Measuring Moisture in oil

[mithko]

Hi,

How is moisture/water content in oil (say from a transformer) measured (in ppm)? What apparatus and test is used?

 

[DTR2011]

Karl Fischer titration

http://en.wikipedia.org/wiki/Karl_Fischer_titration

There are electrical methods for accurately measuring moisture content
of the paper (cellulose) insulation.

OMICRON makes a unit called the Driana, Megger makes a similar product
called IDA. These units make dissipation factor measurements across a wide frequency range (DC-5kHz) and compare measured results against a known curve to extract the difference. The measurement is called dielectric spectroscopy. It is also sometimes referred to as Dielectric Frequency Response.

This measurement is not to be confused with Frequency Response Analysis (FRA), which looks at the mechanical condition of a transformer.

 

[prc]

Driana and IDA are for finding out the water content in oil impregnated paper.For Measuring moisture in oil Karl Fischer titrator is the accurate method. But today most widely used instrument is capacitive sensor where capacitance change due to moisture is used to find out the moisture content in oil.Many makes are availabl,including that of Doble.