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A.3. Solution
Ways to make a current installation safer.
Lightning protection level definition:
Lightning protection level (LPL) is defined in the regulation based on peak current. LPL will be
selected for installation situations where LPL IV is generally used. Protection area will be made
using rolling sphere, its radius is determined in the Table A.7. Example of an actual condition is
shown in the Figure A.3.
LPL
Probability
for min value
Minimum
peak
current [kA]
Probability
for max value
Minimum peak
current [kA]
Rolling sphere
radius [m]
I
0.99
3
0.99
200
20
II
0.97
5
0.98
150
30
III
0.91
10
0.95
100
45
IV
0.84
16
0.95
100
60
Key
1) lightning rod
2) steel mast with antennas
3) handrails
4) interconnected reinforcement
r) radius of the rolling sphere
Key
1) Lightning rod
2) Steel mast with antennas
3) Handrails
4) Interconnected reinforcement
r) Radius of the rolling sphere
Table A.7: Probability and rolling sphere radius for LPL (IEC 62305-1)
Figure A.3: Protection of aerials and other external equipment (IEC 62305-4)
