Covers instrument transformers with both analogue and digital secondary signals used for measurement, protection, and control. Technical Changes in the 2023 Revision

Performed once on a specific design line to prove its theoretical and structural soundess.

Performed once on a specific model line to prove its core design meets all specifications (e.g., short-time current tests and temperature-rise tests).

The general requirements outlined in Part 1 establish the environmental, mechanical, and electrical baselines that all compliant instrument transformers must meet. 1. Standard Service Conditions