This document contains the detailed information of the standard IEEE C37.92-2005. This standard defines the interface between voltage or current transducer systems or sensing systems with analog electronic outputs, and suitably designed protective relays or other substation measuring equipment.
These transducer systems reproduce the power system waveforms as scaled values. This standard also defines requirements for optional intermediate summing or ratio-adjusting amplifiers required to add or subtract the outputs of more than one sensing system for measurement by a single relay or measuring device.
More Information on this standard can be found here.