What is the difference between ASTM D1816 and IEC 60156

When it comes to electrical insulating oils, two commonly used standards for testing and evaluation are ASTM D1816 and IEC 60156. While both these standards serve a similar purpose, there are significant differences in terms of their methodologies and requirements. In this article, we will explore the key distinctions between ASTM D1816 and IEC 60156.

ASTM D1816: A Brief

ASTM D1816, also known as the Standard Test Method for Dielectric Breakdown Voltage of Insulating Liquids Using VDE Electrodes, is an established standard developed by the American Society for Testing and Materials (ASTM). It primarily focuses on determining the dielectric breakdown voltage (BDV) of insulating liquids, which indicates their ability to withstand electrical stress without failure. The test involves applying a voltage to the sample liquid until breakdown occurs. The BDV value is then measured and used to evaluate the liquid's electrical properties.

IEC 60156: A Brief

The International Electrotechnical Commission's (IEC) standard, IEC 60156, titled "Insulating Liquids - Determination of the Breakdown Voltage at Power Frequency," serves a similar purpose to ASTM D1816. It provides guidelines for measuring the breakdown voltage of insulating oils, thereby assessing their electrical strength. However, IEC 60156 is recognized globally and has gained widespread acceptance in many countries. Its procedures and specifications aim to ensure consistency and uniformity in oil testing across different regions and laboratories.

Differences in Methodologies and Requirements

One notable difference between ASTM D1816 and IEC 60156 lies in their test voltage waveforms. ASTM D1816 utilizes a voltage waveform with a 50 Hz/60 Hz power frequency, resembling the typical electrical stress experienced by insulating oils in service. On the other hand, IEC 60156 specifies a specific waveform (1.2/50 μs) that consists of a lightning impulse voltage followed by a 50 Hz/60 Hz alternating voltage. This waveform reflects both normal operating conditions and potential transient events.

Another key distinction is the sample size required for testing. ASTM D1816 typically requires a larger sample volume, around 500 mL, which may not be practical in certain situations where only limited quantities of oil are available. IEC 60156, however, permits testing with smaller sample volumes, usually ranging from 100 mL to 160 mL, allowing for more flexibility.

Furthermore, there are variations in the acceptance criteria specified by these standards. While both ASTM D1816 and IEC 60156 determine the BDV of the insulating liquid, they may have different threshold values for passing or failing the test. These differences can arise due to variations in equipment calibration, statistical analysis, or historical practices in different regions.

In conclusion, although ASTM D1816 and IEC 60156 share a common objective of evaluating electrical insulating oils, there are notable differences in their methodologies and requirements. Understanding these distinctions is crucial for professionals involved in oil testing and quality assessment, as it ensures compliance with the appropriate standard and facilitates accurate interpretation of test results.