– 2 – 61000-5-8 © IEC:2009(E)
CONTENTS
FOREWORD...........................................................................................................................4
INTRODUCTION.....................................................................................................................6
1 Scope...............................................................................................................................7
2 Normative references .......................................................................................................7
3 Terms and definitions .......................................................................................................8
4 General introduction .......................................................................................................10
5 Description of the distributed infrastructure ....................................................................10
6 Spatial variation of HEMP environments .........................................................................11
6.1 Early-time (E1) HEMP spatial variations ................................................................11
6.2 Intermediate-time (E2) HEMP spatial variations.....................................................13
6.3 Late-time (E3) HEMP spatial variations .................................................................13
7 Implications for HEMP coupling to extended conductors ................................................. 13
7.1 General .................................................................................................................13
7.2 Early-time (E1) conducted environments ...............................................................13
7.3 Intermediate-time (E2) conducted environments ....................................................14
7.4 Late-time (E3) conducted environments ................................................................15
8 Relation of HEMP disturbances to natural EM environments...........................................16
8.1 General .................................................................................................................16
8.2 Comparison of HEMP E1 to EFT and surge ...........................................................16
8.3 Comparison of HEMP E3 to currents induced by geomagnetic storms ...................17
9 Protection strategy .........................................................................................................18
9.1 General .................................................................................................................18
9.2 Electric power .......................................................................................................18
9.2.1 Background ...............................................................................................18
9.2.2 Emergency planning, operating procedures and restoration.......................20
9.2.3 HEMP immunity standards for new equipment ...........................................20
9.2.4 Selected retrofit protection.........................................................................21
9.2.5 Application to a high-voltage power substation ..........................................22
9.3 Telecommunication centres ...................................................................................25
9.4 Other infrastructures .............................................................................................25
Bibliography..........................................................................................................................26
Figure 1 – Simplified depiction of the interdependency of critical infrastructures [4] ..............
11
Figure 2 – E1 HEMP tangent radius as a function of the height of burst ................................12
Figure 3 – An example of the area covered by the early-time (E1) HEMP by a 170 km
burst over the United States .................................................................................................
12
Figure 4 – Late-time (E3) electric field waveform from IEC 61000-2-9...................................17
Figure 5 – Vertical conduit geometry for a current transformer (CT) ......................................23
Figure 6 – Covered shallow trench for control cables ............................................................23
Figure 7 – Grounding of control cables at junction box..........................................................24
Figure 8 – Control cable access to equipment.......................................................................24
Table 1 – Peak currents induced by the E1 HEMP on above-ground and buried
conductors ............................................................................................................................
14
Copyright International Electrotechnical Commission
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