Iec Ts 60815-4-2016.Pdf

IEC TS 6081 5 4 Edition 1 0 201 6 1 0 TECHNICAL SPECIFICATION Selection and dimensioning of high voltage insulators intended for use in polluted conditions – Part 4 Insulators for d c systems IE C T S[.]

IEC T S 6081 5-4

Editio 1.0 2 16-10

pol uted conditions –

Part 4: Insulators for d.c systems

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IEC T S 6081 5-4

Editio 1.0 2 16-10

Part 4: Insulators for d.c systems

INT ERNAT IONAL

ELECT ROT ECHNICAL

FOREWORD 4

INTRODUCTION 6

1 Sco e 7

2 Normative referen es 7

3 Terms, definition an a breviated terms 8

3.1 Terms an definition 8

3 2 Ab reviated terms

9 4 Prin iples 9

4.1 General 9

4.2 Overal desig proces 10 5 Materials 1

6 Site severity determination 12 6.1 Input data 12 6.2 d.c p l ution ac umulation cor ection: K p 12 6.3 Chemical comp sition of the p l ution layer (Typ A p lution) 13 6.4 Cor ectin for NSDD (Typ A p l ution) 13 6.5 Cor ectin for CUR (Typ A p l ution, ca an pin in ulators) 14 6.6 Ef ect of diameter on the p lution ac umulation K d 14 6.7 Cor ection for the n mb r of simi ar in ulators in p ral el: K s 14 7 Determination of the referen e d.c site severity 15 8 Determination of the referen e d.c USCD 16 9 Cor ection of the RUSCD for e c can idate in ulator 17 9.1 Cor ection for the efect of diameter on p l ution with tan p rforman e C d 17 9.2 Cor ection for altitu e C a 18 9.3 Determination of the req ired USCD for e c can idate 18 10 Chec in the profi e p rameters 19 10.1 General 19 10.2 Alternatin s ed defined by s ed overhan 19 10.3 Sp cin vers s s ed overhan 2

10.4 Minimum distan e b twe n s ed 2

10.5 Cre p ge distan e vers s cle ran e 21

10.6 Shed an le 2

10.7 Cre p ge factor 2

1 Desig verification 2

1 1 General 2

1 2 Op ratin exp rien e 2

1 3 L b ratory testin 2

An ex A (informative) Hy ro ho icity tran fer materials 2

A.1 Qual tative flas over b haviour 2

An ex B (informative) De en en e of USCD on p l ution severity 2

B.1 Pol ution typ A 2

B.2 Pol ution Typ B 2

Biblogra hic Referen es 2

Fig re 1 – Overal desig proces for d.c in ulation – determination of d.c Site

Fig re A.1 – De en en y of sp cific flas over voltage over con u tivity of an

electrolyte (p rameter: weta i ty of s rface) 2

Fig re B.1 – d.c overhe d l nes Col ected field exp rien e on non HTM ins lators

(u co ted glas an p rcelain in ulators) 2

Fig re B.2 – d.c overhe d l nes Col ected field exp rien e on HTM in ulators

(comp site l ne in ulators) 2

Fig re B.3 – Comp site in ulators: Example of the influen e of CF on USCD

(la oratory tests), se CIGRE Broc ure [1] for more detais 2

Ta le 1 – Typical ran es of K

p

ac ordin to cl matic con ition 13

INTERNATIONAL ELECTROTECHNICAL COMMISSION

Part 4: Insulators for d.c systems

1) Th Intern tio al Ele trote h ic l Commis io (IEC) is a worldwid org niz tio for sta d rdiz tio c mprisin

al n tio al ele trote h ic l c mmite s (IEC Natio al Commite s) Th o je t of IEC is to promote

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with th Intern tio al Org niz tio for Sta d rdiz tio (ISO) in a c rd n e with c n itio s d termin d b

a re me t b twe n th two org niz tio s

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th later

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e p n e arisin o t of th p blc tio , u e of, or rela c u o , this IEC Pu lc tio or a y oth r IEC

The main tas of IEC tec nical commite s is to pre are International Stan ard In

ex e tional circ mstan es, a tec nical commit e may pro ose the publ cation of a tec nical

sp cification when

• the req ired s p ort can ot b o tained for the publ cation of an International Stan ard,

despite re e ted ef orts, or

• the s bject is sti u der tec nical develo ment or where, for any other re son, there is the

future but no immediate p s ibi ty of an agre ment on an International Stan ard

Tec nical sp cification are s bject to review within thre ye rs of publ cation to decide

whether they can b tran formed into International Stan ard

IEC 6 815-4, whic is a tec nical sp cification, has b en pre ared by tec nical commite 3 :

In ulators

The text of this tec nical sp cification is b sed on the fol owing doc ments:

Ful information on the votin for the a proval of this tec nical sp cification can b fou d in

the re ort on votin in icated in the a ove ta le

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

A l st of al p rts in the IEC 6 815 series, publ s ed u der the general title Sele cto n and

dime sio in o fhig -v lag e insu lato rs inte ded fo r use in p olute d co di o ns, 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

the sp cific doc ment At this date, the doc ment wi b

• reconfirmed,

• with rawn,

• re laced by a revised edition, or

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

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

that it c ntains c lo rs whic are c nsid re to be us ful for the c r e t

understa ding of its c nte ts Us rs s o ld therefore print this do ume t using a

c lour printer

Work has b en goin on in CIGRE C4.3 3 an the IEC to prod ce d.c p l ution desig g ides

that re resent the c r ent state of the art The CIGRE work has res lted in an HV d.c

Polution Ap l cation Guidel nes broc ure [1] an the IEC work in this final p rt of IEC 6 815

– Sele cto n anddime nsio in ofhig -v lage insu lators inte ded fo r use in p oluted co di o s

– Part 4: Insu lators for d.c systems

The work re resents a h ge ac umulation of p l ution p rforman e k owled e from variou

sources (b th publ s ed an u publ s ed) never b fore colated into a sin le o u

Contrary to the p rts of IEC 6 815 de l n with a.c this tec nical sp cification covers b th

p lymeric an glas an p rcelain in ulators for d.c s stems in a sin le publ cation It also

covers h brid in ulators ( he ceramic core is ful y covered by a p lymer)

NOT Th pre e t d c me t d e n t a ply to in ulators with c atin s, d e to th v riety of c atin s to b

c n id re This ma b re o sid re at th n xt re isio of this te h ic l s e ific tio , afer g inin more

k owle g a de p rie c a d a b ter d finitio of th c atin c ara teristic a d re uireme ts

The a pro c for d.c in ulator desig an selection with resp ct to p l ution given in this p rt

is diferent to that u ed for a.c The key dif eren es are:

• A simpl fied a pro c is presented whic is inten ed for prel minary desig However,

sin e u der d.c p l ution buid-up an its efects can b more severe than u der a.c the

final desig s ould b b sed as mu h as p s ible on a direct p l ution severity me s red

u der d.c for the site b in stu ied Eq al y direct evaluation of the in ulators selected by

this proces s ould b con idered (A statistical desig a pro c is avaia le in the

CIGRE g idelnes for d.c p lution [1]);

• Two a pro c es are con idered to estimate p lution severity: one u in prior d.c site

severity exp rien e, the other u in site severity me s rements on a.c or u energised

in ulators;

• Cor ection of site severity for sp cific p rameters that have an influen e u der d.c (e.g

p lution u iformity ratio, ef ect of diameter on p l ution ac umulation, NSDD) are

con idered;

• Direct tran fer from cor ected site p l ution severity to neces ary USCD without an u e of

dis rete site severity clas es (as made in IEC 6 815 Parts 2 an 3);

• Recog ition is made of the improved p rforman e of Hy ro ho icity Tran fer Materials

(HTM) as a practical solution for man desig s, nota ly at UHV, whi e takin into ac ou t

p tential hy ro ho icity los ;

• Imp rtan e of the influen e of altitu e;

• Distin t diameter cor ection for flas over p rforman e

Althou h there is some p sitive exp rien e with val dation by testin of traditional glas an

p rcelain in ulators, the ful tran lation of s c test res lts to service con ition is sti u der

con ideration An s c exp rien e is mainly lac in for comp site in ulators, sin e an

agre d stan ardised testin proced re is not yet avai a le The pro lem is ac entuated to

p rcelain/glas as wel comp site tec nolog by the contin in rise in s stem voltages where

over-desig may res lt in u re lstic in ulator len th or heig ts Hen e for this first edition

the verification of a c osen in ulator solution by testin is entirely s bject to agre ment

For p lymeric, nota ly HTM, the p l ution with tan may not b the only neces ary desig

information The desig stres s ould b selected not only to avoid flas over, but also to

as ure a l mited agein of the in ulators in service This item is however out of the s o e of

the present sp cification

Ap lcation with controled in o r en ironment are not in lu ed in the s o e of this

SELECTION AND DIMENSIONING OF HIGH-VOLTAGE

Part 4: Insulators for d.c systems

This p rt of IEC 6 815, whic is a Tec nical Sp cification, is a pl ca le as first a pro c for

the determination of the req ired d.c Unified Sp cific Cre p ge Distan e for in ulators with

resp ct to p lution To avoid ex es ive over or u der desig , existin o eration exp rien e

s ould b comp red an eventual y ad itional a pro riate tests may b p rformed by

agre ment b twe n s p ler an c stomer

It is a pl ca le to:

• Glas an p rcelain in ulators;

• Comp site an h brid in ulators with an HTM or non-HTM hou in

This p rt of IEC 6 815 gives sp cific g idel nes an prin iples to ar ive at an informed

ju gement on the pro a le b haviour of a given in ulator in certain p l ution en ironments

The stru ture an a pro c of this p rt of IEC 6 815 are simi ar to those explained in Part 1,

but ada ted for the sp cific is ues en ou tered with p l uted HV d.c in ulation

The aim of this Tec nical Sp cification is to give the u er simpl fied me n to:

• Identify is ues sp cific to d.c a plcation that can afect the c oice an desig proces ;

• Determine the eq ivalent d.c Site Pol ution Severity (SPS) from me s rements, cor rectin

for electrostatic efects, diameter, p lution distribution an comp sition;

• Determine the referen e USCD for dif erent can idate in ulatin solution , takin into

ac ou t materials, dimen ion an ris factors;

• Evaluate the s ita i ty of dif erent in ulator profi es;

• Dis u s the a pro riate method to verify the p rforman e of the selected in ulators, if

req ired;

This simplfied proces is inten ed to b u ed when comp ra le o erational exp rien e from

existin d.c s stem is in omplete or not avai a le

The simplfied desig a pro c mig t res lt in a solution that ex e d the ph sical con traints

of the project More refined a pro c es for s c cases, e.g u in a statistical a pro c , are

given in the CIGRE d.c g idel nes [1] In extreme cases, e.g for ex e tional y severe site

con ition , alternative solution s c as c an in the l ne route, relocation of con erter

station or u in an in o r d.c yard may ne d to b con idered

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

an amen ments) a pl es

IEC TS 612 5, Artficial p lu tio tests o hig h-v lage ce ramic and gla s insulators to b e

used o d.c syste ms

IEC TS 6 815-1:2 0 , Sele c tio and dime sio in o f high-v lag insu lators inte dedfo r use

in p oluted c o ndi o s – Part 1: D efini o s, info rmato and g en ral p rinciples

IEC TS 6 815-2, Selecto and dime sio in of high-v lag e insu lato rs inte ded fo r use in

poluted condi o s – Part 2: Ceramic and gla s insu lato rs fo r a.c systems

IEC TS 6 815-3, Sele cto n and dime sio nin of hig h-v lage insu lato rs inte ded fo r use in

poluted c o ndi o s – Part 3 : Polyme r insu lators fo r a.c systems

IEC TS 6 0 3, G u idanc e o th mea u reme nt ofh dro h bic ity of insu lato r surfaces

3 Terms, definitions and abbreviated terms

• 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

3.1.1

Unifie Spe ific Cre pag Dista c

USCD

cre p ge distan e of an in ulator divided by the maximum o eratin voltage acros the

in ulator It is general y expres ed in mm/kV

Note 1 to e try: For d.c th ma imum o eratin v lta e is th d.c s stem v lta e a d fin d in IEC 6 0 1-5

3.1.2

Refere c d.c Unifie Spe ific Cre pa e Dista c

RUSCDdc

value of Unified Sp cific Cre p ge Distan e for a d.c s stem at a p l ution site determined

from ESDD an NSDD values cor ected for NSDD, CUR, etc ac ordin to this doc ment

Note 1 to e try: This is g n raly e pre s d in mm/kV

Note 1 to e try: Refere to a Polutio Uniformity Ratio (PU ) in s mec u trie

Note 2 to e try: This is refere to a Co tamin tio Uniformity Ratio in s me c u trie

Note 1 to e try: Furth r informatio o HTM is giv n in An e A.

3.2 Abbre iate terms

ESDD Eq ivalent Salt De osit Den ity

HTM Hy ro ho icity Tran fer Material

NSDD Non Soluble De osit Den ity

SDD Salt De osit Den ity

SES Site Eq ivalent Sal nity

SPS Site Polution Severity

USCD Unified Sp cific Cre p ge Distan e

RUSCD Referen e Unified Sp cific Cre p ge Distan e

CUR Polution (Contamination) Uniformity Ratio

RUSCDd Referen e d.c Unified Sp cific Cre p ge Distan e

4 Principles

The overal proces of in ulation selection an dimen ionin can b s mmarised as fol ows:

• Determination of the a pro riate a pro c (deterministic, statistical etc.) as a fu ction of

avai a le k owled e, time an resources as recommen ed in IEC TS 6 815-1 The

fol owin ste s con ern the simpl fied, deterministic a pro c as des rib d in IEC TS

6 815-1; if the statistical a pro c is c osen, ple se refer to IEC TS 6 815-1 for ful

detai s

Therefore, u in IEC TS 6 815-1:

• col ection of the neces ary input data, nota ly s stem voltage, in ulation a pl cation typ

(l ne, p st, bu hin , etc.);

• col ection of the neces ary en ironmental data, nota ly site p l ution severity

At this stage, a prel minary c oice of pos ible can idate in ulators s ita le for the

a pl cation an en ironment may b made

Then, u in this doc ment for:

• determination of the d.c site severity by a plcation of cor ection factors;

• determination of the referen e d.c USCD (RUSCD);

• cor ection of the RUSCD for e c can idate in ulator;

• c ec in the profi e p rameters;

• verification

It is to b noted that in the fol owin the USCD an the cor ection factors are b sed on a

median b haviour derived from widely spre d res lts (se [1]

1

Despite this, when the

proces is b n hmarked again t service exp rien e the res lts are con istent enou h to give

u eful orientation to identify a ran e of prel minary solution (se [1])

4.2 Ov ral d sign pro e s

The overal desig proces is s own in the flowc arts in Fig res 1 an 2 From these

flowc arts it can b se n that the cre p ge distan e is only selected af er multiple ste s to

cor ect site p l ution me s rements for the factors whic can influen e d.c p rforman e an

whic of en have a more pronou ced ef ect u der d.c than for a.c The desig proces is

compl cated by several factors:

• d.c energised in ulators ex ibit a gre tly dif erent p l ution ac umulation b haviour

comp red to a.c an u -energised in ulators d e to electrostatic ef ects, this

ac umulation is afected by win , p rticle size etc

• comp sition of the p l ution (low solubi ty or slow-dis olvin salts);

• efect of the amou t of non-soluble de osit;

• CUR “Contamination Uniformity Ratio”;

• efect of diameter on p l ution ac umulation;

• non-u iformity of the p lution layer alon or arou d the in ulator;

• efect of diameter on p l ution p rforman e;

• efect of in ulator material on p l ution p rforman e

These p ints are des rib d in more detai in Fig res 1 an 2

Figure 1 – Ov ral de ign proc s for d.c ins lation –

determination of d.c Site Pol ution Se erity

Core t for d.c p lutio a c mulatio

(Core t for ele tro tatic atra tio ,

ta in into a c u t clmatic d ta:

win , rain) – Se 6.2

d

NSDb

CUb

Figure 2 – Ov ral de ig proc s for d.c ins lation –

determin tio of the re uire USCD

dc

for c ndid te ins lating s lutio s

5 Materials

Polymer materials whic ex ibit hy ro ho icity an the ca a i ty to tran fer h dro ho icity to

the layer of p l ution are refer ed to in this Tec nical Sp cification as h dro ho icity tran fer

materials (HTM) Materials whic do not ex ibit hy ro ho icity tran fer are refer ed to as n

on-HTM Hy ro ho icity may be lost in certain con ition (se IEC TS 6 815-3:2 0 , nota ly

Clau e 5), either temp rari y or in some cases p rmanently IEC TS 6 0 3 provides g idan e

on the me s rement of wet a i ty of in ulator s rfaces (se An ex A)

Some other tec nologies exist that are inten ed to improve the p l ution p rforman e of

ty e a d material – Se 8

Core t RUSC

dfor th efe t of

diameter a d altitu e o fla h v r

h dro ho ic co tin s At present it is not p s ible to give sp cific information on the d ra i ty

of the improvement given by s c tec nologies The a pl cation of this doc ment to s c

tec nologies is therefore entirely s bject to agre ment

More information on the asp cts of diferent in ulatin materials u der HV d.c is given in [1]

6 Site s verity determination

• Simi ar data from u -energised or a.c energised in ulators of other typ s than the

referen e in ulator, me s red over a s f iciently lon p riod (e.g at le st one ye r);

• Simi ar data from d.c energised in ulators, me s red over a s ficiently long p riod (e.g

at le st two ye rs for sites with K

pfactor >1,2, u les exp rien e al ows this p riod to b

red ced e.g for sites with K

pfactor 1,1)

The neces ary data is:

• Cl matic data;

• The ESDD an NSDD from the SPS, or the SES, from one of the a ove sources (in the

case of Typ A p l ution the ESDD an NSDD s al b me s red se arately on up er an

ave) o er th total me s re s rfa e

(ie To a d Botom c mbin d), s e An e C of IEC T 6 815-1:2 0

6.2 d.c pol ution a c mulatio c r e tion: K

p

d.c energised in ulators may ac umulate more p l ution than do a.c energised or non

-energised in ulators, d e to the p rmanent static electric field s r ou din d.c in ulators The

ratio of d.c to a.c ac umulated p lution (K

pfactor) varies from one site to another an is the

res lt of a complex interaction of a n mb r of p rameters It is therefore not p s ible to

ac urately predict this ratio

The fol owin g idan e is given with regard to the c oice of K

p(se [1] for more detais):

is typical y 1,1, with a ran e of 1 to 1,2 in are s where maximum site severities

con ition are re c ed in s ort time fol owin sp cific events Typical cases are those

where the win sp ed is the dominant factor that determines the amou t of p l ution

car ied in the air or are s where hig win sp ed prevai A typical example is Typ B

p lution close to the se ;

p

is typical y 1,6, with a ran e of 1,3 to 1,9 in are s where the maximum site severities

con ition are re c ed in times of the order of a few month These are s may b

c aracterised by p l ution either of typ A or B (e.g at some distan e from the co st or

from p lution sources as ociated with h man activity) with moderate win con ition ;

p

is typical y 2,5 with a ran e of 2 to 3 in are s with a p l ution proces in re sin slowly

in time (e.g s owin an in re sin tren in a 1-2 ye r p riod), e.g are s with Typ A

p l ution, c aracterised by h man activity s c as minin , in u try, ro d etc with

It s ould b noted that K

p

can b hig er than the values given a ove when the site location is

c aracterised with exten ed dry p riod an can b lower when there is freq ent natural

cle nin events s c as rain Ta le 1 s mmarises an exten s the information a ove

d.c site p l ution severity by me s rements made on d.c energised in ulators, for as lon a

p riod as p s ible an in lu in an se son l kely to res lt in hig er ac umulation, in order

to get a more precise estimation of the d.c ESDD

K

p

may b af ected by in ulator orientation either red cin or in re sin self cle nin ef ects

6.3 Chemic l c mpo ition of the pol ution la er (Type A pol ution)

It is k own that the presen e of slow-dis olvin or low solubi ty salts in the natural p l ution

layer can red ce the severity of the p l ution with resp ct to sodium eq ivalent salts Also

stu ies have b en made on the ef ect of a pro ortion of calcium salts in the p l ution layer

If volume con u tivity me s rements made d rin site severity evaluation ac ordin to

IEC TS 6 815-1:2 0 , An ex C, s ow a distin t ten en y to in re se with time, then this is an

in ication that slow-dis olvin or low solubi ty salts are present In s c cases, it is ad ised

to stu y the exact c emical comp sition of the p l ution layer, an then to refer to the

information given in [1] an [2]

푁푁푁푁

0

�0,3

6.5 Cor e ting for CUR (Type A pol utio , c p a d pin ins lators)

CUR is the ratio of the Typ A p l ution de osit den ity (se IEC TS 6 815-1) on the lower

s rface of in ulators to that of the up er s rface This can also b expres ed as the in erse,

where it is cal ed T/B (To /Botom Ratio)

Sin e CUR for o en profi es is u ual y l mited to low values, this cor ection is general y only

a pl ed to me s rements from ca an pin in ulators Me s rements from other in ulators

with complex or de p u der-rib profi es may also req ire cor ection, but at present there is

in uf icient data on the neces ary cor ection

The me s red overal ESDD (non-u iform) s al b cor ected to an eq ivalent ESDD (u iform

p l ution) u in :

퐾

CU

=�1,6×퐶퐶퐶

0,6+퐶퐶퐶

�×�1−0,4×lo

1

�1

This cor ection is a pl ed when me s rements from ca an pin or smal er diameter

in ulators are b in u ed to determine the eq ivalent p l ution severity for larger diameter

No cor ection is neces ary for s sp n ion or l ne p st in ulators

NOT Av ra e diameter c lc latio is s own in IEC T 6 815-2 a d – 3

If the site severity me s rements are made on an in ulator of same diameter as the can idate

in ulator, then K

d

= 1

Further detai s on the influen e of diameter on p l ution ac umulation can b fou d in [1]

6.7 Cor e tion for th number of simi ar in ulators in paral el: K

s

In order to take into ac ou t the in re sed ris of flas over d e to havin man simi ar

in ulators in p ral el, a cor ection is a pl ed as fol ows:

• Man in ulators in p ral el (e.g tran mis ion lne section with more than 10 strin s,

as umed to b p l uted to the same degre an s bmited to the same en ironmental

This cor ection only covers the in re sed ris of flas over d e to man o jects b in

s bmit ed to the same stres (i.e al the in ulators in the same p l ution en ironment It do s

not cover the red ction of flas over voltage that can arise from the proximity of in ulator

strin s in multiple strin sets

Cor ection is val d for sites with a moderate n mb r of critical wetin events, e.g 10 p r

ye r For hig er n mb rs of events a further cor ection may b neces ary Further detais can

b fou d in [1]

7 Determination of the reference d.c site severity

For typ A p l ution, the average ESDD (ESDD

a e) from the SPS is cor ected to the referen e

d.c ESDD (ESDD

d) by: