ASTM D924-15
Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity (Dielectric Constant) of Electrical Insulating Liquids

Standard No.

ASTM D924-15

Release Date

2015

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM D924-23

Latest

ASTM D924-23

Scope

4.1 Dissipation Factor (or Power Factor)—This is a measure of the dielectric losses in an electrical insulating liquid when used in an alternating electric field and of the energy dissipated as heat. A low dissipation factor or power factor indicates low ac dielectric losses. Dissipation factor or power factor may be useful as a means of quality control, and as an indication of changes in quality resulting from contamination and deterioration in service or as a result of handling.

4.1.1 The loss characteristic is commonly measured in terms of dissipation factor (tangent of the loss angle) or of power factor (sine of the loss angle) and may be expressed as a decimal value or as a percentage. For decimal values up to 0.05, dissipation factor and power factor values are equal to each other within about one part in one thousand. In general, since the dissipation factor or power factor of insulating oils in good condition have decimal values below 0.005, the two measurements (terms) may be considered interchangeable.

4.1.2 The exact relationship between dissipation factor (D) and power factor (PF ) is given by the following equations:

The reported value of D or PF may be expressed as a decimal value or as a percentage. For example:

4.2 Relative Permittivity (Dielectric Constant)—Insulating liquids are used in general either to insulate components of an electrical network from each other and from ground, alone or in combination with solid insulating materials, or to function as the dielectric of a capacitor. For the first use, a low value of relative permittivity is often desirable in order to have the capacitance be as small as possible, consistent with acceptable chemical and heat transfer properties. However, an intermediate value of relative permittivity may sometimes be advantageous in achieving a better voltage distribution of ac electric fields between the liquid and solid insulating materials with which the liquid may be in series. When used as the dielectric in a capacitor, it is desirable to have a higher value of relative permittivity so the physical size of the capacitor may be as small as possible.

4.3 Theory relating to dielectric measurement techniques and to sources of dielectric loss is given in Test Methods D150.

1.1 This test method describes testing of new electrical insulating liquids as well as liquids in service or subsequent to service in cables, transformers, oil circuit breakers, and other electrical apparatus.

1.2 This test method provides a procedure for making referee tests at a comme......

ASTM D924-15 Referenced Document

• ASTM D150 Standard Test Methods for AC Loss Characteristics and Permittivity (Dielectric Constant) of Solid Electrical Insulation
• ASTM D2864 Standard Terminology Relating to Electrical Insulating Liquids and Gases
• ASTM D2865 Standard Practice for Calibration of Standards and Equipment for Electrical Insulating Materials Testing
• ASTM D923 Standard Practices for Sampling Electrical Insulating Liquids
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

ASTM D924-15 history

• 2023 ASTM D924-23 Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity (Dielectric Constant) of Electrical Insulating Liquids
• 2015 ASTM D924-15 Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity (Dielectric Constant) of Electrical Insulating Liquids
• 2008 ASTM D924-08 Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity (Dielectric Constant) of Electrical Insulating Liquids
• 2004 ASTM D924-04 Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity (Dielectric Constant) of Electrical Insulating Liquids
• 2003 ASTM D924-03a Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity (Dielectric Constant) of Electrical Insulating Liquids
• 2003 ASTM D924-03 Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity (Dielectric Constant) of Electrical Insulating Liquids
• 1999 ASTM D924-99e2 Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity (Dielectric Constant) of Electrical Insulating Liquids
• 1999 ASTM D924-99e1 Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity (Dielectric Constant) of Electrical Insulating Liquids