: Incorporates requirements for digital interfaces and bandwidth, often referencing IEC 61850 protocols for smart grid automation. The Transition from IEC 60044
: Covers rated frequencies from 15 Hz to 400 Hz , as well as dedicated DC applications. iec 618691 pdf
As a general framework, IEC 61869-1 must be read alongside specific product standards (like Part 2 for Current Transformers or Part 3 for Inductive Voltage Transformers). It defines: iec 618691 pdf