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IEM power substation type small power transformers are designed for use in indoor or outdoor substations, for reduction of sub transmission or primary distribution voltage at the distribution or usage voltages, and for three-phase or single-phase industrial or commercial loads.
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Distribution substation type small power transformers are ideal for 3-wire primary distribution voltage reduction to 4-wire usage voltage, for lighting and three-phase and single-phase industrial, light or commercial loads.
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Transformers used in distribution substations have basic differences compared to transformers used in power substations. Normalized basic impulse levels (BIL) in distribution transformers are lower for a same voltage than for those used in power substations.
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In general, the standard used for distribution substations is 149 Fahrenheit, while the standard is 131 Fahrenheit for power transformers.
General uses conditions are described in the following standards: IEEE STD C57.12.00, and IEEE STD C57.12.10. |