Iec Tr 61243-6-2017.Pdf

IEC TR 61 243 6 Edition 1 0 201 7 03 TECHNICAL REPORT Live working – Voltage detectors – Part 6 Guidelines on non contact voltage detectors (NCVD) for use at nominal voltages above 1 kV AC IE C T R 6[.]

IEC T R 61 243-6

Editio 1.0 2 17-0

Liv e wor k ing – Voltage detectors –

Part 6: Guidel nes on non-contact v oltage detectors (NCVD) for use at nominal

v oltages abov e 1 kV AC

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IEC T R 61 243-6

Editio 1.0 2 17-0

Liv e wor k ing – Voltage detectors –

Part 6: Guidel nes on non-contact v oltage detectors (NCVD) for use at nominal

voltages abov e 1 kV AC

INT ERNAT IONAL

ELECT ROT ECHNICAL

FOREWORD 4

INTRODUCTION 6

1 Sco e 7

2 Normative referen es 7

3 Terms an definition 7

4 The prin iples of an NCVD 1

4.1 NCVD desig ed to work at a distan e without an contact 1

4.2 NCVD desig ed to work with referen e p ints 13 4.2.1 General 13 4.2.2 NCVD desig ed to work with one referen e p int 14 4.2.3 NCVD desig ed to work with two referen e p ints 15 5 Dif erent desig s of non-contact voltage detectors 17 6 Limitation an recommen ation of u e for e c typ of NCVD 19 6.1 Prin ip l l mitation 19 6.2 Recommen ation for the selection, cal bration an u e of NCVD 19 6.2.1 Selection of the a pro riate typ of NCVD 19 6.2.2 Cal bration of the selected device 2

6.2.3 Use of the selected device 2

7 Recommen ed req irements 21

7.1 General 21

7.2 Recommen ed general req irements 21

7.2.1 Safety 21

7.2.2 In ication 21

7.2.3 Electromag etic comp tibi ty (EMC) 21

7.3 Recommen ed fu ctional req irements 2

7.3.1 Cle r in ication 2

7.3.2 Cle r p rce tibi ty 2

7.3.3 Temp rature an h midity de en en e of the in ication 2

7.3.4 Freq en y de en en e 2

7.3.5 Resp n e time 2

7.3.6 Power source de en a i ty 2

7.3.7 Testin element 2

7.3.8 Non resp n e to DC voltage (static electric field) 2

7.3.9 Immu ity to electrostatic dis harges 2

7.3.10 Time ratin 2

7.4 Electrical req irements 2

7.4.1 In ulatin material 2

7.4.2 Protection again t brid in for Typ 3 only 2

7.4.3 Resistan e again t sp rkin 2

7.4.4 Resistive (imp dan e) element of Typ 5 only 2

7.5 Recommen ation for mec anical p rforman e 2

7.5.1 General 2

7.5.2 Desig 2

7.5.4 Degre of protection provided by en los re 3

7.5.5 Grip force an deflection 3

7.5.6 Vibration dro an s oc resistan e 31

7.6 Markin s 31

7.7 In tru tion for u e 31

An ex A (informative) General con ideration a out voltage detection 3

A.1 General 3

A.2 Prin iples of fu ctionin of voltage detectors 3

A.2.1 Basic analy is 3

A.2.2 Voltage detection with two contact electrodes (bi-p lar detectors) 3

A.2.3 Voltage detection with one contact electrode 3

A.2.4 Voltage detection without contact electrode 3

An ex B (informative) In tru tion for u e 3

An ex C (informative) In-service care 3

C.1 General 3

C.2 Maintenan e 3

An ex D (informative) Suita le for l ve workin ; double trian le 3

Biblogra h 3

Fig re 1 – NCVD workin at a distan e without an contact 12 Fig re 2 – Ef ect of the relative p sition of the non-contact voltage detector 13 Fig re 3 – NCVD workin at a distan e with one referen e p int 14 Fig re 4 – Non-contact voltage detector with a referen e p int makin contact with the ca le in ulation coverin an in ulated con u tor 15 Fig re 5 – Non-contact voltage detector workin with two referen e points makin contact with the ca an pin of an in ulator 16 Fig re 6 – Non-contact voltage detector workin with two referen e p ints on an u dergrou d ca le 16 Fig re 7 – Directional pro erties of NCVD workin at distan e 2

Fig re 8 – Examples of desig s of NCVDs 2

Fig re A.1 – Bi-p lar voltage detection prin iple 3

Fig re A.2 – Ca acitive u ip lar voltage detection prin iple 3

Ta le 1 – Types of non-contact voltage detector 18 Ta le 2 – Limitation for u e 19 Ta le 3 – Sp cific recommen ation for u e 2

Ta le 4 – Examples of values of the radiu of the cone of detection as a fu ction of the directional pro erties an le 2

Ta le 5 – Cl matic categories 2

Ta le 6 – Minimum len th of the in ulatin element or of the in ulatin stic (L i ) 3

Ta le C.1 – Recommen ed c ec in p ints for in-service care 3

INTERNATIONAL ELECTROTECHNICAL COMMISSION

Part 6: Guidel nes on non-contact voltage detectors (NCVD)

for use at nominal voltages above 1 kV AC

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data of a diferent kin from that whic is normaly publs ed as an International Stan ard, for

example "state of the art"

IEC TR 612 3-6, whic is a Tec nical Re ort, has b en pre ared by IEC tec nical

commit e 7 : Live workin

The text of this Tec nical Re ort is b sed on the folowin doc ments:

Ful information on the votin for the a proval of this Tec nical Re ort can b fou d in the

This doc ment has b en draf ed in ac ordan e with the ISO/IEC Directives, Part 2.

Terms defined in Clau e 3 are given in ialc print throu hout this stan ard

A l st of al p rts of the IEC 612 3 series, publ s ed u der the general title Liv workin –

Vo ltag e de tectors, can b fou d on the IEC we site

The commite has decided that the contents of this doc ment wi remain u c an ed u ti the

sta i ty date in icated on the IEC we site u der "htp:/ we store.iec.c " in the data related to

A bi n ual version of this publcation may b is ued at a later date

IMPORTANT – The 'c lo r inside' lo o on the c v r pa e of this publ c tion in ic te

that it c ntains c lours whic are c nsidere to be us ful for the c r e t

understa din of its c nte ts Us rs s ould th refore print this d c me t using a

c lour printer

With the aim of en urin the safety of the u ers the purp se of a v lag de te cto r is to give a

cle ar indicato of the presen e or a sen e of the o eratin voltage, without any ne d for

interpretation or analytical evaluation by the u er

IEC 612 3-1, IEC 612 3-2 an IEC 6124 -3 a ply to p rta le voltage detectors desig ed to

work cor ectly when they are in direct contact with the b re p rt of the in tal ation to b

tested

At HV an UHV, large distan es b twe n the u er an the b re p rts to b tested make the

han l n of a very lon insu latn eleme t or insulatn stck an ergonomic an safety

con ern In s c situation , it may b come con enient to avoid an contact with the b re p rt

to b tested an to p rform voltage detection at a distan e

This doc ment provides con ideration an p rforman e g idel nes for p rta le “non-contact”

v lage de te cto rs an it can b u ed as a referen e for the develo ment of national, in u try

or man facturer's stan ard(s) or for the selection of a prod ct by u ers

This doc ment has b en pre ared takin into con ideration the provision given in

IEC 614 7

LIVE WORKING – VOLTAGE DETECTORS –

Part 6: Guidel nes on non-contact voltage detectors (NCVD)

for use at nominal voltages above 1 kV AC

This p rt of IEC 612 3, whic is a Tec nical Re ort, is a plca le to p rta le no n-co tac t

v lag e dete ctors (NCVD) with bui t in p wer source, to b u ed to in icate the presen e or

the a sen e of the o pe ratn v lage on electrical s stems for no minal v lages a ove 1 kV

AC an freq en ies of 16 2/3 Hz, 5 Hz an /or 6 Hz

NOT 16,7 Hz is ofe refere c d

This doc ment a ples only to devices that are not desig ed to b u ed in contact with the

b re p rt of the in tal ation on whic the presen e or the a sen e of the op eratn v lag e

has to b tested

This doc ment des rib s only devices, an their b haviour, u in electric field an voltage

gradient detection prin iples even if other prin iples could b u ed It provides p rforman e

g idel nes, recommen ation for u e an recommen ed minimum criteria for selection

Devices l ke p rsonal safety distan e v lag e dete c tors, distan e v lag dete cto rs for

emergen y resp n ers or mac ine o erators are not covered by this doc ment

Ex e t when otherwise sp cified, al the voltages defined in this doc ment refer to phase-

o-phase voltages of thre -phase s stems In other s stems, the a pl ca le phase- o-phase or

phase- o-e rth (grou d) voltages are u ed to determine the o eratin voltage

The fol owin doc ments are refer ed to in the text in s c a way that some or al of their

content con titutes req irements of this doc ment For dated referen es, only the edition

cited a ples For u dated referen es, the latest edition of the referen ed doc ment (in lu in

• IEC Electro edia: avai a le at ht p:/ www.electro edia.org/

• ISO Onl ne browsin plat orm: avai a le at htp:/ www.iso.org/o p

3.1

a aptor

au ible or vis al phenomenon whose presen e, a sen e or variation is con idered as

re resentin information on the con ition “voltage present” or “voltage not present”

Note 1 to e try: A sig al in ic tin o ly th t th N V is re d to o erate is n t c n id re a a ac tiv signal

case where the in ication is u mistaka ly dis ernible by the u er u der specific

en ironmental con ition when the NCVD is in its o eratin p sition

dif erent con tru tion of NCVDs, either as a complete device with or without an insu latn

eleme nt or as a se arate device inten ed to b eq ip ed with an insu latn stck

3.9

dire tional property

pro erty where y an NCVD detects an electrical field relative to a sp cific p sition

3.13

ha d guard

distin tive ph sical g ard se aratin the han le of an NCVD as a complete device from the

insu latn e leme nt

Note 1 to e try: Th p rp s of th h nd g uard is to pre e t th h n s from slp in a d p s in into c nta t

with th insu latn elem ent

3.14

indic tor

p rt of the NCVD that in icates the presen e or a sen e of the op e ratn v lag for the p rt

of the electrical eq ipment or in tal ation to b tested

in ulatin to l made es ential y of an in ulatin tub an /or rod with en fit in s

Note 1 to e try: For v lta e d te tio , a insulatn stck is inte d d to b ata h d to th N V a a s p rate

d vic in ord r to pro id th le gth to re c th in talatio to b te te a d a e u te s fety dista c a d

distin tive visible location or mark on the NCVD to in icate to the u er the ph sical l mit to

whic the NCVD could b in erted b twe n l ve p rts

Note 1 to e try: A lmi mark ma or ma n t b pre e t

3.2

me ium ele tric field

me ium field

in fre sp ce, region where the distribution of the electric field is sl g tly de en ent on the

distan e to the source

ne r ele tric field

ne r field

in fre sp ce, region where the distribution of the electrical field is stron ly de en ent on the

distan e to the source

3.2

nominal distan e

D

n

s ita le value of distan e, b twe n the b re p rt of the in tal ation to b tested an the

NCVD, as ociated with the n minal v lage of the NCVD for cle arindic ato

Note 1 to e try: Th n min l dista ce of th N V is a p rameter a s ciate with its cle r indic ato Th

ma ufa turer c n id ntify th n m in l dista ce dire tly ln e to th c re p n in dis rete n min l v lag e

Note 2 to e try: An NC D ma h v more th n o e n min l dista c e wh n h vin more th n o e n min l

v lage, or o e or more th n o e n m in l v la e ra g In this c s , for e c n min l v lag e or e c n min l

v lage ra g th ma ufa turer c n id ntify at le st o e c ara teristic dis rete n min l v lage Th ma ufa turer

c n th n id ntify th n m in l dista ce dire tly ln e to e c c re p n in dis rete n min l v la e

Note 3 to e try: For s me d vic s,th n m in l dista ce(s) c uld b d fin d b th N V refere c e p oints

3.2

nominal v lta e

U

n

s ita le a proximate value of voltage u ed to identify a s stem or device

Note 1 to e try: Th n min l v lag e of th NC D is a p rameter a s ciate with its c le r indic ato An NC D

ma h v more th n o e n m in l v lag e, or a n m in l v lage ra g Limit v lu s of th n min l v lag e ra g

are n me U

n min

a d U

nmax

[SOURCE: IEC 6 0 0-6 1:19 5, 6 1-01-21, modified – The definition has b en modified to fit

the sp cific context of device or eq ipment an Note 1 to entry has b en ad ed

3.2

non-c nta t v lta e dete tor

v lag e detector that do s not req ire makin ph sical contact with the b re p rt of the

in tal ation (e.g con u tor, bu b r, ca acitive ta for a cable elb w or switc ge r) on whic

the presen e or the a sen e of the o pe ratn v lag has to b tested

3.2

operating dista c ra ge

range of distan es to the b re p rt to b tested declared by the man facturer where the

NCVD wi fu ction pro erly when u ed ac ordin to the in tru tion for u e

Note 1 to e try: For s me d vic s, th o eratin dista c c uld b d fin d b th NC D refere ce p ints

rate v lta e

U

r

value of voltage to whic certain o eratin sp cification are refer ed

Note 1 to e try: Th rated v lag e of th N V is th v lta e s le te from IEC 6 0 1-1:2 0 +AMD1:2 10,

Ta le 2 a d Ta le 3, c lumn 1, whic s o ld eith r b e u l to th n min l v lage (or th hig e t n m in l v lag e

of its n m in l v lag e ra g ), or th n xt hig er v lta e s le te from th s ta le

3.3

refere c point

p int of an in tal ation whic is dif erent from the b re p rt to b tested an whic ne d to b

tou hed in order to give an electrical referen e ac ordin to the prin iple of fu ctionin of

some NCVD

3.3

re pons time

time delay b twe n s d en c an e of the voltage state on the p rt to b tested an the

as ociated c le ar indic ato

minimum voltage b twe n the l ve p rt an e rth (grou d) req ired to give a clear indic ato n

cor esp n in to sp cific con ition as defined in the cor esp n in test

Note 1 to e try: As d fin d in this p rt of IEC 612 3, thresh ld v lag e is relate to s e ific te t c n itio s Us rs

s o ld b aware th t th ir re uireme ts for thresh ld v la e for field o eratio n e to b relate to th te t

Note 1 to e try: Th s dia n stic d vic s are g n raly d s rib d a eith r c p citiv ty e or re istiv ty e

Note 2 to e try: Cle r e id n e is a YE or NO in ic tio with n interpretatio n e e Sometime , v lage

detectors als h v s p leme tary fu ctio (s) s c a th dis la of v lta e v lu s

[SOURCE: IEC 6 05 -6 1:2 14, 6 1-2 -0 ]

4 The principles of an NCVD

4.1 NCVD de ign d to work at a dista c without a y c ntact

A n n-co tac t v lage de te ctor workin at a distan e o erates by detectin the AC electric

field generated in fre air by the energized p rt of the in tal ation to b tested This detection

is typical y car ied out via the u e of a minimum of two internal metal c e le ctrode s p sitioned

at some distan e a art It is p s ible to re resent the electric config ration as b in

eq ivalent to two stray ca acitan es One is me s red b tween the p rt to be tested an the

first (internal) ele c tro de of the v lag de tecto r The other is me s red b twe n the secon

s ould b noted that the closer an NCVD a pro c es the p rt to b tested, the more simi ar it

b comes to a u ip lar ca acitive typ (se An ex A)

Ke

1 p rt to b te te

2 e rth

3 n n-c ontact v lage detector with its two intern l elec trodes

4 p te tial difere c b twe n th two electrodes of th v lag e detec tor

5 ele tric field e uip te tial ln s

Figure 1 – NCVD working at a dista c without a y c nta t

For this desig of detector, the voltage detection is mainly b sed on the evaluation of an

electric field as ociated with a potential dif eren e b twe n the two flo tin ele ctro de s As the

electric p tential at the flo tin electro de s is a fu ction of the electric field distribution, the

distribution of the electric field wi con eq ently af ect the detection In most of the

in tal ation config ration , the electric field arou d a l ne or piece of eq ipment is not u iform

The electrical field stren th an the gradient of field are normal y hig er ne r the l ve p rt an

the stren th an the gradient of field decre ses as the distan e from the l ve p rt in re ses

The relative p sitionin of the NCVD with resp ct to the p rt to b tested is then a p rameter

that may afect the cor ect in ication of this typ of NCVD As i u trated in Fig re 2, the

voltage diferen e develo ed b twe n its two flo tin electrodes wi de end on the gradient

of the electric field at an ne r the location of the NCVD When the v lag de te cto r is close

to the p rt to b tested (Position P1 of Fig re 2 ), the electric field c an es ra idly with the

distan e an a voltage dif eren e wi b e si y detecta le b twe n the two flo tin

ele c trodes Alternatively, if the v lag dete cto r is to far from the p rt to b tested

(Position P2 of Fig re 2 ), the electric field wi c an e only sl g tly with distan e an the

voltage dif eren e acros the two electrodes could b to smal for a cor ect detection

If the p sition of the v lag dete c to r is s c that the electric field is practical y in e en ent of

location (i.e ne rly con tant at the p sition of the vo ltage de te c to r (Position P3 of Fig re 2 ),

no sig ificant voltage diferen e wi b develo ed b twe n the two flo tin ele ctrode s This

may res lt in an in or ect in ication of the v lage dete cto r (e.g a sen e of voltage in te d of

voltage present

The s a e of the p rt to b tested an the distan e b twe n this p rt an adjacent p rts at

dif erent p tential wi also af ect the electric field distribution whic con eq ently may af ect

the in ication of the device The stren th of the electric field at the s rface of an energized

p rt wi decre se with the heig t of that p rt a ove e rth, an wi also decre se as the size

IE

general y red ce the stren th of the electric field distribution local y (in-phase interfe re nce

field) Con ersely, an adjacent p rt at the e rth p tential wi in re se the stren th of the

electric field distribution ne r the energized p rt (out of phase inte rfe re ce field) Final y, l ve

p rts in the vicinity of a de-energized p rt to b tested may cre te local y electric field that

could af ect the cor ect in ication of the device In this case the in ication "voltage present"

can a p ar althou h the p rt is de-energized

Figure 2 – Efe t of the distanc

to the par to be te ted

Figure 2b – Efe t of the p sitio relativ

p te tial dif ere c b twe n th two intern l electrodes of th v la e detector

5 ele tric field e uip te tial ln s

P1 p sitio of th v lage detector clo e to th p rt to b te te

P2 p sitio of th v lage detector far from th p rt to b te te

P3 p sitio of th v lage detector wh re n e uip te tial ln s are cro s d

Figure 2 – Ef e t of the relativ po ition of the no -c nta t v lta e dete tor

As stated previou ly, a pl cation of the NCVD is a very imp rtant con ideration in order to

o tain a rel a le detection

Like ca acitive v lag dete cto rs (IEC 612 3-1), NCVDs may be af ected by electrostatic

dis harges, esp cial y in cases of low voltage an /or far field a pl cation where hig

sen itivity is req ired Electrostatic c arges are typical y generated by mec anical friction

This friction cau es displacement of electron in in ulatin materials an ac umulation of

c arges As static c arges do not vary over time, AC v lage dete c tor s ould not b af ected

However, in case of dis harges of the static c arges the freq en y sp ctrum of these

dis harges contain sig als that vary over a certain time for a s ort p riod an may cau e

ran om trig erin of the detectin circ it

4.2 NCVD de ign d to work with refere c points

Another category of n n-co nta t v lage de te cto rs con ists of those that req ire an electrical

referen e by contactin one or two p rts of the in tal ation other than the b re p rt to b

4.2.2 NCVD d signe to work with one refere c point

The fu ctionin of devices with one refe re nc e p int is general y b sed on ca acitive coupl n

or electric field detection In some cases the re fere nc e p int is con ected to e rth ( or

example, en losed switc gear), whi e in other cases the re fere nc e p int is in contact with the

ca le in ulation coverin of an in ulated con u tor

When the refere c e p int is the electric e rth, the fu ctionin is b sed on the evaluation of

the p tential diferen e (electric field) b twe n the re fere nc e p int an the flo tin e le c trode

3 flo tin elec trode of th v lag e detector

4 refere ce p int of th v lag e detec tor (ele tric e rth)

5 ele tric field e uip te tial ln s

V

p te tial difere c b twe n th flo tin electrode a d th electric e rth

Figure 3 – NCVD working at a dista c with one refere c point

When the refe re ce po int is the ca le in ulation coverin of an in ulated con u tor, the

fu ctionin is b sed on ca acitive coupl n b twe n the co tac t ele c tro de of the v lage

dete cto r an the con u tor, an the stray ca acitan e b twe n the flo tin electro de of the

v lag e de tecto r an e rth (se Fig re 4)

IE

IE

1 n n-c ontact v lage detec tor 5 c ontact elec trode of th v lag e detector

th v lag e detector a d e rth

4 c p citiv c u ln b twe n th contact elec trode

of th v lage detec tor a d th c n u tor

8 e rth

Fig re 4 – Non-c nta t v lta e dete tor with a refere c point ma ing c nta t

with the c ble ins lation c v ring a ins late c nductor

4.2.3 NCVD d signe to work with two refere c points

Devices with two refere ce po ints rely on the detection of a p tential dif eren e

The first example refers to a device desig ed to b u ed on a sin le in ulator of an in ulator

strin where the two refere nce p oints are resp ctively the ca an the pin of an in ulator The

in ulator string is con idered to b a series of ca acitors con ected b twe n the l ve p rt an

e rth The last few in ulators at the e rth side of the in ulator strin may b con idered as

the low side of a voltage divider The v lage de te ctor o erates by detectin the voltage

acros the ca an pin of one in ulator closest to the e rthed side of an in ulator strin , se

Fig re 5

The secon example refers to a device desig ed to b u ed on certain typ s of u dergrou d

ca le It o erates by detectin the voltage acros the semi-con u tive layer an the

con entric neutral of the ca le (Fig re 6) When the ca le is energized, a displacement of

electron in the in ulatin materials cre tes an ac umulation of c arges at the interface of the

in ulatin material an the semi-con u tive layer This generates a voltage p larization

b twe n the semi-con u tive layer an the con entric neutral of the ca le

IE

23

14

8

765

V v lta e a ro s th c p a d pin of o e in ulator (c p cita c ) o th e rth d sid of th in ulator strin

Figure 5 – No -c nta t v lta e dete tor working with two refere c points

5 Dif erent designs of non-contact voltage detectors

The variou typ s of NCVD are presented in Ta le 1 NCVDs are clas ified in five typ s

ac ordin to their desig

Typ s 1, 2 an 3 are NCVD workin at a distan e (without an contact These are the most

commonly u ed typ s worldwide

A Typ 1 NCVD (T1a in Ta le 1) is desig ed to b u ed far from the l ve workin zone an

therefore is not con idered as a "l ve workin device" As s c it do s not fal u der the s o e

of IEC TC 7 Therefore, this doc ment do s not recommen in ication or/an req irements

for this typ of NCVD However, Typ 1 could b u ed from the grou d (T1b in Ta le 1) or a

tower as a “pre-diag ostic” device whose in ication s ould b later confirmed by another typ

of v lag e de tecto r with more rel a i ty

A Typ 2 NCVD (T2 in Ta le 1) is desig ed to b u ed from a tower ne r an in ulator strin

or from the grou d ne r an in ulator column or from an identifia le location an may

p netrate the l ve workin zone This typ of NCVD fal s within the s o e of IEC TC 7 T2 in

Ta le 1 s ows an example of the device in u e from a tower

A Typ 3 NCVD (T3 in Ta le 1) is desig ed to b u ed in ide the l ve workin zone with an

ada ta le insu latng stc k (T3 in Ta le 1) This typ of NCVD fals within the s o e of

IEC TC 7

Typ s 4 an 5 are NCVDs with at le st one re fe re c e p int They are desig ed for sp cific

a pl cation

Typ 4 is desig ed for u e on metal en losed switc ge r an p netrates the l ve workin

zone (T4 in Ta le 1) This typ of NCVD fal s within the s o e of IEC TC 7 Typ 4 is only

desig ed to b u ed on in ulated con u tors (T4 in Ta le 1) an is never u ed within the

l ve workin zone, therefore, it is not con idered as a "l ve workin device" As s c it do s

not fal u der the s o e of IEC TC 7 Therefore, this doc ment do s not recommen

in ication or/an req irements for this typ of NCVD

Typ 5 is desig ed to b u ed on ca an pin in ulator strin (T5 in Ta le 1) This typ of

NCVD fal s within the s o e of IEC TC 7 Typ 5 is only desig ed to b u ed on an

u dergrou d network an is never u ed within the l ve workin zone (T5 in Ta le 1),

therefore, it is not con idered as a "l ve workin device" As s c it do s not fal u der the

s o e of IEC TC 78 Therefore, this doc ment do s not recommen in ication or/an

req irements for this typ of NCVD

Outside the LW zo e (Mostly) o tside the LW zo e Inside the LW zo e

T1a – e ample of ty e 1 T2 – e ample of ty e 2 T3 – e ample of ty e3 T4 – Ty e 4 for switc g ar

a plc tio

T5 – Ty e 5 for in ulator

strin for a rial tra smis io ln

T1b – e ample of u e of a ty e 1 T2 – e ample of u e of a ty e 2 T3 – e ample of u e of a ty e 3 T4 – Ty e 4 for in ulate

6 Limitations and recommendations of use for e ch type of NCVD

6.1 Principal l mitatio s

Sin e the fu ctionin prin iple of most of the NCVD is b sed on the detection of the electric

field generated in fre air by the energized p rt of the in tal ation to b tested, the rela i ty of

the in ication may b influen ed by in-phase or out of phase inte rfe re nc e fie lds De en in

on the typ of NCVD this res lts in sp cific l mitation

In general NCVD workin at distan e s ould b u ed only where the config ration of the

electric circ it is simple in stru ture an is not influen ed by other adjacent circ its an

6.2.1 Sele tio of the appropriate type of NCVD

Due to p s ible hazardou situation as ociated with an in or ect in ication of voltage

a sen e or presen e by a voltage detector, one s ould make s re that the selected NCVD is

the most a pro riate for the config ration b in tested Us al y, v lage dete c tor are

identified by a n minal v lage or a n minal v lag ran e, but one typ of NCVD may not b

a pro riate everywhere on a network at a given voltage b cau e its fu ction is influen ed by

the local electric field config ration an field interferen e When an NCVD is con idered, one

s ould take gre t care selectin the typ that wi work pro erly in the given field con ition

without interpretation from the u er (se Ta le 2 an Ta le 3)

6.2.2 Cal bratio of th s le te d vic

To take into ac ou t the p s ible efect of electric field interferen e an to in re se the

rel a i ty of c lear indic ato n, it may b a pro riate to p rform an on-site cal bration This may

res lt in “c stomizin ” a device for only one location or only one network config ration

Users an man facturers s ould dis u s this is ue an agre on the b st solution On e a

device has b en cal brated on-site, it is recommen ed to cle rly identify the device

ac ordin ly, so that mis se is avoided

6.2.3 Use of the s le te de ic

In terms of o eratin a contact v lag dete ctor cor ectly (IEC 612 3-1, IEC 612 3-2 an

IEC 612 3-3), the proced re is q ite simple an is as fol ows; the u er brin s its co tac t

ele ctrode in contact with the b re p rt to b tested an lo k at (or l sten to) the in ication

In contrast, in case of an NCVD, p rameters l ke the p sitionin of the device relative to the

p rt to b tested, the presen e of e rthed o jects close by, the p s ible u e of a selector, etc

s ould b explained cle rly to the u er to avoid in or ect in ication or an u safe situation

As a general recommen ation, the in ication s ould b c ec ed on op e ratn v lag b fore

every u e

Ta le 3 s mmarizes the recommen ation sp cific for e c typ of NCVD to b in lu ed in

the in tru tion for u e an to b taken into con ideration when trainin the u ers

Table 3 – Spe ific re omme dations for us

Far ele t ic field Medium ele t ic field Ne r ele t ic field One referenc p int Two referenc