ANSI/IEEE C37.90 specifies standard service conditions, standard ratings, performance requirements, and testing requirements for relays and relay systems used to protect and control power apparatus. The standard establishes a common reproducible basis for designing and evaluating relays and relay systems. According to ANSI/IEEE C37.90, a relay system may include computer interface equipment and/or communications interface equipment, such as a carrier transmitter/receiver or audio tone equipment. ANSI/IEEE C37.90 does not cover relays designed primarily for industrial control, for switching communication or other low-level signals, or any other equipment not intended for control of power apparatus.
Retrieved from IHS 10-31-2013
