scope:

This part of IEC/IEEE 61886 is applicable to three-phase and single-phase liquid immersed subsea power transformers (including auto transformers) with at least one winding with rated voltages in the range 3,6 ≤ U_m ≤ 245 kV and with rated power in the range 50 kVA to 300 MVA. The intention is to specify additional requirements that are not covered by the IEC 60076 series and IEEE C57.12 series.

It is the intention of this standard that subsea power transformers are designed and tested either in accordance with IEC 60076 series or IEEE C57.12 series.

For subsea transformers where no winding has a rated voltage above or equal to 3,6 kV, this document can be applicable, either as a whole or in part.

The mechanical design principles are also applicable for liquid-immersed reactors.

Where the terms "subsea transformer" or "transformer" are used, this means "transformer assembly". Where required, it is stated whether transformer accessories like penetrators and connectors are included or not.