Recei ed Decembe 9, 2021, accep ed Decembe 16, 2021, da e o publica ion Decembe 20, 2021,
da e o cu en e sion Decembe 27, 2021.
Digi al Objec Iden i ie 10.1109/ACCESS.2021.3136713
Wind Tu bine O ien ed Solu ions o Imp o e
Powe Quali y and Ha monic Compliance
o AC O sho e Wind Powe Plan s
CARLOS RUIZ 1, GONZALO ABAD 1, MARKEL ZUBIAGA2, DANEL MADARIAGA2,
AND JOSEBA ARZA2
1Elec onics and Compu e Science Depa men , Mond agon Uni e si y, 20500 Mond agon, Spain
2Inge eam Resea ch and De elopmen Eu ope S. L., 48170 Zamudio, Spain
Co esponding au ho : Ca los Ruiz ([email p o ec ed])
ABSTRACT The ope a ion o o sho e wind powe plan s wi h espec o powe quali y and g id code
compliance mus be e i ied o di e en condi ions in he design phase using ha monic analysis me hods.
This pape add esses his e i ica ion by i s conside ing a scena io in which wind u bines ope a e wi h
a ypically used modula ion s a egy, ca ie -based pulse wid h modula ion. The s udies a e pe o med a
se e al ope a ing poin s, no only a he a ed condi ion, and a wo poin s o he elec ical in as uc u e,
a he poin o connec ion o he wind u bine and a he poin o common coupling o he o sho e wind
a m. Fo his ype o modula ion echnique and acco ding o he esonance condi ions o he s udied o sho e
sys em, he ha monic dis o ion o cu en signals is ela i ely high and he compliance o he Ge man – g id
code is no achie ed. To ackle his, wind u bine manu ac u e o ien ed solu ions a e p oposed wi h he aim
o imp o ing he ha monic emission o he o sho e wind a m. The implemen a ion o a pa icula solu ion
o selec i e ha monic elimina ion is p esen ed oge he wi h complemen a y solu ions o u he imp o e he
ha monic emission o he wind powe acili y. Fu he mo e, his pape discloses he modeling app oach o
accoun o an adequa e ha monic assessmen o he wind powe plan unde s udy.
INDEX TERMS Wind ene gy in eg a ion, o sho e wind powe plan s, powe sys em ha monics, powe
ha monic il e , g id code, modula ion s a egies.
I. INTRODUCTION
Ha monics a e a special conce n in he o sho e wind indus y
due o he high pene a ion o powe con e e s in ype-4 wind
u bines [1].
Type-4 wind u bines (WTs) o e many ad an ages,
which is why hey a e ins alled in o sho e wind powe
plan (OWPP) scena ios. Some examples o hese ad an ages
a e inc eased powe ex ac ion e iciency, ol age- and e-
quency suppo , and aul ide- h ough (FRT), which a e p o-
ided by means o p ope con ol o he powe con e e [2].
Despi e he p e ious ad an ages, ype-4 WTs can be
conside ed as a sou ce o ha monics, which signi ican ly
con ibu es o he o e all ha monic emission a he poin
o common coupling (PCC) o he OWPP. Fu he mo e,
his con ibu ion can be wo sened due o he p esence o
The associa e edi o coo dina ing he e iew o his manusc ip and
app o ing i o publica ion was Siqi Bu .
esonances ha may inc ease a gi en ol age- o cu en -
ha monic componen . These esonances can be classi ied
in o se ies- and pa allel esonances and hey occu due o
capaci i e (subma ine cables) and induc i e ( ans o me )
beha io o ins alled powe componen s in combina ion wi h
he impedance o he g id.
Maximum ha monic injec ion limi s o ol age- and
cu en -signals a e commonly imposed by g id codes and
in e connec ion ag eemen s [3], [4]. These limi s a e ypi-
cally e alua ed a he PCC poin o he s eady-s a e condi-
ion. I he OWPP does no ul ill hese limi s, he OWPP
mus be disconnec ed om he main g id wi h i s associa ed
consequences.
The e is a as numbe o e e ences, e.g., [5]–[9] o ci e
some, ha ocus on OWPP s abili y s udies. In hese e -
e ences, a en ion is paid on pa allel esonances and con-
olle aspec s (e.g., bandwid h o cu en -con ol loops,
eed o wa d e ms, bandwid h o he PLL, bandwid h o
167096 This wo k is licensed unde a C ea i e Commons A ibu ion 4.0 License. Fo mo e in o ma ion, see h ps://c ea i ecommons.o g/licenses/by/4.0/ VOLUME 9, 2021
C. Ruiz e al.: WT O ien ed Solu ions o Imp o e Powe Quali y and Ha monic Compliance o AC OWPPs
measu emen il e s, e c.) bu hey do no assess i he OWPP
sys em mee s he ha monic limi s imposed by he g id codes.
On he con a y, e e ences [1], [10], [11] p o ide alu-
able con ibu ions o he s udy o ha monics and s abili y in
OWPPs. Re e ences [1] and [11] p esen he de elopmen
o sys ema ic me hods o ha monic s udies in wind powe
ins alla ions. In hese e e ences, he ha monic dis o ion o
a WPP, wi h WTs ope a ing wi h a ypical Ca ie -Based
PWM (CB-PWM) modula ion, is p esen ed and compa ed
wi h ield measu emen s. Some open aspec s ha equi e
u he in es iga ion a e s a ed in hese e e ences and a e
aken as basis o his pape . These a e:
•The e alua ion o di e en modula ion s a egies.
•S udies ega ding he easibili y o ins alling ha monic
il e s (passi e-, ac i e- and hyb id- il e s) a di e en
nodes along he OWPP.
The aim o his pape is o conduc ha monic s udies in
OWPPs and e alua e g id code compliance om he powe
quali y pe spec i e. The s udies add essed in his pape se e
as complemen a y analysis and con ibu ion o open p oblems
p esen ed in p e ious pa ag aph. A gene al pic u e o he
s udies and con ibu ions o his pape a e p esen ed nex .
Fi s , he ha monic e alua ion is pe o med by conside ing
ha wind u bines ope a e, simila as in e e ence [1], wi h
a ypical CB-PWM modula ion. This assessmen is done a
se e al ope a ing poin s (no only a he a ed condi ion) and
a wo le els o s udy, a he poin o connec ion o he wind
u bine (WTi-poin ) and a he poin o connec ion o he
OWPP o PCC-poin .
Then, WT manu ac u e solu ions a e p oposed o imp o e
he ha monic emission o he OWPP wi h he aim o educing
he possibili y o ins alling ha monic il e s a he o sho e
and/o onsho e subs a ion. The implemen a ion o a pa icu-
la solu ion o Selec i e Ha monic Elimina ion (SHE-PWM)
modula ion, especially designed o sui wi h he ea u es o
he scena io unde s udy, is p esen ed oge he wi h comple-
men a y solu ions o u he imp o e he ha monic emission
o he OWPP.
In o de o conduc he p e ious s udies, a p ope modeling
app oach mus be pe o med. In his sense, he main powe
componen s o an AC OWPP a e modeled o ep esen ha -
monics up o 5 kHz ( equency ange o s udy).
Fo ha objec i e, his pape exploi s he s eng hs and
applicabili y o he WT ha monic model p oposed in e e -
ence [12] o ep esen he ha monic emission o a eal g id
side con e e (GSC). In his sense, i is possible o ep e-
sen he magni ude and phase o ha monics ha a e injec ed
by WTs, which mainly depend on he ype o modula ion
s a egy and con ol loops. I is impo an o ema k ha
expe imen al esul s a WT le el, p o ided in [12], a e used
in his pape o accoun o eal da a o he ha monic emission
o WTs.
The modeling app oach also accoun s o he ep esen-
a ion o he equency-dependen beha io o ans o me s
and subma ine cables. This las componen is ep esen ed by
means o he FDPi model p oposed in [13].
Fu he mo e, Jensen’s wake e ec model is implemen ed
o es ima e he mean wind speed a each WT acco ding o he
spa ial dis ibu ion o he OWPP and wind condi ions. This
allows he e alua ion o di e en ope a ing poin s (i.e., ac i e
powe gene a ion scena ios) acco ding o eali y.
As he main con ibu ion o his pape , he s udies and
he modeling app oach p esen ed he e se e as a gene ic
simula ion ool o s akeholde s wi hin he wind powe indus-
y, o conduc ha monic s udies and e alua e he g id code
compliance o an OWPP om a powe quali y pe spec i e
and du ing he design s age o a wind powe plan .
The pape is s uc u ed as ollows. Sec ion II p esen s he
de ini ion o an OWPP base scena io and he cu en ha -
monic limi s acco ding o he BDEW g id code. Sec ion III
co e s he modeling app oach ha is applied o e alua e
he ul illmen o g id codes in e ms o ha monics and o
ep esen he scena io unde s udy.
Sec ion IV add esses he ha monic e alua ion o WTs
ope a ing wi h CB-PWM. In sec ion V, WT manu ac u e
o ien ed solu ions a e p oposed wi h he aim o imp o -
ing he ha monic emission o he OWPP and he compliance
o he g id code. Sec ion VI p esen s some aspec s ega ding
he obus ness e alua ion o he solu ions p oposed in he
p e ious sec ion when conside ing pa ame e unce ain ies.
Finally, sec ion VII gi es he conclusion.
II. DEFINITION OF AN OWPP BASE SCENARIO AND
SPECIFICATION OF HARMONIC LIMITS
As he i s s ep, i is equi ed o speci y a case s udy and
he ha monic limi s acco ding o a speci ic g id code. These
aspec s a e co e ed nex .
A. DEFINITION OF OWPP BASE SCENARIO
The base scena io is de ined aking in o accoun in o ma ion
o a eal OWPP. The eal OWPP, aken as e e ence, is Alpha
Ven us o sho e wind a m [14]. The main eason o i s
selec ion among o he OWPPs is ha gene al in o ma ion
ega ding ol age le els a di e en buses, wind a m lay-
ou , g ounding scheme, and main elec ical componen s a e
known.
I is impo an o emphasize ha e en hough he OWPP
base scena io is de ined based on Alpha Ven us, i is no an
exac ep oduc ion. I is also wo hy o poin ou ha ce ain
pa ame e s, equi ed o he modeling o he main powe
componen s ha e been assumed due o lack o in o ma ion.
The assump ions we e made acco ding o suppo ing e e -
ences and da ashee s o o he powe componen s.
Fig. 1 depic s he simpli ied single-line diag am o he
OWPP base scena io. The OWPP base scena io has a o al
capaci y o 60 MW. This amoun o powe is gene a ed om
wel e ype-4 WTs.
The s ep up ans o me ins alled inside he WTs, he ea e
called wind u bine ans o me (WTT), inc eases he con-
e e ol age le el om 3.3 kV o 30 kV, which is he ol age
le el o he collec ion ne wo k. The windings o he WTT a e
Dyg1 connec ed.
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C. Ruiz e al.: WT O ien ed Solu ions o Imp o e Powe Quali y and Ha monic Compliance o AC OWPPs
FIGURE 1. Simpli ied single-line diag am o he OWPP base scena io.
The WTs a e clus e ed in o g oups o h ee o ming a col-
lec ion ne wo k wi h a ec angula shape. In o ma ion abou
he wind a m layou and he dis ance o each subma ine
cable o he collec ion ne wo k is shown in Fig. 1. Redundan
connec ions a e no implemen ed o his base scena io.
The collec ion ne wo k hen links all he WTs o an
o sho e pla o m.
The o sho e pla o m has a s ep-up ans o me and a
g ounding ans o me . This s ep-up ans o me , he e a e
called o sho e subs a ion ans o me (OST), inc eases he
ol age o he collec ion ne wo k o 110 kV, which is he
ol age le el o he ansmission sys em. The OST has a a ed
powe o 75 MVA and he windings a e Ygd1 connec ed. The
g ounding ans o me p o ides a neu al in he h ee-phase,
h ee-wi e sys em o he collec ion ne wo k.
The link be ween he o sho e subs a ion o sho e is done
by a single h ee-co e subma ine cable o 60 km long. The
sc eens and a mou o he subma ine cables o he collec ion
ne wo k and ansmission sys em a e g ounded a bo h ends
as depic ed in Fig. 1.
Shun eac o s a e ins alled a bo h ends o he ansmission
sys em. The pu pose o hose eac o s is he managemen
o he eac i e powe h ough he 60 km long subma ine
cable [15]. The ene gy ansmission o he OWPP is imp o ed
since hese shun eac o s educe he equi ed a ed cu en o
he cable and he ac i e powe losses.
Finally, he OWPP is connec ed o he main powe g id o
110 kV.
B. SPECIFICATION OF CURRENT-HARMONIC LIMITS
ACCORDING TO THE BDEW GRID CODE
The BDEW echnical guideline [16] de ines he maximum
cu en injec ion limi o indi idual ha monic componen s,
up o 9 kHz, acco ding o Table 1.
Acco ding o he complemen a y ules [17] done o he
o iginal echnical guideline, he in ege ha monics and high
equency ha monics a e calcula ed (since Janua y 2013) as,
I Azul =i zul ·SkV ·sSA
SGesam
(1)
In addi ion, in e ha monics a e compu ed as,
IµAzul =iµzul ·SkV (2)
Being,
SA: Appa en connec ion powe o he gene a ing plan o
be assessed.
SGesam : To al connec able o planned eed-in powe a he
junc ion poin unde conside a ion.
SkV : Sho -ci cui powe a he junc ion poin unde con-
side a ion.
Fu he mo e, e e ence [17] de ines some addi ional ules.
The app o al o ce i ica ion is achie ed i no mo e han
six calcula ed alues exceed he admissible limi s de ined
in Table 2. E en-numbe ed ha monic cu en s a e exemp ed
om he calcula ion.
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C. Ruiz e al.: WT O ien ed Solu ions o Imp o e Powe Quali y and Ha monic Compliance o AC OWPPs
TABLE 1. BDEW ha monic cu en injec ion limi s ela ed o he ne wo k
sho -ci cui powe . Sou ce [16].
TABLE 2. Admissible limi alues o ce i ica ion app o al [17].
III. MODELING FOR HARMONIC EVALUATION OF AN
OWPP
Once he OWPP scena io and he cu en -ha monic limi s a e
speci ied, i is impo an o disclose he modeling app oach in
o de o pe o m he ha monic e alua ion o he case s udy.
To accoun o an app op ia e ha monic assessmen o
an OWPP, i is equi ed o conside h ee impo an ac o s
in he modeling [18]. Fi s , an accu a e ep esen a ion o
he ha monics injec ed by he wind u bines, i.e., including
magni ude and phase o ha monics. Second, he equency-
dependen cha ac e is ic o ins alled passi e componen s,
e.g., subma ine cables and ans o me s. The hi d ac o o
conside is he e alua ion o di e en ope a ing poin s (i.e.,
ac i e- and eac i e-powe gene a ion) o each wind u bine.
These ope a ing poin s depend on wind condi ions, wind a m
layou , and equi emen s gi en by he g id ope a o . These
h ee aspec s a e co e ed nex .
A. WIND TURBINE HARMONIC MODEL
The wind u bines o he OWPP scena io a e modeled acco d-
ing o he schema ic depic ed in Fig. 2. Since he aim o
his pape is o s udy he applicabili y o he model and
no a deepe s udy o i , he eade is sugges ed o e iew
e e ence [12] o mo e de ails.
Fig. 2 shows he schema ic diag am o he WT ha monic
model based on he WECC ype-4 WT gene ic model. The
main idea o his model is o emula e he g id side con-
e e (GSC) and i s con ol. This is done by implemen ing
simpli ied s uc u es ha ep esen he dynamic beha io
o he WTs (wi hou a high compu a ional bu den) and he
implemen a ion o a ol age sou ce con aining bo h, he un-
damen al componen and he ha monics emi ed by he GSC
con e e .
The ol age commands a e in d-q e e ence ame. The
ol age is limi ed once he ou pu ol age module is compu ed
in o de o no exceed he maximum ol age ha can be gen-
e a ed by he implemen ed modula ion s a egy. This limi ed
ol age is used o es ima e he ampli ude modula ion index
ma, which is equi ed by he ha monic syn hesis block.
The ime esponse o he con e e ou pu ol age can be
syn hesized using he Fou ie se ies expansion. Assuming
a null mean alue and conside ing a ini e numbe o ha -
monics, he con e e ou pu ol age o each phase wi h
espec o he DC-link bus midpoin can be app oxima ed by
equa ions (3), (4) and (5).
Whe e ω1is he angula equency o he undamen al
componen , An,mis he magni ude o he n h ha monic o he
m h ampli ude modula ion index, and θn,mco esponds o he
phase o he n h ha monic o he m h ampli ude modula ion
index. Fu he mo e, δis he phase shi be ween he con e e
ou pu ol age and g id ol age in o de o con ol he powe
low.
The e o e, bo h modula ion s a egies p esen ed in his
pape (CB-PWM and SHE-PWM) a e implemen ed by means
o a able o ha monics and a compu a ion algo i hm block
shown in Fig. 2. This able has alues o equency, magni-
ude, and phase o di e en ma alues as depic ed in Table 3
o illus a i e pu pose. The able o ha monics akes in o
accoun 99 membe o Fou ie se ies. This means he ep e-
sen a ion o ha monics up o a equency o 5 kHz.
a0_GSC ( )≈ma
VBus
2sin (ω1 +δ)
+
N
X
n=2An,msin n(ω1 +δ)+θn,m (3)
b0_GSC ( )≈ma
VBus
2sin ω1 −2π
3+δ
+
N
X
n=2An,msin nω1 −2π
3+δ+θn,m
(4)
c0_GSC ( )≈ma
VBus
2sin ω1 +2π
3+δ
+
N
X
n=2An,msin nω1 +2π
3+δ+θn,m
(5)
As shown in Fig. 2, he model se s he undamen al com-
ponen o he ol age om he ol age se poin s, which a e
de ined by he GSC con ol block. On he con a y, o ha -
monics g ea e han he undamen al componen , he model
sea ches he equi ed ma alue in he able and syn hesizes
he emaining N−1 spec al componen s. When he equi ed
ma alue is no de ined in he able, he An,mand θn,m
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C. Ruiz e al.: WT O ien ed Solu ions o Imp o e Powe Quali y and Ha monic Compliance o AC OWPPs
FIGURE 2. Wind u bine ha monic model – schema ic diag am o he WT ha monic model based on he WECC ype-4 gene ic model. Sou ce [12].
TABLE 3. Table o ha monic con en o a speci ic case o SHE-PWM,
phase-angles a e ela ed o he angle o he undamen al componen .
Sou ce [12].
compu a ion algo i hm akes he uppe and lowe alue ha is
de ined in he able and pe o ms a linea in e pola ion o he
magni ude o he ha monic. Fo he phase, he nea es alue is
FIGURE 3. GSC connec ion il e schema ic.
chosen. The inhe en e o , as a esul o hese simpli ica ions,
is educed by conside ing a g ea e numbe o ma alues.
I is wo h o men ion ha his way o modeling is alida ed
in e e ence [12] wi h eal measu emen s on a downscaled
e sion o he INGECON WIND MV100 con e e .
Once he WT ha monic model is b ie ly desc ibed, i is
impo an o p o ide in o ma ion ega ding he ea u es o he
wind u bines ha a e depic ed in Fig. 1. Table 4 gi es he
pa ame e s o he WT ha monic model in o de o ep esen
he WTs o he OWPP base scena io.
Finally, Fig. 3 depic s he schema ic o he il e ha is
used a he ou pu o he con e e . I is an LCL il e wi h a
damping ci cui o med by esis o Rdand induc o Ld. This
ype o damping ci cui educes he losses in he damping
esis o , because he induc o p o ides a new pa h wi hou
losses o he undamen al cu en -componen o he il e .
Table 5 gi es he pa ame e s o he GSC connec ion il e .
This il e is designed acco ding o he me hodology p e-
sen ed in e e ence [19] in which i is conside ed a ype-4 WT,
he ha monic spec um o a CB-PWM modula ion (p esen ed
in sec ion IV), and he BDEW g id code in e ms o ha monics
al eady p esen ed in sec ion II.
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TABLE 4. Pa ame e s o he wind u bine ha monic model.
TABLE 5. Pa ame e s o he GSC connec ion il e .
The alue o he g id side induc o is no gi en since his
alue is de ined by he sho -ci cui induc ance o he WT
ans o me which is p esen ed la e on.
B. TRANSFORMER MODEL
The powe ans o me s o he OWPP scena io a e mod-
eled conside ing he sa u able ans o me componen (STC)
model and ex ending i s ep esen a ion in equency up o
5 kHz. Fig. 4 shows he equency-dependen STC model o
a wo-winding h ee-legged s acked co e ans o me .
The model includes he ollowing:
•F equency-dependen sho -ci cui impedance.
•Linea co e impedance.
•Ze o-sequence impedance.
FIGURE 4. F equency-dependen STC model o a wo-winding
h ee-legged s acked co e ans o me .
TABLE 6. Pa ame e s o he wind u bine ans o me s (WTT).
TABLE 7. Pa ame e s o he o sho e subs a ion ans o me (OST).
The pa ame e s o he WTT and OST ans o me s a e
gi en in Table 6 and Table 7, espec i ely. ABB 2.35 MVA
ans o me da a is conside ed and same pe -uni alues a e
used o pa ame e iza ion due o lack o in o ma ion.
To include he equency-dependency o ans o me wind-
ing esis ance, he app oach p esen ed in e e ence [20] is
used. The pe -uni Rand Lpa ame e s o he Fos e equi alen
ne wo k o o de h ee a e gi en in Table 8. This app oach
can be easily applied o any ans o me in he ange o
20-500 MVA by escaling he gi en Fos e ci cui pa ame e s
by he 50 Hz winding esis ance. Fo he case o he OST and
WTT ans o me s, 100 MVA and 20 MVA ans o me da a
is selec ed, espec i ely, since hey a e he closes in o ma ion
a ailable o he eal alues.
Be o e con inuing wi h he nex powe componen , i is
impo an o men ion ha i he alues o s ay CHG,CLG,
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TABLE 8. Rand Lpa ame e s o he os e equi alen ne wo k o o de
h ee o ans o me model.
FIGURE 5. F equency-Dependen Pi (FDPi) model o a h ee-co e
subma ine cable. (a) Cascaded FDPi sec ions. (b) De ailed schema ic o an
FDPi sec ion. Sou ce [13].
and CHL capaci ances a e known, hey can be added o he
model as well.
C. SUBMARINE CABLE MODEL
The subma ine cables o he OWPP scena io a e mod-
eled conside ing he F equency-Dependen Pi (FDPi) model
p oposed in e e ence [13]. Fig. 5 shows he elec ical
schema ic o he FDPi model, which physically ep esen s he
se en conduc o s o he h ee-co e subma ine cables shown
in Fig. 1.
As depic ed in Fig. 5(a), he model consis s o
N-cascaded FDPi sec ions. Each FDPi sec ion consis s o
TABLE 9. Pa ame e s o he MVAC collec ion ne wo k cables. Sou ce [21].
TABLE 10. Pa ame e s o he HVAC ansmission link cable. Sou ce [22].
a esis ance- and induc ance ma ix compu ed a nominal
equency. The capaci i e coupling be ween conduc o s is
compu ed a nominal equency as well.
The equency-dependen beha io o he se ies impedance
e ms o each conduc i e laye is ep esen ed by means o a
Fos e equi alen ne wo k. The o de o he FDPi model is
gi en by he numbe o cascaded sec ions (N) oge he wi h
he o de o he Fos e equi alen ne wo ks (M). The o de o
he model is chosen depending on he cable leng h, accu acy,
and equency ange equi emen s. Being his las de ined o
ep esen equencies up o 5 kHz.
The pa ame e iza ion p ocess o he MVAC subma ine
cables (collec ion ne wo k) and HVAC cable ( ansmission
link) is pe o med acco ding o he p ocedu e p esen ed
in [13].
The pa ame e s o he collec ion ne wo k cables a e com-
pu ed acco ding o in o ma ion o he Nexans 2XS2YRAA
18/30(36) kV h ee-co e subma ine cable [21]. Table 9 gi es
elec ical and cons uc ional da a o his cable.
On he o he hand, he pa ame e s o he ansmission link
cable a e compu ed acco ding o in o ma ion o ABB HVAC
110(130) kV h ee-co e subma ine cable [22]. Table 10 gi es
elec ical and cons uc ional da a o his HVAC cable.
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TABLE 11. Pa ame e s o he shun eac o s.
FIGURE 6. Powe g id model. Sou ce [15].
D. SHUNT REACTORS
As poin ed ou in sec ion II.A, shun eac o s a e ins alled a
bo h ends o he ansmission sys em o educe he e ec o
he capaci ance gene a ed by he 60km long HVAC subma ine
cable and o wo k wi h a powe ac o close o one.
Acco ding o a epo o he Na ional G id ESO [23], Alpha
Ven us o sho e subs a ion has a 10 MVA 110kV ixed shun
eac o supplied by A e a. This eac i e alue is conside ed
o he s udies p esen ed in his pape .
Fo he case o he onsho e subs a ion, a ixed shun eac o
o 11.7 MVA is conside ed. I is impo an o men ion ha
a iable compensa o s, e.g. Thy is o -Con olled Reac o s
(TCR) and S a ic Synch onous Compensa o s (STATCOMs),
a e only needed when he e a e e y s ic equi emen s a
he PCC poin o he OWPP, i.e. when i is equi ed comple e
eac i e powe compensa ion. This case is only ul illed o
ce ain ope a ing poin s e alua ed in his pape . Fu he s ud-
ies can be done in his di ec ion o e alua e mo e scena ios.
Table 11 gi es he alues o he shun eac o s conside ed
o he OWPP base scena io.
E. POWER GRID MODEL
The powe g id is modeled as an ideal ol age sou ce and
a sho -ci cui impedance. The sho -ci cui impedance is
conside ed an induc o as a simpli ica ion acco ding o e -
e ence [15]. A g id wi h a sho -ci cui a io (SCR) equal o
20 (s ong g id) is conside ed o he OWPP base scena io and
he s udies ca ied ou in sec ions IV and V. In sec ion VI, he
ha monic e alua ion is es ed o an SCR alue o i e, which
ep esen s a weak g id.
Fig. 6 shows he schema ic o he powe g id model and
Table 12 p o ides i s pa ame e s.
I is impo an o no e ha he sho -ci cui impedance o
he powe g id model can be ep esen ed as a equency-
dependen ne wo k, ins ead o he simpli ied induc o ,
o accoun o capaci i e- and induc i e-beha io a di e -
en equency anges. In o de o do so, in o ma ion o he
TABLE 12. Pa ame e s o he powe g id.
ansmission sys em ope a o (TSO) is equi ed o simula e a
scena io as close as possible o eali y.
F. WAKE EFFECT MODEL
Jensen’s model is adequa e in o de o es ima e he mean
wind speed a each WT acco ding o he spa ial dis ibu ion
o he OWPP and wind condi ions (speed and di ec ion).
This allows o add ess he ha monic assessmen acco ding o
eali y a di e en ope a ing poin s and no jus o he a ed
one.
Jensen’s model has been chosen due o he ollowing ea-
u es [24], [25]:
•Simply and widely used model.
•Low compu a ional load.
•Accu acy is simila o mo e complex models.
Acco ding o Jensen’s wake model, equa ion (6) desc ibes
he downs eam wind speed o a single WT [26].
Vwind,x=Vwind,0
1−1−√1−CT
1+2kwdcx
D u bine 2
(6)
Being,
Vwind,0: ee s eam wind.
Vwind,x: wind speed a dis ance x om he WT.
x: dis ance behind he u bine.
D u bine: diame e o he u bine o o .
CT: h us coe icien .
kwdc: wake decay cons an .
In an OWPP, he mul iple wake e ec among wind u bines
should be aken in o accoun . This can be done by empi ical
me hods [27] such as sum o squa es o eloci y de ici s,
ene gy balance, geome ic sum, and linea supe posi ion.
The sum o squa es o eloci y de ici s is chosen acco ding
o Ka ic ecommenda ions [28]. In his sense, he wind speed
a WTi, which is shadowed by he wake o wind u bines
WTjups eam, is gi en by equa ion (7) acco ding o e e -
ence [27].
Vwind,WTi=Vwind,0
1−
u
u
u
NWTs,up
X
j=1
βWTij 1−Vwind,WTij
Vwind,02
| {z }
kWTi
(7)
Being,
Vwind,WTi: wind speed a WTi.
Vwind,WTij : wind speed a WTidue o he incidence o he
wake o WTj.
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FIGURE 7. Wake e ec ool schema ic.
FIGURE 8. Wind speed gains o each WT o h ee di e en wind
di ec ions: wes , no hwes and no h.
NWTs,up: wind speed a WTi.
βWTij : a io o he shadowed a ea by he wake in ela ion o
he o al o o a ea AWTi.
Jensen’s model has been implemen ed in a ∗.m- ile in
Ma lab R
. This sc ip is added o he Simulink R
-based
model o he OWPP, hus conside ing WT wake e ec in
powe sys em simula ions. Fig. 7 depic s he inpu - and ou pu
a iables equi ed by he Ma lab R
sc ip .
Table 13 gi es he inpu pa ame e s equi ed by he ool.
The u bine diame e co esponds o he alue o he Mul i-
b id M5000 wind u bine om AREVA manu ac u e [29].
The alues o he wake decay cons an and h us coe icien
a e assumed acco ding o ecommenda ions p esen ed in [24].
Wind condi ions a e de ined acco ding o he wind ose
p esen ed in e e ences [30], [31]. Th ee wind di ec ions a e
conside ed o he s udies in his pape . Howe e , i is impo -
an o men ion ha o he wind di ec ions can be e alua ed
as well. The h ee wind di ec ions a e wes , no hwes , and
no h.
The wind speed gains kWTi, o he wel e WTs and o he
a o emen ioned wind condi ions, a e depic ed in Fig. 8.
The powe cu e is used o compu e he ac i e powe
e e ence o each WT as depic ed in Fig. 9. No e ha his is a
TABLE 13. Inpu pa ame e s o he wake e ec ool.
FIGURE 9. Compu a ion o he ac i e powe e e ence o each WT.
simpli ied model, in eali y, he WTs implemen a Maximum
Powe Poin T acking (MPPT) s a egy.
Fig. 10 shows he ac i e powe e e ences o each WT,
i.e., he inpu alues o P e _WTi a iable o Fig. 2 model, o
he wind di ec ions and wind speeds ha a e e alua ed in his
pape . On he o he hand, Fig. 11 depic s he es ima ed ac i e
powe gene a ion o he en i e OWPP.
IV. HARMONIC EVALUATION FOR WTs OPERATING
WITH CB-PWM MODULATION
This sec ion ca ies ou he ha monic e alua ion o WTs
ope a ing wi h CB-PWM. Fo his modula ion s a egy, he
ha monic assessmen is pe o med a wo poin s o he OWPP,
WT poin and PCC poin (see Fig. 1), and o se e al ope a-
ion condi ions.
Fig. 12 shows he ha monic spec um o a ypical
CB-PWM modula ion. Fig. 12(a) depic s he ha monic spec-
um o phase ‘‘a’’ wi h espec o he midpoin o he
DC-link. On he o he hand, Fig. 12(b) shows he line- o-line
ha monic spec um.
As no iced in Fig. 12(a), he equency modula ion index
m is equal o 23. Since his alue is no a mul iple o
h ee, each odd ha monic has posi i e-, nega i e- and ze o-
sequences. Addi ionally, he ha monic spec ums shown in
his igu e e eal he gene a ion o low o de ha monics
(e.g. 3 d, 5 h, 7 h, 9 h, e c.).
A. EVALUATION AT WT POINT
Fig. 13 shows he ha monic spec um o he cu en -signal
ia_WT 1( ) a a ed condi ion. The igu e also shows he
cu en -ha monic limi s imposed by he BDEW g id code a
WT poin . Table 14 gi es a summa y o he compliance o he
g id code o di e en ope a ing poin s conside ing se e al
wind speeds and di ec ions. Fo he e alua ed cases, he wind
u bine is no injec ing eac i e powe o he g id.
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FIGURE 21. Ha monic spec um o cu en signal ia_PCC ( ) plo ed agains
he BDEW ha monic cu en limi s a PCC poin (SCR =20). This scena io
conside s WTs ope a ing a a ed condi ion (wind di ec ion =wes , wind
speed =24 m/s), SHE-PWM modula ion and he change o he DC-link
ol age se poin o GSCs.
SHE-PWM modula ion. Two case s udies a e gi en nex o
exempli y he p e ious p oposals.
1) CHANGE OF THE DC-LINK VOLTAGE SETPOINT
Fo his complemen a y solu ion, he DC-link ol age is
modi ied wi h a low amp a ia ion, unde ce ain limi s,
un il eaching he desi ed se poin . The idea is o inc ease
he ampli ude modula ion index om a alue o 0.91 o an
app oxima e alue o 0.96. This is done by dec easing he
se poin o he DC-link ol age o he GSCs om 5700 V,
p e ious scena ios, o a ol age o 5400 V.
Fig. 21 shows he ha monic spec um o he cu en signal
ia_PCC ( ) o his case s udy a he a ed condi ion. The ig-
u e also shows he cu en -ha monic limi s imposed by he
BDEW g id code a PCC poin .
Acco ding o his igu e, he compliance o he BDEW
g id code is ul illed since he limi s imposed by he BDEW
egula ions a e no in inged. Low equency ha monics,
in e ha monics and high equency ha monics lay wi hin he
allowable limi s.
Table 22 shows a compa ison o he THDi alues o his
case s udy and p e ious scena ios. To gi e an example, he
THDi alue o he low equency subg oup is educed om
a alue o 0.337% o a alue o 0.304%. On he con a y, he
THDi alue o high equency componen s inc eased om a
alue o 0.039% o a alue o 0.052%.
Fig. 22 aids in he isualiza ion o he p e ious compa ison
by depic ing he ha monic spec um o he cu en signal
o he las wo case s udies and by showing how a ge ed
ha monics, i.e., 17 h and 19 h ha monic, a e educed. Fo
example, he ha monic o o de 17 h is educed om a alue
o 0.12% o a alue o 0.01%. Fo he case o ha monic 19 h,
his is educed om a alue o almos 0.06% o a alue o
0.017%.
TABLE 22. Compa ison o he THD alues a PCC poin o GSCs ope a ing
wi h a DC-link bus ol age o 5400 and p e ious scena ios.
FIGURE 22. Ha monic compa ison o cu en signal ia_PCC ( ). The op
igu e ep esen s he case s udy conside ing SHE-PWM and
Vbus =5700 V. The bo om igu e ep esen s he case s udy conside ing
SHE-PWM and Vbus =5400 V.
TABLE 23. Pa ame e s o he edesigned GSC connec ion il e .
Be o e con inuing wi h he nex complemen a y solu ion,
i is impo an o poin ou ha e en hough he esul s o his
case s udy a e only p esen ed a he a ed condi ion bu hey
we e also es ed a o he ope a ing poin s. BDEW g id code
is ul illed o hese o he ope a ing poin s as well.
2) REDESIGN OF THE GSC CONNECTION FILTER
Fo his complemen a y solu ion, he GSC connec ion il e
is edesigned by aking in o accoun he ha monic spec um
o SHE-PWM modula ion. The edesign o he LCL- l il e
is pe o med by ollowing he me hodology p esen ed in
e e ence [19] and depic ed in Fig. 23.
Table 23 gi es he pa ame e s o he GSC connec ion
il e ha is edesigned by aking in o accoun he p e ious
p ocedu e.
Fig. 24 shows he SHE-PWM spec um and he Bode plo
o he ans e unc ion I+
a_PCC (s)/V+
ab_GSC1(s), which is also
alid o he nega i e-sequence. The SHE-PWM spec um is
depic ed o se e al s acked ma alues.
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FIGURE 23. Me hodology o he design o he GSC connec ion il e .
Sou ce [19].
FIGURE 24. Risk o ampli ica ion o ha monics o GSCs using SHE-PWM
modula ion and edesigned il e . (a) SHE-PWM line- o-line spec um
wi h di e en ma alues s acked. (b) Bode plo o ans e unc ion
I+
a_PCC (s)/V+
ab_GSC1(s).
As shown in Fig. 24(b), he GSC connec ion il e is
designed so ha he esonance equency (new s 2) lays close
o he ha monic o o de 9 h. This is done o gua an ee ha no
ha monic exci a ion is possible since he modula ion elim-
ina es he su ounding ha monics. Fu he mo e, he LCL- l
il e is designed so ha he an i- esonan equency lays on
he 17 h ha monic, which is he i s non-elimina ed ha monic
ha appea s in he cu en . The a enua ion le el o his
ha monic is high, almos equal o −120 dB.
Fig. 25 shows he ha monic spec um o he cu en -signal
ia_PCC ( ) a he PCC poin and a he a ed condi ion. The
igu e also shows he cu en -ha monic limi s imposed by he
BDEW g id code. Acco ding o his igu e, he compliance
o he BDEW g id code is ul illed since he es ic ions o
ce i ica ion app o al a e no in inged. In ege ha monics,
in e ha monics and high equency ha monics lay wi hin he
allowable limi s. E en hough he esul s o his case s udy
a e only p esen ed a a ed condi ion bu hey we e also es ed
a o he ope a ing poin s. BDEW g id code is ul illed o
o he ope a ing poin s as well.
FIGURE 25. Ha monic spec um o cu en signal ia_PCC ( ) plo ed agains
he BDEW ha monic cu en limi s a PCC poin (SCR =20). This scena io
conside s WTs ope a ing a a ed condi ion (wind di ec ion =wes , wind
speed =24 m/s), Vbus =5700 V,ma≈0.91, SHE-PWM modula ion and
he edesign o he GSC connec ion il e .
FIGURE 26. Ha monic compa ison o cu en signal ia_PCC ( ). The op
igu e ep esen s he case s udy conside ing SHE-PWM, ini ial GSC
connec ion il e , and Vbus =5700 V. The bo om igu e ep esen s he
case s udy conside ing SHE-PWM, edesigned il e , and Vbus =5700 V.
Fig. 26 shows he spec um o he cu en -signal ia_PCC ( )
o his scena io and o he las 20 ms ime window, o be e
isualiza ion. As expec ed, ha monics o o de 17 h and 19 h
( ed ba s) a e highly educed compa ed o he i s case s udy
conside ing SHE-PWM modula ion, ini ial GSC connec ion
il e and a DC-link ol age o 5700 V.
Table 24 gi es he THDi alues o he cu en -signal
ia_PCC ( ). This able also p o ides he THDi alues o p e-
ious cases o compa a i e pu poses. I is shown ha lowe
THDi alues a e ob ained when conside ing he SHE-PWM
o ien ed il e .
The THDi alue o he low equency subg oup is u he
educed o a alue o 0.239%. An imp o emen o 2.041% is
achie ed in compa ison wi h he scena io in which he WTs
ope a e wi h a ypical CB-PWM modula ion.
Finally, i is wo h o poin ou ha he solu ion e alua ed in
his las case s udy is he mos easible among he p esen ed
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C. Ruiz e al.: WT O ien ed Solu ions o Imp o e Powe Quali y and Ha monic Compliance o AC OWPPs
TABLE 24. Compa ison o he THD alues a PCC poin o he edesign o
he GSC connec ion il e and p e ious scena ios.
ones in e ms o ha monic dis o ion le els, BDEW g id code
compliance, and complexi y.
VI. ROBUSTNESS EVALUATION DUE TO PARAMETER
UNCERTAINTY
The aim o his sec ion is o ca y ou he obus ness e al-
ua ion due o pa ame e unce ain y o he WT o ien ed
solu ions p oposed in his a icle.
To add ess his objec i e, wo main aspec s a e ana-
lyzed. Fi s , changes in Bode plo s o he ans e unc ion
I+
a_PCC (s)/V+
ab_GSC1(s), shown in p e ious sec ions, a e p e-
sen ed due o pa ame e a ia ion o he main powe com-
ponen s o he OWPP. This is pe o med o ha e a gene al
idea on how he a ia ion o hese pa ame e s changes he
equency alue o esonances ( s 1 o s 4), he ‘‘new’’ a enu-
a ion le el ha will see each ha monic and he way ha monics
o he same o de a e added a he PCC poin o he OWPP.
As second aspec , he e alua ion o ha monics is pe o med
o an SCR alue o i e, p obing ha he implemen ed con-
ol loops and he pa icula solu ion o SHE-PWM p oposed
in sec ion V gi e good esul s in e ms o ha monic compli-
ance e en when conside ing he connec ion o he OWPP o
a ela i ely weak g id.
A. CHANGES IN BODE PLOTS DUE TO PARAMETER
VARIATION
Fig. 27 o Fig. 29 depic he changes in s udied Bode plo s
when a ying he pa ame e s o he GSC connec ion il e ,
he capaci ance alues o bo h ypes o subma ine cables,
and he sho -ci cui impedance o he g id (o SCR). E en
hough he changes in Bode plo s a e shown o he posi i e-
sequence, hey a e also alid o he nega i e-sequence.
I is wo h o poin ou ha he changes depic ed nex a e
in ag eemen wi h he in o ma ion gi en by he pa icipa ion
ac o s in Table 16. I is also impo an o ake in o accoun in
conjunc ion wi h hese Bode plo s, he ha monic spec um o
SHE-PWM s a egy, al eady shown in Fig. 18(a), o p edic
he isk o ha monic ampli ica ion and he e en ual in inge-
men o he BDEW g id code.
FIGURE 27. Changes in Bode plo s o he ans e unc ion
I+
a_PCC (s)/V+
ab_GSC1(s) due o a a ia ion o GSC connec ion il e
pa ame e s. (a) Lc alue. (b) C alue. (c) Ld alue. (d) Rd alue.
Fig. 27 shows he changes in Bode plo s due o a a ia ion
o ±20% o he GSC connec ion il e pa ame e s o Table 5.
Fig. 27(a) shows he e ec o a ying he il e induc ance
Lcon he i s ou se ies esonances. Rega ding he equency
a ia ion, se ies esonance s 1 dec eases while inc easing
he induc ance alue. The maximum a ia ion is lowe han
10 Hz. On he o he hand, se ies esonance s 2 is he one
ha exhibi s he highes change, a maximum a ia ion o
app oxima ely 20 Hz. This se ies esonance dec eases while
inc easing he induc ance alue. Finally, he equency alues
o emaining esonances ba ely change. Rega ding he le el
o a enua ion, no big changes a e no iced.
Fig. 27(b) shows he e ec o a ying he il e capaci ance
C on he i s ou se ies esonances. Rega ding he e-
quency a ia ion, se ies esonance s 2 is he one ha exhibi s
he highes change, a maximum a ia ion o app oxima ely
50 Hz. This se ies esonance dec eases while inc easing
he capaci ance alue. Remaining se ies esonances ba ely
change in bo h magni ude and equency.
The Bode plo s shown in Fig. 27(c) and (d) ba ely change.
I can be in e ed om p e ious poin s ha no changes in
compa ison wi h he ones ob ained in subsec ion V.A a e
expec ed o he il e a ia ions e alua ed p e iously.
Fig. 28 shows he changes in Bode plo s due o a a ia ion
o ±20% o he capaci ance alues o he subma ine cables
gi en in Table 9 and Table 10.
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FIGURE 28. Changes in Bode plo s o he ans e unc ion
I+
a_PCC (s)/V+
ab_GSC1(s) due o he a ia ion o he capaci ance o
subma ine cables. (a) Capaci ance Ccc o he MVAC subma ine cables
(b) Capaci ance C c o he HVAC subma ine cable.
Fig. 28(a) shows he e ec o a ying he capaci ance Ccc
alue on he i s ou se ies esonances. Rega ding he e-
quency a ia ion, se ies esonance s 4 is he one ha exhibi s
he highes change, a maximum a ia ion o app oxima ely
250 Hz. This se ies esonance dec eases while inc easing
he capaci ance alue. Remaining se ies esonances ba ely
change in bo h magni ude and equency.
I can be in e ed om p e ious easons ha no changes
in compa ison wi h he ones ob ained in subsec ion V.A a e
expec ed o his case o ha monics o o de lowe han 40.
Fo ha monics o o de 40 o 60, changes in hei magni-
udes a e expec ed in compa ison wi h he ones ob ained in
subsec ion V.A.
Fo he case o Fig. 28(b), he e is no isk o ha monic
ampli ica ion since low o de ha monics a ound he i s
se ies esonance s 1 a e no injec ed by pa icula solu ion
o SHE-PWM p esen ed in sec ion V. The main conce n is
o ensu e he s abili y o he sys em since he low equency
alue o esonance s 1, a ound 260 Hz ( ed line) and e en
lowe o o he cases, can a ec he bandwid h o he WT
con ol loops and make he sys em uns able i i is no p op-
e ly uned.
In his sense and in o de o gua an ee he s abili y o he
sys em, wo possible ac ions can be employed:
- A educ ion o he bandwid h o he WT con ol loops
(cu en -con ol bandwid h, PLL bandwid h, measu e-
men il e s bandwid h, e c.). The main d awback o his
s a egy is ha he dynamic beha io o he sys em will
be slowe . This is ha he se ling ime and ising ime
will be inc eased which is no always an op ion.
- The implemen a ion o ad anced con ol s uc u es such
as ac i e damping s a egies.
Fig. 29 shows he changes in Bode plo s due o a a ia ion
o he SCR alue. The SCR alue is a ied om a alue o
20 o a alue o i e wi h an addi ional middle alue o 10.
An SCR equal o 20 ep esen s a s ong g id while an SCR
alue o i e ep esen s a ela i ely weak g id [37].
FIGURE 29. Changes in Bode plo s o he ans e unc ion
I+
a_PCC (s)/V+
ab_GSC1(s) due o a a ia ion o he sho ci cui a io (SCR) o
he powe g id.
FIGURE 30. Ha monic spec um o cu en signal ia_PCC ( ) plo ed agains
he BDEW ha monic cu en limi s a PCC poin (SCR =5). This scena io
conside s WTs ope a ing a a ed condi ion (wind di ec ion =wes , wind
speed =24 m/s), Vbus =5700 V,ma≈1.15, SHE-PWM modula ion, and
GSC connec ion il e alues o Table 5.
In gene al, i can be concluded ha connec ing he OWPP
base scena io o a weak g id ends o loca e he esonance
s 1 o lowe equency alues. This esonance is shi ed in
equency om a alue o 287.88 Hz o an app oxima e alue
o 190 Hz o he a ia ions e alua ed.
To e alua e he ha monic compliance o his las case, he
BDEW ha monic limi s needs o be upda ed acco ding o he
in o ma ion p esen ed in subsec ion II.B since he SCR alue
has changed.
Fo he scena ios p esen ed in Fig. 28(b) and Fig. 29, ime-
domain simula ions mus be un o ake in o accoun bo h,
s abili y and ha monic compliance o he g id codes. I is no
an easy ask o p edic he expec ed ou come as in compa ison
wi h he conclusions s a ed o Fig. 27.
B. HARMONIC EVALUATION OF THE OWPP BASE
SCENARIO WITH SCR =5
In o de o pe o m he ha monic e alua ion o he OWPP
base scena io wi h a SCR alue o i e, ime-domain simula-
ions a e un o e i y he ul illmen o he BDEW g id code
in e ms o ha monics.
Fig. 30 shows he ha monic spec um o he cu en -signal
ia_PCC ( ) a he PCC poin and as close as possible o he
a ed condi ion. The igu e also shows he upda ed cu en -
ha monic limi s imposed by he BDEW g id code when
167114 VOLUME 9, 2021
C. Ruiz e al.: WT O ien ed Solu ions o Imp o e Powe Quali y and Ha monic Compliance o AC OWPPs
conside ing a SCR alue o i e. Acco ding o his igu e,
he compliance o he BDEW g id code is ul illed since he
es ic ions o ce i ica ion app o al a e no in inged.
In ege ha monics, in e ha monics and high equency ha -
monics lay wi hin he allowable limi s.
E en hough he compliance o he BDEW g id code
is ul illed, i is impo an o no e ha ha monics o
o de 17 and 19 a e e y close o he maximum allowable
limi s. This should be conside ed as a wa ning message and
an aspec o u he imp o e.
VII. CONCLUSION
This pape has p esen ed he ha monic e alua ion o an
OWPP scena io. I is wo h o poin ou ha he s udies and he
modeling app oach p esen ed in his pape se e as a gene ic
simula ion ool o s akeholde s wi hin he wind powe indus-
y, o conduc ha monic s udies and e alua e he g id code
compliance o an OWPP om a powe quali y pe spec i e
and du ing i s design s age. The ollowing conclusions can
be poin ed ou ega ding he s udies ca ied ou .
Fi s and in gene al e ms, he ha monic assessmen mus
be ca ied ou no only a wind u bine le el bu also a
wind powe plan le el, i.e., a he PCC poin o he OWPP,
and o di e en ope a ing poin s, ac i e- and eac i e-powe
e e ences.
As p esen ed in sec ion IV-A o WTs ope a ing wi h he
commonly used CB-PWM modula ion, he ha monic e alua-
ion a WT le el esul s in he local compliance o he BDEW
g id code. Howe e , he ul illmen o he g id code migh
no be achie ed o se e al ope a ing poin s when pe o ming
he ha monic e alua ion o an OWPP wi h esonances a low
equency alues. Thus, addi ional wind u bine analyses o
speci ic applica ions (i.e. wind a m layou , ansmission link
dis ance, sho -ci cui a io o he g id, and o he cha ac e is-
ics o he elec ical ne wo k) a e needed.
An example o he a o emen ioned si ua ion has been ca -
ied ou in sec ion IV-B whe e he compliance o he BDEW
g id code a he PCC poin o he OWPP base scena io is no
achie ed. Fo his scena io, h ee impo an ac o s hea ily
a ec he cu en ha monic emission and he compliance o
he BDEW g id code.
Fi s , he magni ude o he ha monics injec ed by he
GSCs. Second, he a enua ion le el o he sys em a ound
hese ha monics, especially i a esonance ma ches o is close
o a ce ain ha monic o ha monics. Thi d, he way ha monics
o he same o de a e added a a speci ic poin o he OWPP.
The summa ion o ha monics depends mainly on he ope -
a ing poin o he wind u bines and he phase shi o he
elec ical in as uc u e o he OWPP ha sees each WT.
To imp o e he ha monic emission o he OWPP and he
compliance o he g id code in e ms o ha monics, WT o i-
en ed solu ions ha e been p esen ed in his pape . The imple-
men a ion o a pa icula solu ion o SHE-PWM modula ion
has been p esen ed oge he wi h complemen a y solu ions
o u he imp o e he ha monic emission o he OWPP.
This ype o modula ion s a egy is mo e sui ed o be used
in scena ios o OWPPs ha ing esonances a low- equency
alues (a ound 100 Hz o 400 Hz), as he analyzed. The
obus ness e alua ion is done showing ha o a SCR alue
o i e (weak g id), he solu ion p oposed in his a icle s ill
mee s he g id code in e ms o ha monics.
E en hough, his obus ness e alua ion is me o o he
condi ions, he e a e open p oblems and u u e issues ha
he au ho s encou age hei u he in es iga ion. One o
hem is he e alua ion and compa ison o o he modula ion
schemes o he WTs, such as Selec i e Ha monic Mi iga ion
(SHM-PWM) which educes, does no elimina es, he mag-
ni ude o a g ea e numbe o ha monics o a gi en numbe
o ansi ion angles.
Ano he aspec o ocus on is he design o ad anced WT
con ol s a egies ha ensu e he s abili y o he sys em o
a wide ange o pa ame e a ia ions and mainly when he
OWPP is connec ed o an ex emely weak g id o when he
pe u ba ion capabili y o he OWPP canno be neglec ed.
As las poin and mixing he p e ious wo aspec s, he
design o an uppe le el algo i hm implemen ed in he wind
u bines ha au oma ically changes he modula ion s a egy
and/o unes he con ol loops o achie e s abili y and o mee
g id code equi emen s in e ms o ha monics.
REFERENCES
[1] L. H. Kocewiak, Ha monics in La ge O sho e Wind Fa ms. Aalbo g,
Denma k: Aalbo g Uni ., 2012.
[2] I. E lich, F. Shewa ega, C. Fel es, F. W. Koch, and J. Fo mann, ‘‘O -
sho e wind powe gene a ion echnologies,’’ P oc. IEEE, ol. 101, no. 4,
pp. 891–905, Jan. 2012.
[3] T. Acke mann, Wind Powe in Powe Sys ems, 2nd ed. Hoboken, NJ, USA:
Wiley, 2012.
[4] D. Xu, F. Blaabje g, W. Chen, and N. Zhu, Ad anced Con ol o Doubly
Fed Induc ion Gene a o o Wind Powe Sys ems, 1s ed. Hoboken, NJ,
USA: Wiley, 2018.
[5] L. Sainz, L. Monjo, J. Ped a, M. Cheah-Mane, J. Liang, and
O. Gomis-Bellmun , ‘‘E ec o wind u bine con e e con ol on
wind powe plan ha monic esponse and esonances,’’ IET Elec . Powe
Appl., ol. 11, no. 2, pp. 157–168, Feb. 2016.
[6] S. Zhang, S. Jiang, X. Lu, B. Ge, and F. Z. Peng, ‘‘Resonance issues
and damping echniques o g id-connec ed in e e s wi h long ansmis-
sion cable,’’ IEEE T ans. Powe Elec on., ol. 29, no. 1, pp. 110–120,
Jan. 2014.
[7] J. B. Glasdam, ‘‘Ha monics in o sho e wind powe plan s employing
powe elec onic de ices in he ansmission sys em,’’ Aalbo g Uni .,
Aalbo g, Denma k, Tech. Rep., 2015.
[8] H. Kocewiak, J. Hje ild, and C. L. Bak, ‘‘Wind u bine con e e con ol
in e ac ion wi h complex wind a m sys ems,’’ IET Renew. Powe Gene .,
ol. 7, no. 4, pp. 380–389, Jul. 2013.
[9] E. Eb ahimzadeh, F. Blaabje g, T. Lund, J. G. Nielsen, and P. C. Kjæ ,
‘‘Modelling and s abili y analysis o wind powe plan s connec ed o weak
g ids,’’ Appl. Sci., ol. 9, no. 21, p. 4695, No . 2019.
[10] Z. Liu, J. Rong, G. Zhao, and Y. Luo, ‘‘Ha monic assessmen o wind
pa ks based on sensi i i y analysis,’’ IEEE T ans. Sus ain. Ene gy, ol. 8,
no. 4, pp. 1373–1382, Oc . 2017.
[11] K. Yang, ‘‘On ha monic emission, p opaga ion and agg ega ion in wind
powe plan s,’’ Lulea Uni . Technol., Luleå, Sweden, Tech. Rep., 2015.
[12] C. Ruiz, M. Zubiaga, G. Abad, D. Mada iaga, and J. A za, ‘‘Valida ion o
a wind u bine ha monic model based on he gene ic ype 4 wind u bine
S anda d,’’ in P oc. 20 h Eu . Con . Powe Elec on. Appl., 2018, p. 10.
[13] C. Ruiz, G. Abad, M. Zubiaga, D. Mada iaga, and J. A za, ‘‘F equency-
dependen Pi model o a h ee-co e subma ine cable o ime and equency
domain analysis,’’ Ene gies, ol. 11, no. 10, p. 2778, Oc . 2018.
[14] Fac -Shee Alpha Ven us, Alpha en us, 2015.
[15] M. Zubiaga, G. Abad, and J. A. Ba ena, Ene gy T ansmission and G id
In eg a ion o AC O sho e Wind Fa ms. Rijeka, C oa ia: InTech, 2012.
VOLUME 9, 2021 167115
C. Ruiz e al.: WT O ien ed Solu ions o Imp o e Powe Quali y and Ha monic Compliance o AC OWPPs
[16] Technical Guideline—Gene a ing Plan s Connec ed o he Medium-
Vol age Ne wo k, BDEW, Be lin, Ge many, 2008.
[17] Rules and T ansi ional Pe iods o Speci ic Requi emen s Complemen a y
o he Technical Guideline?: Gene a ing Plan s Connec ed o he Medium-
Vol age Ne wo k—Guideline o Gene a ing Plan s’ Connec ion o and
Pa allel Ope a ion Wi h he Medium-Vol age, BDEW, Be lin, Ge many,
2013.
[18] M. B ad , B. Bad zadeh, E. Camm, D. Muelle , J. Schoene, T. Siebe ,
T. Smi h, M. S a ke, and R. Walling, ‘‘Ha monics and esonance issues
in wind powe plan s,’’ in P oc. PES T&D, May 2012, pp. 1–8.
[19] M. Zabale a, E. Bu gue e, D. Mada iaga, I. Zubimendi, M. Zubiaga, and
I. La azabal, ‘‘LCL g id il e design o a mul imegawa medium- ol age
con e e o o sho e wind u bine using SHEPWM modula ion,’’ IEEE
T ans. Powe Elec on., ol. 31, no. 3, pp. 1993–2001, Ma . 2016.
[20] N. Chiesa and B. Gus a sen, ‘‘F equency-dependen modeling o ans-
o me winding impedance om R(w)/L measu emen s,’’ IEEE T ans.
Powe Deli ., ol. 29, no. 3, pp. 1511–1513, Feb. 2014.
[21] Subma ine Powe Cables, Nexans, Pa is, F ance, 2013.
[22] XLPE Subma ine Cable Sys ems, ABB, Zü ich, Swi ze land, 2014.
[23] Na ional G id ESO, Elec ici y Ten Yea S a emen 2012, Appendix E:
Technology Shee s. 2012.
[24] M. De-P ada-Gil, C. G. Alías, O. Gomis-Bellmun , and A. Sumpe , ‘‘Max-
imum wind powe plan gene a ion by educing he wake e ec ,’’ Ene gy
Con e s. Manage., ol. 101, pp. 73–84, Sep. 2015.
[25] R. J. Ba helmie, G. C. La sen, S. T. F andsen, L. Folke s, K. Rados,
S. C. P yo , B. Lange, and G. Schepe s, ‘‘Compa ison o wake model
simula ions wi h o sho e wind u bine wake p o iles measu ed by soda ,’’
J. A mos. Ocean. Technol., ol. 23, no. 7, pp. 888–901, Jul. 2006.
[26] N. O. Jensen, ‘‘A no e on wind gene a o in e ac ion,’’ Tech. Rep., 1983,
pp. 1–16.
[27] M. Thø ge sen, T. Sø ensen, and P. Nielsen, ‘‘WindPRO/PARK: In o-
duc ion o wind u bine wake modelling and wake gene a ed u bulence,’’
Tech. Rep., 2005.
[28] I. Ka ic, J. Hojs up, and N. O. Jensen, ‘‘A simple model o clus e
e iciency,’’ in P oc. EWEC, ol. 1, 1986, pp. 407–410.
[29] AlphaVen us. (2019). Alpha Ven us. [Online]. A ailable: h ps://www.
alpha- en us.de/english
[30] A. Wes e hellweg, B. Cañadillas, F. Kinde , and T. Neumann, ‘‘Wake
measu emen s a alpha en us–dependency on s abili y and u bulence
in ensi y,’’ J. Phys., Con . Se ., ol. 555, Dec. 2014, A . no. 012106.
[31] A. Wes e hellweg, B. Canadillas, F. Kinde , and T. Neumann, ‘‘De ailed
analysis o o sho e wakes based on wo yea s da a o alpha en us and
compa ison wi h CFD simula ions,’’ DEWI Mag., ol. 22, no. 42, p. 7,
2013.
[32] G. Ve ghese, I. Pe ez-A iaga, and F. Schweppe, ‘‘Selec i e modal anal-
ysis wi h applica ions o elec ic powe sys ems, Pa II: The dynamic
s abili y p oblem,’’ IEEE T ans. Powe App. Sys ., ol. PAS-101, no. 9,
pp. 3126–3134, Sep. 1982.
[33] I. Pe ez-A iaga, G. Ve ghese, and F. Schweppe, ‘‘Selec i e modal analysis
wi h applica ions o elec ic powe sys ems, PART I: Heu is ic in oduc-
ion,’’ IEEE T ans. Powe App. Sys ., ols. PAS–101, no. 9, pp. 3117–3125,
Sep. 1982.
[34] B. Wu, High-Powe Con e e s and AC D i es. Hoboken, NJ, USA: Wiley,
2006.
[35] E. F. Fuchs and M. Masoum, Powe Quali y in Powe Sys ems and Elec i-
cal Machines, 2nd ed. New Yo k, NY, USA: Academic, 2015.
[36] F. Blaabje g, Con ol o Powe Elec onic Con e e s and Sys ems, ol. 1.
New Yo k, NY, USA: Academic, 2018.
[37] M. Gup a, A. Ma inez, and S. Saylo s, ‘‘Expe iences wi h wind powe
plan s wi h low SCR,’’ Tech. Rep., Ma . 2015, pp. 1–24.
CARLOS RUIZ was bo n in Managua, Nica agua,
in 1989. He ecei ed he M.Sc. deg ee in powe
elec onics and he Ph.D. deg ee in elec ical engi-
nee ing om Mond agon Uni e si y, Spain, in
2015 and 2020, espec i ely.
He wo ked as a pa - ime Teache wi h he
Elec onics Depa men , Na ional Uni e si y o
Enginee ing, Nica agua, in 2012, 2013, and 2016.
In 2020, he joined he Elec onics and Compu e
Depa men , Mond agon Uni e si y. His main
esea ch in e es s include he ha monic e alua ion and s abili y analysis o
elec ical powe sys ems, mainly o sho e wind powe plan s.
GONZALO ABAD ecei ed he deg ee in elec-
ical enginee ing om Mond agon Uni e si y,
in 2000, he M.Sc. deg ee in ad anced con ol om
The Uni e si y o Manches e , U.K., in 2001, and
he Ph.D. deg ee in elec ical enginee ing om
Mond agon Uni e si y, in 2008.
He joined he Elec onics and Compu ing
Depa men , Mond agon Uni e si y, in 2001.
He has coau ho ed se e al a icles, pa en s, and
books in he a eas o wind powe gene a ion, mul-
ile el powe con e e s, and con ol o elec ic d i es. His main esea ch
in e es s include enewable ene gies, powe con e sion, and mo o d i es.
MARKEL ZUBIAGA ecei ed he M.Sc. deg ee in
elec ical enginee ing and he Ph.D. deg ee om
Mond agon Uni e si y, Spain, in 2005 and 2011,
espec i ely.
Since 2011, he has been wo king as a Resea ch
and De elopmen Enginee wi h he Renew-
able Ene gy Sys ems Depa men , Inge eam. His
esea ch in e es s include powe elec onics, wind
powe , g id o ming con ol, and ene gy ansmis-
sion sys ems.
DANEL MADARIAGA was bo n in Bilbao, Spain,
in 1973. He ecei ed he M.Eng. deg ee in indus-
ial enginee ing om he Uni e si y o he Basque
Coun y, Bilbao, in 1998, and he M.Sc. deg ee in
physics om UNED, Mad id, Spain, in 2008.
In 1998, he joined he Resea ch and De el-
opmen Depa men , Inge eam Technology, S.A.,
Zamudio, Spain, whe e he was mainly in ol ed
in esea ch on high-powe in e e s, especially on
ec o con ol, i mwa e design and p og amming,
ma hema ical modeling, space- ec o pulsewid h modula ion (PWM), and
h ee-le el neu al-poin -clamped in e e s. His cu en esea ch in e es s
include sol ing he polynomial equa ion sys ems appea ing in selec i e
ha monic elimina ion PWM echniques, and modula ion echniques o bal-
ancing he dc bus o 3-L NPC in e e s.
JOSEBA ARZA ecei ed he B.Sc. deg ee in
powe elec onics om he Uni e si y o Mon-
d agon, Spain, in 1994, he M.Sc. deg ee in elec-
ic machines om he École Na ionale Supé ieu e
d’Ingénieu s Élec iciens de G enoble, F ance,
in 1996, and he Ph.D. deg ee in d i es con ol
and egula ion om he Ins i u Na ional Poly ech-
nique de G enoble, F ance, in 1999.
In 1999, he joined Inge eam as a Resea ch and
De elopmen Enginee in con ol and egula ion
o indus y, ma ine, ac ion, wind, sola , and g id applica ions. Since 2016,
he has been he Resea ch and De elopmen Manage wi h Inge eam Powe
Technology, S.A., and he Managing Di ec o wi h Inge eam Resea ch and
De elopmen Eu ope, S.L.
167116 VOLUME 9, 2021
