he he ieci, he w cucs evese hei piies. a Bipe sse is cbii w p schees wih gu eu, s shw i igue 2.3 [2]. Wih bh pes i pei, he ibce cue fw i he gu ph c be he ve w vue.
8 or BEGInnErS and BEyond HVDC
this is ve c gee wih he wig pei cpbiiies: •
•
Figure 2.3: Bipolar HVDC System
•
•
•
•
2.3
Figure 2.4: Bipolar System with Monopolar Metallic Return or Pole Outage
duig uge e pe, he he cu be pee ciuus wih gu eu. pe uge, i cse g-e gu cue fw is uesibe, he bip sse cu be pee i p eic eu e, i pppie dC gees e pvie, s shw i igue 2.4. tse he cue he eic ph bck wihu ieupi equies meic reu tse Beke (mrtB) he speci-pupse swichge i he gu ph e ei. Whe sh ieupi pwe fw is peie, such beke is ecess. duig iece gu eeces eece ies, pei is pssibe wih ceci eus he guig gi he eis, wih he ibce cue bewee he w pes he ve w vue. Whe e pe c be pee wih u cue, he w pes he bip schee cu be pee wih iee cues, s g s bh gu eeces e cece. I cse pi ge dC ie isui, e bh pes cu be ciuus pee euce vge. I pce gu eu, hi cuc c be e e--e. this cuc cies ubce cues uig bip pei seves s he eu ph whe pe is u sevice. Back-to-Back HVDC Links
Bck--bck HVdC iks e speci cses p HVdC iececis, whee hee is dC sissi ie bh cvees e ce he se sie. ecic ess ech cvee is usu weve-puse
9 or BEGInnErS and BEyond HVDC
cvee ui, he vves bh cvees be ce i e vve h. the c sse, cig equipe uxii sse be iege i cguis c he w cvees. dC es e equie, e eeces eece ies, he eu ceci beig e wihi he vve h. I is ip e h arEVa t&d hs evepe sui bck--bck HVdC ik which es equie shig ec, hece, hee is exe dC isui [3]. igue 2.5 shws w iee cicui cguis use b arEVa t&d bck--bck HVdC iks.
Figure 2.5: Back-to-Back DC Circuits
Gee, bck--bck HVdC ik, he dC vge ig is w he his vve cue ig is high i cpis wih HVdC iececis vi vehe ies cbes. the es is h vve css e uch e vge-epee, s he highe he vge he gee he ube hiss. a w vge ei wiig c be bui i he cvee se he aC es cpesi [4]. Se ecive pwe swichig seps c hus be chieve. a ge bck--bck HVdC sse c cpise w e iepee iks s h he ss e cvee ui wi cuse ss u pwe cpbii.
Sasaram 500 MW Back-to-Back Converter Station
10 or BEGInnErS and BEyond HVDC
3 WHAT IS HVDC? a sipe epesei HVdC iececi is shw i igue 3.1. aC pwe is e cvee peig s ecie. the upu his ecie is dC pwe, which is iepee he aC supp equec phse. the dC pwe is sie hugh cuci eiu; be i vehe ie, cbe sh egh busb ppie he dC eis sec cvee. this sec cvee is pee s ie-cue ivee ws he dC pwe fw i he eceivig aC ewk.
Figure 3.1: Basic HVDC Transmission
Figure 3.2: The Gating and Commutation o a Thyristor
Cvei HVdC sissi uiizes ie-cue his echg. igue 3.2 shws sipe his cicui. Whe ge puse (i g) is ppie whie psiive w vge is ipse bewee he e che (Vh), he his wi cuc cue (i l). Cuci ciues wihu uhe ge puses s g s cue fws i he w ieci. this “u-” kes pce whe he cue ies evese. Hece, his cvee equies exisig eig aC vge (Vc) i e pee s ivee. this is wh he his-bse cvee pg use i HVdC is kw s ie-cue cvee (lCC).
11 or BEGInnErS and BEyond HVDC
H400 8.5 kV, 125 mm Thyristor valves
HV converter transormers 400 kV / 380 MVA at Al Fadhili
GCCIA HV switchyard at Al Fadhili
12 or BEGInnErS and BEyond HVDC
Figure 4.1: Typical SLD or a Bipole HVDC Converter
13 or BEGInnErS and BEyond HVDC
4 A LOOK AT THE SINGLE LINE DIAGRAM (SLD) OF ONE END OF A HVDC BIPOLE CONVERTER AC System
Converter
Filter
Filter
Figure 4.2 (a) Single busbar
Converter
Converter
AC System
Filter
Filter
Figure 4.2 (b) Single busbar with separate converter breaker
igue 4.1 (ppsie) shws pic Sld e e bipe vehe sissi ie HVdC cvee si. the wig iscussi eviews he j cpes which ke up he cvee si. 4.1
AC Switchyard
the aC sse cecs HVdC cvee si vi “cvee bus”, which is sip he aC busb which he cvee is cece. the aC ceci(s), he HVdC ceci(s) g wih cecis aC hic es he pssibe s such s uxii supp se, ii ecive pwe equipe, ec., c be ge i seve ws ice b: eibii/euc equiees, peci eeig equiees, he ube sepe swichbe cvees c pcice i aC subsi esig. igue 4.2 shws seeci aC ceci gees h c be use i HVdC cvee sis sig wih () sipe, sige, 3-phse busb wih e swichbe ceci he aC sse he swichbe aC hic es cece iec i. I such gee i is pssibe use he aC hic es ecive pwe supp he aC sse wihu hvig he cvee eegize (s he aC sse ceci is c). igue 4.2(b) shws schee cpizig w cvees icues ii cicui beke eice ech cvee. I his gee he aC hic es c be use aC ecive pwe supp wihu eegizig he cvee. Hweve, i c wih igue 4.2(), busb u wi esu i he cpee uge he cvee si. t pvie se ii euc ube busb gee c be use s shw i igue 4.2(c). I igue 4.2(c) aC busb uge wi esu i hse s cece h busb beig iscece ui he iscecs c be ge e-cec he he eiig, “heh” busb. discec egee wi pic ke i he e e secs cpee i se cicusces such uge be ccepbe, hece he gee shw i igue 4.2() c be use, whee ech is cece vi eice cicui beke ech busb, wig s isceci ececi i he eve
14 or BEGInnErS and BEyond HVDC
Converter
Converter AC System
ss busb (pic u 300 s). a isvge he gee shw i igue 4.2() is he ge ube aC cicui bekes equie. I e euce he ube cicui bekes, he gee shw i igue 4.2(e) c be use. I igue 4.2(e) w s c be iiviu swiche bewee w hee-phse busbs vi hee cicui bekes, hece, his cgui is c kw s “beke---h” gee. m he gees aC swich cgui exis hve bee use i sscii wih exisig HVdC schees.
Filter
4.2 Filter
Figure 4.2 (c) A double busbar
AC Harmonic Filters
Cvee pei esus i bh he geei aC cue hics he bspi ecive pwe. I e ii he ipc hese aC hic cues he bsbe ecive pwe, he cvee si icues shu cece swichbe aC hic es, eihe cece iec he cvee busb cece “e busb” which, i-u, is cece he cvee busb. the aC hic es e uic swiche- wih cvei aC cicui bekes whe he e eee ee hic pece ecive pwe pece iis. the aC hic es e pic cpse high vge cece cpci bk i seies wih eiu vge cicui cpizig i-ce i-isue ecs, esiss cpci bks. these cpes e seece pvie he equie pece he aC hic e esue h he e is eque e. 4.3
High Frequency Filter
the cvee pei wi esu i he geei ve high-equec ieeece which wi ppge u i he aC sse he cvee bus. Whis he giue equec his ieeece is e ipce he se pei he aC sse, hee e se isces whee his high-equec ieeece be uesibe, i picu whe he aC sse uses Pwe lie Cie (PlC) sigig. PlC sigig is sse which sis cuici sig s piue-ue sig, supeipse he ue equec vge sig aC pwe sse. this sse is use, i se pwe sses, s cuici sse bewee aC sse peci evices. Hweve, he high-equec ieeece geee b cvee pei c vep wih he equecies use PlC cuicis (pic i he ge 40 kHz 500 kHz). theee, i is seies ecess icue High equec (H) e ( PlC e) i he ceci bewee
15 or BEGInnErS and BEyond HVDC
he cvee bus he cvee i e ii he ieeece h c ppge i he aC sse. Converter
as wih he aC hic e, he H e cpises high vge cece cpci bk, i-ce i-isue ec ii w vge cicui cpse cpcis, ecs esiss which e eee s uig pck. 4.4
Converter Transormer
Converter
AC System
Filter
Filter
the cvee se is he iece bewee he aC sse he his vves. tpic he HVdC cvee se is subjece dC vge isui sess s we s he aC vge sess expeiece b pwe se. these aC dC sesses e ue iee. the aC vge sess is pei i he isuig i ee b he gee peiivi he eis, whis he dC sess is gvee b he esisivi he isuig eis which, i u, v wih peig ciis. I ii, i is ip h he cvee se be he esige ke i csiei bh he ue equec he aC hic cues h wi fw he cvee hugh he cvee se he aC hic es. tpic, he cvee se is ge s ehe s-ie wiig fig-s e sec wiigs. thee is - pchge he ie wiig. 4.5
Figure 4.2 (d) A double bus, double breaker
Converter
the cvee pvies he si aC dC dC aC s equie. the bsic buiig bck he cvee is he six-puse bige; hweve, s HVdC cvees e cece s weve-puse biges. the weve-puse bige is cpse 12 “vves” ech which ci seies-cece hiss i e chieve he dC ig he HVdC schee. HVdC pwe sissi schee, he vves sscie wih ech weve-puse bige e cie wihi pupse bui buiig kw s “vve h”. bck--bck schees, whee bh he seig eceivig e he HVdC ik e ce he se sie, i is pic he vves sscie wih bh es he ik be ce wihi he se vve h.
16 or BEGInnErS and BEyond HVDC
4.6
DC Smoothing Reactor
dC shig ecs e equie pwe sissi schees; he e equie arEVa bck--bck schees. AC System
Filter
Filter
Converter
Figure 4.2 (e) A breaker-and-a-hal
HVdC sissi schee, he dC shig ec pvies ube ucis bu picip i is use : ) euce he dC cue ippe he vehe sissi ie cbe b) euce he xiu pei u cue h cu fw he dC sissi cicui i cvee u c) i he dC sie esces he schee equecies h e uipes he ue aC equec ) pec he his vve s sies igiig he dC sissi ie ( expe ighig sike) the dC shig ec is ge i-ce i-isue ec is picip ce he high vge ei he HVdC cvee schees e , bew, 500 kVdC. abve 500 kV, he dC shig ec is c spi bewee he high vge eu eis. 4.7
DC Filter
Cvee pei esus i vge hics beig geee he dC eis he cvee, h is, hee e siusi aC hic cpes supeipse he dC ei vge. this aC hic cpe vge wi esu i aC hic cue fw i he dC cicui he e geee b his aC hic cue fw c ik wih jce cucs, such s pe-wie eecuici sses, iuce hic cue fw i hese he cicuis. I bck--bck schee, hese hics e cie wihi he vve h wih eque shieig , wih cbe schee, he cbe scee pic pvies eque shieig. Hweve, wih pe-wie dC sissi i be ecess pvie dC es ii he u hic cue fwig i he dC ie. the dC e is phsic sii aC e i h i is cece he high vge pei vi cpci bk; he cpcis g wih ecs esiss e he cece he high vge cpci bk i e pvie he esie uig pig. 4.8
DC Switchgear
Swichge he dC sie he cvee is pic iie iscecs eh swiches schee ecgui se iece pei.
17 or BEGInnErS and BEyond HVDC
Ieupi u eves is e b he ce ci he cvee heee, wih he excepi he nBS, es equie swichge wih cue ieupi cpbii. Whee e h e HVdC Pe she c sissi cuc (pic he eu) i is vgeus be be cue he dC cue bewee sissi phs wihu ieupig he dC pwe fw. igue 4.1 shws pic Sige lie dig (Sld) HVdC sissi schee uiizig dC sie swichge se he dC cue bewee iee phs whis . the wig swiches c be ieie igue 4.1. nBGS - nutl Bus Goud Switch
this swich is pe bu whe cse i si cecs he cvee eu he si eh . opei wih his swich c be iie i he cvee c be pee i bipe e wih bce cues bewee he pes, h is, he dC cue eh is ve s. the swich is s be pe, cuig s dC ubce cue u he swich i he dC cicui. nBS
- nutl Bus Switch
a nBS is i seies wih he eu ceci ech pe. I he eve eh u e pe, h pe wi be bcke. Hweve, he pe eiig i sevice wi ciue ee dC cue i he u vi he c eu ceci. the nBS is use ive he dC cue w he bcke pe gu. GrTS - Goud rtu Tsf Switch
the ceci bewee he HVdC cuc he eu pi icues bh high vge iscec GrtS is use s p he swichig pei cgue he HVdC schee s eihe gu eu pe eic eu pe. the iscec is iie pe i he HV cuc is eegize i e ise he eiu vge GrtS he high vge. the GrtS is cse, wig he csig he iscec i e pu he HV cuc i pe wih he eh ph. the GrtS is s use cue he cue he HV cuc seig he ph he eh ( gu eu) ph. oce cue fw hugh he HV cuc is eece s hvig sppe, he iscec c be pee, wig he HV cuc be eeegize high vge.
18 or BEGInnErS and BEyond HVDC
mrTB - mtllic rtu Tsf Bk
the mrtB is use i cjuci wih he GrtS cue he dC cue bewee he eh (gu eu) pe, hewise uuse, HV cuc (eic eu). the mrtB cses i e pu he w ipece eh eu ph i pe wih he eic eu ph. the mrtB us s be be pe, cusig cue fwig hugh he eh eu cue i he uch highe ipece eic eu ph. 4.9
DC Transducers
dC cece suces i w pes, hse esuig he dC vge he schee hse esuig he dC cue. dC vge esuee is e b eihe esisive dC vge ivi e pic vge ivie. the esisive vge ivie cpises seies cece esiss vge esuee c be ke css w vge e esis which wi be ppi he dC vge ppie css he whe esisive ivie sseb. opic vge suces eec he segh he eecic e u busb wih he use Pcke ces. dC cue esuee bh c peci equies eecic pcessig sse. mesuee c be chieve b geeig geic e wihi esuig he which is sucie cce he geic e u busb hugh he esuig he. the cue equie geee he geic e i he esuig he is he ppi he cu cue fwig hugh he busb. devices usig his eh e c kw s Ze ux Cue tsuce (ZCt). opic cue esuee kes use , gs hes, he eec i which he phse pic sig i be pic cbe is ifuece b he geic e busb u which he cbe is wu. B esuig he phse chge bewee he geee sig he sig efece bck he busb, he giue he cue c be u.
19 or BEGInnErS and BEyond HVDC
5 STATION LAYOUT the cvee si is spi i w es: •
•
the aC swich which icpes he aC hic es H es the “cvee is” which icpes he vve h(s), he c sevices buiig, he cvee ses he dC swich
a expe cvee si u icuig he aC swich he cvee is is shw i igue 5.1 wih he cu sie shw i igue 5.2. 5.1
Figure 5.2: Lindome, Sweden, Converter Station; Part o the 380 MW KontiSkan HVDC Interconnection
AC Switchyard
as wih aC swich, he cpexi heee he spce ccupie vies, epee up he u bh eees c-swiche eees be iecece. HVdC cvee si, he aC swich be p j e he gi heee hee be uipici eees, ech wih is sscie wes, ie e ecs, sep-up/w ses, ec. Cvese, he cvee si cu be ce he peiphe he ewk heee hee be e w eees gsie he cvee equipe. I bh cses, hweve, he spce ccupie b hese aC cecis wi be pppie he aC vge eve(s). tpic, he i HVdC cvee sscie cpes ce i he aC swich e he aC hic es. these cpise gu-eve ue cpes ce wihi ece- cpu. Cpu ccess is pssibe ce he es hve bee ise ehe. High equec e cpes, g wih suge eses, aC cicui bekes, iscecs eh swiches e usu ue sucues w wk-u ccess whie he equipe is ive. 5.2
Converter Island
I e HVdC cvee sis, he his vves e s ws ce is i pupse bui ecsue kw s vve h. this ecsue pvies ce, ce evie i which he his vves c se pee wihu he isk expsue pui u ciis.
20 or BEGInnErS and BEyond HVDC
Figure 5.1: Lindome, Sweden, Converter Station Layout; Part o the 380 MW KontiSkan HVDC Interconnection
420 kV AC busbars 285 kV DC lines Converter Transformers AC filters DC filters
Outdoor Valve Cooling System
Thyristor Valves Valve Cooling System
Control Building
H400 Thyristor Valves
Converter Transormers
Smoothing Reactor
AC Filters
21 or BEGInnErS and BEyond HVDC
Wihi he vve h, he his vves e pic suspee he he buiig wih he w vge beig cses he he high vge beig he wes pi he vve. a i gp bewee he b he vve he vve h f pvies he high vge isui. the vve h hs ie e scee cveig ws , he he f. this scee cees cge i e ci he eecgeic ieeece geee b he his vve pei. the iegi his scee is pic iie b hvig he vve ceci sie cvee se bushigs puig i he vve h cecig he bushig ues he buiig scee. the dC swich vies wie i cpexi phsic gee bewee pjecs. u dC es, he ji he equipe (iscecs, eh swiches, suces, ec.) is pic ue sucues cee wk-u e wih he dC e, i pese, gu ue wihi ece- e. Hweve, whee su shieig is equie u he dC ec, his be gu ue wih he su shieig i he sepe ws ecsue, s ig he se bie. Whe he dC e is ce is, i is e c hve he ji he equipe ue gu eve i e vi excessive heigh equiee he buiig. I such cicusces, ccess he whe, ps , he dC e is ce b ece- ecsue. the c sevices buiig is s ce he cvee is. this buiig gee cis equipe s such s: • • • • • •
5.3
C Cig p auxii suppies isibui Beies Wkshp oces Acoustic Noise
Ivib hee e equiees esuig c evie ues ee he cusic ise subsi ( he iusi sie) c geee eihe is bu he ees ppe. much he equipe i HVdC cvee si geees cusic ise whe peig heee ceu csiei is equie i es equipe u i e iiize he cusic ise he pi esuee.
22 or BEGInnErS and BEyond HVDC
tpic cusic ise suces wihi cvee si (esue s su pwe (P ω)) e: • • • • • •
dC shig ec (110 B(a) su pwe) Cvee se (105 B(a) su pwe) Vve cig (i bs ces) (100 B(a) su pwe) aC hic e ec (100 B(a) su pwe) tse cig (105 B(a) su pwe) aC hic e cpcis (80 B(a) su pwe)
as ppxii, he cusic ise su pessue (l ω(a)) iiviu pi suce, isce ‘χ’ he cpe is ccue s ws: lω(χ) = Pω - 20 x lg10 χ - 8 whee, lω(χ) = he su pessue isce χ (i ees). Pω = he cusic su pwe he pi suce (B(a)). χ = he isce he pi suce which he su pessue is be ccue (i ees). I e ee he bu, ees esiece, cusic ise ii, i be ecess cusic ise bies i he equipe ise. the bies ke he ws ecsues.
23 or BEGInnErS and BEyond HVDC
6 HOW DOES A LINE COMMUTATED CONVERTER WORK? 6.1
Six-Pulse Diode Converter Bridge
Six-puse cvees e he buiig bck HVdC sses. a expe six-puse cvee, which eps ies, is shw i igue 6.1. dies cuc i he sequece 1,2,3,4,5,6, s he siis bewee e ie he ex ccu ee i he uppe we h-biges. Ech ie cucs 120°, i eve 360° cce, s h he successive cucig pis ies e 1 2, 2 3, 3 4, 4 5, 5 6, 6 1.
Figure 6.1: Six-Pulse Converter
1
3
Vc
Va
Vd
Vb
2
Figure 6.2: Current Switching Pattern o a Six-Pulse Converter
the cucig pi is ws h pi ies which hve he ges iseus aC vge bewee he. the he ie pis e cece iseus se vge hece e subjece evese vge css hei eis. as ie psses, he eive piues he cvee’s hee aC supp phses (vve-wiig vges) chge, s i igue 6.2 he vge B-C beces gee h he vge a-C vve 3 kes ve he cue which h bee fwig i vve 1. this pcess is kw s “cui”. I his ieizi, he e iec vge, V, eeges s xe vue, eeie eie b he se i, he ccui which is shw i igue 6.3. this vue is kw s he “n-l dC Vge”, Vi, he cvee. 6.2
Commutation
I pcice, he se cue e ie he ex equies ie ie, sice he cue se is swe w b he cui ecce (e up ecce i he cvee se, he his vve
24 or BEGInnErS and BEyond HVDC
√2.EL(RMS)
+π/6 Vdio = 1 π/3
√2.EL cos wt d(wt)
-π/6 +π/6
Vdio = 3√2.EL [sin wt]
-π/6
s u i he H eig cicui). this puces ”vep” bewee successive peis cuci i e h he six-puse bige. igue 6.4 shws h he e iec vge (V) hs bee euce cpe igue 6.2. igue 6.4 s shws he vve cue wve uig he cui pcess, whee cue s i e vve, whie he cue ises i he ex vve i sequece. the ie ke cue he cue e vve he ex is ce he “vep ge”, μ.
Vdio = 3√2.EL(RMS) π
-π/6
6.3
wt
+π/6
I his cvee, shw i igue 6.5, i is pssibe v he e iec vge b cig he is which he hiss e ue .
Figure 6.3: The No-Load DC Voltage o a Six-Pulse Bridge
a his is ue (e) b ppig sh puse is ge ei us whe he exe cicui ces is e cue ze. I his cse, cue ze is bugh bu b he cui pcess whe he ex his is e.
1
μ
Thyristor Controlled Converter
3 μ
Vc
Va
Vd
Vb
2
the ig e ge α is ee s he ge bewee he phse vge cssig he vve-wiig vge he is whe he his is e. this is iuse i igue 6.6. this e ge eeies whe he cui pcess wi cece cseque eeies he e iec vge (V ). V is ppi he csie α; i.e. he gee he e ge, he se he e iec vge. Ze vge is eche s α ppches 90°. 6.4
Figure 6.4: Eect o Commutation on Converter Operation
The Inversion Process
B icesig he ig ge, α, be 90°, he vge e he phse--phse vge cece he dC eis vi he cucig hiss wi be pei egive, hece he dC ei vge wi be egive. as, be 90°, he ig ge he cvee beces ge, i is e c ee he “exici ge” “g”, γ. this exici ge epeses he ie bewee he e he vep pei he ie whe he phse vge sscie wih he u-gig vve beces e psiive/egive h h he ex vve
25 or BEGInnErS and BEyond HVDC
i sequece, i is heic expesse s: γ = 180° - µ - α
I us be e h he c he upu vge six-puse bige is chieve b he ig ge, α. the exici ge, γ, is esue he vibe u ie he vve wig he pi i ie whee he vve is e. 6.5
Figure 6.5: Thyristor Converter
1 μ α
3 μ α
Vc
Direct Voltage
Va
Vd
tpic vge wves css vve uig ecici ivesi e shw i igues 6.9 6.10 especive. the “ches” i he wves e cuse whe cui kes pce, becuse cui is cu ep ie--ie sh cicui, ipse b he cvee vves. this es give ise hev u cues hweve, s he is he cue i he vve which hs jus e eches equi wih he i iec cue, he vve which is eiquishig cue us , bekig he cicuig cue ph. 6.6
Vb 2
Figure 6.6: Eect o Firing Angle on Converter Operation
Valve Voltage Waveorm
Twelve-Pulse Bridge Rectifer
Becuse he high pwe eves sscie wih HVdC sissi, i is ip euce he cue hics geee he aC sie he vge ippe puce he dC sie he cvee. this is chieve b es cecig w six-puse bige cicuis i seies he dC sie/pe he aC sie he weve-puse bige cgui (igue 6.11) I igue 6.11 ech he biges is cece he aC ewk b sige-phse hee-wiig se. oe he ses is cece (s/s) y/y he he (s/e) y/ Δ; he Δ is he dC sie. thugh his ceci he biges hve phse ieece 30° i eeig aC pwe. mechic he vves c be gupe i hee pe scks ciig u vves cece i seies.
26 or BEGInnErS and BEyond HVDC
1 6 3
α
2
α
C
C
Vd = 0 A
A
- Vd
B
B
γ
3 1
2
Figure 6.7: Eect o Firing Angle as it Approaches 90°
Figure 6.9: Rectifer Valve Voltage Waveorm (excluding commutation overshoots)
Figure 6.8: Eect o a Firing Angle o 140°
27 or BEGInnErS and BEyond HVDC
Figure 6.10: Inverter Valve Voltage Waveorm (excluding commutation overshoots)
Figure 6.11: Twelve-Pulse Converter
28 or BEGInnErS and BEyond HVDC
7 CONTROL OF A HVDC LINK
Figure 7.1: Inverter control system
Csie igue 7.1, he vge css he ecie is psiive wih espec bh is e ei s we s he eh eeece. the ivee ei is, hweve, geeig egive vge wih espec is e ei bu, s i is cece i evese pe he ecie, is vge wih espec he eh eeece is s psiive. as he ecie vge he ivee vge e iepee ce, he c hve iee vues hece hee wi be vge ieece css he esis i he dC cicui which, s g s he ecie vge is ge h he ivee vge, wi cuse dC cue fw. this c sip be expesse s: I d = V rectife - V Invete r d Ue , se-se pei, he ivee c sse is ge ii he dC vge cei pi he HVdC ik (kw s he “cpuig pi”) ge vue. this ge vue is pic 1.0 pu sissi schee bu bck--bck schees, whee he dC sissi sses c be ige, his vue c be vie pvie uhe egee ecive pwe c. the “cpuig pi” is usu he ecie dC ei hece he ivee us ccue his vge bse he dC vge he ivee eis, he dC cue he kw esisce he sissi cicui (his e qui beig esube b he HVdC ce i eecuicis bewee he ecie he ivee e vibe). the ecie cs he dC cue fwig i he cicui es his b jusig is upu dC vge give cue fw s escibe b he bve equi. thee e ube ws h six-puse cvee c be ce i HVdC ik.
29 or BEGInnErS and BEyond HVDC
ecie he c pis e: •
•
Cs vve wiig vge c – Wih his eh c, he cvee se pchge is use ii he vge ppie he aC eis ech six-puse bige cs ge vue. C he cue is he chieve b vii i cvee peig ge. Cs ig ge ge c – Wih cs vve wiig vge c, he ig ge we pwe sissi eves c be ge. t euce he ge ve which he ig ge c pee i he se se , he cvee se pchge c be use v he ppie aC vge he six-puse bige hece ii he ge ve which he ig ge pees.
ivee he c pis e: • •
•
Cs vve wiig vge c – this is he se s he equive ecie c. Cs g ge ge c – this is sii he ecie “cs ig ge ge c” bu cs he ivee exici ge ise he ig ge. Cs exici ge c (CEa) – Wih his eh c, he ivee dC vge is we v i e chieve cs exici ge wih vig dC cue. the ivee cvee se pchge is use jus he ppie aC ei vge i e ii he dC vge wihi xe, se-se, ge.
30 or BEGInnErS and BEyond HVDC
8 STATIC CHARACTERISTICS the sic chceisics c be csiee s he ceeb cex he cvee s, i he se w s i u uch sehig h wih u h u ve i quick w, wihu he ivvee highe bi ucis, he sic chceisics escibe he w i which he cvee esps sies wihu ivvig highe c ucis.
Figure 8.1: A Basic Six-Pulse Converter Model
the six-puse bige iuce i Seci 4 c be sipie be i seies wih esis s shw i igue 8.1. ne h he esis shw i igue 8.1 is cu esis bu is sip icue i he bve cicui siue he vge egui eec he ipece he cvee bige ceci. this esis es hve sscie I ²r sses. Csie he cicui shw i igue 8.1. as he dC cue hugh he cvee iceses up 1.0 pu, he vge p css he “esis” iceses, eucig he vge he dC ei he cicui s shw i igue 8.2. oce 1.0 pu dC cue, he vge c he be vie b icesig he ig ge. a ig ge 90°, he dC vge is ze bu he dC cue, i suppie sepe suce, eis 1.0 pu. Whe i ivee e, he cvee wi w dC cue fw hugh i suppie b sepe dC cue suce. as he ig ge iceses (exici ge eceses), he cvee dC ei vge iceses up he iiu exici ge which pi he dC cue us be euce chieve uhe iceses i dC ei vge, wig cs exici ge ie. B veic fippig he ivee chceisic pig i he se gph s he ecie chceisic, he peig pi, which is he pi whee he ecie chceisic he ivee chceisic css, is u s shw i igue 8.3.
Figure 8.2: Converter Operating Profle
Hweve, wih hese sic chceisics, s c be see i igue 8.4, i he aC vge ppie he ecie s he hee e uipe cssve pis bewee he ecie he ivee. Hece, he peig pi c be eeie. t vece his, he bsic cvee chceisics e ie i e c he w h he cvees esp uig sie eves. a expe pcic chceisic is shw i igue 8.5. ne h i igue 8.5 he cs cue chceisic he ivee is we dC cue h he cs cue chceisic he ecie. Ue pei, he ivee cs he dC vge he ecie cs he
31 or BEGInnErS and BEyond HVDC
α = Constant
γ = Constant
Figure 8.3: The Basic Static Characteristic o an HVDC Link
α = Constant
γ = Constant
Figure 8.4: The Basic Static Characteristic o an HVDC Link with Reduced Rectifer AC Terminal Voltage Vdc
Rectifier
α
= Constant
1.0 γ
= Constant
Inverter Imargin
1.0
Figure 8.5: A Practical HVDC Link Static Characteristic
Id
dC cue. Hweve, i he aC ei vge he ecie s such h he ecie chceisic shw i igue 8.5 csses he ivee cs cue chceisic, he he ivee wi ii he dC cue his eve wih he dC vge beig ice b whee he ecie chceisic csses he ivee cs cue chceisic. the gi bewee he ecie cs cue chceisic he ivee cs cue chceisic is kw s he “cue gi”. Se ic chceisics c be supeipse he sic chceisic s shw i igue 8.6. expe, cuve cs e pwe c be supeipse iicig he equie dC cue give chge i dC vge ii he ecie dC ei pwe. ahe chceisic h c be supeipse is e cs ecive pwe. I he peig pi wee be iie g he ecive pwe cuve, he pi he ecive pwe bsbe b he cvee wu ei cs. Cseque, i hee is euci i, expe, he ecie aC sse, he, b wig ppxie cs ecive pwe cuve, he chge i ecive pwe he ivee ei is iiize, eve hugh hee is chge i e pwe. Cseque, he cvee bus vge he ivee wu ei ppxie cs.
32 or BEGInnErS and BEyond HVDC
α = Constant
γ = Constant
Figure 8.6: Constant Real and Reactive Power Characteristics Superimposed on the Static Characteristics
33 or BEGInnErS and BEyond HVDC
9 REACTIVE POWER IN AC SYSTEMS recive pwe is ihee wihi aC pwe sses. I is qui h esus he s cpcice iucce wihi eees he pwe sse. Is eec is shi, i phse, he cue aC wve wih espec he vge aC wve hece eucig he iseus vue vge uipie b cue. I e ssess he eec his phse shi, he aC pwe is csiee s w cpes; he “re” pwe which esus he i-phse cpe vge cue he u--phse cpe vge cue which is eee s “recive” pwe. recive pwe c eihe be eig, h is he cue wve is phse vce wih espec he vge wve, ggig, h is he cue wve is phse ee wih espec he vge wve. I HVdC sses, i is cvei csie eig ecive pwe s “suce” “gee” ecive pwe ggig ecive pwe s “” “bsbe” ecive pwe. Hece, ecive pwe esuig cpcice is geee ecive pwe esuig iucce he cvee is bsbe. a aC ewk is cpse gees, Va cpess, sissi ies vius iucive cpciive s. recive pwe fw hugh he aC sse esus i vge vii bewee busbs. Whe ii ecive pwe suce is cece busb wihi he aC sse, he vii i vge bh h busb iecece busbs shu si be iie wihi he se-se iis. theee, hee is ws ii he ecive pwe h c be cece busb.
34 or BEGInnErS and BEyond HVDC
10 THE REACTIVE POWER LOAD OF A CONVERTER Cvees e ecive pwe s he pee wih e ig ge which es siui whee he cue gs he vge. I ii, he cvee se ipece (pus he s vve ipece) iuces ii g i he cue which is bseve s he vep ge. the cvee peig vep ge is uci he peig cue he cvee se ekge ecce:
[ cos( δ ) - Id Id x χ ] - δ
-1
µ = cos
p
0
µ Id Id 0 χ p
= he cvee vep ge (), = cvee dC peig cue (pu), = e cvee dC peig cue (pu), = cvee se ekge ecce (pu), δ = cvee c ge, = ph (α) ecie pei (), = g (γ) ivee pei (). he vep ge he cvee ig ge, he cvee peig pwe c c be ppxie ccue s ws: cos φ = ½ x [cos( δ )+cos( δ+ µ)] Hece he ecive pwe bspi is ppxie: Qdc = tan [cos -1 ( φ )] x Pdc Whee: Qc = he ecive pwe bspi he cvee (pu), csφ = he pwe c he cvee (°), Pc = he e pwe he cvee si (pu). the ecive pwe bspi cvee e c be ppxie s ws:
[
]
Qdc 0 = tan cos -1 (cos δ - χ p ) 2
Whee, Qdc 0 = he ecive pwe bspi he cvee e dC cue (pu).
35 or BEGInnErS and BEyond HVDC
Vc
(α+μ) = 0° IDEAL Case
Vb Converter Line Current Ia -30
0
30
60
90
120
150
180
210
240 270 300 330 360
Va
390
Fundamental Component Converter Line Current
μ = 16°
Va
φ
Ia
(α + μ) = 68°
Va φ
Ia
(α + μ) = 90°
Va φ
Ia (α + μ) = 165°
Va Ia
Figure 10.1: Lagging Currents in a Rectifer and an Inverter
φ
36 or BEGInnErS and BEyond HVDC
11 REACTIVE POWER SOURCES WITHIN A CONVERTER STATION the i suces cpciive (psiive) ecive pwe i HVdC si e he aC hic es. Hic es hve w pupses: eucig he hics ijece i he aC sse geeig ecive pwe. a aC e is cpse cpcices, iucces esisces bu ue equec he HV-cece cpci is he i cibu he ecive pwe geee.
Q e = (C¹, V) Figure 11.1: The Single Line Diagram o a typical AC Harmonic Filter
Lindome AC Filters
37 or BEGInnErS and BEyond HVDC
12 CONTROLLING CONVERTER REACTIVE POWER I e ee he aC hic pece, ech e hs be swiche i cei dC pwe sissi eve. this is kw s “pe-p” c, s shw i igue 12.1. these pis e eeie aC hic suies.
Q
C ci he cvee c be use i he ecive pwe exchge wih he aC sse. I HVdC schee, he dC pwe is ee s: dC Pwe = dC Vge x dC Cue Filter switching P
Figure 12.1: Filters Switched with Changing DC Power
Typical operating area 100 ) % ( e g a t l o V C D t e g r a T
DC Power (%)
Figure 12.2: Typical Operating Range o DC Voltage on a Back-to-Back Scheme
100
Hece, give dC pwe eve he vge c be euce he cue ppie icese he expese ii I ²r sissi sses. theee, i he ube es eegize ee aC hic e pece excees he ecive pwe exchge iis, he cvee peig ciis c be chge icese he ecive pwe bsbe b he cvee i e chieve he esie exchge ge bewee he cvee si he aC sse. the chge i dC ciis is chieve b weig he dC vge which equies he ig e ge be icese wih icese i dC cue, ii he dC pwe cs, he vep ge iceses, hece he ecive pwe bsbe b he cvee iceses. I us be e h, s he dC sie he cvee is c he ecie ivee, chgig he dC ciis wi euce, icese, he ecive pwe bh ecie ivee gehe. igue 12.2 shws pic peig ge he dC vge bck--bck HVdC cvee. I igue 12.2 he uppe ii is ee b he iiu wbe peig ges he cvee whis he we ii is ee b he xi u vge sie h c be ppie he cvee esuig he ig vge ecie ecve vge ivee.
38 or BEGInnErS and BEyond HVDC
13 VOLTAGE STEP CHANGES ahe equiee ipse ecive pwe c is h exceeig specie aC vge sep chge s csequece swichig e bk ( ecive pwe eee). as ppxii, he giue vge sep chge, s csequece swichig e, c be ppxie s: QSWItCH SCli - Qtotal
ΔV =
Whee: ΔV = he chge i aC vge (p.u.) SCli = he iiu Sh Cicui leve he aC sse i which he swichig pei is ke pce (mVa) QSWItCH = he ecive pwe sep be ipse he aC sse (mVa) Qtotal = he ecive pwe cece he cvee bus icuig he ecive pwe be swiche (mVa) Whee he sep chge i aC vge excees ee ii, i is pssibe icese he eecive ii b ipsig ppsie chge i ecive pwe he cvee busb. this ppsie chge c be chieve hugh cvee ci b ppig s chge he dC vge whis iiig he dC pwe s iscusse i Seci 12 bve. as expe, csie swichig i e aC sse h hs ue equec VAr ig, which wu excee he aC vge sep chge ii. B icesig he dC cvee bspi he se is s he e bk cicui beke cses, he e ecive pwe exchge wih he aC sse c be ce hece he sep chge i aC vge.
39 or BEGInnErS and BEyond HVDC
14 EFFECTS OF HARMONICS IN AC POWER SYSTEMS Hics wihi pwe sse e ee s he ui he vge cue iege uipe he ue equec. Hece, expe, 50 Hz sse, he pesece 5h hic vge es h hee is ii 250 Hz cpe e he vge wve which wi is he vge wve s shw i igue 14.1. Figure 14.1 (a): Three-Phase undamental requency sine wave
the pesece hics i he pwe sse c esu i se uesibe eecs cece pwe sse equipe, expe, he pesece hics c esu i: • • •
•
Figure 14.1 (b): Example o 5% 5th Harmonic Distortion on a Three-Phase AC Waveorm
oveheig cpci bks oveheig gees Isbii pwe eecic evices Ieeece wih cuici sses
40 or BEGInnErS and BEyond HVDC
15 SOURCES OF HARMONICS IN AC POWER SYSTEMS a equipe h icues -ie eee is cece pwe sse c esu i he geei hics s csequece eihe is esig is pei. Expes hics suces wihi Pwe Sse e: • • •
Pwe cvees (HVdC, SVC, ives) desic eecics (eevisi, vie, pes cpues, ec.) n-ie evices tses Vge iies uesce ighs rig mchies PWm cvees ■ ■
• • •
Vry THD Max %
Vyb THD Max %
Vbr THD Max %
Planning Limit
8
7
6
n o i t r o t s i D c i n o m r a H
5
4
3
2
1
0
27/06/2004 00:00
28/06/2004 00:00
Figure 15.1: An example o excessive background harmonic distortion on an 11 kV network
29/06/2004 00:00
30/06/2004 00:00
01/07/2004 00:00
02/07/2004 00:00
03/07/2004 00:00
04/07/2004 00:00
05/07/2004 00:00
41 or BEGInnErS and BEyond HVDC
16 HOW CONVERTERS CAUSE HARMONICS
Figure 16.1: AC/DC converter represented as AC harmonic current source on AC side
Figure 16.2: AC/DC converter represented as AC harmonic voltage source on DC side
the aC/dC cvee is suce hics. this is becuse he cvee cecs he supp he ce pei ue equec cce hece he cue w he supp is siusi. See he aC sie, cvee c be csiee s gee cue hics (igue 16.1), he dC sie gee vge hics (igue 16.2). the cu eve hics geee b aC/dC cvee is uci he ui ve which picu phse is equie pvie uiieci cue he . Hece, he highe he “Puse ube” he cvee, which es he e swichig bewee phses wihi cce, he we he hic isi i bh he aC ie cue he dC ei vge.
42 or BEGInnErS and BEyond HVDC
17 PULSE NUMBER AND HARMONIC CANCELLATION the i cpes pic HVdC cvee ei e shw i igue 17.1. the ci he his sequei swichig esus i cue wves i he ie sie he se which csiss ”bcks” cue s shw i igue 17.2. I uie sis is pee he ieize wves shw i igue 17.2, he wig esus e bie: 1) y/y I = 2 x √ 3 x I d x cos ω t - 1 cos 5 ω t + 1 cos 7 ω t - 1 cos 11 ω t + 1 cos 13 ω t ... π 5 7 11 13
[
]
2) y/Δ I = 2 x √ 3 x I d x cos ω t + 1 cos 5 ω t - 1 cos 7 ω t - 1 cos 11 ω t + 1 cos 13 ω t ... 5 7 11 13 π
[
Figure 17.1: A typical twelve-pulse converter bridge
]
I c be see equis (1) (2) h ech six-puse bige geees hic es 6 ± 1, = 1, 2, 3 ..., hee e ipe hics (3, 6h, 9h...) pese h = 1, 3, ec., he hics e phse shie b 180°. the ieize giues he six-puse hics e shw i tbe 17. B cbiig w six-puse biges wih 30° phse shi bewee he, i.e. b usig y/y y/ Δ ses s shw i igue 17.1 suig equis (1) (2), weve-puse bige is bie. the ieize giues he weve-puse hics e shw i tbe 17.2. the cue wves shw i igue 17.3 ppe i he c ceci he ses shw i igue 17.1. I uie sis is pee his ieize wve, he wig esu is bie: 3) I = 4 x √ 3 x I d x cos ω t - 1 cos 11 ω t + 1 cos 13 ω t - 1 cos 23 ω t + 1 cos 25 ω t ... π 11 13 23 25
[
]
43 or BEGInnErS and BEyond HVDC
thus, i weve-puse bige, he hic es 6 ± 1, = 1, 3, 5 ... e eecive ccee i he c supp evig he chceisic weve-puse hics i.e.
12 ± 1, = 1, 2, 3, ...
the ieize wves shw bve wi, i ei, be ie b he ecce he supp sse (i he se ecce). due his cuig ecce, he hic cue giues e euce cpe hse ppicbe pue sque wve puses. the equis give bve e bse he ssupis h, s, he dC cue is ie, h is, he dC ec is iie , sec, he aC sse vge wves e siusi. Becuse bh hese ssupis e vi pcic sses, e cpex ccuis e ecess pupse bui cpue pgs e use. Figure 17.2: Idealized line winding currents in a Twelve-Pulse Bridge
COMBINED
Figure 17.3: Idealized Waveorm o the AC Supply Current o a Twelve-Pulse Bridge
the usu pubishe ue gphs hese cues give giues . speci pupses (e.g. e hic cibui w e biges sigh iee ig ges ecces) bh giue phse (i.e. vec suis) e equie.
44 or BEGInnErS and BEyond HVDC
ue
(50 Hz)
1
ue
(50 Hz)
1
5h
(250 Hz)
0.2
5h
(250 Hz)
-
7h
(350 Hz)
0.14
7h
(350 Hz)
-
11h
(550 Hz)
0.09
11h
(550 Hz)
0.09
13h
(650 Hz)
0.08
13h
(650 Hz)
0.08
17h
(850 Hz)
0.06
17h
(850 Hz)
-
19h
(950 Hz)
0.05
19h
(950 Hz)
-
23
(1150 Hz)
0.04
23
(1150 Hz)
0.04
25h
(1250 Hz)
0.04
25h
(1250 Hz)
0.04
( x 50 Hz)
1/
( x 50 Hz)
1/
Table 17.1: Idealized Harmonic Magnitudes in a Six-Pulse Bridge
Table 17.2: Idealized Harmonic Magnitudes in a Twelve-Pulse Bridge
45 or BEGInnErS and BEyond HVDC
18 DC HARMONICS the ieize vge css ue six-puse cvee is shw i igue 18.1, he ieize vge css weve-puse cvee is shw i igue 18.2. the vge is ix iec vge hics. tbe 18.1 shws he hics he dC sie puce b sixpuse cvee.
No-Load DC (Vd 0)
(DC)
1.0000
6h
(300 Hz)
0.0404
12h
(600 Hz)
0.0099
18h
(900 Hz)
0.0044
24h
(1200 Hz)
0.0025
Table 18.1: Idealized DC Voltage Harmonics (RMS) at the Terminals o a Six-Pulse Bridge
1
1
) . u . p ( e g a t l o V C D
0.8
) . u . p ( e g a t l o V
0.6 0.4
C D
0.2
0.8 0.6 0.4 0.2 0
0 0
100
200
300
Electrical Degrees
Figure 18.1: The Idealized Voltage Across the DC Terminals o a SixPulse Bridge at no-load
0
100
200
300
Electrical Degrees
Figure 18.2: The idealized voltage across the DC Terminals o a Twelve-Pulse Bridge at no-load
46 or BEGInnErS and BEyond HVDC
19 CHARA CHARACTER CTERISTIC ISTIC AND NON-CHARACTERISTIC HARMONICS the hic cues eive he exii he ie cvee, s escibe i Seci 17, e kw s he “chceisic hics” cvee. Hweve, pcic cvee c cuse he hic cues be geee which esu -ie peig ciis. these hics e eee s “-chceisic hics”. n-chceisic hics c esu seve suces; ubce “egive phse sequece” i he supp aC sse wi esu i he geei 2 hic vge v ge he dC sie b he cvee; hic h ic peice b he 6 12 sis escibe pevius wi wi give ise 3 hic cue beig ijece bck i he aC sse b he cvee. Ubce bewee he cvee se ekge ecces he y Δ biges wi esu i s u ech he cssic hics – which shu hve bee cpee ccee – si beig pese i he aC sie cue. S cpcice which is ihee i, expe, he cvee se vve wiig bushigs wi pvie s ph wihi he cvee hic cues fw eig he geei ipe hics such s, 3, 9h 15h he dC sie ±1 hese hic ubes he aC sie. as, i c iccucies wihi he cvee ce esuig i he ig isce bewee vves bige beig peec seic (he e is uch ess h 0.1° eecic) wi cuse he geei hics uipes bh he aC dC sie he cvee. 19.1
Cross-Modulation Harmonics
I ii he chceisic -chceisic hics which c be geee b cvee, hee is hi pe hic eee s css-ui hics. these hics esu he c h i HVdC ik he dC cue is eve peec sh. this is picu ue i he cse bck--bck cvee whee hee is ie ipece bewee he w cvees , i s cses, i is ipcic is sucie iucce bewee he cvees ke sigic ipc he ieci bewee he. I s cses, he aC ceci e cvee is ee, eve ise i se h he he cvee. theee, theee, eve whee he w aC sses iecece b he dC ik e e i he se aC equec (50 Hz 60 Hz), he cu peig equecies be sigh iee hece he hic aC sie cues dC sie vges geee b he cvees, which e uipe he ppie aC sse equec, wi be iee equecies. I he cse whee he w aC iecece sses pee iee aC equecies, expe e 50 Hz e 60 Hz, he he ieece i he hics geee b he cvees wi be ge. the cu dC sies he cvees e cece gehe hece he hic vge
47 or BEGInnErS and BEyond HVDC
isi cuse b e cvee wi be ppie he dC eis he he cvee vice ves. these hic vge isis wi cuse isi i he cicuig dC cue which wi cuse hics be geee i ech cvee h e uipe he he cvee’s aC sse equec is w. expe, he 60 Hz cvee wi hve aC cue hics cespig 11h 13h hic 660 Hz 780 Hz especive cespig dC sie hic 720 Hz. Hweve, his 720 Hz isi wi esu i 660 Hz 780 Hz cpes i he aC cue hics he 50 Hz cece cvee. neihe hese equecies e iege uipe 50 Hz , s csequece, -iege hics e puce.
48 or BEGInnErS and BEyond HVDC
20HARMONIC 20 HARMONIC FILTER DESIGN, TYPES OF FILTERS the aC sie cue wve HVdC cvee, s e iscusse pevius, is high siusi, , i we fw i he cece aC ewk, igh puce uccepbe eves isi. aC sie es e heee equie s p he HVdC cvee si i e euce he hic isi he aC sie cue vge ccepb w eves.
C1
HVdC cvees s csue subsi ecive eci ve pwe, ge ppi which us be suppie c wihi he cvee si. Shu-cece aC es ppe s cpciive suces ecive pwe ue equec, i cvei HVdC schees he aC es e use cpese s he ecive csupi he cvee. aii shu cpcis ecs ccsi Sic Va Cpess (SVCs), Sic Cpess. (StatComs) schus cpess, s be use esue h he esie ecive bce is iie wihi specie iis ue ee pei ciis.
L1
R1
Figure 20.1: 1: Single-T Si ngle-Tuned uned BandB andPass Filter Circuit
the esig he aC es, heee, hs sis hese w equiees hic eig ecive pwe cpesi, vius pei ses eves. 20.1
1.0E+05
Filter Circuit Confgurations
90
1.0E+04 45
e d 1.0E+03 u t i n g a 1.0E+02 M
0
-45 1.0E+01
1.0E+00
-90 0
4
8
12
16
20
24 24
28 28
32 32
Harmonic Number
Figure 20.2: 20. 2: Single-T Single -Tuned uned Band-Pass Filter - Impedance Characteristic
36 36
40 40
44 44
48 48
e s a h P
thee e vius pssibe cicui cguis h c pve suibe aC sie es HVdC cvee sis. sis . this seci eviews hese esigs give bckgu ii he vges isvges picu e pes. o shu-cece es e csiee i his seci. the ces picu e esigs pp HV- EHV-cece es equ mV-cece es, e.g. ei-cece es.
49 or BEGInnErS and BEyond HVDC
the chice he piu e sui is he espsibii he cc wi ie pjec pjec. the esig wi be ifuece b ube cs h be specie b he cuse: • •
•
• • • • •
specie hic iis (vge isi, eephe ieeece cs, cue ijeci), aC sse ciis (supp vge vii, equec vii, egive phse sequece vge, sse hic ipece), swiche e size (ice b vge sep ii, ecive pwe bce, se-excii ii eb schus chies, ec.), evie eecs (bie epeue ge), cvee c seg (vge vevge c, ecive pwe c), sie e (iie swich bs), ss evui ciei, vibii eibii equiees.
diee e cguis wi pssess cei vges isvges whe csieig he bve cs. as he e esig pece specs e csiee, ii equipe such s suge eses, cue ses vge ses e ie he cicuis shw. I HV EHV ppicis, suge eses e use wihi he es ge he isui eves he equipe. 20.2
Advantages and Disadvantages o Typical Filters
tw i e pes e use : •
he ue e b-pss e which is shp ue e seve hic equecies.
these e es ue specic equec, equecies. the e chceize b eive high q (qui) c, i.e. he hve w pig. the esisce he e be i seies wih he cpci iuc (e e i is sip he ss he iuc), i pe wih he iuc, i which cse he esis is high vue. Expes ue es icue sige (e.g. 11h) ube (e.g. 11/13h) ipe (e.g. 3/11/13h) ue pes •
he pe e high-pss e eig w ipece ve b b equecies.
these e es esige p e h e hic, expe e ue 24h hic wi give w ipece bh 23 25h hic, eve s he highe hics. dpe es ws icue esis i pe wih he iuc which puces pe chceisic equecies bve he uig equec. Expes pe es icue sigeue pe high-pss (e.g. HP12) ube-equec pe high-pss (e.g. HP 12/24).
50 or BEGInnErS and BEyond HVDC
the isici bewee hese w e pes seies be s s epeig he chice q-vue iee e equecies.
C1
C2
L1
R1
L2
R2
HVdC schee wih weve-puse cvee, he ges chceisic hics wi be he wig: 11h, 13h, 23, 25h, 35h, 37h, 47h, 49h. as he eve he 11h 13h hic e gee wice s high s he es he hics, c pcice is pvie b-pss es he 11h 13h hic high-pss es he highe hics. due csiei s hs be ke cceig he pssibe w-e esce bewee he aC ewk he es shu bks. Whe big HVdC schee is be ise i wek aC sse, w-e hic e (s e ue 3 hic) be s eee.
Figure 20.3: Double-Tuned BandPass Filter - circuit 20.3
Band-Pass Filter
a b-pss e csiss lC seies esce cicui s shw i igue 20.1. igue 20.2 shws he ipece giue phse b-pss e.
1.0E+05
the vges he isvges sige-ue b-pss e e s ws:
90
advtgs:
1.0E+04 45
e d 1.0E+03 u t i n g a 1.0E+02 M
0
e s a h P
• • •
-45 1.0E+01
1.0E+00
-90 0
4
8
12
16
20
24
28
32
Harmonic Number
Figure 20.4: Double-Tuned Band-Pass Filter - Impedance Characteristic
36
40
44
•
Sipe ceci wih w cpes, opiu pig e hic, lw sses, lw iece equiees.
Disdvtgs:
48 •
• •
muipe e bches be eee iee hics, Sesiive euig eecs, m equie pssibii jusig ecs cpcis.
20.4
Double-Tuned Band-Pass Filter
a ube-ue b-pss e hs he equive uci w sige-ue es. Is cgui is shw i igue 20.3, is ipece p i igue 20.4.
51 or BEGInnErS and BEyond HVDC
the vges he isvges ube-ue b-pss e e s ws: C1
advtgs: L1
R1 • • •
C2
L2
•
R2
•
opiu pig w hics, lwe ss h w sige ue bches, o e HV cpci ec eee e w hics, miiges iiu e size pbe w giue hic, ewe bch pes, ciiig e euc.
Disdvtgs: C3
L3
R3 • • •
Figure 20.5: Triple-Tuned BandPass Filter - Circuit
•
Sesiive euig eecs, m equie pssibii jusig ecs cpcis, Cpex iececi, wih 4 5 C-l-r cpes, requies w eses c isui eves. 20.5
1.0E+05
90
1.0E+04 45
e d 1.0E+03 u t i n g a 1.0E+02 M
0
-45 1.0E+01
1.0E+00
-90 0
4
8
12
16
20
24
28
32
Harmonic Number
Figure 20.6: Triple-Tuned BandPass Filter Tuned to 3rd, 11th and 24th Harmonic - Impedance Characteristic
36
40
44
48
e s a h P
Triple-tuned band-pass flter
this pe e is eecic equive hee pecece ue es, bu is ipeee s sige cbie e. igue 20.5 shws he cicui gee igue 20.6 he ipece/equec espse pic ipe-ue e. the use ipe-ue es cu ipve he pei equiees ecive pwe c. this wu be picu ipce w- ciis i 3 hic e is eee i he cicui he begiig. as he e sii i ue ube-ue es hei eis wbcks e s escibe i seci 20.2 bve. ech he bve gees, sesiivi euig hs bee ieie s isvge. Hweve, wih he ii esiss ( hece ii sses) ke he e gee pe s iscusse i seci 20.2, his euig c be iige.
52 or BEGInnErS and BEyond HVDC
21 AC HARMONIC PERFORMANCE AND RATING CALCULATIONS the bsis hic isi e pece ccuis c be expie wih eeece igue 21.1. I I Is Z Zs Figure 21.1: Circuit Analysis or AC Filter Perormance Evaluation
= hic cues he cvee = hic cues i he e = hic cues eeig he supp sse = hic ipece he e = hic ipece he aC sse
the cue vge isi c be ccue he wig expessis: 4) I sn =
5) V n =
Z n x I n Z n + Z sn
Z n x Z sn x I n Z n + Z sn
I e ccue hic pece esig he es (i.e. Z ), i is essei h eie ii be vibe he hic cues geee b he HVdC cvee (I ) he hic ipece he supp sse (Zs). 21.1
Figure 21.2: Typical Supply Network Impedance Diagram
Harmonic Impedance o the Supply System
I e ccue ssess vge cue isi, i is essei h he ipece he supp sse be kw ech hic iees. this is pic h is e p ee ues. Hweve, ck kwege he sse hic ipece cu e uecic e esig, e h wi eque eue hics.
53 or BEGInnErS and BEyond HVDC
thee e seve ehs eig he sse ipece:
X φ1
21.1.2
r 2r R
φ2
Z plane
Figure 21.3: AC Network Impedance
Impedance Circle Method
I supp sse wih sigic shu cpcice, he ipece he sse c ppe eihe iucive (r + jX l) cpciive (r – jX C) he Pi C Cupig (pcc) hic equecies. Ievib, esces wi ccu whe he iucive (X l) cpciive (-X C) cpes e equ he esisce cpe (r) eis. igue 21.2 shws pic ipece cus supp sse s he equec chges 50 Hz bu 255 Hz. I his expe, he sse ppes iucive 100 Hz, bu cpciive 150 Hz wih esce cse 140 Hz. uhe esces ccu bew 245 Hz bve 250 Hz. the sse ipece c chge ve pi s chges i equec. the bve cus ppies e sse cgui; wih iee geei, ie uge ciis, uhe ipece ci wu ccu. I e esue h he sse hic ipece (Z s) use i e esig ccuis is ppicbe pese uue sse cguis, cice is w which ecses he ccue ci. a expe such cice is shw i igue 21.3. Whe peig e esig suies, he sse ipece is ke be vue wihi he cice which esus i he ges hic isi (i.e. Vs Is). Cpue xiizi uies e use sech he ipece e ech hic. I e efec he pcic ei sse ipece, iiis he sech e e specie. lii ies ges φ1, φ2 (pic 75° - 85°) e c use, iiu vues r be specie. this eh is se s i ihee ces sse chges uue equiees. Hweve, i is s pessiisic s ech hic, picu w es, which wi v wihi iie ge, wihi ge cice. the use his ppch esu i ve-esige expesive e.
54 or BEGInnErS and BEyond HVDC
21.1.3
Polygon Method
+jX
a ech hic, he sse wi hve iscee vue ipece cespig iee cguis. theee ech hic he sse ipece c be ee b pg which ecpsses he ccue iscee hics. Such pg is shw i igue 21.4. the cpue xiizi uie seches ech ee pg ech hic ccue he ges hic isi (Vs Is). R
this eh gives eisic ssesse he sse ipeces, vis pbes ve-esigig he e.
-jX
Figure 21.4: Impedance Polygon
55 or BEGInnErS and BEyond HVDC
22DC HARMONIC PERFORMANCE AND RATING CALCULATIONS the dC sie hic pece HVdC schee is, i se especs, sipe ccue h h he aC sie. Cpis igue 21.1 igue 22.1 shws h he bsic sis cicui is sii. Hweve, uike he aC sse, which c exis i iee ses (h is, iee cguis sissi ies, s, geei, ec) he dC sse is ee sse wih ew pssibe chges i cgui. igue 22.2 shws spe equec vesus ipece p vehe sissi ie. the pece ssesse eh vehe dC sissi ie is bse iuce cue, h is, he cue h wu fw i cuc pe he dC ie. the highe he eh ipece, he highe he iuce cues i pe ie, s his pe ie wi pese vibe cue eu ph. Cvese, i es whee he eh ipece is w, he cue iuce i pe ie wi be w. the esig ig he dC sie e is, heee, ifuece b he eh ciis sscie wih he dC ie.
Figure 22.1: Circuit Analysis or DC Filter Perormance Evaluation 105 104 ) s m h o ( e c n a d e p m I
103 102 101 100 10-1 0
1000
2000
3000
Frequency (Hz)
Figure 22.2: Typical HVDC Line Impedance Characteristic
4000
5000
Whe peig i bce bipe e, he hic cues wi fw hugh he dC ies i such w h pi g he ie, he iseus hic cues i e pe’s dC cuc wi be equ ppsie h i he he (ssuig h bh pes e peig ieic, h is, he se dC vge, dC cue, esuee es, eces, ec). theee, he cues iuce i pe cuc wi be euce. Hece, pic, he ws-cse dC hic pece he cse which ees he dC e ig, is pe pei.
56 or BEGInnErS and BEyond HVDC
a ip csiei i he esig dC e, s ppse aC e, is he i cpci bk s, he dC sie, his wi be subjec he ppie dC vge hece he shig he dC vge s we s he aC vge us be ce. this es h he esisive vge isibui ees be ce i dC cpcis (igue 22.3). his es i is c dC e cpci bks be csuce s e sige bk s ppse spi bk whee he spi bks wu hve ps isus bewee he cpci cks isub he vge isibui ue ekge cues css he.
Figure 22.3: DC Filter Capacitor
57 or BEGInnErS and BEyond HVDC
23CONTROL FACILITIES PROVIDED BY HVDC SCHEMES the bsic c pee HVdC cvee is he dC cue which cicues bewee he ecie ivee ssuig h he dC vge is iie cs vue (which is pic ue dC pwe sissi schees bu ws ue bck--bck schees). Hweve, he HVdC ce c jus he dC cue fw i espse he pe-se be pees esue quiies pviig exee fexibe s p pwe sse’s sissi isucue. tpic c eues pvie vibe s ii eue e escibe bew: 23.1 Power Control
the pwe see bewee he seig eceivig e he HVdC ik is ce ee pe-se vue he pi i he cicui whee he dC pwe is ee, kw s he cpuig pi. tpic he cpuig pi is he ecie dC ei bu i c s be he ivee dC ei, he i-pi he dC sissi cucs (e.g., he be bewee w cuies), he ivee aC ei he ecie aC ei. I he pwe e is chge he he pwe e wi p he ew pwe se eve e chge (kw s he “p e”) pe-seece b he pe. tpic he xiu pwe ii is ee b ve ce which is ciuus ccuig he he cpbii he cvee si equipe.
Figure 23.1: Power control
58 or BEGInnErS and BEyond HVDC
23.2 Frequency Control
a HVdC schee c c he aC equec aC sse b uic jusig he pwe beig eivee i h aC sse i e bce he wih he supp. the s pwe c b he HVdC euces he ue-equec ve-equec which c esu chgig i s pwe sse such s is . equec c c s be ppie s iis he pwe c uci. expe, he seig e c be ge s h i wi ciue supp pwe vi he HVdC ik he eceivig e s s g s he seig e aC sse equec is bve se hesh vue. I his w he seig e c be pece sevee sse isubce s csequece isubce i he eceivig e aC sse. the cbii HVdC schee is ve ip is seies eee s pviig “ew”. Wih pwe sse csisig “iss” aC iecece wih dC, his “ew” ppe HVdC wi iige he isk cscig bck-us css uipe iecece aC sses [5]. ohe equec iis c be ppie, expe he eceivig e aC sse cu hve uppe equec ii uic sp uhe iceses i he pwe beig eivee b he HVdC schee. Equ, he eceivig aC sse c hve we equec ii which, i eche, uic iceses he pwe beig eivee i he eceivig aC sse, hugh his c be veie b he seig e iiu equec ii escibe bve, h is, he seig e sse wi hep u he eceivig e aC sse s uch s pssibe wihu iskig csce iue.
Figure 23.2: Frequency control
59 or BEGInnErS and BEyond HVDC
23.3 Power Modulation Control
the pwe beig see hugh HVdC ik c be uic ue pvie pig w-equec pwe sciis wihi eihe, bh, iecece aC sses s eeie b suies uig he esig phse he HVdC schee.
Figure 23.3: Power Modulation Control
23.4 Runback / Power Demand Override (PDO)
I espse cei eves, such s ss aC sissi ie, ss aC gee ss j , he HVdC iececi c be pge esp i pe-ee e. expe, i he ss ie esu i isbii wihi he aC sse, he HVdC iececi c be pe-pge euce he pwe se pe-eeie p e se vue s esbishe b cc suies. Equ, he ss gee c be pepge uic icese he pwe fw hugh he HVdC iececi.
Figure 23.4: Runback/Power Demand Override (PDO)
60 or BEGInnErS and BEyond HVDC
23.5 DC Protection
a eie escipi he pecis use wihi HVdC si is be he scpe his cue. Hweve, i is wh ig h wihi HVdC cvee si he pes peci uiize i w cegies: • •
Cvei (aC) subsi peci dC peci
aC cece equipe such s cvee ses aC hic e cpes, g wih eees busbs, e pece usig cvei aC peci es. the cvee, g wih he dC cicui, is pece usig hwe swe specic pupse esige b arEVa t&d. tpic dC specic pecis icue: • • • • • • • • • • •
aC > dC aC ovecue dC dieei dC ovecue dC > aC aC ovevge ase aC Uevge ab ig ge lw dC cue dC Uevge
61 or BEGInnErS and BEyond HVDC
24HVDC THYRISTOR VALVES the e “vve” eives he e s HVdC, whe ecu-c vves wee use his uci. mecu-c vves pee i iee w (beig essei vcuu ubes, hece he e “vve”) bu i essei he se jb s e his vve. igue 24.1 shws he ecu c vves suppie b arEVa t&d (he Egish Eecic) he nes rive Bipe 1 HVdC pjec i C; hese vves h he highes ig ecu-c vves eve e. Whe hiss wee iuce, he e “vve” ws eie.
Figure 24.1: Mercury-Arc Valves on the Nelson River Bipole 1 HVDC Project
the his vve is he bsic cpe he e HVdC cvee, whse pei is iscusse i seci 6.3. Hweve, e his vve cpises seies-cece hiss i e pvie he ecess bckig vge cpbii. thiss use HVdC vves e gs he ges seicucs pe puce ius. igue 24.2 shws 8.5 kV his wih cive siic iee 115 (which ss ie s siic ig 125 iee, hece such hiss e e eee s “125 ” hiss). Such cpes e expesive hee be hus such cpes i HVdC si. meve, he e quie eice equie ge ii cpes c pec he. I c, hugh i is he s bvius cpe his vve , he hiss ccu supisig w pecege he vve cs. me his vves e eive size, h is s h he buk he e esig wk is cie u uig he puc evepe phse, hece, ppig he vves picu pjec is eive sighw e. a is sipes, he wk ivve picu pjec
Figure 24.2: Modern 8.5 kV 125 mm Thyristor: Alloyed Silicon Slice (Let) and Complete Capsule (Right)
62 or BEGInnErS and BEyond HVDC
jus ivve pig he ube seies-cece hiss ccig he vge ig equiees ipse b he ve sse esig. HVdC vves e s eve ise s iiviu uis. ne ws, seve vves e cbie gehe i “muipe Vve Ui”, mVU. the mVU eihe be ue iec he f , e c , suspee he ceiig. ec isui, he vve esig is e ge s h he we-vge vves (usu hse sscie wih he de-cece six-puse bige) e use s p he isui which he highe-vge vves (usu hse sscie wih he s-cece bige) e ue. Hece he wvge e is he e which he vve is che he f ceiig. the vves e pic scke veic i ”quivve” sucues, wih hee such quivves beig equie ech e ech pe. igue 24.3 shws pic suspee mVU.
Figure 24.3: Typical suspended MVU or HVDC or a 285 kVDC Application (dimensions approx 6 m x 4 m x 8 m tall)
Ceu ei hs bee pi pssibe e iiii pcesses wihi he e his vve. a cpes e geeus e, bh he ( iiize he isk veheig) eecic ( he cpes i pe wih he his e specie wih vge igs i excess hse he bes his which cu be ecuee). the pig cpcis, expe, e i-ee csuci. Hece, he pei spe e hughu he vve c be viu isisse b he eis cpes use.
63 or BEGInnErS and BEyond HVDC
25THYRISTOR VALVE COOLING CIRCUIT Aluminum Heatsink PEX Hose Stainless Steel Electrode
‘O’ Ring
Figure 25.1: The Protective Electrode System Used in AREVA’s Water-Cooled HVDC Valves
Nylon nut
I e exc he sses ecie he hiss he cpes, chieve eque w epeue ise i hese cpes, i is essei pvie se ce cig cicui. me his vves use iqui cig b pue eiize we, which, whe use wih high vge equipe is se s g s he we is u-pue, wih iic cis. deiizig equipe esues h he cucivi he we is ve w vue.
We cig is ws pvie he hiss pig esiss, usu s he i/ ec dC gig esis. the we c is isibue i pe eve his eve i he vve vi isuig psic pipes, he wse he is ejece u-ue ces. the esig he we cig cicui is ip egieeig sk i e esue h he sse hs eque fw es i ciic es vis excessive high fw es h cu cuse esi, w fw es h e ccuui gs pckes. Eve hugh he we cucivi i HVdC vve is exee w, i is eve ze, hece, is pei cusig uesie eeccheic eecs hs bee wie ecgize. U-pue eiize we c hve ve w cucivi, ess h 0.1 µS/c. Hweve, e hw sphisice he eiizi equipe, i is pssibe euce he cucivi cpee ze, becuse we ws isscies i H + oH- is, exe gvee i b epeue. as csequece, we pipe spig w pis iee eecic peis wi ievib c s ekge cue. Whe he ppie vge is aC, he csequeces his e picu seius, bu whe he ppie vge hs dC cpe, cei eeccheic ecis ievib ke pce he e che eeces. auiu, which is wie use s hesik ei becuse is excee he cucivi, is ve vuebe csi i he eve h ekge cues fwig i he we e we ipige iec he uiu. I e peve ge he uiu, i is ecess esue h he ekge cues fwig i he we fw iec we uiu bu ise pss vi se ie eece ei. I his w (shw igue 25.1) he vuebe uiu is pece ge.
64 or BEGInnErS and BEyond HVDC
arEVa t&d’s s we-ce HVdC vves hve w bee i sevice sice 1989 [6] hse he nes rive pjec hve bee i sevice sice 1992, see igue 25.2. arEVa hs iie he se esig picipes use hse pjecs, up he pese , is HVdC vves s is aCtS cvees. arEaVa t&d hs i excess 70,000 s-iee (15 ) 8,000 ge-iee (50-75 ) cig cecis ise i such cvees u he w. Eve wih such ge ise bse, hee hve bee epe pbes cuse b eeccheic esi epsii i arEVa’s HVdC vves.
Figure 25.2: A valve hall rom Valve Group VG13 o the Nelson River project in Canada, showing the large developed length used or the coolant pipework to span the distance between earth and the base o the valve stack at 330 kVDC.
Cooling plant
65 or BEGInnErS and BEyond HVDC
26HVDC CONVERTER TRANSFORMERS AND THEIR CONFIGURATIONS the cvee se cs s he iece bewee he HVdC cvee he aC sse pvies seve ucis icuig: •
• •
• •
Figure 26.1: Comparison o AC and DC Voltage Stress Distribution in a Typical Converter Transormer
Pviig gvic isi bewee he aC dC sses Pviig he cec vge he cvees liiig eecs se se aC vge chge cvee peig ciis (pchge) Pviig u-iiig ipece Pviig he 30° phse shi equie weve-puse pei vi s e wiigs
aC se isui is esige wihs aC vge sesses. these vge sesses e eeie b he shpe peiivi he isui eis use wihi he se bu is gee ccee i he isuig i. Cvee ses e, hweve, expse aC vge sess dC vge sess. the isibui he dC vge sess is pei ee b he esisivi he isuig eis hece e sess is ccee i he wiig isui h i he isuig i. this esisivi vies ue seve cs icuig he epeue he eis he egh ie he vge sess is ppie. this is wh he iei ecgize esig equiees e h he dC vge sess be ppie pei ie i e esue h se-se vge sess isibui is chieve.
66 or BEGInnErS and BEyond HVDC
1x3 phase/3 windings
2x3 phase/2 windings
3x 1 phase/3 windings
the cvee se is he ges p ie be shippe sie HVdC pjec. Hece sp esicis such s weigh heigh, i he se hs g ve ue bige expe, c hve j ipc he seece cvee se gee. igue 26.2 iuses he c ecgize se gees i HVdC schees. lwes cs c be chieve b iiizig he ube eees he cvee se is bke w i, hece he wes cs is pic 3-phse, 3-wiig se. Hweve, ue shippig iis, such se be pcic s he gee shu be csiee. Whee spe cvee se is eee ecess, bse vibii sis he schee, he i is e cs-eecive use 1-phse, 3-wiig se gee, s e spe ui c epce he i-sevice uis, whis 2-wiig gees equie w spe uis be suppie.
6x 1 phase/2 windings
Figure 26.2: Typical Converter Transormer Arrangements
a ip csiei i he esig cvee se is he seeci he ekge ecce s his wi csiue he j p he cvee’s cuig ecce. the ekge ecce us pii esue h he xiu u cue h he his vve c wihs is exceee. Hweve, be his iii, he seeci ekge ecce us be bce cficig esig issues, he s ip which c be suize s ws: lwe ipece gives: • • • •
lwe egui p Highe u cue te ce lwe weigh
Highe ipece gives: • • • •
lge egui p lwe u cue She ce Highe weigh
tpic he piu ekge ecce wi be i he ge 0.12 pu 0.22 pu. 1-Phase, 3-Winding Converter transormer or the 500 MW Chandrapur Back-to-Back scheme
67 or BEGInnErS and BEyond HVDC
27RELIABILITY AND AVAILABILITY OF AN HVDC CONVERTER reibii vibii ssesse is he ecgize w ssessig he pece HVdC cvee schee [7]. CIGrE cecs eibii vibii exisig HVdC schees u he w pubishes bi-u ep iicig wh pece is beig chieve hse schees h pvie he ep. 27.1
Reliability
reibii is esue he cpbii he HVdC ik si pwe bve se iiu ee vue pi i ie ue peig ciis. reibii is expesse s he ube ies i e e he schee is icpbe s iig pwe bve iiu ee vue. this ibii si bve ee pwe eve is ee ce ouge re (.o.r.). 27.2
Availability
“avibii” is ceci sigic, expe, i he schee is uvibe uig ies ze ig, he uvibii he schee wi hve ipc. HVdC schees, he e is, heee, use epese “eeg vibii”. Eeg vibii is he bii HVdC schee si, ie, pwe up he e pwe. Hece, cvee schee which c si 1.0 pu pwe 100% he ie wu hve eeg vibii 100%. a uge he HVdC schee , expe, he uge e pe i bipe, wi ipc he eeg vibii, eucig he gue ess h 100%.
68 or BEGInnErS and BEyond HVDC
28LOSSES IN A CONVERTER STATION a ip ceci csiei pwe iececi is he eecic sses wihi he ceci, h is, he u pwe s i he pcess siig he pwe e ci he. lsses wihi ie cue cvee schee e ceu csiee uig he esig phse i e esue h he eiship bewee cpi equipe cs he eecive cs sses c be piize. I ccuig he eecive cs he sses, he puchse us csie he ui he ci p he HVdC ik, he expece cs eecici uig his pei he expece iees e uig his pei. B kig hese vues, he e pese vue he sses c be ccue, h is, gue which epeses cs he we usig he equipe wihi he ewk. the ss evui is ssesse b uipig cs/kW gue b he HVdC suppie’s guee sses. igues 4,000 USd/kW 5,000 USd/kW e c . igue 28.1 shws he pic spi bewee equipe wihi HVdC sissi schee whis igue 28.2 shws he spi bewee equipe bck--bck HVdC schee.
8%
1%
0% 5% 1% 5%
3%
4%
5%
Cvee tse
2%
Cvee Vves Vve Cig P
35%
25%
50%
dC Shig rec
56%
aC Hic es H ie auxiiies Figure 28.1: Typical Split o Losses Within an HVDC Transmission Scheme
Figure 28.2: Typical split o Losses Within a Back-to-Back HVDC Scheme
69 or BEGInnErS and BEyond HVDC
29CONTRACT STAGE STUDIES FOR A HVDC CONTRACT arEVa hs he cpbii ueke wie vie pwe sse evie suies i e ssis puchse i evepig HVdC schee. Pesee bew is escipi ecee suies pee uig he cc phse HVdC cvee schee csuci.
70 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
mi Sch Pts
objecive
t ee he ge peig ciis he HVdC schee he j cpe igs.
desig d Expece Su
Csise peig he HVdC schee ue iee peig ciis, he ube his vve eves he cvee se ig.
Equipe aece
this vves, cvee ses ecive pwe bks (aC hic es).
mehg
the se-se peig pees he HVdC schee css is peig pwe ge e ccue chee peig ciis. the vius peig pees, equipe eces esuee es h e ppicbe he schee e vie bewee suies i e expe he buies he HVdC schee’s pei.
71 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
rctiv Pow
objecive
t esbish he ecess sub-bk ig swichig sequece ee he ecive pwe c equiees he schee.
desig d Expece Expece Su
recive recive pwe bk/aC bk/aC hic hic e bk bk mVa ig, ig, swichig swichig sequece sequece bks ue ue iee peig ciis cvee ecive pwe bspi cpbii uiizi.
Equipe aece
recive pwe bk/aC hic es.
mehg
the HVdC cvee bspi ue exees peig cii eces, esuee es peig dC vge e esbishe s p he mi Schee Pees eps. his cvee bspi, he ecive pwe equie, wig he pppie ece ciis, is esbishe. Usig he ecive pwe exchge iis, esbishe swich pis wi be ccue which keep he e ecive pwe iechge he cvee pus aC ecive pwe bks wih he aC sses wihi he esbishe iis.
72 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
Hoic Filt
objecive
t evue he aC sie hic cues geee b he cvees s uci dC pwe esbish aC hic e sui which ees he hic iis he pjec.
desig desig d Expec Expece e Su Su
ie ie esig esig p pg g,, cpe cpe vues vues ig ig .
Equipe aece
aC hic es.
mehg
the sis pee b arEV rEVa esbishes he cbiis he aC sse cvee ciis, such s equec, epeue, se ipece, ec; which wu gi ve ise he xiu eves hic isi he eis he HVdC si. the hic cues geee b he ecie ivee he HVdC cvee e evue usig igi cpue pg ce JESSICa. the JESSICa pg ccues he giue he iiviu hic cues heic sis he equec i behviu he cvee. the pece he aC hic es hei pei sses e ccue usig he ewk hic peei pg HarP. the pg es he es he ijece cues he cvees. a s heic xiizi echique is use sech ech hic ipece e he ipece which puces he xiu vue v ue vge chse e, cue i chse bch. this sse ipece is isee i he he ipece ix he cicui beig ze he hic cue peei su. the pg he sves oh’s w, usig s ix heics echiques. this pceue is epee ech hic iees.
73 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
rI, TVI d PLC Filt.
objecive
t evue he high-equec ieeece geee b he cvees esbish PlC e r sceeig sui which ees he iis he pjec.
desig desig d Expece Expece Su Su
PlC PlC e e esig esig p pg g,, cp cpe e vue vuess i ig g . . r shieig he vve hs.
Equipe aece
PlC es, vve h rI scee.
mehg
the cpes he cvee si wi be ee i he pppie equec ge he ecess eve ei. o s ipce wi be he cvee ses, he cvees he PlC es. the PlC equec ise wi be ccue he eev busbs wih ge sissi ie ipeces ve he ge PlC equecies iees. the ie ieeece 15 15 he subsi ece wi be ccue kig i i ccu pcic eves r sceeig ppie he vve hs.
74 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
Isultio Cooditio
objecive
t esbish he pppie pecive eves si suge eses hece BIl, cece ceepge si equipe.
desig d Expece Su
the su wi ie pecive eves si suge eses, equipe BIl ceepges ceces he dC sie he cvee se.
Equipe aece
a isui.
mehg
he xiu vve wiig dC vge g wih he specie xiu aC sse peig vge, he pppie suge ese pecive eves e ccue bse hisic . his , he isui eves pi equipe e ccue s we s he isui eves isus. the ccue isui eve isus is cece pvie isu which wi pvie he ecess wihs fshve pbbii he dC sie equipe. Ceces bewee equipe he dC sie he cvee se e s ccue.
75 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
Tsit Ovvoltg Stud
objecive
the bjecive his su is eeie he sie vevge cue sesses j cvee si equipe icuig suge eses, which bsis hei isui cii. Suge ese eeg bspi equiees wi s be eeie.
desig d Expece Su
tsie vevge eves. Suge ese peci eves eeg bspi.
Equipe aece
Cvee si equipe, es suge eses.
mehg
the isubces csiee c be cegize s: ) Swichig ipuse suies ivvig u ppici cece he cvee aC busbs, siui se he eegizi eves e swichig eves. hese suies, he ses i he vicii he cvee sis e epesee b eecgeic es which icue -ie sui eecs. the cse pxii he es he ses c give ise eesce eecs, picu i he es ses bece ise he i sse. n-ie sie eecs suge eses e s epesee s pppie. b) lighig he s ipuse suies ivvig iec ighig sikes bck-fshves he icig aC dC sie ies, e busb fshves gu the isui eves he si equipe wi be cie wih he pecive eves he suge eses he sesses he e eeie chieve suibe ese equipe esig. the sie vevges be suie ue his heig e se h hse he ue equec ep vevge pe, ccupig uch she ie sce wih se ise ie. the us heee be suie wih s eecgeic pg. I he ccuis, cicui cpes (r, l C) he cvee cse-up equive aC sse e epesee s ecess icuig jce ies, ee b isibue pees epeseis equive Pi t secis s pppie. S cpcice, se sui suge eses e icue whee pppie phses e epesee sepe. a ge peig ciis is ivesige, gehe wih eves eig sie vevges, i e eeie ws vevges eeg uies aC dC sie suge eses he cpes.
76 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
Cotol Sst Dic Pfoc Stud
objecive
the bjecive his su is piize he c pees pvie sbe pei g ic pece he HVdC schee. this su wi be pii cie u usig phsic cs arEVa’s re tie digi Siu (rtdS).
desig d Expece Su
Sic chceisics, c sse ucis pees, veici sbii, espse ies u ecve.
Equipe aece
C equipe
mehg
High vge equipe i he especive cvee sis (e.g. cvee ses, aC/dC es dC es) s we s eev gees sep-up ses wi be epesee i he siu e. deive equive aC sse ewk es wi be use epese he aC sses. this dic Pece Su wi be use chieve he wig bjecives: • • • • •
•
• • •
Evui dC c peci ucis. Ci sbe pei. Ci sic chceisics c se pis. Evui he pece he aC/dC sse iee dC sse c es. Evui dC sse pece dC-sie isubces such s cvee bckig, pe bckig, vve wiig us, icuig esi pecive shuw whe equie. desi he dC sse espse i ccce wih he specie espse ciei, icuig c sse sep espses ecve aC sse us. desi he dC sse sie espse ecive cpe swichig Suig he ieci wih c chies uig isubces. Evui he pece he dC sse uig sevee aC us subseque u ceig. this wi icue he evui dC pwe u-bcks, i ecess, chieve sbe sse ecve.
77 or BEGInnErS and BEyond HVDC
78 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
audibl nois
objecive
t ivesige he cusic ise eves he sie buies.
desig d Expece Su
Ci h he equipe esig ees he xiu cusic ise iis he bu.
Equipe aece
acusic-cive equipe icuig cvee ses, cvee se ces, e cpcis, i ciiig vve cig he exchges.
mehg
Iiviu equipe suppies’ ii givig he cusic ise peice iiviu ies wi be ee i gphic epesei he sie u. the peic swe pes he cusic ise ccuis usig he ehg se u i he wig ss. •
•
•
ISo 9613-1: aeui su uig ppgi us, P 1: Ccui su b he sphee (s eii 1993-06-01). ISo 9613-2: aeui su uig ppgi us, P 2: Gee eh ccui (s eii 1996-12-15). VdI 2571: Schbshug v iusiebue (Su eissi iusi buiigs).
79 or BEGInnErS and BEyond HVDC
Audible noise plot
80 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
Fudtl Fquc Ovvoltg Studis (FFTOV)
objecive
the bjecive his su is ssess he pece he dC iececi, is cs cpesig equipe he vevge iiig eue i espse ge ejeci isubces i he equive aC/dC sse, i e eeie he esuig ep vevges.
desig d Expece Su
mxiu ue equec sie vevges expeiece b sse eecic pwe equipe.
Equipe aece
Eecic pwe equipe i he vicii he HVdC cvee sis.
mehg
specie bse cses he sse, equive ewk ( ) sie pe suies ( sh pei ew cces) wi be e pi u ejeci ciis. aC sse uge cii siuis e suie sii. the pppie su cses wi be epee wih wihu he ecive pwe bspi e (tCr e) c vge iiig cis i e eeie is eecs, chceisics igs. the su equies he usu fw sie sbii pe /es he ewk ipeces, s, gees/cs peig eves/eues. the su es ecessie ve ge, u aC ewk be ee i e chieve is bjeci ves cvee si esig/ssesse. the xiu ue equec toVs ccu whe hee is ss pwe sissi i he HVdC ik, which c ccu ue : ) Bckig he ik. this cuses he cvee se cicui bekes pe heeb isig he cvee si. a e i ippig he es wi cuse high vevges ue he pi ejeci he HVdC ik ecive pwe e which ecs bh es he ik. b) thee-phse si us cse i he cvee HV busbs which c s cuse ss dC sissi, hugh he cvee ses ei cece his scei. wig cece he u, toVs c be high i he pei bee u pwe se is eesbishe.
81 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
rlibilit d avilbilit
objecive
t ee he ve eibii vibii he cvee si equipe, c he equipe esig he ecee spes ee he specie equiee.
desig d Expece Su
the eeg vibii he ce ouge re sscie wih iee schee cguis.
Equipe aece
a sigic p ies e csiee s p he evui.
mehg
a eibii su e is bui b gupig gehe se es, kw s ‘subsses’. a subsse is ceci cpes ( se subsses) whse iiviu eibiiies c be cbie gehe he bsis hei ie-eiships (epeecies) pvie ve esue subsse eibii. the subsse is he ee s sige cpe wih is w iue epi chceisics. I his w, eibii su e c be sipie b csiei is eibii i u shi i se qui epeseive subsse ues. thee e xe ues egig he w i which cpes e cbie gehe subsses; he chice is bse he ue he p he expeiece exisig isis. Expes subsses e: ) Cvee vve, cpizig; hiss, ge uis, iig uis, gu-eve eecics, cig cpes, ec. b) Hic e, cpizig: iucs, cpcis, esiss, Cts, iss, aC cicui bekes, ec. a eibii su e cpee sse is bui up b eig gehe he subsses which i cis i es he eec hei iues he he subsses.
82 or BEGInnErS and BEyond HVDC
Typical Contract Reports
Titl
Losss
objecive
t ccue he ‘s ucue’ sses he cvee si.
desig d Expece Su
t pei ss p.
Equipe aece
ne.
mehg
the cvee si sses pei ue i aC sse vge equec ciis wih i equipe pees u bie epeue pic 20 °C wi be pesee. the su wi cpie esus equipe c ess g wih he ppse i peig ciis pese he cvee si sses i ccce wih he ue ee i IEC 61803 , i peee b he cie, IEEE S 1158.
83 or BEGInnErS and BEyond HVDC
30REFERENCES [1] PL Sorensen, B Franzén, JD Wheeler, RE Bonchang, CD Barker, RM Preedy, MH Baker, “Konti-Skan 1 HVDC pole replacement”, CIGRÉ session 2004, B4-207. [2] JL Haddock, FG Goodrich, Se Il Kim, “Design aspects o Korean mainland to Cheju island HVDC transmission”, Power Technology International, 1993, Sterling Publication Ltd p.125. [3] BT Barrett, NM MacLeod, S Sud, AI Al- Mohaisen, RS Al-Nasser, “Planning and design o the AL Fadhili 1800MW HVDC Interconnector in Saudi Arabia”, CIGRÉ Session 2008, B4114. [4] RP Burgess, JD Ainsworth, HL Thanawala, M Jain, RS Burton, “Voltage/var control at McNeill Back-to-Back HVDC convertor station”, CIGRÉ Sesson 1990, p.14-104. [5] NM MacLeod, DR Critchley, RE Bonchang, “Enhancing the control o large Integrated AC Transmission Systems using HVDC technology”, Powergrid Europe conerence, Madrid, Spain, May 2007. [6] DM Hodgson, “Qualifcation o XLPE tube systems or cooling high-voltage high-power electrical equipment”, Power Engineering Journal, November 1991. [7] CD Barker, AM Sykes, “Designing HVDC Schemes or Defned Availability”, IEE Colloquium (Digest), n 202, (1998), p.4/1–4/11
84 or BEGInnErS and BEyond HVDC
31 APPENDIX Questionnaire – Data Requirements or an HVDC Scheme
the ipce ech quesi is ee b he wig cegies: a a is he iiu ii equie ebe qui be pepe B a is iiu ii equie ebe buge pps be e, e.g. esibii su C a is he ii, iiu echic eiis equie he ie e w Pese e h i is i he iees he Use speci i he equi s uch his ii s pssibe - which pupse we wu be pese e u vice i equie - sice, hugh teees c ke hei w ssupis whe is issig, his c e icuies whe ees e juice. Ceg
1.
aC Sse ech ei
1.1
Vge i xiu ciuus iiu ciuus xiu sh ie ui iiu sh ie ui
1.2
equec i xiu ciuus iiu ciuus xiu sh ie ui iiu sh ie ui
aB
1.3
Sh cicui eves, xiu iiu, ech sge he evepe
aB
1.4
Isui eves
a
1.5
Ceepge cece isces
a
1.6
Hic ipece
aB aB aB a a
aB aB aB a a
85 or BEGInnErS and BEyond HVDC
a
1.7
disi / tI iis aC sse. Which hics e be ssesse?
a
1.8
Is he aC sse si esisce ehe?
a
1.9
Wh e he esig csis (ube eees, secui ciei, cue Use pcice, ec) he aC swichig si? ae hee he ge ses cece he cvee si busb? I s, give se igs, ecces, p ge, ec.
a
1.10
Give eis uevges uis aC sse us, bh uig he us uig he u cece pei bh i bck-up peci, sige phse hee phse us i he e iee.
aB
1.11
Give esus aC sse isubce suies icuig sie vge equec viis, eis iis ccepbe Va geei/ bspi swichig uig e he isubce.
aB
1.12
) Wh is xiu peie sep vge chge isig e swichig? b) Wh is he xiu peie pe vge chge ve wh ie ui?
aB
1.13
Wh is xiu ep (
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