What is the Power Factor of MIDEL ester fluids?
Power factor is the ratio of resistance current to capacitance current in an insulation system.
In new mineral oil transformers power factor is used to determine the level of insulation dryness. For operating transformers, changes in power factor can indicate increased levels of moisture or other contaminants in the insulation system. There are several variables that impact power factor measurements, even for new, essentially dry uncontaminated units, including:
the ratio of solid to fluid insulation
the type of dielectric fluid
temperature at time of measurement
Understanding MIDEL Power Factor
The dielectric dissipation factor of ester-based liquids is higher than that of mineral oil, due to the polar chemical structure of the ester. This in turn leads to higher power factor values for clean, dry insulation than would normally be seen with mineral oil.
Experience gained during the testing of transformers and published research has shown that the power factor of a new distribution transformer filled with MIDEL liquid will be around 50% higher than the same design with mineral oil.
In power transformers the liquid to solid insulation ratio will be higher and therefore the ester liquid will have more influence on the power factor value. It should be expected that the power factor will be approximately doubled after retrofill in a power transformer.
More questions on ester fluids?
This post is one of the 15 top questions we get asked on retrofilling transformers with ester fluids. Here is the full list of the frequently asked questions on ester fluid retrofilling: