IEC 60092-303:2023

Electrical installations in ships - Part 303: Equipment - Power transformers and reactors

IEC 60092-303:2023 is applicable to all transformers used for power and lighting and, where appropriate, to static convertors, starting transformers, static balancers, earthing transformers, saturable reactors and transductors for use in ships, including single-phase transformers rated higher than 1 kVA, and three-phase transformers rated higher than 5 kVA, unless special requirements are specified. This document applies to transformers with rated voltage up to and including 36 kV.
This fourth edition cancels and replaces the third edition published in 1980 and Amendment 1:1997. This edition includes the following significant technical changes with respect to the previous edition:
- environmental conditions,
- load harmonic currents,
- Transformers for special applications,
- design and construction,
- transformers for essentials services.

General Information

• Status: Published
• Publication Date: 22-Aug-2023
• ICS: 47.020.60 - Electrical equipment of ships and of marine structures
• Technical Committee: TC 18 - Electrical installations of ships and of mobile and fixed offshore units
• Drafting Committee: MT 6 - TC 18/MT 6
• Current Stage: PPUB - Publication issued
• Start Date: 23-Aug-2023
• Completion Date: 01-Sep-2023

Relations

• Revises: IEC 60092-303:1980/AMD1:1997 - Amendment 1 - Electrical installations in ships. Part 303: Equipment - Transformers for power and lighting
• Effective Date: 05-Sep-2023

Overview

IEC 60092-303:2023 - "Electrical installations in ships - Part 303: Equipment - Power transformers and reactors" is the fourth edition (2023) of the IEC marine standard for shipboard transformers and reactors. It applies to transformers used for power and lighting and, where appropriate, to static convertors, starting transformers, static balancers, earthing transformers, saturable reactors and transductors. The standard covers single‑phase transformers rated above 1 kVA, three‑phase transformers rated above 5 kVA, and equipment with rated voltages up to and including 36 kV. Instrument transformers are excluded.

This edition updates and replaces the 1980 edition (and 1997 amendment), adding modern requirements on environmental conditions, load harmonic currents, design and construction, special applications (e.g., propulsion, shore connection) and transformers for essential services.

Key topics and technical requirements

• Scope & applicability: ratings, voltage limits (≤ 36 kV) and types of transformers for shipboard use.
• Service conditions: voltage/frequency ranges, inclinations, vibration resistance, and ambient temperature considerations in shipboard environments.
• Harmonics: guidance for transformers serving networks with current total harmonic distortion (THD) above 5% and references to converter transformer requirements (IEC 61378‑1). Annex A gives methods to reduce harmonic disturbances.
• Design & construction: materials, insulation levels, clearance and creepage distances, enclosure degrees of protection, winding arrangements, terminals and cooling arrangements.
• Cooling & essential services: specific cooling and monitoring requirements for transformers serving primary and secondary essential services (propulsion, steering, safety systems).
• Performance aspects: voltage regulation, parallel operation capability and tests to validate operation and safety.
• Testing & documentation: factory and type tests, plus documentation obligations for essential‑service transformers.

Practical applications and users

IEC 60092-303 is used by:

• Shipbuilders and naval architects specifying shipboard electrical systems.
• Marine electrical designers and system integrators selecting and sizing marine transformers and reactors.
• Transformer manufacturers producing shipboard-rated power transformers and converter/propulsion transformers.
• Classification societies, port authorities and regulatory bodies for survey and compliance checks.
• Ship operators, maintenance teams and test laboratories performing acceptance tests, inspections and troubleshooting.

Practical uses include specifying transformer construction for harsh marine environments, ensuring compatibility with converter-driven propulsion systems, controlling harmonic heating, and defining redundancy and monitoring for essential services.

Related standards

• IEC 60076 series (Power transformers)
• IEC 61378‑1 (Converter transformers)
• Other parts of IEC 60092 (e.g., Parts 101, 201, 304, 401, 501, 503, 509)
• IEC/IEEE 80005 (utility connections in port)

For procurement or compliance, obtain the full IEC 60092‑303:2023 text from the IEC Webstore to ensure complete requirements and normative references are followed.

Standards Content (Sample)

IEC 60092-303 ®
Edition 4.0 2023-08
INTERNATIONAL
STANDARD
Electrical installations in ships –
Part 303: Equipment – Power transformers and reactors

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IEC 60092-303 ®
Edition 4.0 2023-08
INTERNATIONAL
STANDARD
Electrical installations in ships –

Part 303: Equipment – Power transformers and reactors

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 47.020.60  ISBN 978-2-8322-7335-7

– 2 – IEC 60092-303:2023 © IEC 2023
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Service conditions . 7
4.1 Voltage and frequency . 7
4.2 Environmental condition . 8
4.2.1 General . 8
4.2.2 Vibration . 8
4.2.3 Ambient temperature . 8
4.3 Load current harmonic content . 8
4.4 Transformers for special applications . 8
4.4.1 Propulsion transformers . 8
4.4.2 Transformers for shore-connection . 8
5 Design and construction . 9
5.1 General . 9
5.2 Materials . 9
5.3 Insulation level, clearance and creepage distances . 9
5.4 Degrees of protection of enclosures . 9
5.5 Transformer winding arrangement . 9
5.6 Terminals . 10
5.7 Cooling arrangements . 10
6 Voltage regulation . 10
7 Parallel operation . 10
8 Transformers for essential services – Construction and documentation
requirements . 10
8.1 Cooling arrangements for essential services . 10
8.1.1 General . 10
8.1.2 Cooling arrangements for secondary essential services . 11
8.1.3 Cooling arrangements for primary essential services . 11
8.2 Alert and monitoring . 11
8.3 High voltage transformer . 11
8.4 Documentation requirements . 11
9 Tests . 11
Annex A (informative) Method for reducing harmonics disturbances . 12
Bibliography . 13

Figure A.1 – Screen between primary and secondary winding . 12
Figure A.2 – Phase shifting in transformers with multiple windings . 12

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL INSTALLATIONS IN SHIPS –

Part 303: Equipment – Power transformers and reactors

FOREWORD
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 60092-303 has been prepared by IEC technical committee 18: Electrical installations of
ships and of mobile and fixed offshore units. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 1980 and
Amendment 1:1997. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) environmental conditions were added as 4.2;
b) 4.3 for load harmonic content was added;
c) 4.4 transformers for special applications was added;
d) Clause 5 for design and construction of transformers was added;
e) definitions for "essential services" were added and described in the new Clause 8.

– 4 – IEC 60092-303:2023 © IEC 2023
The text of this International Standard is based on the following documents:
Draft Report on voting
18/1831/FDIS 18/1851/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts of the IEC 60092 series, published under the general title Electrical installations
in ships, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
INTRODUCTION
The IEC 60092 series contains international standards for electrical installations in sea-going
ships, incorporating good practice and co-ordinating, as far as possible, existing rules.
These standards form a code of practical interpretation and amplification of the requirements
of the International Convention on Safety of Life at Sea, a guide for future regulations which
may be prepared and a statement of practice for use by shipowners, shipbuilders and
appropriate organizations.
– 6 – IEC 60092-303:2023 © IEC 2023
ELECTRICAL INSTALLATIONS IN SHIPS –

Part 303: Equipm
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