IEEE Std C62.55:2020 pdf download.IEEE Guide for Surge Protection of DC Power Feeds to Remote Radio Heads.
This guide covers the application of SPDs used to protect the dc power feeds of remote radio heads (RRHs) and power supplies of optical fiber cable systems feeding the antenna systems.
1.2 Word usage
The word shall indicates mandatory requirements strictly to be followed in order to conform to the standard and from which no deviation is permitted (shall equals is required)
The word should indicates that among several possibilities one is recommended as particularly suitable, without mentioning or excluding others; or that a certain course of action is preferred but not necessarily require.
The word may is used to indicate a course of action permissible within the limits of the standard (may equals is permitted to).
The word can is used for statements of possibility and capability, whether material, physical. or causal (can equals is able to).
2. Normative references
The following referenced documents are indispensable for the application of this document (i.e., they must be understood and used, so each referenced document is cited in text and its relationship to this document is explained). For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments or corrigenda) applies.
3. Definitions, acronyms, and abbreviations
3.1 Definitions
For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary Online should be consulted for terms not defined in this clause.
remote radio head (RRI-I): The radio frequency (RF) module of a radio base station (RBS), which can be installed separated from the base band unit (BBU). [adapted from ITU-T K.97(2014)]
NOTE I Optical fiber is commonly used to connect the BBU to the RRFI.’
NOTE 2—The RF module is also called remote radio unit (RRU).
3.2 Acronyms and abbreviations
BBU base band unit
DUT device under test
FTTA fIber to the antenna
MOV metal-oxide varistor
RBS radio base station
RF radio frequency
RRH remote radio head
SPD surge protective device
TVS transient voltage suppressor
4. The problem
Antennas at tower tops are predominately fed by coax from radio equipment at the base of the tower. To reduce transmission losses and mechanical loading on the tower, RRHs arc placed at the top of the tower next to the antenna. Optical fiber cables carrying the signal information are run up to the RRH equipment, where the optical signals are converted into radio frequency (RF) power to drive the antennas. The RRI-1 is generally powered by a low voltage dc line (typically 48 V) run up to the equipment from a power supply at the base of the tower. Towers can be over 610 m (2000 ft) tall, and the lightning surges to these towers can have very high 12t (the lightning action integral).IEEE Std C62.55 pdf download.