I have some DGA data that I am using to determine the over all health condition of the transformer insulation system.
To determine the strength of paper insulation, I depend on Furans value or DP. However, a significant quantity of my data records do not have the Furans value.
Thanks
According to IEC 60599-2007 ; When excessive paper degradation is suspected (CO2/CO less than 3), it is advisable to ask for a Furanic compounds analysis or a measurement of degree of polymerization of paper samples, when this is possible.
- Detected Gases: Same as above except CO2 and CO present
- Interpretation; Same as above except arcing in combination with cellulose.
HELLO
1 and 2-According to IEEE standard C57.104-2008, this ratio is
normally more than seven. For the CO2/CO ratio, the respective values of CO2 and CO should exceed 5000 μL/L (ppm) and 500 μL/L (ppm) in order to improve the certainty
factor, i.e., ratios are sensitive to minimum values.
3-methanol detection (chemical makers)
best regards
The IEEE standard is a useful guide as mentioned by Simon above. However, it is only a guide. Also try to use the rate of change to if possible predict when the gases will reach critical levels and if warranted, try to use PD detection techniques (ultrasound) if the application is critical.
Beside IEEE also IEC 60599 is applicable. A ratio < 3 indicates electrical aging and >10 thermal aging. But this is only one indicator, you should also take a view to the DP of furanic compounds or dielectric response as well as insulation resistance measurements. Literature recommendation: "Review of chemical indicators of degradation of cellulosic electrical paper insulation in oil-filled transformers" A.M. Emsley, G.C. Stevens, IEE Proc.-Sei. Meas. Technol., Vol. 141, No. 5, September 1994
According to IEC 60599-2007 ; When excessive paper degradation is suspected (CO2/CO less than 3), it is advisable to ask for a Furanic compounds analysis or a measurement of degree of polymerization of paper samples, when this is possible.
- Detected Gases: Same as above except CO2 and CO present
- Interpretation; Same as above except arcing in combination with cellulose.
Thanks all for your valuable contributions. As explained, I have a situation where Furans tests were not conducted on some transformers in a facility while the Furans tests were done on a few, critical, conservator type, large transformers. The other transformers are small (10MVA range) and mostly Nitrogen sealed. What will be the most common reasons for not doing Furans tests? Save money or any other factors?
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