IEC 61620-1998 PDF

Full title and description

Insulating liquids - Determination of the dielectric dissipation factor by measurement of the conductance and capacitance - Test method (IEC 61620:1998). This standard specifies a method for simultaneous measurement of conductance (G) and capacitance (C) to calculate the dielectric dissipation factor (tan δ) of insulating liquids used in transformers and other electrical equipment.

Abstract

IEC 61620:1998 describes a test procedure and apparatus requirements for measuring very low values of dielectric dissipation (tan δ) in insulating liquids. The method uses a waveform and measurement sequence that separates capacitive and conductive currents, permitting reliable determination of tan δ for both unused insulating liquids and liquids in service. Technical details include test-cell recommendations, temperature control, and measurement-chain resolution appropriate for highly insulating fluids.

General information

• Status: International Standard (published / current as a base IEC publication; identified as IEC 61620:1998).
• Publication date: 27 November 1998.
• Publisher: International Electrotechnical Commission (IEC).
• ICS / categories: 17.220.99, 29.040.01 (insulating fluids; electrical engineering / metrology).
• Edition / version: Edition 1.0 (1998).
• Number of pages: 43 pages (IEC published PDF/page count).

Scope

Specifies a laboratory test method for the determination of the dielectric dissipation factor (tan δ) of insulating liquids by simultaneous measurement of conductance and capacitance. The procedure applies to unused insulating liquids and to liquids in service in transformers and other electrical apparatus, and is intended to permit accurate measurements at very low loss levels. Normative references and sampling requirements (for example sampling per IEC sampling practice) are included.

Key topics and requirements

• Measurement principle: separation of capacitive and conductive currents using a specific waveform and timing to derive G and C and calculate tan δ.
• Test-cell design: recommends three‑terminal cells (per related IEC cell standards) and provides guidance for electrode geometry and gap to minimise errors for highly insulating liquids.
• Apparatus and signal requirements: characteristics for the voltage generator (amplitude, frequency, rise time, low ripple) and measurement chain resolution to resolve small capacitances and low conductances.
• Temperature control and sample handling: temperature stability (typically within ±1 °C), sample preparation, labelling and conditioning requirements to ensure repeatability.
• Measurement range and uncertainty: method enables determination of very low tan δ values (method suitable down to very small loss levels and across a wide range of tan δ).

Typical use and users

Test laboratories, transformer and electrical-equipment manufacturers, utilities and maintenance organisations, and research centres use IEC 61620 to characterise insulating oils and other insulating liquids, to assess in-service condition, and to verify product quality and conformity to performance requirements. National standards bodies have adopted/transposed this IEC publication in regional EN/CEN or national versions.

Related standards

IEC 61620 references and complements other IEC publications relevant to insulating liquids and test cells, notably IEC 60247 (test apparatus and cells for liquid dielectrics) and IEC 60475 (sampling of insulating liquids). It has also been adopted as EN 61620 in regional standards collections.

Keywords

insulating liquids; dielectric dissipation factor; tan delta; conductance; capacitance; test method; transformer oil; test cell; dielectric loss; liquid dielectrics.

FAQ

Q: What is this standard?

A: IEC 61620:1998 is an international standard that specifies a laboratory test method for determining the dielectric dissipation factor (tan δ) of insulating liquids by measuring conductance and capacitance.

Q: What does it cover?

A: It covers the measurement principle and sequence, recommended test-cell characteristics, apparatus performance (signal source and measurement chain), temperature control, sample handling and reporting necessary to obtain reliable tan δ values for both new and in-service insulating liquids.

Q: Who typically uses it?

A: Accredited test laboratories, transformer and electrical-equipment manufacturers, utilities (for condition monitoring), procurement/specification engineers, and researchers working with liquid dielectrics.

Q: Is it current or superseded?

A: IEC 61620 was published in 1998 (edition 1.0). As published by the IEC it remains the base IEC publication (status shown as the IEC base publication); users should check national/adopted versions and the IEC webstore for any amendments or later revisions. The IEC record lists the 1998 edition as the base publication.

Q: Is it part of a series?

A: It is part of the body of IEC standards for liquid dielectrics and test methods and is used alongside related standards such as IEC 60247 (test cells) and IEC 60475 (sampling). Regional/adopted versions exist (for example EN versions) that reproduce IEC 61620 content.

Q: What are the key keywords?

A: insulating liquids; dielectric dissipation factor; tan δ; conductance; capacitance; test method; transformer oil; liquid dielectrics.