As per ___ guidelines, if the ratio of carbon dioxide (CO₂) and carbon monoxide (CO) in dissolved gas analysis is ___, it is predicted that the condition of paper insulation inside the transformer is poor.

• A. IEC-599, less than 11
• B. IEC-899, less than 11
• C. IEC-899, more than 11
• D. IEC-599, more than 11

Answer: (D)

There is one IEC guideline, number is IEC 599,
Statement of guideline is that "If the ratio of carbon dioxide and Carbon monoxide in Dissolve gas analysis test result is more than 11, it is predict that the condition of paper insulation inside the transformer is poor."
For healthy condition this ratio will be between 4 to 11.