Technical Centre
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Analysis – recording the water in oil activity profile over the temperature range tells us what is happening in the transformer. Calculating the water in cellulose is easy as the Analysis examples explain. All that is required is a reliable / repeatable process using known values to calculate the water in cellulose. If it is done the same way all the time, the results are extremely consistent. There are only a few perceived and real variables to consider when calculating the water in cellulose.
This section covers the perceived variables when measuring the volume of water in the oil. There is some confusing debate in this area, especially in oil solubility.
Acid oil – a description of how the oxidation by-products are held in the oil - Oil “solubility” – does it effect the water in cellulose calculation
- Karl Fischer method – not accurate with oxidised / acid oil
- Sensor method – always accurate values – new and oxidised oil
- Cellulose DP – does it effect the water in oil activity
The diagnostic results in the Trojan Examples section are based on these findings, and our own results from accurately measuring and removing water from numerous transformers.
Equilibrium curves to download and print out (PDF)
- Altmann/Buvkis 2003 – accurate with Sensors
- Oommen 1984 – Closest to Altmann findings
Papers
Altmann/Bukvis 2003 – The Oil-Moisture problem of aged transformers
Coming soon – oil dielectric focus
The water in cellulose volume and load profile controls the oil dielectric. This section will cover the tight relationship between the oil relative saturation and dielectric values. Can we calculate the dielectric if we know the relative saturation?
Links
Weidmann ACTI