scope:

Wire-line communication facilities serving electric supply locations often require special high-voltage protection against the effects of fault-produced ground potential rise or induced voltages, or both. Some of the telecommunication services are used for control and protective relaying purposes and may be called upon to perform critical operations at times of power system faults. This constitutes a major challenge in the design and protection of the telecommunications system because power system faults can result in the introduction of interfering voltages and currents into the telecommunication circuit at the very time when the circuit is most urgently required to perform its function. Even when critical services are not involved, special high-voltage protection may be required for personnel safety and plant protection at times of power system faults. Effective protection of any wire-line telecommunications circuit requires coordinated protection on all circuits provided over the same telecommunication cable.

This recommended practice presents workable methods for protecting wire-line communication circuits entering electric supply locations. It is important to note that special high-voltage protection for the purpose of personnel safety and plant protection may be required even when critical services are not involved. In the case of leased circuits mutually agreeable methods for the installation of protective equipment owned by either party are presented.

This recommended practice has been prepared by the Wire-Line Subcommittee of the Power Systems Communications Committee of the IEEE Power Engineering Society. This standard represents the consensus of both power and communications engineers.

This recommended practice presents engineering design practices for special high-voltage protection systems intended to protect wire-line telecommunication facilities serving electric supply locations.

The following topics are included in this document:

a) A description of the electric supply locations environment, i.e., ground potential rise (GPR), induced voltages, lightning, and switching transients

b) A discussion of special high-voltage protection devices

c) Definitions of service types and service performance objectives for electric supply locations telecommunication services

d) Special protection theory and philosophy

e) Special protection system design guidelines

f) Personnel safety considerations

g) Grounding

h) Cables with metallic members

Other telecommunication alternatives such as radio and optical fiber systems are excluded from this document.