Iec 61000 4 23 2016

This p rt of IEC 610 0 is an international stan ard that esta l s es the test con e ts, set-ups, req ired eq ipment, an test proced res f or protective devices again t HEMP radiated dist

IEC 61 000- 4- 23

Editio 2.0 2 16-10

Elect romagnet ic compat ibi ity (EMC) –

Part 4- 23: Test ing and measurement t echniques – Test met hods for prot ect ive

devices for HEMP and ot her radiat ed dist urbances

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IEC 61 000- 4- 23

Edit io 2.0 2 16-10

Elect romagnet ic compat ibi ity (EMC) –

Part 4- 23: T est ing and measurement t echniques – Test met hods for prot ect ive

devices for HEMP and ot her radiat ed dist urbances

FOREWORD 6

INTRODUCTION 8

1 Sco e 9

2 Normative ref eren es 9

3 Terms an def i ition 10 4 HEMP test con e ts 15 4.1 General 15 4.2 Testin of s ieldin en los res 16 4.2.1 General 16 4.2.2 Bui din s 19 4.2.3 Shelters an s ielded ro ms 2

4.2.4 Ca inets, rac s an b xes 21

4.3 Testin of s ielded ca les an con ectors 2

4.3.1 General 2

4.3.2 Testin of ca le s ield 2

4.3.3 Testin of ca le con ectors 2

4.4 Testin of s ieldin materials 2

4.4.1 General 2

4.4.2 Con u tin gas ets 2

4.4.3 Con u tin s e ts an s re n 2

4.4.4 Cut-of f waveg ides an honey ombs 3

4.5 Summary of test con e ts 3

5 Test method for me s rin the s ieldin ef fectivenes of HEMP protection faci ties 3

5.1 General 3

5.2 Electromag etic field testin 3

5.2.1 General 3

5.2.2 Pulse f ield testin 3

5.2.3 CW f ield testin 4

5.3 Cur ent injection test proced res 5

5.3.1 General 5

5.3.2 Injection testin of en los res 5

5.3.3 Tran fer imp dan e an admit an e of ca le s ield an con ectors 5

5.3.4 Testin of gas et material 5

An ex A (informative) HEMP test con e ts f or electrical s stems 6

A.1 Overview 6

A.2 Typ s of HEMP tests 6

A.2.1 General 6

A.2.2 Sy tem-level tran ient tests 6

A.2.3 CW f ield i umination tests 61

A.2.4 Cur ent injection testin 61

A.2.5 Partial i umination testin 6

A.2.6 Subs stem an comp nent testin 6

A.3 Definition of the testin interf ace 6

A.4 Use of test data 6

A.4.1 General 6

A.4.2 Ac e tan e of new s stems 6

A.4.3 Sy tem as es ments 6

A.4.4 Hard es s rvei an e monitorin 6

A.4.5 Sy tem desig 6

A.5 Testin u certainties 6

An ex B (informative) Characterization of s ielded ca les 6

B.1 Fu damentals of ca le s ieldin 6

B.2 Definition of tran f er imp dan e an tran f er admit an e 6

B.3 Relative sig ifican e of Z′ an Y′ 71

An ex C (inf ormative) Eq ipment f or HEMP pulse me s rements 7

C.1 General 7

C.2 Sen ors f or HEMP me s rements 7

C.2.1 B- an H-f ield sen ors 7

C.2.2 D- an E-f ield sen ors 7

C.2.3 Cur ent sen ors 7

C.3 Sig al tran mis ion 7

C.3.1 General 7

C.3.2 Fibre o tic l n s 7

C.3.3 Fibre o tic tran d cers 7

C.4 Sig al detection an proces in 7

An ex D (inf ormative) Eq ipment f or CW testin 8

D.1 General 8

D.2 Anten a s stem 8

D.3 Power ampl fier 8

D.4 Receiver (network analy er) 8

D.5 Ref eren e an resp n e sen ors 8

D.6 Fibre o tic s stem 8

D.7 Limitation of me s rements 8

An ex E (informative) Characterization of a planar s ield for HEMP protection 8

E.1 General 8

E.2 Pro lem ge metry 9

E.3 Eq ivalent circ it re resentation 91

E.3.1 General 91

E.3.2 Chain p rameter re resentation of the s ield 9

E.3.3 Circ it resp n es 9

An ex F (informative) In ide-to-out me s rement method 9

F.1 Purp se 9

F.2 Comp rison of existin SE test method 9

F.3 In ide-to-out SE test of s ielded ro ms 9

F.3.1 Me s rements of the in ide-to-out SE 9

F.3.2 Summary 101

Biblogra h 10

Fig re 1 – Example of me s red mag itu e an phase of the tran fer f un tion

T(ω) = H

in /H

out for a s ielded en los re 17

Fig re 2 – Electric field an mag etic field s ieldin ef fectivenes of a 0,5 mm thic

alumin m en los re [2 ] 18

Fig re 3 – Me s red mag etic field s ieldin ef fectivenes SE f or a buidin 19

Fig re 4 – Con e tual i u tration of the HEMP test of a bui din 19

Fig re 5 – Il u tration of a s ielded ro m or en los re ex ited by HEMP field 21

Fig re 6 – Il u tration of eq ipment rac s, ca inets an b x ex ited by internal HEMP disturb n e 21

Fig re 7 – A general s ield ex ited by c r ent injection 2

Fig re 8 – Basic config ration f or tran f er imp dan e me s rement 2

Fig re 9 – Me s red tran f er imp dan e mag itu e an phase of tran f er imp dan e p r u it len th for four braided s ield ca les with go d s ieldin pro erties 2

Fig re 10 – Basic con g ration f or tran f er admitan e me s rement 2

Fig re 1 – Test con g ration f or tran f er imp dan e me s rement of a ca le con ector 2

Fig re 12 – Examples of con u tin gas ets u ed as HEMP protection devices 2

Fig re 13 – Circ it model re resentin the b haviour of a con u tin gas et f or HEMP protection 2

Fig re 14 – Me s rement config ration for the resistivity of a sample 2

Fig re 15 – Test con e t for me s rin the resistivity with s race pro es 3

Fig re 16 – Con e ts f or s ieldin eff ectivenes me s rement of con u tin s e ts an s re n 3

Fig re 17 – Example of the calc lated plane-wave s ieldin ef fectivenes of a 0,01 mm thic plate of dif ferent material as a fu ction of f req en y 3

Fig re 18 – Cut-of waveg ides an honey omb u ed as protective elements 3

Fig re 19 – Examples of f ul -s ale, pulse- adiatin HEMP simulators 3

Fig re 2 – Test proced re for the pulse test 3

Fig re 21 – Typical con g ration of a CW test f aci ty 4

Fig re 2 – Example CW me s rement set-up 41

Fig re 2 – Test an analy is proced res for con u tin a CW test 4

Fig re 2 – Analy is flow diagram for extra olatin a me s red CW sp ctrum to the HEMP resp n e 4

Fig re 2 – Example s an f rom 9 kHz to 3 GHz for the ambient electromag etic field f rom commu ication sig als 4

Fig re 2 – Test proced re for the ambient EM ex itation test 4

Fig re 2 – Double-en ed TEM cel for field i umination testin of smal en los res 4

Fig re 2 – Example test set-up f or field i umination in the TEM cel 4

Fig re 2 – Il u tration of the sin le-en ed TEM cel an as ociated eq ipment 4

Fig re 3 – Test set-up f or the plane-wave s ieldin eff ectivenes me s rements 5

Fig re 31 – Test set-up for the H-ield s ieldin eff ectivenes me s rements 51

Fig re 3 – Example of anten a location for the local zed anten a tests for a h p thetical s ielded en los re or f aci ty 5

Fig re 3 – Test con e t an eq ipment config ration f or c r ent injection testin of a s ielded en los re or b x 5

Fig re 3 – Surace pro e for volume resistivity me s rement 5

Fig re A.1 – Sample HEMP interaction diagram i u tratin p netration mec anisms, s stem resp n es an generic test interace location 6

Fig re B.1 – Ge metry of a s ielded co xial l ne with an internal circ it 6

Fig re B.2 – Co xial ca le located over a con u tin grou d plane 6

Fig re B.3 – Two p r u it-len th circ its f ormed by the s e th an its groun return, an the s e th an the internal con u tor 6

Fig re C.1 – Mag etic field sen ors [2 ] 7

Fig re C.2 – Sin le-slot, c l n rical coi sen or [2 ] 7

Fig re C.3 – Two- an f our slot c l n rical coi sen ors [2 ] 7

Fig re C.4 – Electrical con g ration of an E-ield sen or [2 ] 7

Fig re C.5 – Biconical E- ield sen or 7

Fig re C.6 – E- ield sen or mou ted on a con u tin grou d plane [2 ] 7

Fig re C.7 – Eq ip tential s a es f or an o timal y desig ed E- ield sen or [2 ] 7

Fig re C.8 – Rogows i coi u ed for c r ent me s rements [2 ] 7

Fig re C.9 – Toroidal c r ent sen or made of mag etic material [23] 7

Fig re C.10 – Voltage pic -up p ints on the ed es of the toroidal sen or [2 ] 7

Fig re C.1 – Example of a sin le-c an el f ibre o tic tran mis ion s stem [2 ] 7

Fig re C.12 – At en ation of co xial l nes an fibre o tic ca les as a f un tion of f req en y 7

Fig re D.1 – Variou anten as f or CW testin 81

Fig re D.2 – Relation hip b twe n the CW anten a an the in ident HEMP field 8

Fig re D.3 – In ident an grou d- eflected field contribution to the ref eren e sen or ex itation 8

Fig re D.4 – Me s red referen e H-ield sp ctrum an its in erse Fourier tran form 8

Fig re D.5 – Me s red sen or resp n es an cal bration f un tion 8

Fig re D.6 – Me s red tran fer f un tion, cor ected by cal bration fi e 8

Fig re E.1 – Example of a general s ieldin pro lem 8

Fig re E.2 – Behaviour of the imp dan e ratio EH as a fu ction of distan e f om a source [2 ] 9

Fig re E.3 – Con u tin sla of thic nes , d, an infinite extent servin as an electromag etic b r ier 91

Fig re E.4 – Eq ivalent circ it re resentation of the s ieldin pro lem 9

Fig re E.5 – Two-p rt re resentation of a circ it 9

Fig re F.1 – Test set-up for the outside-to-in an in ide-to-out SE me s rement 10 Ta le 1 – Recommen ed test proced re for dif ferent test o jects 3

Ta le 2 – Dimen ion an comp sition of distan es d 1 to d , with referen e to Fig re 3 5

Ta le 3 – Dimen ion an comp sition of distan es d 1 to d , with referen e to Fig re 31 51

Ta le 4 – Me s rement f req en ies an anten as in plane-wave 5

Ta le 5 – Me s rement f req en ies an anten as in mag etic f ield 5

Ta le E.1 – Surace resistan e an electrical p rameters f or selected materials 9

Ta le F.1 – Comp rison with other standard 9

Ta le F.2 – Test s ielded ro ms 9

Ta le F.3 – Comp rison of the SE me s rement res lts 101

INTERNATIONAL ELECTROTECHNICAL COMMISSION

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p te t rig ts IEC s al n t b h ld re p n ible f or id ntif yin a y or al s c p te t rig ts

International Stan ard IEC 610 0-4-2 has b en pre ared by s bcommit e 7 C: Hig p wer

tran ient phenomena, of IEC tec nical commit e 7 : Electromag etic comp tibi ty

It f orms Part 4-2 of IEC 610 0 It has the statu of a b sic EMC publ cation in ac ordan e

with IEC Guide 10

This secon edition can els an re laces the f irst edition publs ed in 2 0 This edition

con titutes a tec nical revision

This edition in lu es the f ol owin sig if i ant tec nical c an es with resp ct to the previou

edition:

a) updates to the s ieldin eff ectivenes (SE) test method in Clau e 5;

b) a new An ex F des ribin method for testin ‘ n ide-to-out’ has b en ad ed

The text of this standard is b sed on the fol owin doc ments:

Ful inf ormation on the votin f or the a proval of this stan ard can b foun in the re ort on

votin in icated in the a ove ta le

This publ cation has b en draf ted in ac ordan e with the ISO/IEC Directives, Part 2

A l st of al p rts in the IEC 610 0 series, publ s ed u der the general title El ectroma n t ic

c mp t ibility (EMC), can b fou d on the IEC we site

The commit e has decided that the contents of this publ cation wi remain u c an ed u ti

the sta i ty date in icated on the IEC we site u der "ht p:/webstore.iec.c " in the data

related to the sp cif i publ cation At this date, the publ cation wi b

• recon rmed,

• 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 'colour inside' logo on the cov r pa e of this publ c tion in ic te

that it contains colours whic are consid re to be us f ul f or the cor e t

understa din of its conte ts Us rs s ould th ref ore print this doc me t using a

colour printer

Mitigation method an devices

Part 6: Ge eric Sta d rd

Part 9: Mis el a eous

Eac p rt is f urther s bdivided into several p rts, publ s ed either as international stan ard ,

as tec nical sp cif i ation or tec nical re orts, some of whic have alre d b en publs ed

as section Others wi b publs ed with the p rt n mb r fol owed by a das an a secon

n mb r identifyin the s bdivision (example: IEC 610 0-6-1)

The IEC has initiated the pre aration of stan ardized method to protect civi an society f rom

the ef fects of hig p wer electromag etic (HPEM) environments Su h ef fects could disrupt

s stems f or commu ication , electric p wer, inf ormation tec nolog , etc

This p rt of IEC 610 0 is an international stan ard that esta l s es the test con e ts, set-ups,

req ired eq ipment, an test proced res f or protective devices again t HEMP radiated

disturb n es

An ex F provides examples of the SE test method placin the TX anten a in ide the b r ier

ELECTROMA GNETIC COMPA TIBILITY (EMC) –

Part 4-23: Testing and measurement techniques –

Test methods for protective devices for HEMP

and other radiated disturbances

This p rt of IEC 610 0 provides a protective devices test method for HEMP an other

radiated disturb n es It is primari y inten ed f or HEMP testin but can b a pl ed to other

external y generated radiated disturb n es where a pro riate It provides a brief des ription

of the most imp rtant con e ts for testin of s ieldin elements For e c test, the f ol owin

b sic information is provided:

– the retical f ou dation of the test ( he test con e ts);

– test set-up in lu in outside-to-in an in ide-to-out me s rements;

This p rt of IEC 610 0 has b en updated to in lu e a new test method

Due to the avai a le sp ce, a tran mitin anten a p sition outside the b r ier has mainly

b en s g ested However, nowaday , man EMP protection f aci ties in practical u e do not

actual y have enou h sp ce avai a le outside the electromag etic b r ier d e to ph sical

con traints s c as concrete wal s or soi to alow the method des rib d in IEC 610

0-4-2 :2 0 (edition 1) to b a pl ed cor ectly From exp rien e many f aci ties have avai a le

sp ce f or a 1 m se aration or les only

Therefore, in man practical cases it is not p s ible to me s re s ieldin ef fectivenes

ac ordin to the test method of previou doc ments The con tru tors for EMP protection

f aci ties are also u wi in to bui d faci ties with extra sp ce for me s rements with the

tran mit in anten a outside the b r ier due to the gre t exp n e an ineff i ien y of the

o erational workin are f or new or existin bui din s

This doc ment provides ad itional y a method that al ows the tran mit in anten a to b

placed in ide the en los re an the receivin anten a outside the b r ier (‘ n ide-to-out’

method) An ex F in lu es test set-up an proced re examples

The f ol owin doc ments are ref er 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 pl es For u dated ref eren es, the latest edition of the ref eren ed doc ment (in lu in

an amen ments) a pl es

IEC 6 0 0-161, Int ern tion l Electrot ec nic l Vo a ulary (IEV) – Part 161: Ele troma n t ic

c mp tibility (avai a le at www.electro edia.org)

IEC 610 0-2-9, El ectroma n tic c mp t ibility (EMC) – P art 2: Enviro me t – Se tion 9:

Descript ion of HEMP e viro me t – Rad iated d isturb n e

IEC 610 0-5-3, Electroma n t ic c mp tibility (EMC) – Part 5-3: Install ation a d mit igat io

g id el ines – H EMP protection c n e ts

intentional or inad ertent holes, crac s, o enin s or other dis ontin ities in a s ield s race

Note 1 to e try: Inte tio al a erture p ints-of -e try are pro id d for p rs n el a d/or e uipme t e try a d e re s

a d f or v ntiatio thro g a ele troma n tic b rier

3.3

at e uation

red ction in mag itu e (as a res lt of a sorption an s at ering) of an electric or mag etic

f ield, a c r ent or a voltage, u ual y expres ed in decib ls

3.4

ba dwidth (of a d vic )

width of a f eq en y b n over whic a given c aracteristic of an eq ipment or tran mis ion

c an el do s not dif fer f om its ref eren e value by more than a sp cif ied amou t or ratio

[SOURCE: IEC 6 0 0-161:19 0, 161-0 -0 , modified – the note has b en deleted

3.5

ba dwidth (of a emis ion or signal)

width of the f req en y b n outside whic the level of an spectral comp nent do s not

ex e d a sp cif ied p rcentage of a ref eren e level

[SOURCE: IEC 6 0 0-161:19 0, 161-0 -10]

3.6

bou de wa e simulator

typ of simulator for prod cin electromag etic f ield in a localzed region of sp ce ref er ed to

as a "test volume"

3.7

box

en los re that contain electrical eq ipment

Note 1 to e try: Su h b x s u u ly c ntain mo ule of s b y tems

3.8

3.8.1

< mis ion> emis ion whic has a b n width gre ter than that of a p rtic lar me s rin

a p ratu or receiver

con uctiv point of e try

electrical wire or ca le or other con u tive o ject, s c as a metal rod, whic p s es throu h

test tec niq e by whic , throu h some external me n , a c r ent is f orced to f low in a circ it

at a desired location

Note 1 to e try: For EMP te tin p rp s s, it is a pro e s b whic simulate EMP tra sie t c re t p ls s are

intro u e into a c mp n nt, circ it or s stem to me s re d ma e or u s t thre h ld

3.13

c t off fre ue c

<waveg ide lowest f req en y for whic there is no at en ation of the electromag etic field

pro agatin in a los les waveg ide

Note 1 to e try: Below this fe u n y, th f i ld ate u te e p n ntialy with dista c alo g th wa e uid

3.14

dip le

straig t anten a, u ual y f ed in the center, that prod ces maximum radiation in a plane normal

to its prin ip l axis

3.15

dire t driv

ex itation of an electrical s stem by directly a plyin a voltage or c r ent source (either

tran ient or contin ou wave) to s stem ca les or s races as a me n of simulatin the

eff ects of tran ient EM pulses

direction of the electromagnetic plane-wave pro agation vector k , whic is p rp n ic lar to

the plane containin the vectors of the electric an the mag etic field

3.18

ele tric field stre gth

E

mag itu e of the electric f ield vector of an electromag etic wave or of a f ield cre ted by an

electric c arge distribution, me s red in volt p r meter

ele troma netic disturba c

an electromag etic phenomenon whic may degrade the p rorman e of a device,

eq ipment or s stem, or ad ersely aff ect l vin or inert mater

[SOURCE: IEC 6 05 -161:19 0, 161-01-0 ]

3.21

ele troma netic e vironme t

total ty of electromag etic phenomena existin at a given location

[SOURCE: IEC 6 05 -161:19 0, 161-01-01, modif ied – the note has b en deleted

3.2

ele troma netic puls

EMP

al typ s of electromag etic field prod ced by a n cle r explosion

Note 1 to e try: Ele troma n tic p ls is als refere to a n cle r ele troma n tic p ls (NEMP)

3.2

(ele troma n tic) ra iation

a) phenomenon by whic energ in the f orm of electromag etic waves emanates fom a

source into sp ce

b) energ tran fer ed throu h sp ce in the form of electromag etic waves

[SOURCE: IEC 6 05 -161:19 0, 161-01-10, modified – the note has b en deleted

3.2

ele troma netic topology

des ription of the intercon ection of s ield or electromag etic b r iers in a s stem that lmit

the EMP en ironment within the s stem

3.2

e ternal coupl ng

proces by whic an in ident electromag etic f ield strikes the exterior p rtion of a

con u tin s stem en los re an in u es c r ents an c arges

3.2

ga k t

element, normal y electrical y con u tive an flexible, u ed to se l an a erture in an

en los re

proces of decre sin the v lnera i ty of a s stem or comp nent by desig tec niq es, for

example by protectin again t, or decoupl n f rom, an u desira le external en ironment s c

as EMP

3.2

high-altitude ele troma n tic puls

HEMP

electromag etic pulse prod ced when a n cle r explosion oc urs outside the e rth's

atmosphere, typical y a ove an altitu e of 3 km

f ul IRA with a f ul p ra olc dis or half IRA with a divided p ra olc dis on a con u tin

grou d plane an an imp dan e tran f ormer f rom 5 Ω to 10 Ω

mag itu e of the mag etic f ield vector of an electromag etic wave, or the field prod ced by a

c r ent flowin in a wire, lo p anten a, etc me s red in amp res p r meter

3.3

outside- o-in

con entional test method where the receivin anten a is placed in ide an the tran mit in

antenna is placed outside of the s ielded en los re

3.3

ov ral s ielding

global s ielding

protection of an entire entity by u e of a sin le s ieldin en los re or some practical

eq ivalent, s c as the protection of the contents of an entire bui din by s ieldin the entire

ele tric l c re t p s in thro g c n u tors c n e tin th two v lume (wire , c ble , c n uits, pip s, d cts,

etc.)

3.3

point of -e try

PoE

ph sical location (p intp rt on the electromag etic b r ier, where EM energ may enter or

exit a to ological volume, u les an adeq ate PoE protective device is provided

Note 1 to e try: A PoE is n t lmite to a g ometric l p int PoEs are cla sif i d a a erture PoEs or c n u tor

PoEs a c rdin to th ty e of p n tratio Th y are als cla sifie a arc ite tural me h nic l stru tural or

ele tric l PoEs a c rdin to th arc ite tural e gin erin dis ipln in whic th y are u u ly e c u tere

Note 1 to e try: Commo PoE prote tiv d vic s in lu e wa e uid s b low c t-off , clo ure plate f or a erture

PoEs, a d fiters a d s rg ar e ters o p n tratin c n u tors

mes or s e t metal c hou in desig ed expres ly f or the purp se of se aratin

electromag etical y the internal an external en ironment

[SOURCE: IEC 6 05 -161:19 0, 161-0 -3 ]

3.4

s ielding de ra ation

general or local zed red ction of electromag etic s ieldin eff ectivenes as a res lt of

o enin s, p netration , we r, impro er uti zation, etc

s ieldin ef fe tiv ne s

SE

me s re of the red ction or at en ation in the electromag etic field stren th at a p int in

sp ce cau ed by the in ertion of a s ield b twe n the source an that p int, u ual y

expres ed in decib ls (dB)

3.4

s in ef e t

ten en y of alternatin c r ent to con entrate in the s race layer of a con u tor, res ltin in

the eff ective resistan e of the con u tor in re sin with f eq en y

3.4

col ection of eq ipment, s bs stems, s i ed p rson el, an tec niq es ca a le of p rf ormin

or s p ortin a def i ed o erational role

Note 1 to e try: A c mplete s stem in lu e relate fa i tie , e uipme t, s b y tems, materials, s rvic s a d

p rs n el re uire for its o eratio to th d gre th t it c n b c n id re s lfs f ficie t within its o eratio al or

s p ort e viro me t

3.4

tra sie t, adjective an nou

p rtainin to or desig atin a phenomenon or a q antity whic varies b twe n two

con ec tive ste dy states d rin a time interval s ort comp red with the time-s ale of interest

[SOURCE: IEC 6 05 -161:19 0, 161-0 -01]

3.4

prote tion de ic

device providin protection to a con u tive PoE

Note 1 to e try: It ma , f or e ample, c n ist of o e or more of th f olowin : a s ark g p, a metal o id v ristor

(MOV) or a f ilter Th s d vic s are u e to re u e th ele tric l disturb n e whic p n trate a ele troma n tic

b rier

3.5

wa e uide below c t off

waveg ide whose primary purp se is to at en ate electromag etic waves at f eq en ies

b low its lowest c t-of f eq en y, whi e at the same time providin a ph sical o enin into a

s ielded en los re

3.51

wire me h

con ected wire f abric normal y u ed for protection of a ertures in an electromag etic b r ier

A key asp ct in HEMP protection is des ribin an u in the electromag etic s ieldin

to olog of the s stem This amou ts to locatin an c aracterizin the variou s races (or

electromag etic b r iers) within the s stem en losin region (volumes) protected again t

HEMP In re l s stems, o enin s s al b present in the s ield f or the normal o eration an

f un tionin of the eq ipment in ide These o enin s degrade the s ieldin , an if the

degradation is to large, variou typ s of HEMP protection devices s al b provided at these

p netration p ints in the s ield The location of the variou p netration p ints an the typ s of

protective devices determine the location an typ of test to b con u ted to verify the s stem

s ieldin

As an example, a h p thetical case of a bui din containin a hig ly s ielded s re n ro m is

con idered In ide the s re n ro m, it is as umed that there are several eq ipment

en los res, ln ed together by s ielded ca les an con ectors The first s ieldin s rf ace in

this s stem is the bui din en los re De en in on the typ of bui din , this may or may not

provide sig ificant s ieldin for the interior volume After energ p netration alon

ina pro riately protected sig al an p wer l nes field p netration throu h a ertures in the wal

(in ludin crac s an ina pro riate joints) an dif fu ion throu h the wal are the main

p thway f or external energ to le k into the s ielded ro m L rge a ertures in the f orm of

commu ication l nes, may b present Tests of these in ivid al p netration mec anisms

s al b req ired to evaluate the s ieldin provided by this en los re

In ide the bui din , the HEMP field is at en ated somewhat by the buidin wal s or en los re

Th s, the electrical disturb n e exp rien ed by the internal s re n ro m is lower than that of

the ambient external HEMP field Becau e the internal s ielded ro m is sp cifical y desig ed

to red ce the EM field in ide, it is exp cted that it wi fu ction pro erly – if the variou

protection devices a pl ed to the s ield p netration are o erational Field p netration

throu h crac s an joints in the wals, dif fu ion throu h the s ield material an con u tive

p netration alon sig al wires are the main p thway f or energy to le k into the s ielded

ro m

In ide the s re n ro m, the con u tin exteriors of the eq ipment hou in an the s ielded

ca les form the third b r ier in this h p thetical s stem As b fore, the EM energ is a le to

p netrate into these internal b xes by con u tive p netration , a erture p netration an by

diff usion More ver, energ p netration throu h braided ca les an ca le con ectors may

oc ur on the lnes l n in the variou internal eq ipment en los res

An ex A des rib s test con e ts for b th con u tive an radiated disturb n es In Clau e 4,

variou method are des rib d for testin protective me s res again t the radiated HEMP

en ironment only These tests in olve the direct generation of EM field actin on eq ipment

en los res or s ield , or the injection of c r ent an c arge onto s ield to simulate the

radiated field interaction to the stru tures In the remain er of Clau e 4, a brief introd ction

into the variou HEMP test con e ts an tec niq es f or radiated field disturb n es is given

The sp cific test proced res are presented in Clau e 5

4.2 Te ting of s ielding e clos re

There are several dif ferent way of c aracterizin the b haviour of protective en los res

Below, variou test con e ts are examined that serve to des rib the s ieldin b haviour of

the in ivid al s ieldin elements in q estion An ex A s ould b con ulted f or more

information regardin these typ s of HEMP tests In te d, test method for verifyin the

protection levels provided by in ivid al s ieldin comp nents within the s stem wi b

examined an in ication given as to what s ould b me s red in the tests

Field tra sfer fu ctio s

A common me s re of s ieldin is o tained by examinin the stren th of the internal EM field

relative to the inten ity of the external ex itation EM field (i.e the f ield with the bui din

removed) Becau e the external an internal EM en ironments can b defined in terms of

either the E-field or the H-f ield, an b cau e these f ield are vector q antities, a large n mb r

of f ield combination is p s ible More ver, these f ield are time-varyin in nature, d e to the

tran ient nature of the HEMP thre t

Con iderin the internal an external f ield to b decomp sed into their feq en y-domain

sp ctra, a me s re of the at en ation provided by the bui din is provided by the f ield tran fer

f un tion T(ω) whic is the ratio of s ita ly c osen field q antities as

)(

)(

ωω

ω

o tin

AA

(1)

where

)(ω

o t

A re resents the sp ctral mag itu e an phase comp nents of a p rtic lar vector

comp nent of either the E or H ex itation f ield outside the faci ty; an

)(ω

in

A re resents a mag itu e an phase comp nent of either E or H in ide the bui din

De en in on the c oice of the internal an external field , this ratio can b dimen ionles or

have dimen ion of an imp dan e (in ohms) or an admit an e (in siemen )

The field tran fer fu ction in Eq ation (1) is a complex valued fu ction, havin b th a

mag itu e an phase An i u tration of a me s red tran fer f un tion b twe n the external

ex itation an the internal H- ield f or a sample s ieldin en los re is i u trated in Fig re 1 If

an ac urate re resentation of the internal tran ient field is to b determined f om

me s rements of T(ω), b th q antities s al b me s red If only a relative in ication of the

at en ation as a f un tion of the f eq en y is desired for the bui din , then it is s ff i ient to

o t

f or a s ielde e clos re

Shiel d in efe tiv n s

The s ieldin ef fectivenes of a f aci ty is closely related to the s ield tran fer f un tion

dis u sed a ove in that it comp res the relative mag itu es of two simi ar field comp nents in

the feq en y domain However, this q antity contain les information b cau e the phase

inf ormation is lac in Shieldin eff ectivenes of the en los re is defined as f ol ows:

IEC Fre u n y (Hz)

)(1

log2log

re resent s ita le external an internal E- or H-f ield q antities

Th s, it is closely related to the mag itu e plot of the tran f er f un tion f or the field

Becau e of the f un amental dif feren es in electric an mag etic s ieldin mec anisms at low

f req en ies, the s ieldin eff ectivenes f or electric field , denoted by SE

E, an for mag etic

f ield , S E

H, are sig ificantly diff erent at low f req en ies Fig re 2 i u trates the the retical

s ieldin provided by a closed alumin m s el of a thic nes of 0,5 mm General y, S E

H

is les

than S E

E

at low f req en ies (below 10 kHz), d e to the f act that the low- req en y mag etic

f ield is a le to diff use throu h the protective en los re wal s more e si y than do s the

electric field It is for this re son that mag etic f ield S E is typical y u ed at lower f equen ies

(b low 10 MHz), an at hig er feq en ies (a ove 10 MHz) the S E for electric or mag etic

field can b u ed to c aracterize an en los re

Fig re 2 – Ele tric f ield a d ma netic f ield s ielding ef fe tiv n s

of a 0,5 mm thic aluminum e clos re [2 ]

As a further example of the me s red mag etic field s ieldin ef fectivenes of a re l

en los re, Fig re 3 i u trates the b haviour of S E

H

as me s red f or the same bui din

dis u sed in Fig re 1 It s ould b noted that the s ieldin has several p ak an n ls,

cor esp n in to internal an external resonan es of the en los re, as wel as f req en

y-de en ent p netration that oc ur in ad ition to the simple diff usive p netration of field

Figure 3 – Me s re ma netic f ield s ielding eff ectiv n s SE

Hfor a bui din

4.2.2 Bui dings

For a bui din s c as that i u trated in Fig re 4, the internal HEMP-in u ed resp n e arises

mainly f rom con u tive an a erture-typ p netration Th s, an test of the glo al en los re

s ieldin s ould strive to adeq ately ex ite these p netration The field p netration by

diff usion throu h the bui din s ield (i.e the wals of the en los re) is general y smaler than

that of the con u tin s ield in ide the wal s

The HEMP test con e t for ph sical y large bui din s req ires either the ex itation by HPEM

ultra-wide an (UWB), contin ou wave (CW) sig als simulatin f ield on the exterior of the

test o ject (se the dis u sion of the variou test inter ace location in Fig re A.1) For this

ex itation, the me s rement of a s ita le internal resp n e in u ed by this external field is

ne ded

Figure 4 – Conc ptual i ustration of the HEMP te t of a bui ding

On the exterior of the bui din , the radiated or simulated HEMP ex itation field is expres ed

by the fol owin p rameters (se IEC 610 0-2-9):

– the in ident field (plu grou d- eflected field, if an ) waveform c aracteristic (s c as its

ampltu e, rise time, an f al time);

– the ex itation field polarization;

– the amou t of the s stem exterior i uminated by the radiated or simulated f ield

Detai s of how this external f ield may b prod ced or a proximated are presented in 5.2

IEC Fre u n y (Hz)

Diff erent typ s of internal resp n es can b c osen to des rib the s ieldin of the faci ty

en los re These in lu e the internal E- or H-f ield or the in u ed voltage an c r ent on

internal con u tors Con eq ently, diff erent me s res f or the s ieldin can b generated f or

an p rtic lar s stem More ver, the location of the internal o servation p int can vary, again

givin rise to wide variation of s ieldin f i ures of merit

4.2.3 Shelters a d s ielde rooms

For a s elter or a s ielded ro m, it is as umed that the radiated HEMP en ironment is sti

b in a pl ed to the exterior of the en los re where the in ident HEMP field are as umed to

provide the main ex itation to the stru ture Con eq ently, the test con e ts f or these

en los res are simiar to those f or large buidin s These smal er en los res can again b

c aracterized by either

– a complex-valued f ield tran fer f un tion, or

– a s ieldin eff ectivenes

It s ould b ke t in min , however, that there wi also b tran ient sig als con u ted into this

f aci ty on con u tin PoEs s c as p wer l nes an data lnes, an these s al b ad res ed

se arately, as dis u sed in IEC 610 0-5-3

The main diff eren e b twe n large bui din s without con u tin s ielded en los res an

s elters or s ielded ro ms is that the HEMP protection levels provided by these smal er

en los res wi b sig if i antly hig er, sin e they are sp cif i al y desig ed to provide a hig

degre of s ieldin Con eq ently, the internal sig al levels are u ual y smal er than in the

case of ju t bui din s This makes the me s rements more s s e tible to noise In ad ition,

d e to the smal er size, the eff ects of internal cavity resonan es wi oc ur at hig er

f req en ies As a res lt, q asi-static s ieldin con e ts are a plca le over a wider ran e of

f req en ies for these en los res (se IEC 610 0-5-3)

Fig re 5 i u trates a generic s ielded ro m with several PoEs of the s ieldin b r ier

identified

NOT Power a d sig al c n u tin p n tratio s are n t i u trate , a th y are c n id re s p rately in

IEC 610 0-4-2

Characterizin the overal b r ier s ieldin by a f ield tran fer f un tion T(ω), or by s ieldin

ef fectivenes S E, provides a glo al me s re of the p netration eff ects f rom al of the

p netration mec anisms in icated in Fig re 5 That is to say, the internal field arise f om the

p netration fom al of the PoEs taken together, alon with the dif fu ion throu h the material

in the wals of the s ield Other me s rement tec niq es are avai a le for c aracterizin the

protection provided by the in ivid al p netration (s c as the gas et, air vent, s ielded

con uit, etc.) an these are dis u sed in 4.4

Figure 5 – I lustration of a s ielde ro m or e clos re e cite by HEMP fields

These en los res are typical y located within an existin EM b r ier, whic sig if i antly

modifies the electromag etic f ield en ironment ex itin the s stem An internal b x or an

eq ipment ca inet is ex ited by a combination of the internal EM field plu injected c r ents

on ca le s ield comin f rom other eq ipment that have also b en ex ited by the local field

This is i u trated in Fig re 6

Figure 6 – I lustration of e uipme t ra k , c binets a d box e cite

by internal HEMP disturba c

Field il l umin tion test

For tests of these en los res in olvin the EM f ield in ide a larger en los re, the previou

con e t of field i umination can b ado ted to me s re the glo al s ieldin provided by the

eq ipment As b fore, this s ieldin may b c aracterized by

– a complex-valued field tran fer fu ction, or

– a s ieldin eff ectivenes of the en los re

Due to the smaler size of these en los res, however, dif fic lties in this me s rement can

arise f rom the den e internal p c in of internal electronic comp nents Of ten this makes it

dif fic lt to locate s ita le EM field sen ors in ide the b x Furthermore, b cau e the testin is

c aracterization of the HEMP field en ironment Final y, the intercon ection b twe n the

variou eq ipment items can b rather complex, an if a sin le b x or eq ipment rac is

tested, its me s red resp n e may b con idera ly dif ferent f rom that fou d when it is

con ected to the rest of the s stem

Shiel d tra sfer imp d an e

An alternative to the field testin of b xes an smal en los res is to u e the con e t of a

tran f er imp dan e of the en los re (se An ex E) This is simi ar to the tre tment of a

s ielded ca le dis u sed in 5.3, an in olves testin at a b x level interace in the s stem In

this case, a c r ent I(t is injected onto the s rf ace of the b x or rac , an an o en-circ it

voltage V

o(t ) on a s ita le internal sen e wire is me s red In this f orm of testin , it is

imp rtant to en ure that the injected c r ent f lows over the exterior of the b x in the same

way as when the b x is con ected to the rest of the s stem This impl es that the c r ent exit

p int ( he grou d con ection) has to b maintained so that the injected c r ent can b

removed pro erly

Fig re 7 i u trates a general s ielded en los re ex ited by an external c r ent injection Ju t

in ide the s el at p ints a an b, a sen e wire is con ected to the s ield, an the o en-circ it

voltage V

o

is me s red The tran fer imp dan e of this en los re is a complex valued

q antity, def i ed in terms of the f req en y domain sp ctral comp nents as

( )

( )

(ω)ω

ω

IV

(ω) is the me s red o en-circ it voltage on the sen e wire

This s ield tran f er imp dan e value varies, de en in on the location of terminals in ide the

en los re f or determinin the o en-circ it voltage F r adeq ate sen in of the s ieldin

provided by the entire en los re, the voltage sen e p ints s ould b located within the

en los re, ne r the c r ent injection location

Figure 7 – A ge eral s ield e cite by c r e t inje tion

The s ield tran fer imp dan e is a fu ction of the electrical pro erties of the s ieldin

material, as wel as the s ield dimen ion an the nature of an imp rection in the

en los re s c as se ms, a ertures, etc In the sp cial case of a thin spherical s ield in

whic there are no a erture p netration , it is p s ible to calc late the H- ield s ieldin

eff ectivenes S E

H, given the s ield tran fer imp dan e an the d.c resistan e of the s ield

throu h the relation hip:

IEC Cure t injec t io p int

Cure t e t ra tio p int

a

b

( )

'3

log2

t2

10H

RZa

γ is the pro agation con tant in the s ieldin material, given by γ ≈ �푗푗푗푗;

σ is the electrical con u tivity of the s ield material (in S/m);

Z

t

is the s ield tran fer imp dan e (in Ω/m);

R′ is the p r u it len th d.c resistan e of the s ield (in Ω/m)

4.3 Te ting of s ielde c ble a d con e tors

Shielded ca les are feq ently u ed to tran mit inf ormation b tween eq ipment contained

within two protective en los res As s c , one can def i e two distin t tran mis ion l nes: an

external l ne havin c r ents an c arges flowing on the exterior of the ca le, together with a

p s ible grou d-plane return, an an internal l ne con istin of the con u tors in ide the

s ield HEMP field can ex ite the external tran mis ion lne, an if the ca le s ield is

imp rect, some of the external c r ents an c arges can p netrate throu h the s ield an

ex ite the internal l ne This le d to an u wanted resp n e in the "protected" eq ipment In

4.3, test con e ts for this coupl n mec anism are examined

An ex B s mmarizes imp rtant asp cts of the c aracterization of a ca le s ield This in olves

two p rameters: the s ield tran fer imp dan e an the tran fer admitan e For most practical

ca le s ield , the tran fer imp dan e is a complex valued, feq en y-de en ent fu ction,

des rib d by re l an imaginary p rts, or eq ivalently, by a mag itu e an phase fu ction

The tran fer admit an e, however, is primari y re ctive, an is eff ectively modeled by a

f eq en y in e en ent ca acitan e

Whi e the tran fer imp dan e is a fu ction of the s ield pro erties only, the tran fer

admit an e de en s on b th the s ield an the config ration of the external tran mis ion lne

It is p s ible, however, to present the me s red tran fer admitan e p rameter in another

form: that of the s ieldin le kage p rameter, whic is in e en ent of the external circ it

Subclau e 4.3.2 con iders test method f or the tran fer imp dan e an admit an e q antities,

ke pin in min that the lat er quantity de en s on the detais of the external circ it, s c as

the external l ne heig t, wire radiu , an nature of the local grou d plane ne r the ca le

4.3.2 Te ting of c ble s ield

4.3.2.1 Determination of the tra sfer impe a c

Althou h there are several diff erent test config ration f or me s rin the tran fer imp dan e

of a ca le s ield, they are al related to the b sic config ration s own in Fig re 8 An external

voltage source V

s

f eed the x = 0 en of a ca le s ield of len th L whic is con ected to the

grou d (i.e the ref eren e con u tor) throu h a s ort-circ it at the o p site en of the ca le

The resistan e Z

s

at the source l mits the c r ent flowin in the ca le exterior

The in er (co xial) con u tor of the s ielded ca le is s orted to the s ield at the x = L en of

the l ne, an the o en-circ it voltage, V

i, is me s red at the x = 0 en Un er the as umption

that

– the internal an external tran mis ion l nes are electrical y s ort (L < λ ), an

– that there is negl gible f ield ex itation of the in er ca le d e to f ield enterin throu h the

ei'

t'

t'

t

V

VZ

LIV

jXR

is the ef fective source imp dan e of the external voltage source (in Ω)

When u in these expres ion , it is very imp rtant to en ure that the l ne is electrical y s ort

As the f req en y in re ses, the c r ent distribution on the exterior ca le b gin to have

p riodic n l s an p ak d e to reflection fom the s orted en of the l ne More ver, there

are internal reflection f rom the s ort on the interior ca le These os i ation are the cau e of

sig if i ant er ors in the me s rement of tran fer imp dan e at hig feq en ies

Fig re 8 – Ba ic configuration for tra sfer impe a c me s reme t

Fig re 8 i u trates the typical f req en y domain b haviour of the me s red tran fer

imp dan e for four diff erent braided ca les havin re sona ly go d s ieldin At low

f req en ies, Z′

t

is primari y resistive, with a value eq al to the p r u it-len th d.c resistan e

of the s ield At hig er f eq en ies, the f ield p netration throu h the a ertures in the braid of

the s ield b gin to aff ect the internal resp n e an the s ieldin b haviour is sl g tly

degraded Ac omp n in this in re se in tran f er imp dan e at hig f req en ies is an

electrical phase variation – a q antity that it is es ential to k ow if an detai ed calc lation

are to b per ormed u in the me s red Z′

a) – Mag itu e b) – P a e

NOT At hig fe u n ie th c rv s are pro ortio al to √frath r th n f, whic in ic te th t re p n e are n t

wel re re e te b a simple in u ta c

Figure 9 – Me s re tra sfer impe a c ma nitu e a d pha e of tra sf er impe a c

per unit le gth for f our braide s ield c ble with good s ielding pro ertie

4.3.2.2 Determination of the tran fer a mit a c

The evaluation of the tran f er admitan e of the ca le s ield uti zes the general test

config ration s own in Fig re 10 This is simiar to the config ration f or the tran f er

imp dan e me s rements, but with dif ferent termination at the ca le en s Usin Eq ation

(B.9), together with the same as umption as for the tran fer imp dan e, the tran fer

admit an e of the s ield can b expres ed as

S/m1

'

e'

i

si'

t

SCCj

VI

is the external p r u it-len th ca acitan e of the co xial ca le (in F/m)

Th s, a me s rement of the internal con u tor c r ent arisin fom the external source

voltage provides the tran f er admitan e Un er the a proximation that Y′

t

is purely re ctive,

the s ield le kage p rameter can b determined, if the internal an external p r u it-len th

ca acitan es of the co xial ca le are k own The p rameter S is a sin le, re l-valued n mb r,

an de en s only on the c aracteristic of the braided ca le Hen e, it is a u eful des riptor

for ca le s ield

IEC Fre u n y (MHz)

IEC Fre u n y (MHz)

Figure 10 – Ba ic conf iguration f or tra sf er a mit a c me s reme t

4.3.3 Te ting of c ble conne tors

Con ectors on s ielded ca les are often more imp rtant in determinin the overal s ieldin

of the ca le s stem than is the ca le s ield This is b cau e the con ector introd ces an

inter uption to the s ield, an , as s c , presents an imp rection in the s ieldin to olog

One way to re resent the eff ects of the con ector (as se n by the internal, or s ielded,

tran mis ion l ne circ it is by u in dis rete voltage an c r ent sources at the location of the

con ector The stren th of these sources are related to the external c r ent an voltage on

the con ector multipl ed by dis rete tran f er imp dan e an admitan e p rameters

re resentin the con ector, mu h as in the case of the distributed ca le s ield p netration

As in the case of a braided s ield, the lump d tran fer imp dan e of a con ector contain

b th a resistive an re ctive p rt, an the tran f er admitan e of a con ector is primariy

ca acitive However, ca le con ectors are alway desig ed so that there is very smal E-f ield

p netration throu h the device Con eq ently, the tran fer admitan e eff ects of the

con ector are almost alway mu h lower than the ef fects f om the tran fer imp dan e

Us al y, the lump d tran fer imp dan e p rameter is the only one req ired

The test con g ration for ca le con ectors is simi ar to that f or the ca le s ield tran f er

imp dan e dis u sed previou ly Fig re 1 i u trates the general test config ration f or s c

me s rements The same req irements for the test eq ipment for the ca le s ield test are

required here, an the con tru tion of the outer s ield s al b s c that it is a mu h b t er

s ield than the con ector This impl es that a sol d s ield is prefera le to a braided s ield for

this me s rement

Figure 1 – Te t configuration for tra sfer impe a c

me s reme t of a c ble conne tor

Given a me s rement of the internal o en-circ it voltage, the tran fer imp dan e of the

con ector is determined by the expres ion

si

s

ei

tt

t

VV

Z

IV

jxR

It s ould b noted that whi e the len th of the ca le, L, do s not a p ar explcitly in this

expres ion, it is neces ary that L < λ Th s L s ould b as s ort as p s ible to maximize the

f eq en y ran e of val dity for the me s rements

4.4 Te ting of s ielding materials

Imp rection in the s ieldin to olog of a s stem can often b protected by u in localzed

method s c as gas ets (on se m or b twe n do rs an their jambs), con u tin s e ts or

s re n (coverin a ertures), an other sp cial zed me s res l ke honey ombs an

waveg ides b yon c t-of f Characterizin these protection me s res is les o viou

b cau e their b haviour de en s not only on their in ivid al electrical comp sition, but also

on how the devices are con ected to the s ieldin to olog For example, a very lon crac

mig t b protected by fi in it with a con u tin material This could b ef fective in protectin

again t c r ents f lowin acros the crac : the con u tin material lets the c r ent p s over

the crac without mu h distortion an the H-f ield on the s ielded side is minimized However,

for c r ents p ral el to the crac , the presen e or a sen e of the protective f il n is

u imp rtant The c r ent is not sig ificantly aff ected by the sl t, an an protection again t

this c r ent comp nent is u neces ary

In des ribin tests s ita le for these comp nents, theref ore, an atempt is made to

c aracterize the intrin ic s ieldin pro erty of the protection device, in e en ently of how it is

u ed in a p rtic lar in talation This me n that a p rtic lar comp nent mig t b clas ified as

a "go d" protective device in one in tal ation, but d e to the p rtic larities of how it is u ed in

another faci ty, con idered to b a "p or comp nent in another in tal ation Evaluatin the

glo al b haviour of a s stem, together with al of its protection devices, is the role of s stem

level testin , a s bject whic is b yon the s o e of this stan ard

4.4.2 Condu tin ga k ts

Fig re 12 s ows several config ration of a con u tin gas et servin as a HEMP protection

device The b sic mec anism for protection is that the gas et f orms a con u tin p th

b twe n the two p rts of the en los re; this ke ps c r ent an c arge f rom "le kin " into the

in ide (i.e into the protected region) Eac of the thre config ration in the fig re has a

dif f erent s ieldin b haviour, d e to the dif feren es in the ge metry of the en los re wals

that s r ou d the gas et

Figure 12 – Ex mple of con ucting ga k ts us d a HEMP prote tion de ic s

A simple yet general circ it model for a gas et se l can b made by notin the imp rtant p rts

of the ge metry in Fig re 12 Cur ent flowin f rom one con u tor to another has to p s

throu h the gas et an this wi present an electrical resistan e to the c r ent Simi arly, the

f lat plates on either side of the gas et a p ar local y as a ca acitan e throu h whic a

displacement c r ent can f low Final y, the metal con u tors of the two wals form an

in u tan e in this circ it

Fig re 13 s ows the eq ivalent circ it re resentation of s c a gas eted o enin The

resistan e of the gas et an the ca acitan e of the gas et o enin a p ar in p ral el, an

this combination is in series with the in u tan es re resentin the c r ent p th throu h the

wal s of the en los re Sp cific values f or L an C de en on the local ge metry of the se l,

where s the value of R de en s on b th the ge metry an on the intrin ic electrical pro erties

of the gas et material

Fig re 13 – Circ it model repre e ting the be a iour

of a con ucting ga k t f or HEMP prote tion

These circ it values can b me s red or calc lated u in simple models for the sp cific

s a e an ge metry u der con ideration for a given pro lem F r c aracterizing the electrical

pro erties of the gas et material, however, me s rements of electrical resistivity of the gas et

material can b u ed This q antity is in e en ent of the s r ou din s of the gas et an can

b u ed to ran the ef fectivenes of one typ of gas et with another It s ould b noted,

however, that s c gas ets are u ual y made of flexible material, an , therefore, their

c aracteristic are de en ent on contact pres ure as in al examples of Fig re 12 The age of

gas et materials is also a factor

Fig re 14 i u trates the me s rement config ration for the resistivity This is the four

electrode method, an it is sp cial y desig ed so that me s rements of materials with very

low resistivities can b made For this me s rement, a bloc of the gas et material is

san wic ed b twe n two electrodes made f rom co p r or another hig ly con u tin material

An external d.c voltage source is con ected acros the two outer electrodes an a c r ent is

al owed to p s throu h the electrode The res ltin voltage dro acros the sample is

me s red u in a hig input imp dan e voltmeter, so as not to disturb the c r ent flow in the

IEC

Ga k et

Ga k et Cov er

sample With these p rameters me s red, the d.c resistivity of the sample material is given

by the expres ion:

LA

IV

os

is the d.c resistivity of the sample material in (Ω·m);

A is the cros -sectional are of the gas et material (in m

is the voltage dro acros the sample (in V)

Figure 14 – Me s reme t configuration f or the re istivity of a s mple

Simi ar me s rements can b made at hig er f eq en ies an a f req en y-de en ent gas et

imp dan e can b me s red However, this q antity is of l mited u e, b cau e its f req en y

variation are e si y conf used with those of the gas et-mou tin hardware an s r ou din s

Con eq ently, the d.c resistivity is the most commonly u ed p rameter f or c aracterizin the

gas et material

4.4.3 Condu tin s e ts a d s re ns

Con u tin s re n or s e ts of con u tin material are often u ed to l mit the HEMP

p netration throu h a ertures in the s ield Su h protection devices in lu e

– wire mes s re n ;

– con u tive p int co tin s;

– vac um metal zed co ting ;

– f lame/arc spray ;

L

A re A Bulk a k et mat erial Elec t ro e

As in the case of gas etin material, it is p s ible to c aracterize these protection devices

either by me s rements of their s ieldin b haviour as in tal ed in a sp cific to ological

config ration, or by an alternate me s rement of some intrin ic electrical pro erty of the

s ieldin material Whi e this later me s rement may not ac urately in icate how the

protection device wi f un tion in an arbitrary in tal ation, it do s provide a u ef ul tec niq e f or

distin uis in b twe n one protection material an another in a self con istent man er Two

test con e ts for con u tin a erture protective devices are dis u sed in 4.4.3.2 an 4.4.3.3:

one whic me s res the resistivity of the con u tin material, an another whic me s res

the s ieldin ef fectivenes of the material u ed f or s ieldin u der control ed con ition

4.4.3.2 Me s reme t of material re istivity

The resistivity of the material comprisin the protective cover of an a erture is one p rameter

that may b u ed to c aracterize its s ieldin As in the case of the con u tin gas et

des rib d in 4.4.2, the resistivity of a con u tin s e t can b determined u in the test

config ration s own in Fig re 14 An alternative a pro c is to u e a me s rement tec niq e

in whic the d.c resistivity is me s red with pro es located on the s race of the sample as

in icated in Fig re 15

Figure 15 – Te t conc pt f or me s ring the re istivity with s rfa e probe

In this test, a con tant d.c c r ent source I is con ected to two electrodes se arated by a

distan e L an in go d electrical contact with a bloc of con u tin material In resp n e to

this c r ent, a voltage V

s

is in u ed acros the two electrodes This voltage may b me s red

by a hig imp dan e voltmeter an the resistivity is again given by the expres ion in

Eq ation (8) The same expres ion is u ed in the present case, b cau e it is as umed that

the bloc is a go d con u tor an the c r ent ten s to f low u iformly acros the cros

-sectional are A of the material f rom one electrode to the other

It is imp rtant to note that this me s rement proced re is a plca le only at low f req en ies

where the s in depth of the material in q estion is very large comp red to the thic nes of the

sample If the feq en y of the c r ent source were al owed to in re se, the s in de th (given

by 훿=�휌

(휋 휋 푗)

⁄

) decre ses an , at some p int, b gin to b comp ra le with the thic nes of

the material u der test At this p int, the detai s of the c r ent distribution in the con u tor

cros -section s al b taken into ac ou t, as dis u sed in An ex E

As noted in An ex E, b th the s rf ace imp dan e (relatin the tan ential E-ield outside the

protective b r ier to the ex itation s race c r ent an the tran f er imp dan e (relatin the

tan ential E-f ield in ide the protective b r ier to the ex itation s rf ace c r ent may b

calc lated (se Eq ation (E.14) an (E.18) , on e the material resistivity is k own Th s, the

ele tro e

d.c me s rement of the resistivity can b u ed to infer the s ieldin pro erties of the material

f or hig er f equen ies

4.4.3.3 Shielding ef fe tiv ne s me s reme ts

A more direct a pro c for c aracterizin the s ieldin b haviour of a wire mes or

con u tin s re n is to me s re its s ieldin eff ectivenes u der stan ard con ition It is

wel k own that in the ne r field (or eq ivalently, for low f eq en ies), the electric an

mag etic f ield p netrate into a con u tor diff erently Con eq ently, a s ield s al b

c aracterized in general by two dif ferent s ieldin ef fectivenes p rameters For f ar f ield

s ieldin , where the in ident field on the s ield is a plane wave, the two s ieldin

ef fectivenes values b come eq al, an this sin le value may b u ed to c aracterize the

protection

Fig re 15 i u trates a me s rement con e t f or the plane-wave s ieldin eff ectivenes of

s re n an s e ts Fig re 15 a) s ows the ide l situation, in whic a plane wave is in ident

up n an infinite s re n The s ieldin of this s re n can b c aracterized by the f ol owin

eq ation (se Eq ation (2) :

dBlog

2

in

o t

10A

The res ltin s ieldin ef fectivenes de en s on the an le ψ that the in ident field makes

with the normal to the s e t Normal y, the an le ψ = 0° is c osen f or def i in the s ieldin

pro erties of the infinite plane

For actual me s rements, the ide l zed con g ration of Fig re 16 ) can ot b re l zed, d e

to the fact that the source prod cin the in ident f ield is not of infinite size, nor is it in nitely

f ar fom the s re n More ver, the s re n is not infinitely large This impl es that the

me s rements made u in the test config ration in Fig re 16 ) can b diff erent f rom those

exp cted fom a the retical tre tment of the infinite plane ge metry, d e to the f ol owin

eff ects:

– the non-plane-wave nature of the in ident field f rom the source;

– the radiation p tern f rom the source;

– diff raction fom the ed es of the s re n

To minimize this dif fic lty, it is common to req ire the f ol owin con ition to b maintained in

the me s rement config ration:

With these as umption , an a proximation to the plane-wave s ieldin ef fectivenes of the

s re n is o tained by makin two me s rements of the selected primary f ield comp nents at

the o servation location The first me s rement is with the plate removed an is denoted as

in place in f ront of the radiator, an is denoted as

m

c ov ereE

(or m

c ov ereH

) The s ieldin

eff ectivenes f or this con g ration is then evaluated as

dB

log2

SE

(10)

Figure 16 – Con epts f or s ieldin ef fe tiv ne s me s reme t

of condu tin s e ts a d s re ns

As an example of the plane-wave s ieldin eff ectivenes of a plate of dif ferent material,

Fig re 17 presents calc lated data f or co p r, aluminium an iron s e ts, e c havin a

thic nes of 0,01 mm Simi ar res lts are exp cted for materials havin other con u tivities

Figure 17 – Ex mple of th c lc late pla e-wa e s ielding ef fe tiv ne s

of a 0,01 mm thic plate of dif fere t material a a fu ction of fre ue c

4.4.4 Cut of f wa e uide a d hone combs

Another typ of HEMP protection me s re is to u e one or more c t-of waveg ides or

honey omb stru tures in a con u tin wal , as i u trated in Fig re 18 This p rmits the e s

flow of air or other non-con u tin material in an out of an en los re, whi e at the same time

providin large atenuation to the EM field en ironment The test con e t f or this penetration

protection method is identical to that for the con u tin mes or s re n s own in Fig re 15

IEC

Ob erv atio

p int

Ein

Infinit e c n uctin

s e t or s re n

k

Hin

Hm

107

1088

As b fore, the waveg ides or honey omb protection s al b located in a hig ly con u tin

wal , an s ieldin eff ectivenes me s rements s al b made with an without the wal

present, as des rib d in 4.4.3

Figure 18 – Cut off wa e uide a d hone comb us d a prote tiv eleme ts

4.5 Summary of te t conc pts

A numb r of diff erent test con e ts have b en presented in Clau e 4 f or diff erent asp cts of

s ielded s stems Ta le 1 s mmarizes the recommen ed test con e ts for the dif ferent

s stem comp nents In selectin the variou tests, it is imp rtant to re l ze that there is never

a "b st" test f or a s stem Eac test has its stron p ints an its flaws Eac test has

u certainties an er ors in the res lt, for example test o ject an me s rement eq ipment

interaction, test o ject varia i ty, u if ormity of field , non-l ne r eff ects an me s rement

er ors In selectin a test, theref ore, the u er s ould caref ul y con ider the fol owin

requirements f or the pro osed test:

– wh is the test b in con u ted?

– is the test re l y neces ary?

– what is the exp cted res lt f om the test?

– what is the req ired ac urac of the test res lts?

An wers to these q estion wi serve to put the variou test proced res into b t er

p rsp ctive an wi al ow the u er to select the pro er test an minimize the cost of the

testin

IE C

Ob erv tio p int

Ein

Wa e uid s

b y n c t-of f

k

Hin

Et

Ht

Table 1 – Re omme de te t proc dure for dif fere t te t obje ts

Becau e of the diverse way to simulate the eff ects of HEMP on a s stem, there is a wide

variety of f aci ties, eq ipment con g ration , an proced res that can b u ed to p r orm

tests on protection devices Clau e 5 s mmarizes test proced res for e c of the test

con e ts presented in Clau e 4

5.2 Ele troma netic f ield te tin

As noted in the interaction seq en e diagram of Fig re A.1, testin can b done either by

generatin the ex itation E- an H-f ield at a testin inter ace within the s stem, or by

simulatin the ef fects of these field interactin with the s stem b r iers by injectin

a pro riate c r ent an c arge on the s rf aces Subclau e 5.2 dis u ses simulation method

f or the field ex itation of the s stem u der test

5.2.2 Puls f ield te ting

5.2.2.1 Ful -sc le s stem i umin tion

Ful -s ale pulse testin is most s ita le for p r ormin a hig -confiden e, s stem-level

as es ment Becau e it is ca a le of providin mu h more information a out the s stem

resp n e to HEMP, it is seldom u ed to evaluate only the s ieldin b haviour of a sin le

protective element of the s stem, s c as the outer s ieldin b r ier

The in ident HEMP f ield are typical y prod ced by a ca acitive dis harge MARX generator

whic stores energ in ca acitor b n s over a p riod of several min tes an then dis harges

the energ in a time of the order of several nanosecon s into a ph sical y large radiatin

stru ture ( ypical dimen ion b in of the order of 5 m to 10 m) The radiatin stru ture can

b have l ke a waveg ide to con u t the field to the test o ject, or it can b have l ke an

anten a radiatin in fe sp ce In either case, the test o ject is i uminated by a tran ient

HEMP field an it resp n s in the a pro riate man er Typical y, the test o ject s ould not b

gre ter than one-third to half the heig t of the workin volume of the simulator so as to

minimize the plate interaction an to b t er a proximate f re -sp ce con ition Fig re 19

i u trates several example typ s of f ul-s ale simulators Alternative typ s of simulators

havin dif ferent pro erties can also b con idered

a) Vertic l y p lariz d, b u ded-wave simulator

b) A lternate co f i uratio for a vertic ly p lariz d,b u ded-wave simulator

c) Horizo taly p lariz d radiatin simulator

d) Vertic l y p lariz d radiatin simulator

e) A irb rne h rizo taly p lariz d radiatin simulator

Figure 19 – Ex mple of f ul -s ale, puls -ra iatin HEMP simulators

Test set u

Fig re 19 ) i u trates the typical test set-up for this typ of HEMP testin The test o ject is

located in the "workin volume" of the simulator A referen e f ield sen or is located in the

workin volume at a location where it wi not b severely af fected by the s at ered field f rom

the test o ject (The man facturer of the f aci ty wi u ual y provide information as to the

o timum location of the workin volume an referen e sen or.)

The test o ject is in trumented ac ordin to the go ls of the p rtic lar test This in olves

placin E- or H-ield pro es, c r ent pro es or voltage pro es at pre-selected p ints within the

s stem, an con ectin these to the data ac uisition computer by me n of the non

may in olve con ection to the p wer main an to other con ected eq ipment, whic can

aff ect the test res lts

Control of the pulser an the data ac uisition s stem is car ied out in an eq ipment ro m

whic is located u der or ne r the simulator stru ture It s ould b desig ed so that it do s

not inter ere with the simulator f ield , an it is u ual y s ielded so that the simulation f ield do

not ad ersely af fect the data recordin an proces in eq ipment

Test e uipme t

Aside f om the b sic simulator f aci ty ne ded to simulate the HEMP en ironment, the

f ol owin typ s of eq ipment are ne ded f or this typ of testin :

– E- an H-ield ref eren e sen ors f or me s rin the tran ient ex itation simulator f ield ;

– E- an H-f ield sen ors for me s rin f ield within the s stem u der test;

– c r ent an voltage sen ors f or me s rin internal wire resp n es;

– calbration eq ipment for al sen ors;

– fib r o tic tran mit ers, receivers an ca le for data extraction;

– tran ient digitizers for e c data c an el (rise time of 1 n );

– data ac uisition computer an mas storage medium;

– data proces in computer an plot ca a i ty

Detai s of these eq ipment items are provided in An ex C

Test pro edure

This is a tran ient test: the pulser is fired an the tran ient resp n e of the s stem is

me s red with the waveform digitizin eq ipment If this test is u ed to c aracterize the f irst

layer of s ieldin of the s stem, as defined in An ex A an in Clau e 4, it is neces ary to

con ert the me s red tran ient resp n es into the f req en y domain to evaluate the s stem

tran fer f un tion T(ω) or the s ieldin ef fectivenes , S E Fig re 2 s mmarizes the ste s in

this test proced re It s ould b noted that af ter the resp n e ratio R(ω)/F(ω) has b en

computed, cor ection to the tran fer f un tion may b ne ded This situation arises when the

desig of the simulator is s c that the sp ctrum F(ω) has a very smal value at certain

f req en ies At these f req en ies, the resp n e R(ω) is dominated by noise an the ratio can

have a large pseu o- esonan e