Moisture in the solid part of power transformer insulation (paper, pressboard) is one of the most critical condition parameters. Water enters transformers from the atmosphere (breathing, leaky seals) and during installation and repair. Aging of the oil-paper insulation also increases the moisture level. Typically, the solid part of the insulation structures holds most part of the water, i.e. 200 times more than the oil.
Moisture entering in oil-paper insulations can cause dangerous effects:
- Decreases the dielectric withstand strength
- Accelerates cellulose aging (the so-called de-polymerization)
- Causes the emission of gas bubbles at high temperatures and may lead to a sudden electrical breakdown.
Assessing the moisture content in insulation is thus a key factor to ensure transformer reliability and longevity. Since the traditional oil sampling method has several reasons that it is a very inexact approach, OMICRON uses dielectric measurements for moisture determination.
Learn more about OMICRON's solutions in the area of Power Transformer Moisture Measurement
DIRANA
FDS-PDC Dielectric Response Analyzer
