"The owner" required the need for an electric power driven, gas compressor station in one of their primary service territories. The compressor station was designed to include a high voltage substation
that would interconnect with the local utility. One of the primary concerns in the design of the grounding system for this gas compressor facility was to select a conductor that would be able to withstand high electric fault currents for a short period and would not interfere with the facility's
existing cathodic protection system. A typical high voltage substation utilizes a bare copper ground grid. Unfortunately a buried copper ground grid would require an impractical upgrade of the cathodic protection system to protect the existing underground pipelines and other structures. It was estimated that the existing facility cathodic protection system would require 60 to 80 amperes (A) of additional DC impressed current if a bare copper grounding system was used. Various substitutes for copper wire were explored, including zinc-coated copper and zinc coated steel conductors. Another option that was investigated was the use of electrical isolator and surge protection devices that would permit use of copper in the electrical substation. A zinc coated steel conductor was selected as the grounding system conductor for the electrical
substation and the gas storage facility. The zinc exterior layer is a material that produces less impact on the DC facility cathodic protection system than bare copper. It is also a material that can be reasonably
protected by the facility cathodic protection system. A steel conductor core with a diameter of 0.72 inch (1.83 cm) was selected to satisfactorily carry the local utility's requirement of a 63,000 A (63 kA) line-to-ground fault current.
Keywords: grounding, compressor station, high voltage substation, electric fault current, safety