Page 7 - dehn-protects-cell-sites-ds104-e

d.c. outdoor box
remote
radio head / unit

telecommunication /
information technology
system

utility (230/400 V)

base station (radio base station)

power supply
unit
optical fibre
cable

baseband
48 V d.c. unit (BBU)
feeder cable

mast

The lightning protection system of a mobile communication
system comprises
• An external lightning protection system and
• An internal lightning protection system consisting of
surge protective devices.
In order to plan protection measures, the mobile commu-
nication system is divided into lightning protection zones.
The rolling sphere method is used to determine LPZ 0 **
A
and LPZ 0 **.
B
LPZ 0** is the outer zone where the threat is due to the
full lightning electromagnetic field and where the internal

systems may be subjected to the full or partial lightning
current. LPZ 0** is subdivided into:
• LPZ 0 A **: Parts of the mobile communication system
which may be subjected to direct lightning strikes and
the full lightning electromagnetic fi eld.
• LPZ 0 B **: Parts of the mobile communication system
which are protected against direct lightning strikes, but
where the full lightning electromagnetic fi eld is present.
LPZ 1** is the inner zone that is protected against direct
lightning strikes. However, impulse currents must be limited
by current distribution, isolating interfaces and SPDs***
on the zone boundaries.

* Lightning Protection System
** Lightning Protection Zone
*** Surge Protective Device

7