IEC 61378-1:2011

Overview

IEC 61378-1:2011 - Converter transformers: Part 1 - Transformers for industrial applications is the International Electrotechnical Commission standard that specifies requirements for the design, specification and testing of power transformers and reactors integrated into semiconductor converter plants. It covers converter-connected transformers of any power rating used with devices such as thyristor and diode rectifiers and converters driving large industrial processes. The 2011 edition adds important technical updates (see Key changes).

Keywords: IEC 61378-1:2011, converter transformers, industrial applications, thyristor rectifiers, diode rectifiers, transductors, regulating transformers.

Key topics and technical requirements

The standard addresses both functional and test requirements relevant to converter duty, including:

• Scope & classification: normal and unusual service conditions, unit classifications.
• Ratings and terminal identification: rated power, voltages, currents, phase displacement and rating plate information.
• Winding design and arrangements: valve/high-current windings, multiple active parts in one tank, geometric coupling and implications for losses and current sharing.
• Losses and temperature: methods to determine load loss under non‑sinusoidal (converter) currents, eddy-current effects, tank losses, hot‑spot temperature assessment for high-current windings.
• Current sharing: measurements, considerations for high-current valve windings and winding arrangements.
• Electrical characteristics for converters: commutating reactance, inductive voltage drop, phase displacement (including 30° options added in this edition).
• Special components: guidance on regulating units (step‑down regulating transformers/autotransformers) and transductors for d.c. voltage regulation.
• Tests and test procedures: dielectric tests, load-loss and temperature‑rise tests (total loss injection), voltage ratio/phase displacement measurements, short‑circuit and noise tests.
• Informative annexes: practical examples, duty cycles, measurement methods, design-review guidelines, 3D simulation for tank losses, and correlation with related ratings.

Key changes in the 2011 edition

• Addition of winding connections with 30° phase displacement
• Support for transformers with more than one active part in the same tank
• Revised reference power definition
• Inclusion of regulating transformers feeding converter transformers
• New guidance on current sharing and hot spot temperature in high-current windings
• Inclusion of transductors used with diode rectifiers

Practical applications and users

IEC 61378-1:2011 is essential for:

• Transformer designers and manufacturers producing converter‑grade transformers and reactors
• Electrical engineers specifying equipment for electrolysis plants, scrap melting furnaces, large drives and variable‑speed drives
• OEMs and system integrators designing semiconductor converter plants
• Test laboratories and QA teams performing acceptance and type testing for converter transformers

Related standards

• The standard contains a normative Annex J correlating ratings with IEC 60146‑1‑1 (power electronic converters). Users should consult IEC 60146 series for converter-specific requirements and system-level considerations.

This standard enables reliable, efficient converter transformer design and testing for demanding industrial power‑conversion applications.