National foreword

This Published Document is the UK implementation of ISO/TR 23583:2026.

The UK participation in its preparation was entrusted to Technical Committee ISENFE/8, Corrosion of metals and alloys.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

This publication is not to be regarded as a British Standard.

Compliance with a Published Document cannot confer immunity from legal obligations.

This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 October 2026.

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

Many factors affect the sulfur corrosion of copper windings in power equipment in the power industry. These include:

temperature;
corrosive sulfide concentration in oil;
acid products derived from oil-paper insulation aging;
moisture;
the type of electric field (AC or DC electric field);
electric field strength;
the contact state between the copper winding and the insulating paper;
the quality of the copper winding.

These have a significant influence on the occurrence of sulfur corrosion and the generation of corrosion products. The current assessment methods of sulfur corrosion of copper windings do not sufficiently consider these factors. Existing standards (e.g. ASTM D 1275A, ASTM D 1275B, IEC 62535, GB/T 25961) test specifications or methods for testing whether the quality of insulating oil meets the requirements.

As for the corrosion of copper, the existing standards are test methods for the corrosion of copper metal in the atmospheric environment, petroleum products, etc. Standards such as GB/T 38265.15, ASTM D 130 and ISO 6251 specify special testing or assessment methods for lubricants, oil and copper parts in atmospheric environments (e.g. pipelines, tower parts and other structures), which does not fully apply to power equipment.

Therefore, with reference to the existing standards for corrosive sulfur detection in insulating oil, this document proposes a sulfur corrosion test method for copper winding in electric field for power equipment. The method includes pre-treatment, model construction, the corrosion test method and corrosion level judgments for copper windings.

This document contributes to controlling the quality of copper windings in electric power equipment, reducing the failure of electric power equipment due to sulfur corrosion and prolonging the service life of power equipment, which has great significance in improving the safe operation of power grids.

This document considers the effects of actual working conditions (e.g. electric field, the contact state between the copper winding and the insulating paper) and the quality of the copper winding on the sulfur corrosion of copper windings in power equipment. It considers the influencing factors listed in this Introduction to avoid the assessment deviation of sulfur corrosion resistance of copper windings in the existing standards.

1 Scope

This document specifies the assessment of copper winding sulfur corrosion in power equipment. It is applicable to the sulfur corrosion resistance testing of copper windings in newly installed and in-service power equipment.

2 Normative references

3 Terms and definitions

4 General regulation

5 Specimen preparation

5.1 Copper winding

5.2 Insulating oil

5.3 Insulating paper

5.4 Dibenzyl disulfide

6 Instruments and equipment

6.1 Thermostatic oil tank

6.2 Vacuum drying immersion oil tank

6.3 Electric heating experimental tank

6.4 DC/AC power supply

6.5 Plasma coupled atomic emission spectrometer

7 Preparation of test

7.1 Establishing a pig-tail model

7.2 Drying treatment

7.3 Immersion oil

8 Test procedures

8.1 Heating

8.2 Remove the sample after cooling

9 Evaluation of oil sulfur corrosion resistance performance

9.1 Qualitative evaluation

9.2 Quantitative evaluation

9.3 Grading criteria for quantitative evaluation

Bibliography