Furuno 9ZWWR2120, Руководство по установке

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S2E-17-0209_IM_WR2120_C
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4.2. New standard lightning and angle of protection
Lightning rod height and protection efficiencies were revised when IEC standards were renewed in
2003, replacing the older 1990 standard. The angle of protection decreases as the height of protected
structure gets higher. Any protection level of structure over 60 meters will not be enacted in the
protection angle because a lightning rod is ineffective for buildings over 60 meters when a side-on
lighting strike hits side of a building.
Protection
level
Protection
efficiency
Rolling sphere
method
Protection angle method (height: h)
Mesh
method
(m)
Radius(m)
See Figure 6 below
I 0.98 20 5
II 0.95 30 10
III 0.9 45 15
IV 0.8 60 20
*: Applicable only to rolling sphere and mesh methods.
Figure A-6: Protection angle corresponding to the class of LPS (IEC62305-3)
5. Conclusion
For some installations it is difficult to add a tall lightning rod because of area height regulations and
restrictions. It may be necessary to carefully consider all potential lightning protection solutions.
Figure A-7:
Lightning rod angle of protection at protection
level IV (Protection efficiency 0.80)
Figure A-8:
Protective range of rolling sphere method