Protection of SF6 Gas Insulated Substations - Industry Survey Results

This paper summarizes the result of an industry survey of gas insulated equipment protection practices and develops recommendations where necessary. Tables are included to show the type of gas insulated equipment located at each substation (current transformers, voltage transformers, switches, bus bars, bushings, lightning arresters, and cable end terminations), the equipment configuration (single or three conductors), the type of gas monitoring equipment used (density or pressure), the use of gas monitoring equipment (alarm and/or trip), unique relaying protection applications, and unique operating procedures. Gas insulated circuit breakers are specifically excluded from this survey.