This guide provides general guidelines toward the preparations of a functional specification of transmission fixed-series capacitor (FSC) banks using overvoltage protection based on three technologies: - metal oxide varistors - metal oxide varistors with a forced-triggered bypass gaps - thyristor valve bypass The commercial aspects of the specification for a particular project are outside the scope of this guide. This guide does not apply comprehensively to thyristor-controlled series capacitors. A more complete reference is IEEE Std 1534(TM)-2002. The standard for fixed-series capacitors is IEEE Std 824(TM)-2004.