What is the calibration interval for electronic instrument current and voltage transformers? Is there any equipment for calibration of sensors with the interface conforming to IEC 61850-9-2LE standard?

The calibration interval for fiber optical instrument transformers for current and voltage is 8 years. The calibration is carried out according to the Calibration Methodology MP 2203-0293-2015 "Electronic fiber optical current transformers EFOCT with digital output" approved by FGUP "All-Russian scientific research institute of metrology n. a. D. Mendeleev" in November of 2015. There is a similar document for voltage instrument transformers.

All the shipped instrument transformers for current and voltage are supplied with a primary calibration mark.