Dielectric response analysis on instrument transformers
Moisture in the solid part of the paper insulation is one of the most important factors that impact the condition of instrument transformers. The ingress of moisture from the atmosphere during installation or repairs can easily occur. Over time, increasing moisture content causes the aging of the oil-paper insulation.
Moisture in oil-paper insulation can reduce the dielectric strength or accelerate the aging of the cellulose (so-called depolymerization) and lead to eventual failure.
Therefore, determining the moisture content in the insulation is an important measure to ensure the reliability and lifetime of current and voltage transformers. Since it can be problematic to take oil samples from instrument transformers, which can lead to rather inexact measurement results, our testing systems use dielectric measurements for moisture determination.