SIST EN 61203:1997

Synthetic organic esters for electrical purposes - Guide for maintenance of transformer esters in equipment

Guide to the maintenance of synthetic organic esters, originally complying with the requirements of EN 61099, in transformers with rated voltages up to 35 kV.

Synthetische organische Ester für elektrotechnische Zwecke - Leitlinie zur Wartung von Transformator-Estern in Betriebsmitteln

Esters organiques de synthèse à usages électriques - Guide de maintenance des esters pour transformateurs dans les matériels

Guide de maintenance des esters organiques de synthèse, satisfaisant à l'origine aux exigences de la EN 61099 et utilisés dans les transformateurs de tension de service inférieure ou égale à 35 kV.

Synthetic organic for electrical purposes - Guide for maintenance of transformer esters in equipment (IEC 1203:1992)

General Information

• Status: Published
• Publication Date: 31-Jul-1997
• ICS: 29.035.20 - Plastics and rubber insulating materials
• ICS: 29.180 - Transformers. Reactors
• Technical Committee: TPD - Fluids for electrotechnical applications
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Aug-1997
• Due Date: 01-Aug-1997
• Completion Date: 01-Aug-1997
• Ref Project: EN 61203:1994 - Synthetic organic esters for electrical purposes - Guide for maintenance of transformer esters in equipment

Relations

• Replaced By: SIST EN IEC 61203:2025 - Synthetic esters - Guidelines for maintenance and use in electrical equipment
• Effective Date: 01-Sep-2025
• Revised: SIST EN IEC 61203:2025 - Synthetic esters - Guidelines for maintenance and use in electrical equipment
• Effective Date: 26-Jan-2023

Overview

EN 61203:1994 - published by CLC and aligned with IEC 1203:1992 - is a practical guide for the maintenance of synthetic organic esters for electrical purposes used as transformer fluids. The standard addresses maintenance and in-service care of transformer esters in equipment with rated voltages up to 35 kV, helping operators preserve dielectric performance, reduce failure risk, and manage ageing of ester-filled electrical assets. It was developed in the context of earlier requirements of EN 61099.

Key Topics

The guide focuses on practical, maintenance-oriented aspects rather than prescriptive test limits. Major technical topics covered include:

• Properties and behaviour of synthetic organic esters in service (ageing, dielectric role).
• Inspection and monitoring recommendations for ester-filled transformers and associated equipment.
• Sampling and condition assessment procedures to determine fluid health and trends over time.
• Handling, storage and contamination control to prevent degradation (moisture, particulates, chemical contamination).
• Filling, topping-up and replacement practices to maintain dielectric integrity and safe operation.
• Compatibility and material interactions, including seals, gaskets and tank materials that interact with esters.
• Safety, environmental and operational considerations for working with synthetic esters in the field.

Note: EN 61203 is a guidance document; it provides recommended maintenance practices and considerations rather than prescriptive performance specifications.

Applications

EN 61203 is used to inform maintenance programs and asset-management decisions where synthetic organic esters are used as insulating and cooling fluids in transformers and reactors with voltages up to 35 kV. Typical users include:

• Utility and distribution companies managing ester-filled transformers
• Transformer manufacturers and service contractors
• Substation maintenance engineers and asset managers
• Testing laboratories and condition-monitoring teams
• Health, safety and environmental officers handling fluid replacement or disposal

Applying the guidance helps extend equipment life, reduce unplanned outages, and support safe handling and environmental compliance when using synthetic organic esters.

Related Standards

• IEC 1203:1992 - original international reference equivalent to EN 61203
• EN 61099 - earlier related requirements referenced in the standard
• Other transformer-insulation and dielectric fluid standards (refer to national and industry lists for complementary test methods and acceptance criteria)

Keywords: EN 61203, synthetic organic esters, transformer maintenance, transformer esters, 35 kV, IEC 1203, CLC, EN 61099.

Standards Content (Sample)

SLOVENSKI STANDARD
01-avgust-1997
Synthetic organic for electrical purposes - Guide for maintenance of transformer
esters in equipment (IEC 1203:1992)
Synthetic organic esters for electrical purposes - Guide for maintenance of transformer
esters in equipment
Synthetische organische Ester für elektrotechnische Zwecke - Leitlinie zur Wartung von
Transformator-Estern in Betriebsmitteln
Esters organiques de synthèse à usages électriques - Guide de maintenance des esters
pour transformateurs dans les matériels
Ta slovenski standard je istoveten z: EN 61203:1994
ICS:
29.035.20 3ODVWLþQLLQJXPHQLL]RODFLMVNL Plastics and rubber insulating
PDWHULDOL materials
29.180 Transformatorji. Dušilke Transformers. Reactors
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
...