Would you like more information on instrument transformers or the IEC 61869 series?
This International Standard applies to instrument transformers with an analogue output, intended for use with electrical measuring instruments and electrical protective relays. Iec 61869-1 Pdf
You're looking for information on IEC 61869-1! Would you like more information on instrument transformers
IEC 61869-1 is a standard for instrument transformers, specifically covering the requirements for voltage transformers. Here's a brief overview: Iec 61869-1 Pdf