Lightning Protection For Ac Power; Lightning Protection For Trunk Cables - Huawei Airbridge BTS3612A-1900 Technical Manual

Technical Manual
Airbridge BTS3612A CDMA Base Station
II. Measures of internal lightning protection
The AC lightning arrester at the AC input port prevents the AC from direct lightning
stroke or inductive lightning. The lightning protection index of the AC input port is 40kA.
E1 lightning protection board at the E1 port of the BTS3612A protects E1 signal ports.
The lightning protection index of E1 port is 5kA.
The antenna and feeder lightning arrester at the feeder inlet protects the BTS against
the striking current coupled into the feeder when the steel tower gets lightning stoke.
The equalized electric potential connection and insulation design of the cabinet prevent
the cabinet from the damage of lightning stroke.

6.2.2 Lightning Protection for AC Power

The overall power supply for the BTS3612A is large, so an AC lightning arrester is used
at the AC input port as the first level of lighting protection measures. This parallel
lightning protection can effectively prevent the BTS3612A from the damage of lightning
stroke. This protection function:
Adopts symmetric compound circuits, applicable to the power supply environment
with poor electric network quality.
Adopts temperature-controlled circuit breaking technology with embedded
over-current protection circuits to prevent the cabinet from the danger of fire.
Adopts full protection of both common mode and differential mode.
Adopts dual-color luminotrons to indicate the working states of the cabinet.

6.2.3 Lightning Protection for Trunk Cables

The BTS3612A supports multiple transmission modes: E1 (75Ωcoaxial cables and
120Ω twisted pairs), T1 (100Ω twisted pairs), SDH and microwave transmission.
E1/T1 ports are liable for lightning induction. Therefore, various lightning protection
measures for E1/T1 ports are introduced in the following.
The BESP is added at the trunk cable inlet for the lightning protection at E1/T1 ports of
the BTS3612A. The connection is shown in Figure 6-1.
Chapter 6 Lightning Protection and Grounding
6-2
System Principle