EN 61198:1994

Overview

EN 61198:1994 - adopted by CLC and reproduced as SIST EN 61198:1997 - specifies test methods for the determination of 2‑furfural and related furan compounds in mineral insulating oils. These furanic compounds are generated by the thermal and chemical degradation of cellulosic insulation materials used in electrical equipment. The standard provides a consistent framework for sampling and analysis of oil removed from transformers and other oil‑filled apparatus to assess the condition of paper insulation.

Key Topics

• Scope and applicability: Defines the type of mineral insulating oils and electrical equipment from which samples are taken and the purpose of furan analysis for insulation condition monitoring.
• Analytical focus: Procedures and requirements for detecting and quantifying 2‑furfural (2‑furaldehyde) and related furans formed during cellulose degradation.
• Sampling and sample handling: Guidance to ensure representative oil samples and to minimise changes to furan concentrations between sampling and analysis.
• Performance criteria: Requirements for test reproducibility, sensitivity and reporting so results are comparable across laboratories.
• Reference to IEC: The document extract references IEC 1198:1993, indicating alignment with international electrotechnical practice.

Applications

• Transformer condition monitoring: Furan levels are key indicators of ageing or degradation of paper insulation in power and distribution transformers.
• Asset management: Utilities and grid operators use furan testing to plan maintenance, refurbishment or replacement of oil‑filled equipment.
• Quality control & acceptance testing: Manufacturers and test laboratories use the standard to verify oil and equipment condition during production, commissioning or acceptance.
• Forensic investigation: Following electrical incidents, furan analysis helps assess prior thermal or chemical stress to insulating materials.

Who uses this standard

• Electrical utilities and power companies
• Transformer and electrical equipment manufacturers
• Accredited testing laboratories performing oil analysis
• Maintenance and asset‑management engineers responsible for high‑voltage equipment

Related standards (if applicable)

• National adoptions such as SIST EN 61198:1997 reflect the EN/CLC endorsement.
• The EN references IEC practice (IEC 1198:1993 in the extract), indicating harmonisation with international methods for insulating oil analysis.
• Users commonly consult EN 61198 alongside other insulating oil test standards and transformer diagnostic protocols for comprehensive asset condition assessment.

Keywords: EN 61198, 2‑furfural, furan compounds, mineral insulating oils, transformer oil analysis, cellulosic insulation degradation, CLC, SIST EN 61198.