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Elec ical Powe and Ene gy Sys ems
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Cha ac e iza ion o non-in en ional emissions om dis ibu ed ene gy
esou ces up o 500 kHz: A case s udy in Spain
I. Fe nandez
a
, N. U ibe-Pé ez
b
, I. Eizmendi
a
, I. Angulo
a
, D. de la Vega
a,⁎
, A. A inda
a
, T. A zuaga
c
a
Dp . Communica ions Enginee ing, Uni e si y o he Basque Coun y (UPV/EHU), Alda. U quijo s/n, 48013 Bilbao, Spain
b
Tecnalia Resea ch & Inno a ion, Pa que Tecnológico de Vizcaya Ed. 700, 48160 De io, Vizcaya, Spain
c
ZIV Au oma ion, Zamudio, Spain
ARTICLE INFO
Keywo ds:
Dis ibu ed ene gy esou ces
Elec omagne ic in e e ence
Elec omagne ic measu emen s
Na owBand powe line communica ions
Noise measu emen
Non-in en ional emissions
ABSTRACT
Na ow Band Powe Line Communica ions (NB-PLC) sys ems a e cu en ly used o sma me e ing and powe
quali y moni o ing as a pa o he Sma G id (SG) concep . Howe e , non-in en ional emissions gene a ed by
he de ices connec ed o he g id may some imes dis u b he communica ions and isola e me e ing equipmen .
Though some esea ch wo ks ha e been ecen ly de eloped o cha ac e ize hese emissions, mos o hem ha e
been limi ed o equencies below 150 kHz and hey a e mainly ocused on in-house elec onic appliances and
ligh ning de ices. As NB-PLC can also be alloca ed in highe equencies up o 500 kHz, he e is s ill a lack o
analysis in his equency ange, especially o emissions om Dis ibu ed Ene gy Resou ces (DERs). The
iden ifica ion and cha ac e iza ion o he emissions is essen ial o de elop solu ions ha a oid a nega i e impac
on he p ope pe o mance o NB-PLC.
In his wo k, he non-in en ional emissions o diffe en ypes o DERs composing a ep esen a i e mic og id
ha e been measu ed in he 35–500 kHz equency ange and analyzed bo h in ime and equency domains.
Diffe en wo king condi ions and coupling and commu a ion p ocedu es o mains a e conside ed in he analysis.
Resul s a e hen compa ed o he limi s ecommended by egula o y bodies o spu ious emissions om com-
munica ion sys ems in his equency band, as no specific limi s o DERs ha e been es ablished. Field mea-
su emen s show clea diffe ences in he cha ac e is ics o non-in en ional emissions o diffe en de ices,
wo king condi ions and coupling p ocedu es and o equencies below and abo e 150 kHz. Resul s o his s udy
demons a e ha a u he cha ac e iza ion o he po en ial emissions om he diffe en ypes o DERs connec ed
o he g id is equi ed in o de o gua an ee cu en and u u e applica ions based on NB-PLC.
1. In oduc ion
Dis ibu ed Ene gy Resou ces (DERs), including Dis ibu ed
Gene a ion (DG) and Dis ibu ed S o age (DS), a e being p og essi ely
in eg a ed in he Low Vol age (LV) sec ion o he elec ical ne wo k and
hei managemen needs o be accomplished o he p ope unc ioning
o he Sma G ids (SGs).
Fo his pu pose, se e al echnologies o Na owBand Powe Line
Communica ions (NB-PLC) o p o ide da a ansmission in sma me-
e ing sys ems ha e been de eloped [1,2]:
•PRIME (PoweRline In elligen Me e ing E olu ion) specifica ion [3],
published by In e na ional Telecommunica ion Union in Re-
commenda ion ITU-T G.9904 [4], includes 2 e sions: PRIME 1.3.6
[5] and PRIME 1.4 [6,7].
•G3-PLC specifica ion [8], published in Recommenda ion ITU-T
G.9903 [9].
•IEEE 1091.2 s anda d [10].
These NB-PLC echnologies ope a e in he 3–500 kHz equency
ange, which includes CENELEC bands (3–148.5 kHz) defined by he
Comi é Eu opéen de No malisa ion Elec o echnique, he FCC band
(9–490 kHz) se by he Uni ed S a es Fede al Communica ions
Commission, and he ARIB band (10–450 kHz) specified by he
Japanese Associa ion o Radio Indus ies and Businesses [11]. Mos o
he ecen ly de eloped communica ion echnologies a oid he lowes
equency ange (3–30 kHz) due o he high le el o noise and in e -
e ing emissions exis ing in he elec ical g id.
Al hough NB-PLC echnologies allow he use o obus modula ion
and coding echniques, s ong dis u bances p esen in he ansmission
h ps://doi.o g/10.1016/j.ijepes.2018.08.048
Recei ed 1 Ap il 2018; Recei ed in e ised o m 13 July 2018; Accep ed 26 Augus 2018
⁎
Co esponding au ho .
E-mail add ess: [email p o ec ed] (D. de la Vega).
Elec ical Powe and Ene gy Sys ems 105 (2019) 549–563
A ailable online 06 Sep embe 2018
0142-0615/ © 2018 The Au ho s. Published by Else ie L d. This is an open access a icle unde he CC BY license
(h p://c ea i ecommons.o g/licenses/BY/4.0/).
T
channel may deg ade he communica ions in some cases. These channel
dis u bances a e mainly non-in en ional emissions in he NB-PLC e-
quency bands gene a ed by de ices connec ed o he elec ical g id,
such as elec onic appliances and ligh ning de ices, bu also DERs such
as pho o ol aic (PV) in e e s, ba e y cha ge s, hyd opowe sys ems o
wind u bines. As mo e enewable powe gene a o s, elec ic ehicle
(EV) cha ge s and ene gy-efficien de ices a e added o he g id, he
numbe and ampli ude o he emissions inc eases. The p ope cha -
ac e iza ion o he diffe en ypes o non-in en ional emissions is e-
qui ed o know in ad ance he po en ial in e e ences ha NB-PLC will
ha e o ace. As a e e ence, in Decembe 2017, he IEC es ablished a
join wo king g oup o TC77A and CISPR SC/H o define equi emen s
o he egula ion o emissions om 2 kHz o 150 kHz, in o de o en-
su e he compa ibili y o elec ical p oduc s. CENELEC has ecen ly
ecommended he analysis o he non-in en ional emission le els bo h
in ime and equency domains also [12].
Mo eo e , he cha ac e iza ion o non-in en ional emissions in he
elec ical g id has been mainly limi ed o he equency ange up o
150 kHz; howe e , he e is an inc easing in e es in Eu ope o ex end
he equency ange o NB-PLC up o 500 kHz. As ew field measu e-
men s ha e been ca ied ou o hese highe equencies, pa icula ly
o DERs, a de ailed cha ac e iza ion o he diffe en ypes o non-in-
en ional emissions in he equency ange up o 500 kHz is needed, in
o de o es ima e i hese emissions migh cause p oblems in he com-
munica ions, and he e o e, i hey should be limi ed h ough egula-
ion. A po en ial solu ion is ha he u u e coding echniques used by
NB-PLC in hese highe equencies mus be adap ed o ace he di -
e en ypes o dis u bances o he p opaga ion channel, in o de o
ensu e he da a ansmission.
In his pape , non-in en ional emissions gene a ed by diffe en ypes
o DERs ha compose a ep esen a i e mic og id ha e been measu ed
and cha ac e ized in he equency ange om 35 kHz o 500 kHz. This
equency ange includes cu en and expec ed equencies used by he
abo e-men ioned NB-PLC ansmission echnologies. Field measu e-
men s we e ca ied ou acco ding o he measu ing me hods e-
commended by CISPR (Comi é In e na ional Spécial des Pe u ba ions
Radioélec iques) o complian ecei e s, including wo ypes o de-
ec o s: CISPR quasi-peak and CISPR a e age [13–15]. The emissions
eco ded in he field measu emen s ha e been compa ed o he limi s
defined by he Eu opean S anda d EN-50065-1 o conduc ed pe u -
ba ions om mains communica ing equipmen [16], as no specific
limi s o DERs ha e been es ablished. The esul s o he pape will help
o enable he p ope pe o mance o NB-PLC in an elec ical g id wi h a
high numbe o DERs.
The pape is o ganized as ollows. Fi s , non-in en ional emissions
analyzed in diffe en p e ious measu emen campaigns a e summa ized
in Sec ion 2. Then, in Sec ions 3 and 4 he measu emen campaign ha
has been specifically ca ied ou in his wo k and he analysis o he
esul s ob ained om measu emen s a e ho oughly desc ibed, espec-
i ely. Finally, he main conclusions, including he po en ial effec o
non-in en ional emissions on NB-PLC, a e desc ibed in Sec ion 5.
2. Non in en ional emissions gene a ed by de ices connec ed o
he g id
Th oughou he li e a u e, non-in en ional emissions ha e been
mainly classified in h ee diffe en ypes [17,18]:
•Impulsi e noise: he swi ching p ocedu e o powe ansis o s used
o DC/AC con e sion gene a es impulsi e signals o high ampli ude
a ound 100 kHz and abo e.
•Ha monics o he swi ching equency: swi ching de ices gene a e
spu ious signals in mul iples o he swi ching equency, which is
usually abo e 10 kHz, o in o he cases e en abo e 20 kHz o be
inaudible.
•Colo ed backg ound noise: his kind o noise is usually highe in
lowe equencies and i can be cha ac e ized by se e al sou ces o
whi e noise in non-o e lapping equency bands.
CENELEC, he Eu opean commi ee o elec o- echnical s anda di-
za ion, launched he SC 205 Wo king G oup 11 o p omo e, ga he and
analyze non-in en ional emissions in elec ical g ids, and o de e mine
adequa e immuni y le els o communica ions. The p oblema ic o non-
in en ional emissions is summa ized in he s udy epo SC 205 A o
CENELEC [12]. Addi ionally, he IEC has launched a join wo king
g oup o TC77A and CISPR SC/H o define equi emen s o he eg-
ula ion o emissions, in o de o ensu e he compa ibili y o elec ical
p oduc s in he equency band assigned o NB-PLC.
Acco ding o he eques s o hese egula o y bodies and s anda -
diza ion commi ees, in his epo , some examples o non-in en ional
emissions gene a ed by a wide ange o de ices o he 2–150 kHz ange
a e analyzed, and a a lowe ex en , o equencies up o 500 kHz:
•Powe supplies: These de ices usually include a small in e e ha
employs swi ching echniques and, as obse ed in some measu e-
men campaigns, he le els o he gene a ed non-in en ional emis-
sions could be high [19–21]. I was also demons a ed in o he
s udies based on measu emen s ha he powe supplies o diffe en
elec onic de ices gene a ed emissions ha affec ed he NB-PLC
[22–29].
•Elec onic de ices including in e e s: The powe de ices ha in-
clude in e e s (such as ele a o s o unin e up ed powe supplies)
a e being mo e equen ly used bo h in comme cial and esiden ial
en i onmen s [30]. Some esea ch ca ied ou in diffe en en i on-
men s wi h diffe en ypes o in e e s (including PV sys ems)
p o ed ha he ha monics o he swi ching equencies eached
conside able le els [19,31,32]. The non-in en ional emissions gen-
e a ed by de ices such as PV in e e s, in e e s o he con ol o
engines o he ones included in some washing machines some imes
dis u bed he communica ions [23,33–37].
•Elec ic ools: Tools such as d ills and saws also gene a ed emissions,
in his case, up o 500 kHz, as demons a ed in [19].
•Ligh ning equipmen : The non-in en ional emissions gene a ed by
compac lamps, fluo escen lamps and LED lamps we e also ana-
lyzed in some measu emen campaigns up o 500 kHz [38–40].In
o he s udies, i was obse ed ha he communica ions be ween
diffe en de ices we e some imes los [41,42].
•O he equipmen such as he ec ifie s included in cell owe s and
fibe swi ches some imes affec ed he communica ions [43,44].
This Wo king G oup is now demanding ecen esul s in his a ea
ha p o ide he basis o upda ed c i e ia and e e ence le els [12].
Apa om he s udy epo SC 205 A o CENELEC, o he mea-
su emen s campaigns ha e been ca ied ou in he las yea s, al hough
he analyzed equency ange has been mainly limi ed o 2–150 kHz
[18,45–59]. All hese s udies demons a e he need o ca y ou addi-
ional field measu emen s, mainly o DER de ices, due o he wide
a ie y o de ices ha gene a e emissions o diffe en na u e, le el and
a ia ion in ime and equency.
In many o he desc ibed s udies, he ol age le els we e usually
compa ed o limi s defined by CISPR specifica ions:
•Non-in en ional emissions gene a ed by ligh ning equipmen
(CISPR15, EN 55015) [60].
•Non-in en ional emissions gene a ed by induc ion cooking equip-
men (CISPR11, EN 55011) [61].
•In en ional emissions gene a ed by mains communica ing equip-
men (EN 50065-1).
•Non-in en ional emissions gene a ed by mains communica ing
equipmen (EN 50065-1).
These limi s, oge he wi h he ol age limi s o in en ional
I. Fe nandez e al. Elec ical Powe and Ene gy Sys ems 105 (2019) 549–563
550
communica ion signals gi en in IEC 61000-2-5 [62] and he limi s
gi en in EN 50160 [63], ela ed o elec ic powe quali y, we e pub-
lished by IEC in he documen TS 62578 Ed. 2:2012 [64] (see Fig. 1).
Howe e , specific limi s o non-in en ional emissions om DERs
and o he ypes o equipmen ha e no been es ablished ye , so ha he
limi s o pe u ba ions gene a ed by mains communica ing equipmen
gi en in EN 50065-1 ha e been gene ally used as a e e ence [18].
These specific limi s a e labeled in Fig. 1 as ‘non-in en ional PLC ou -o -
band emission’. A compelling easoning o his assump ion is p oposed
in [45], based on he ac ha he emission limi s o PLC de ices ac-
co ding o EN 50065-1, which a e he mos es ic i e limi s, should be
applied o ensu e he p ope pe o mance o he communica ions. Fo
his eason, in he p esen s udy, he non-in en ional emissions ob ained
in he field measu emen s will be compa ed o he limi s de e mined by
EN 50065-1 o PLC de ices, shown in he abo e-men ioned cu e, a
he bo om in Fig. 1.
Addi ionally, he EN 50065-1 defines diffe en le els o he limi s,
conside ing ha CISPR quasi-peak and CISPR a e age de ec o s can be
used [13–15]. O iginally, hese de ec o s we e defined o be im-
plemen ed by analog componen s; nowadays, hey a e usually im-
plemen ed using digi al signal p ocessing, as in his wo k [13]. The
quasi-peak de ec o is in ended o de ec he maximum alues o he
signal, bu applying RC fil e ing in o de o smoo h he ansi ions, as
he peak alue is eached a e he cha ging ime o he cha ge RC fil e
and he discha ge ansi ion is fla ened by he esponse o he dis-
cha ge RC fil e . The ou pu o hese fil e s is hen sen o ano he fil e
ha simula es a c i ically damped me e . In he case o he a e age
de ec o , i a e ages a se o inpu alues and again he esul is e ch o
a c i ically damped me e . The cha ging and discha ging RC fil e s and
he c i ically dumped me e a e digi ally implemen ed by IIR fil e s.
The cu es de e mined by EN 50065-1 o PLC de ices, conside ing
quasi-peak o a e age de ec o s, a e ep esen ed in Fig. 2,up o
500 kHz. Unlike Fig. 1, hey a e ep esen ed in linea scale, o acili a e
a di ec link o he esul s o he field measu emen s.
3. Measu emen campaign and da a p ocessing
3.1. Mic og id equipped wi h dis ibu ed ene gy gene a ion and s o age
The measu emen campaign was ca ied ou a CEDER-CIEMAT
acili ies, a na ional ins i u ion o he esea ch, g ow h and p omo ion
o enewable ene gies, whe e a eal mic og id was ins alled o be
managed and moni o ed [65].AsFig. 3 shows, his mic og id is com-
posed o se en Medium Vol age (MV) o Low Vol age (LV) T ans o -
ma ion Cen e s (TCs), each TC p o ided wi h one o wo Powe
T ans o me s (PTs). A wide ange o DG and DS sys ems a e p esen a
he diffe en LV pa s o he mic og id, including PV in e e s, ba e ies
and ba e y cha ge s, wind u bines, and a hyd opowe sys em com-
posed o a u bine and a pump. They o m a ep esen a i e dis ibu ed
mic og id ha includes dis ibu ed enewable gene a ion, s o age and
consump ion. Each de ice is p o ided wi h a sma me e (SM) ha
implemen s PRIME 1.3.6 s anda d o ad anced me e ing, con ol and
moni o ing.
Fig. 4 shows a mo e de ailed scheme o one o he se en TCs o he
mic og id (PEPA III). This is one o he wo cen e s wi h wo PTs, so
ha wo LV b anches a e linked o his TC. In one b anch, h ee single-
phased PV in e e s (PV1, PV2 and PV3) and a ba e y cha ge (BC) a e
Fig.1. Recommended emission limi s below 150 kHz o diffe en scena ios [64]. The cu e on he bo om ep esen s he limi s o non-in en ional ou -o -band
emissions om PLC ansmi e s.
Fig. 2. Limi s de e mined by EN 50065-1 o non-in en ional ou -o -band
emissions o PLC de ices, up o 500 kHz, in linea scale.
I. Fe nandez e al. Elec ical Powe and Ene gy Sys ems 105 (2019) 549–563
551
loca ed; in he o he b anch, a h ee-phased PV in e e (PV4), he
hyd opowe u bine (HT) and he hyd opowe pump (HP). Measu e-
men s o po en ial non-in en ional emissions om all o hese de ices in
he equency ange up o 500 kHz we e eco ded.
Measu emen s we e also aken in a wind u bine (WT) loca ed in a
LV b anch o he o he TC p o ided wi h wo PTs (PEPA I in Fig. 3).
Finally, po en ial non-in en ional emissions om oo op PV panels
loca ed in wo office buildings we e also eco ded and analyzed (PV5
and PV6 in Fig. 3).
Table 1 summa izes he mos ele an ea u es o he de ices in-
cluded in he analysis. As i can be obse ed, he mic og id unde es is
a ep esen a i e example o a medium-size mic og id, and he DERs
ha compose he mic og id a e ypical de ices o common mic og ids
based on enewable esou ces.
3.2. Measu emen me hodology
The measu emen s we e pe o med be ween he neu al and he
phase a he inpu o he associa ed SM o each de ice (in he h ee-
phased elemen s only one o he phases was conside ed).
Measu emen se was composed o he ollowing equipmen :
•TABT-2 –LV capaci i e couple [66], which allows measu ing he
NB-PLC signal and/o he noise p esen a ha poin . The equency
ange o his de ice is 10–600 kHz.
•An i su MS2690A Signal Analyze [67]. This measu emen equip-
men ope a es om 50 Hz o 6 GHz.
The An i su MS2690A Signal Analyze digi izes and eco ds he
measu emen da a in IQ (In-phase, Quad a u e) samples, which allows
signal pos -p ocessing o spec al and empo al analysis. This is in line
Fig. 3. Ou line o he elec ical a chi ec u e o he mic og id a CEDER-CIEMAT [65].
Fig. 4. Scheme o PEPA III TC and he DERs in he LV b anches [47].
Table 1
Lis o he main ea u es o he de ices included in he analysis (ope a ing
powe , swi ching equency o he in e e s and co esponding TC.
Type o de ice Fea u es TC
Hyd opowe u bine (HT) 60 kW, h ee-phased PEPA III
Hyd opowe pump (HP) 18 kW, h ee-phased PEPA III
PV in e e (PV1) 5 kW, single-phased @ 16 kHz PEPA III
PV in e e (PV2) 5 kW, single-phased @ 16 kHz PEPA III
PV in e e (PV3) 5 kW, single-phased @ 16 kHz PEPA III
PV in e e (PV4) 15 kW, h ee-phased @ 16 kHz PEPA III
PV in e e (PV5) 10 kW, h ee-phased @ 5 kHz CT-SUB-E01
PV in e e (PV6) 10 kW, h ee-phased @ 5 kHz CT-2-E03
Ba e y cha ge (BC) 8 kW, single-phased PEPA III
Wind u bine (WT) 3.2 kW, single-phased PEPA I
I. Fe nandez e al. Elec ical Powe and Ene gy Sys ems 105 (2019) 549–563
552
wi h he ecen ecommenda ion om CENELEC o analyze he non-
in en ional emission le els bo h in ime and equency domains [12].
Signal analyze s ha e wo ad an ages when compa ed o oscillo-
scopes. Fi s , he signal analyze used in hese measu emen s p o ides
16 bi s o esolu ion, which ep esen s a highe esolu ion wi h espec
o he common high-speed Analog- o-Digi al Con e e s ADCs. Second,
longe measu emen pe iods can be eco ded when a signal analyze is
used. In hese field ials, i was decided o limi he measu emen in-
e al o each IQ file o 5 s, which allows he analysis o he signal
a ia ions du ing he common pe o mance o he de ices, including
he ansi ion pe iods be ween diffe en ope a ional s a es. The e-
quency ange was limi ed o he band o in e es om 35 kHz o
500 kHz, as i includes cu en and expec ed equencies o he abo e-
men ioned NB-PLC ansmission echnologies in Eu ope. Fig. 5 shows a
snapsho o he ials p e ious o he field measu emen s, whe e a
compa ison be ween he esul s p o ided by an oscilloscope and he
abo e-men ioned Signal Analyze was ca ied ou .
Wi h he pu pose o cha ac e izing each de ice, a oiding he po-
en ial influence o con iguous de ices in ope a ion in he same LV
b anch, each de ice unde es was elec ically isola ed du ing he
measu emen s. Only PV5 and PV6 did no ulfill his equi emen , as i
was no possible o isola e he in e e s o hese de ices om o he
equipmen loca ed in he same building.
Since he measu emen s we e eco ded in o m o IQ samples, he
spec al analysis was ca ied ou by applying he Fas Fou ie T ans o m
(FFT) o ime domain scan, which educes significan ly he measu e-
men ime wi hou deg ading he accu acy o he esul s. This me hod
mee s he equi emen s o he specifica ion published in CISPR 16-1-1
[13], which includes he use o FFT-based ins umen s in s anda d-
complian measu emen s.
3.3. Da a p ocessing
The da ase s ob ained in he field measu emen s we e p ocessed
acco ding o CISPR specifica ions [13–15]:
•A Gaussian ime-windowing composed o a 6 dB bandwid h o 9 kHz
in he 150–500 kHz ange and a 6 dB bandwid h o 200 Hz in he
35–150 kHz ange was applied.
•A ime o e lap o mo e han 75% is equi ed o ensu e ha mea-
su emen unce ain y o he pulse ampli ude emains
wi hin ± 1.5 dB. An o e lap o 93% was employed in his case, in
o de o ensu e ha his condi ion was ulfilled.
•The equency s ep size should be equal o less han he hal o he
equi ed alues o 6 dB bandwid h. Acco dingly, in his analysis he
numbe o poin s o he FFT was selec ed o be a qua e o he
equi ed bandwid h (50 Hz o he 35–150 kHz ange and 2.25 kHz
o he 150–500 kHz ange).
•The equi ed cha ge and discha ge ime cons an s and he me e
ime cons an s o quasi-peak and a e age de ec o s we e digi ally
implemen ed by means o Infini e Impulse Response (IIR) fil e s.
•The minimum measu emen ime was 10 ms in he 35–150 kHz band
and 0.5 ms in he 150–500 kHz band [15]. In hese ials, longe
measu emen in e als we e used, in o de o cha ac e ize he signal
ime- a iabili y o he emissions.
•The ime slo s whe e PRIME 1.3.6 signal bu s s we e p esen we e
emo ed, in o de o a oid ha he communica ion signals dis o
he esul s and o ensu e ha only non-in en ional emissions we e
conside ed.
Following his me hodology, he quasi-peak and a e age ol age
alues o he non-in en ional emissions gene a ed by each de ice we e
ob ained. Then, hey we e compa ed o he limi s defined by EN-50065-
1, which p oposes quasi-peak ol age limi s o he equency ange up
o 500 kHz, bu a e age ol age limi s only o he 150–500 kHz ange,
as i has been desc ibed in Sec ion 2. This compa ison p o ides use ul
in o ma ion o e alua e he significance o he non-in en ional emis-
sions eco ded in he measu emen s.
Spec og ams o each eco ded IQ sample se we e also calcula ed
and ep esen ed in a colo scale, in o de o analyze he e olu ion in
ime o he Powe Spec al Densi y (PSD) alues. Hence, bo h spec al
and ime pe o mance o each de ice in diffe en wo king egimes could
be p ope ly cha ac e ized. A Gaussian ime-windowing o 200 Hz
bandwid h was used o his pu pose, wi h a 50 Hz s ep size.
Addi ionally, he a iabili y wi h ime o he emissions was quan-
ified by calcula ing he s anda d de ia ion o he signal en elope (in a
200 Hz o 9 kHz bandwid h, depending on he equency ange, ac-
co ding o CISPR specifica ions [13–15]).
4. Resul s
In his sec ion, he esul s o he measu emen campaign a e de-
sc ibed. They show g aphically and nume ically he ampli ude and
a iabili y o he non-in en ional emissions o each de ice o diffe en
wo king egimes. Resul s a e classified acco ding o he DERs ha
compose he mic og id.
4.1. Hyd opowe sys em
The hyd opowe sys em is composed o a CMC Hyd o Pel on u bine
[68] wi h a h ee-phased asynch onous IPS gene a o [69] and a S e -
ling SIHI pump [70]. The u bine gene a es ene gy om he wa e flow
alling om a ank loca ed in a highe place, while he pump is ac i-
a ed spo adically o efill he ank.
4.1.1. Hyd opowe u bine (HT)
Fig. 6 shows he spec og am o he non-in en ional emissions o he
HT du ing he coupling o he mains powe p ocess. Du ing he cou-
pling p ocess, he PSD le els o he non-in en ional emissions we e
conside ably highe , mainly o lowe equencies. Once he HT was
coupled and wo king a a no mal condi ion (ON s a e in he spec o-
g am), a se o ha monics o 9.1 kHz o dec easing ampli ude was
gene a ed by he HT. This is ela ed o he ac ha he asynch onous
gene a o s a e gene ally designed o ha e a ious powe elec onics
Fig. 5. Field ials: measu emen s de eloped by an oscilloscope and he Signal
Analyze used in he s udy.
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con e e s, which in e nally apply swi ching echniques [71–73].
The e o e, ha monic equencies a e mul iple alues o he swi ching
equency o he swi ching de ice o he u bine.
Fig. 7 shows he quasi-peak and a e age ol age le els o non-in-
en ional emissions o he u bine in no mal ope a ion (ON s a e), o-
ge he wi h he limi s s a ed in EN-50065-1. Resul s show ha ha -
monics o 9.1 kHz we e gene a ed by he HT o e colo ed backg ound
noise, wi hou exceeding he limi s (excep a single na owband com-
ponen a 102.4 kHz).
I should be no ed ha he sha p ansi ion a 150 kHz is caused by
he diffe en bandwid h alues used in he ime-windowing applied o
equency anges below and abo e 150 kHz, as desc ibed in he da a
p ocessing p ocedu e, and i is no due o a sudden inc ease o noise
le el a hese equencies. I should also be eminded ha EN-50065-1
p oposes quasi-peak ol age limi s o he whole equency band, bu
a e age ol age limi s a e defined only o he 150–500 kHz ange; his
is he eason o calcula ing he a e age le els only o his ange.
As he coupling p ocess occu s in a e y sho ime (app oxima ely
in 0.2 s), sho e han he ime cons an s used o calcula e he quasi-
peak and a e age ol age le els, ep esen a i e alues o he coupling
p ocess canno be calcula ed. Howe e , he PSD le els ob ained in he
spec og am indica e ha he ol age le els we e conside ably highe
du ing his sho ime pe iod.
Rega ding he ime a iabili y du ing ON s a e, s anda d de ia ions
alues we e in he ange om 1.5 o 3 dB o ha monics o 9.1 kHz,
whe eas in he es o equencies, s anda d de ia ion alues be ween 5
and 9 dB we e ob ained.
In o de o p o ide a mo e de ailed cha ac e iza ion o he non-in-
en ional emissions, he CDF (Cumula i e Dis ibu ion Func ion) o he
emissions a specific equencies has been calcula ed. The CDF o he
noise p esen in he g id has been also calcula ed and included as a
e e ence (see Fig. 8). The selec ed equencies ha e been iden ified
wi h colo ed a ows in he co esponding equency esponse and
spec og am (Figs. 6 and 7), and included in Fig. 8, o clea ly ela ing
Fig. 6. Spec og am o he non-in en ional emissions o he HT du ing he coupling o he mains powe p ocess.
Fig. 7. Vol age le els and s anda d de ia ion o he non-in en ional emissions gene a ed by he HT in ON s a e.
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he a ia ion wi h ime and equency and he CDF:
Resul s o he CDF demons a e ha he non-in en ional emissions
gene a ed by swi ching modules a e high ampli ude emissions s able in
ime, while he noise alues ollow a ypical Gaussian cu e o lowe
le el. This cha ac e is ic is ulfilled by he non-in en ional emissions
om all he swi ching de ices; i is desc ibed only o his de ice as a
ep esen a i e case.
4.1.2. Hyd opowe pump (HP)
Fig. 9 shows he spec og am o he non-in en ional emissions o he
HP when i was u ned on. Du ing a ansi o y s a e, he PSD le els o
he non-in en ional emissions we e highe han in he ON s a e, mainly
below 150 kHz. The spec og am also shows ha he non-in en ional
emissions we e colo ed backg ound noise shaped plus a s ong na -
owband noise componen a 87.5 kHz.
The quasi-peak and a e age ol age le els o he non-in en ional
emissions du ing he ansi o y s a e a e shown in Fig. 10 and compa ed
o he limi s. The quasi-peak le els o lowes equencies we e ap-
p oxima ely 5 dB highe han he limi s, while in he 70–150 kHz ange
hey we e below he limi s, wi h he excep ion o a na owband com-
ponen a 87.5 kHz, which exceeded he limi in 8 dB. Fo he
150–500 kHz ange, he quasi-peak le els exceeded he limi s in up o
24 dB and he a e age le els in up o 19 dB.
Fig. 11 shows he le els o non-in en ional emissions du ing he
no mal ope a ion (ON s a e) o he HP. The quasi-peak le els below
150 kHz dec eased conside ably when he HP s a ed he no mal
wo king egime, and emained below he limi o all his equency
ange, excep he na owband componen a 87.5 kHz, which exceeded
in 8 dB. Howe e , o he 150–500 kHz ange, he le els emained high,
wi h he excep ion o he a e age le els a ound 180 kHz.
Wi h espec o he ime a iabili y o he non-in en ional emissions,
s anda d de ia ion alues up o 17 dB we e ob ained, wi h highe a-
lues in he 150–500 kHz ange o bo h he ansi o y s a e and he ON
s a e.
4.2. PV in e e s
Th ee single-phased Inge eam [74] PV in e e s (PV1, PV2 and
PV3) and o he h ee h ee-phased PV in e e s (PV4, PV5 and PV6)
we e analyzed in he field ials. All hese in e e s use swi ching
echniques o ans o m he DC powe in o con olled AC powe wi h
wo diffe en swi ching equencies: 16 kHz o PV1, PV2, PV3 and PV4
and 5 kHz o PV5 and PV6.
Fou o hem (PV1, PV2, PV3 and PV4) could be isola ed om he
es o he powe de ices in he g id, and he e o e, an indi idual
analysis was ca ied ou .
4.2.1. Single-phased PV in e e s
In Fig. 12, he spec og am o he coupling o PV1 o mains is e-
p esen ed. Du ing he ON s a e, ha monics o he swi ching equency
(16 kHz), wi h a dec easing ampli ude wi h equency, a e gene a ed.
The coupling p ocess shows a high le el o colo ed backg ound noise
Fig. 8. Abo e, Cumula i e Dis ibu ion Func ion o non-in en ional emissions a wo diffe en equencies (45.7 kHz and 118.4 kHz) and noise p esen in he
elec ical g id (122.9 kHz). Below, iden ifica ion o hese equencies in he equency esponse and in he spec og am o he measu emen s (Figs. 6 and 7).
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du ing a ew milliseconds.
The quasi-peak and a e age ol age le els, oge he wi h he s an-
da d de ia ion o he a iabili y o non-in en ional emissions o he
h ee single-phased PV in e e s in ON s a e a e shown in Figs. 13–15.
As i can be obse ed, high ampli ude ha monics o he swi ching e-
quency (16 kHz) a ose o e colo ed backg ound noise in he h ee
cases, especially in he 35–150 kHz ange, wi h le els o 32, 18 and
27 dB o e he limi s a he hi d ha monic o swi ching equency
(48 kHz) o PV1, PV2 and PV3, espec i ely.
Fo equencies highe han 150 kHz, he emissions om PV1 we e
o high-le el (20 dB o e he limi s a 176 kHz), he ol age le els om
PV2 we e below he limi s, while o PV3 he colo ed backg ound noise
exceeded he quasi-peak and a e age limi s o a wide ange o e-
quencies in up o 8 dB and 14 dB, espec i ely (see Figs. 13–15).
Wi h espec o he ime a iabili y, he highes s anda d de ia ion
alues we e ound in he 150–500 kHz ange o PV1.
4.2.2. Th ee-phased PV in e e s
The quasi-peak and a e age ol age le els o he emissions o he
h ee-phased PV in e e s showed lowe le els du ing ON s a e, as only
a componen a 48 kHz in he PV4 exceeded he limi in 7 dB (see
Figs. 16–18). In he 150–500 kHz ange, he emissions we e below he
limi s o he h ee in e e s, wi h he excep ion o he PV5. I is e-
ma kable ha , o in e e s PV5 and PV6, he colo ed backg ound noise
did no dec ease wi h equency, as i can be obse ed in Figs. 17 and
18, and he e o e, he a e age le els o emissions o PV5 exceeded he
limi s in he 430–500 kHz ange.
Wi h espec o he ime a iabili y, s anda d de ia ions lowe han
10 dB we e ound in he h ee de ices.
Las , he coupling p ocess was e y simila o ha shown in Fig. 12.
4.3. Ba e y cha ge (BC)
Fig. 19 shows he non-in en ional emissions du ing ansi ion o ON
s a e o he S ude ba e y cha ge [75], whe e high PSD le els can be
obse ed in he 35–500 kHz ange du ing he sho ansi ion pe iod.
Once he cha ge was ON, ha monics o 12 kHz a ose, gene a ed by
he in e nal swi ching echniques used by he BC (see Fig. 20). Only he
Fig. 9. Spec og am o he non-in en ional emissions o he HP when i was u ned on.
Fig. 10. Vol age le els and s anda d de ia ion o he non-in en ional emissions gene a ed by he HP in he ansi o y s a e.
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hi d and fi h ha monics o 12 kHz exceeded he limi s in 27 and 8 dB,
espec i ely, so ha o equencies highe han 72 kHz, almos all he
measu ed le els emained below he limi s.
Rega ding he ime a iabili y, he ime s anda d de ia ion alues
a ied be ween 1 and 10 dB in he en i e band.
4.4. Wind u bine (WT)
Finally, an Enne a [76] wind u bine con aining an in e nal di ec
d i e pe manen magne , a synch onous gene a o and a con e e was
analyzed in he field ials. Fig. 21 shows ha he na u e o he non-
in en ional emissions o he WT in no mal wo king egime was a co-
lo ed backg ound noise, oge he wi h some na owband emissions
sepa a ed app oxima ely 20 kHz in he 70–150 kHz ange. In he
35–150 kHz ange, he le els we e below he limi s, excep o he
115–117 kHz equency ange; howe e , in he 150–500 kHz ange he
le els we e up o 16 dB o e he limi s. As desc ibed abo e, his sha p
ansi ion a 150 kHz is caused by he diffe en bandwid h alues used
in he da a p ocessing o equency anges below and abo e 150 kHz.
Rega ding he ime a iabili y, he s anda d de ia ion a ied be-
ween 6 and 17 dB in he en i e band.
5. Discussion and conclusions
In his sec ion, he non-in en ional emissions gene a ed by diffe en
DERs in he measu emen campaign a e analyzed bo h in equency and
in ime domains. Addi ionally, he po en ial impac on NB-PLC is
e alua ed, by compa ing he esul s o he limi s asce ained in EN-
50065-1 [16].
5.1. Analysis in he equency domain
Fou ypes o non-in en ional emissions ha e been obse ed in he
equency domain:
•A se o high ampli ude na owband emissions a ha monic e-
quencies o he swi ching equency o he PV in e e s, he BC and
he HT.
Fig. 11. Vol age le els and s anda d de ia ion o he non-in en ional emissions gene a ed by he HP in ON s a e.
Fig. 12. Spec og am o he non-in en ional emissions o he PV1 du ing he coupling o he mains powe p ocess.
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