Rules for Verification of Instrument Transformers for Measurement - Part 1: Standard Current Transformers

This specification outlines the mandatory requirements for verifying measuring instrument transformers, specifically focusing on standard current transformers as the first part of a broader series. The document establishes precise technical criteria and methodological procedures necessary to ensure the accuracy and reliability of measurement units during calibration processes. It defines the scope of applicable equipment, detailing the classification of current transformers based on their rated accuracy classes and nominal transformation ratios. The text prescribes the necessary environmental conditions for testing, including temperature, humidity, and stability of the power supply during verification. Furthermore, it specifies the approved testing methods and the sequence of operations required to evaluate ratio error and phase displacement. The standard provides detailed instructions on the preparation of instruments, the selection of reference standards, and the recording of results. It also addresses the criteria for determining conformity and the protocols for handling deviations found during the inspection. This framework supports the consistent application of measurement practices across various sectors relying on precise electrical measurements.