Natural esters as insulating fluids — Some other features

Natural esters are candidate fluids for transformer insulation system. Recently the most common insulation system in power transformers is paper-oil system. Oil generally mean petroleum based insulating fluid. As there are efforts to preserve sustainable development, crude oil products should be eliminated and replaced by natural products, which are easily biodegradable. In past it was shown that natural esters may reach qualities of mineral oils in some parameters (from electrical parameters it is typically electric strength), while they remain worse in others (typically dissipation factor). Although there are some difficulties, by proper design they should be eliminated. The paper concentrates on specific aspects of designing insulation elements by preserving the same lifetime as in case of mineral oils.