IEC 62770:2013

FOREWORD
INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 Properties, their significance and
  test methods
5 Classification, identification, general delivery
  requirements and sampling
Annex A (normative) - Summary of the test method
        for evaluating oxidation stability of unused
        natural esters
Annex B (informative) - Specifications of low-viscosity
        insulating fluids derived from natural esters
Bibliography

IEC 62770:2013 describes specifications and test methods for unused natural esters in transformers and similar oil-impregnated electrical equipment in which a liquid is required as an insulating and heat transfer medium. Natural esters with additives are within the scope of this standard. Because of their different chemical composition, natural esters differ from insulating mineral oils and other insulating fluids that have high fire points, such as synthetic esters or silicone fluids. Natural, ester-derived insulating fluids with low viscosity have been introduced but are not covered by this standard. Pertinent properties of such fluids are given in Annex B. This standard is applicable only to unused natural esters. Reclaimed natural esters and natural esters blended with non-natural esters fluids are beyond the scope of this standard.