Chapter
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Error! Style not defined.
2-5
cables in the equipment room should be routed in a radiating or flat way. Three
independent grounding cables should be used. The protection ground of the DC power
distribution system, the work ground of the power system and the lightning protection
ground.
The grounding resistance of the BTS should be less than 5
Ω
. The engineering requires
the grounding resistance to be the smallest possible. The magnitude of grounding
resistance is affected by grounding post resistance, leading wire resistance, contact
resistance between the grounding post and soil, and soil type of. The greatest impact on
grounding resistance comes from soil type. In areas with poor soil conditions, some
resistance-reducing agent (such as propenamide) may be added around the grounding
stake to meet the requirements. Changes in temperature will also cause variations in
resistance. In cold areas, the impact of temperature on the resistance may be reduced
by burying the stake deeply into the ground. Grounding stakes are usually made of
galvanized materials, in proper size. The connection cables from the grounding stake to
the equipment should adopt copper-sheathed wires of good conductivity (core wire
section area less than 50mm
2
, and length as short as possible). If necessary, anti-erosion
protection can be provided to the grounding connection parts to guarantee
low-resistance connection.
The working ground refers to the loop formed through the earth to transmit energy and
information. For instance, the 3-phase AC power supply neutral line ground and the
positive battery ground are both working grounds. This grounding approach can resist
electromagnetic interference and crosstalk.
The protection ground refers to the grounding of the metal shell of the power supply
equipment to prevent hazards to human body due to power leakage.
In addition, the ground for lightning protection should be used to prevent lightning
strike from damaging the equipment and to protect the safety of lives and properties.
2.1.6 Inspection of the Installation Environment for the Outdoor Antenna Feeder
System
1. Check whether the height and the size of the feeder window comply with the
requirements of the BTS equipment and the engineering design drawing.
2. Check the height, weight bearing and grounding of the outdoor cabling rack
against the engineering design.
