IEEE Std C37.241-2017 pdf download – IEEE Guide for Application of Optical Instrument Transformers for Protective Relaying.
4. Introduction 4.1 Overview Optical sensor technology to replace current transformers (CTs) and voltage transformers (VTs) has been demonstrated for over 20 years. These sensors use optics and electronics to achieve accuracy, linearity, dynamic range, and efficient installation far beyond the capabilities of familiar electromagnetic and capacitive instrument transformers. Commercial products have been available for most of that time, with a widening array of choices and manufacturers. However, the commercial transition to new sensors has been gradual, in light of the familiarity and reliability of conventional instrument transformers. Accordingly, the objective of this guide is to provide the reader with a factual understanding of the technical and economic bases for choosing optical instrument transformers (OITs) when familiar sensor technologies remain widely available. This guide provides information on technologies of optical voltage and current sensors, their performance characteristics, their incorporation in measurement systems for protection and control, installation, and maintenance requirements, testing requirements, and application considerations. The following clause outlines the topics covered in detail in the remainder of the guide. 4.2 Optical voltage and current sensing technologies Clause 5 provides a review of the technologies for optical voltage and current sensors in the electric power industry. It introduces the reader to the scientific principles that optical instrument transformers use to measure electrical quantities. It illustrates the product packaging alternatives that arise from these measurement techniques.
4.6 Installation and commissioning Clause 9 contains information and considerations for the installation and commissioning of optical instrument transformers. 4.7 Testing of optical instrument transformers Clause 10 provides guidance on testing optical instrument transformers, including factory testing, site acceptance testing, commissioning tests, and on-site accuracy testing. 4.8 Reliability and redundancy Clause 11 provides a review of reliability and redundancy considerations for optical instrument transformer applications. It highlights the interaction between the optical instrument transformers and the overall protection scheme architecture. 4.9 Industry standards Annex B presents an informative annex explaining IEEE and IEC standards related to optical instrument transformers available at the time of writing of this guide.