CLC/TC 14/WG 21 - Revision of HD 428 and HD 538

This document describes the list of typical accessories used for liquid and dry type Medium Power Transformers (≤ 3 150 kVA).

This document describes a special test for tanks of liquid-immersed transformers which during service are hermetically sealed and fully filled with liquid and volume change of the liquid due to temperature change compensated by elastic deformation of the cooling element for Large Power Transformers having a rated power greater than 3150 kVA.

This document defines the energy performance of non-conventional technology Medium Power Transformers in compliance with EN 50708-1-1.

This document describes the special tests for Medium Power Transformers ≤ 3150 kVA compliant with the EN 50708 2 series: - for corrugated tank for liquid immersed transformers, - for the method of measurement of losses for one winding in Highest Voltage (HV) and windings in Lowest Voltage (LV) for liquid immersed and dry type transformers.

This document applies to all power transformers in scope of TC 14.

The scope of this document is to define the energy performance of liquid immersed single-phase Medium Power Transformers in compliance with EN 50708 1 1:2020.

TC - Correction of technical errors

The scope of this document is to define the energy performance of Medium Power Transformers in compliance with EN 50708-1-1:2020.