ASTM D877/D877M-19e1 PDF

Full title and description

ASTM D877/D877M-19e1 — Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using Disk Electrodes. This test method describes procedures for measuring AC dielectric breakdown voltage of insulating liquids (power-frequency range) using opposed flat disk electrodes; it is used to screen insulating and cooling liquids (for example transformer oils) for electrical strength and contamination sensitivity.

Abstract

This standard defines two procedures (A and B) for determining the electrical breakdown voltage of insulating liquid samples using disk electrodes. The method uses an AC power-frequency voltage (45–65 Hz), requires repeat breakdown measurements and statistical treatment of results, and is intended primarily for liquids as received (not filtered/degassed). Results are used to indicate presence of contaminants (water, particles) and to compare sample condition against specification limits.

General information

• Status: Active standard (current designation D877/D877M-19e1).
• Publication date: December 1, 2019 (designation 19e1 indicates the 2019 edition with editorial change).
• Publisher: ASTM International (American Society for Testing and Materials).
• ICS / categories: 29.040.10 — Insulating oils / Electrical insulating liquids.
• Edition / version: D877/D877M-19e1 (2019 edition, editorial change “e1”).
• Number of pages: 6 pages (concise test method document).

Publication details and basic bibliographic data are listed in ASTM catalog entries and standards distribution services.

Scope

Describes two procedures (A and B) for measuring AC dielectric breakdown voltage of insulating liquids using opposed flat disk electrodes. Procedure A is intended for liquids in which insoluble breakdown products settle readily (typical mineral oils and many hydrocarbon-based insulating fluids); Procedure B applies when insoluble breakdown products do not settle during the required test interval (heavily contaminated samples, some silicone fluids). The test is a screening method for oil condition as received and is not intended for filtered/degassed liquids where other methods (for example D1816) are preferred. The AC test frequency range is 45–65 Hz.

Key topics and requirements

• Test geometry: opposed flat disk (disk) electrodes (nominal 1 in / 25.4 mm diameter) with a standard gap of approximately 0.1 in (2.54 mm / 2.5 mm).
• Voltage characteristics: AC power-frequency voltage (45–65 Hz) applied with a controlled, essentially linear rate of rise (commonly 3 kV/s) until breakdown occurs; automatic protection or circuit interruption required to limit discharge energy.
• Number of measurements: multiple breakdowns (typically five) with prescribed intervals between breakdowns and statistical evaluation (mean and criteria for repeatability) as specified in the method.
• Procedures A and B: selection depends on sample behavior after breakdown (settling of insoluble products) and on fluid type (silicones and heavily contaminated samples may require Procedure B).
• Limitations and sensitivity: the D877 disk-electrode configuration is especially influenced by particulate contaminants and large fibers; it is less sensitive to small amounts of dissolved water than some spherical/VDE-electrode methods (e.g., D1816 or IEC 60156). Interpretation must account for electrode geometry and gap when comparing results to other standards.
• Reporting and calibration: report mean breakdown voltage, test temperature, electrode condition, gap, and rate of rise; calibration and measurement traceability (IEEE 4 recommendations) are required for accurate results.

Typical use and users

Used by laboratory technicians, transformer and switchgear maintenance engineers, oil-testing laboratories, and manufacturers of insulating fluids and electrical apparatus for quality control, acceptance testing, and field screening of insulating liquids (transformer oil, cable fluids, silicone fluids where applicable). Commonly applied in routine oil monitoring programs, acceptance of new oil shipments (as-received condition), and troubleshooting when contamination or degradation is suspected.

Related standards

Standards commonly referenced or compared with D877 include ASTM D1816 (dielectric breakdown using VDE/spherical electrodes, more sensitive to dissolved water and used for some factory/referee testing), IEC 60156 (international BDV test with spherical electrodes), IEEE Standard 4 (measurement and instrumentation guidance for AC dielectric tests), and other ASTM documents on sampling and oil specifications (e.g., D923, D3487, D4652). When selecting a test method, users should note electrode geometry, gap, and stirring requirements because results are not directly interchangeable between methods.

Keywords

dielectric breakdown, breakdown voltage, insulating liquids, transformer oil, disk electrodes, BDV, test cup, Procedure A, Procedure B, power-frequency AC, electrode gap, electrical insulating liquids.

FAQ

Q: What is this standard?

A: ASTM D877/D877M-19e1 is a standardized test method for measuring the AC dielectric breakdown voltage of insulating liquids using opposed flat disk electrodes; it provides procedures, apparatus, and reporting requirements for screening insulating fluids.

Q: What does it cover?

A: It covers two procedures (A and B) for determining dielectric breakdown voltage at power frequency (45–65 Hz) using disk electrodes with specified gap and rate-of-rise conditions. It includes sample preparation notes, electrode and test-cup requirements, number and timing of breakdown measurements, and criteria for result reporting and repeatability.

Q: Who typically uses it?

A: Oil-test laboratories, transformer and electrical equipment maintenance personnel, fluid manufacturers, and quality/acceptance testing facilities use D877 for routine screening and comparative BDV checks on insulating liquids.

Q: Is it current or superseded?

A: The designation provided here is D877/D877M-19e1 (2019 edition with editorial change). Users should confirm status and any later revisions or corrigenda through ASTM International for the absolute current status before formal use.

Q: Is it part of a series?

A: It is part of ASTM’s suite of electrical insulating liquid test methods and is commonly referenced alongside related ASTM test methods and guides (for sampling, BDV with other electrode types, specifications for insulating oils, and IEEE measurement guidance).

Q: What are the key keywords?

A: Breakdown voltage (BDV), dielectric strength, disk electrodes, insulating liquids, transformer oil, test cup, Procedure A, Procedure B, AC power-frequency test.