Presented by Dinesh Chhajer, Megger

Relaying Current Transformers serve as one of the critical components in the design and operation of a protection scheme. CT performance under fault conditions should be within its operating characteristics for a true representation of fault magnitudes and reliable operation of the protection scheme. CT saturation, incorrect polarity, ratio inaccuracies, wrong burden sizing and insulation failure can all lead to mis- operation of protective schemes, or possibly a failure of protection schemes altogether. Unreliable and perhaps unpredictable CT performance could increase the risk of potentially permanent damage to critical electrical assets. To ensure proper installation and operation, CTs are often subjected to one or more tests performed in accordance with standards, such as IEEE C57.13.1 and NETA ATS and MTS.