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IEC_60599_C2H2_TO_H2_GAS_RATIO

IEC_60599_C2H2_TO_H2_GAS_RATIO

Formula​

=IEC_60599_C2H2_TO_H2_GAS_RATIO(dga, hasCommunicatingOltc?)

Description​

Performs an interpretation of the DGA based on the ratio of Acetylene(C2H2) to Hydrogen(H2).

Refer to IEC 60599:2022, Section 5.7 - O2/N2 ratio, page 17

Output​

The outcome of the application of this rule.

5.7 C2H2/H2 ratio, Analysis for sample taken on Fri Feb 24 2023 
  Indication of OLTC contamination, Acetylene to Hydrogen ratios higher than 2 or 3 in the main tank (3.00 in this case) are considered as an indication of OLTC contamination. This can be confirmed by comparing DGA results in the main tank, in the OLTC and in the conservators. The values of the gas ratio and of the acetylene concentration depend on the number of OLTC operations and on the way the contamination has occurred (through the oil or the gas).
          If contamination by gases coming from the OLTC is suspected, interpretation of DGA results in the main tank should be made with caution by subtracting background contamination from the OLTC, or should be avoided as unreliable. 
  No communication between OLTC and main tank, This transformer has been identified as not having communication between the On-Load Tap Changer oil and the main tank oil. This makes the investigation of this diagnosis more urgent as there should not be any contamination between OLTC and main tank.