Maintenance of natural ester (Envirotemp FR3 dielectric fluid) filled transformer

Transformers are designed, manufactured and tested according high standards of practice, and it is an assumption of this document they meet the required levels of quality and reliability for proper operation and long-term performance in service.

Due to some similarities between Envirotemp™ FR3™ fluid and conventional mineral oil, many of the traditional procedures are acceptable for FR3 fluid filled transformers. This paper aims to support maintenance repair and retrofill for FR3 fluid filled transformers, which may be different from those traditionally applied in mineral oil or the ones applied for other natural ester fluids, and may require specific additional steps for specific transformers or local conditions.