When searching for the "best" resource regarding IEC 61869-1, you are looking for the definitive global standard that governs the general requirements for instrument transformers. As the core document of the IEC 61869 series, this standard replaces the older IEC 60044 series and establishes the modern benchmark for current and voltage transformers used in power systems. What is IEC 61869-1? IEC 61869-1 is titled "Instrument transformers – Part 1: General requirements." It serves as the umbrella standard for the entire family of instrument transformer standards. Its primary function is to define the general definitions, safety requirements, and testing protocols that apply to all specific types of instrument transformers, whether they are inductive, electronic, or optical. Adn432 Hot - 3.79.94.248