This guide assists users in specifying the functional requirements for transmission static synchronous compensator (STATCOM) systems using forced commutated technology based on voltage sourced converter topologies. This guide covers specifications, applications, engineering studies, main component characteristics, system functions and features, factory testing, commissioning, and operations of the STATCOM systems. A number of sections in the guide can be used for active filters and for industrial or distribution system applications. However, reactive power compensation, mitigation of load disturbances, or phase unbalance compensation for industrial and distribution system applications are not included in this guide. Commercial terms and conditions for the purchase of the STATCOM systems are also beyond the scope of this document. General terms and conditions forming the commercial part of a specification for a particular project are outside the scope of this document.