What is the polarization index?

The polarization index is particularly significant in assessing insulation quality, specifically in electrical systems. It is defined as the ratio of a dielectric absorption test's measurement taken at 10 minutes to that taken at 1 minute. This ratio helps indicate the insulation's integrity and overall condition. A higher polarization index suggests better insulation quality, indicating that the insulation is able to hold a charge effectively over time, which is critical in preventing electrical failures.

Understanding this measurement allows electrical professionals to make informed decisions about potential maintenance or replacement needs for electrical equipment. An ideal polarization index generally ranges from 2 to 4, where values below this can indicate issues such as moisture ingress or degradation of the insulating material.

The other options do not accurately describe the polarization index. For example, while electrical stress may relate to insulation problems, it does not define the polarization index itself. Similarly, the ground bond test measures different parameters of safety and functionality in electrical systems. Methods to verify insulation quality at high voltage may involve different testing techniques not specifically tied to the polarization index.