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Power Factor for New Mineral Oil

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    Power Factor for New Mineral Oil

    Power factor of new mineral oil? my answer 0.5% which was wrong and supposedly correct answer was 0.05%..But according to NETA-ATS 2013 Table 100.3 there is no 0.05 %.

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    ASTM Method D924 Oil Power Factor

    Quote Originally Posted by Salcama View Post
    Power factor of new mineral oil? my answer 0.5% which was wrong and supposedly correct answer was 0.05%..But according to NETA-ATS 2013 Table 100.3 there is no 0.05 %.
    Give table 100.4 a look over, specifically ASTM Method D924...

    ASTM Method D924 indicates the dielectric losses of the oil, or energy that is dissipated as heat. Useful for measuring changes within the insulating oil resulting from contamination or deterioration. The power factor of insulating oil equals the cosine of the phase angle between an ac voltage applied and the resulting current. For mineral oil, the power factor of new oil should not exceed 0.05 percent at 25 degrees C.
    Last edited by madMAX; October 18, 2016 at 01:14 PM.

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    Was the question asking for power factor of a new liquid-filled transformer or just the fluid itself? I believe power factor of new liquid filled transformers should be 0.5% and power factor of new oil @ 25 degrees C should be 0.05% according to NETA specs.

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    Mineral Oil

    I have always gone off .5%. I know FR3 is 1%.

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  9. Bespey is offline Junior Member
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    Quote Originally Posted by Salcama View Post
    Power factor of new mineral oil? my answer 0.5% which was wrong and supposedly correct answer was 0.05%..But according to NETA-ATS 2013 Table 100.3 there is no 0.05 %.
    The confusion in the questions lies in comparing the power factor of an Oil filled xfmr vs just the oil itself.
    new oil filled XFMR = 0.5 (table 100.3)
    new oil = 0.05 (table 100.4) - correct answer

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