DGA (Dissolved Gas Analysis) Of Transformer Oil

DGA TEST

Dissolved Gas Analysis (DGA) is a diagnostic technique used to assess the condition of the mineral oil in power transformers. It involves analyzing the gases dissolved in the transformer oil to detect any potential faults or abnormalities.

The most important parameters to look for in DGA are the concentrations of various gases present in the oil. The key gases and their respective fault indications are as follows:

1. Hydrogen (H2): The presence of hydrogen indicates potential overheating or partial discharges in the transformer.

2. Methane (CH4): Methane is a byproduct of thermal degradation or arcing. Its presence may indicate potential issues with the transformer's insulation.

3. Ethylene (C2H4): Ethylene is an indication of thermal degradation of paper insulation.

4. Acetylene (C2H2): The presence of acetylene is a strong indication of arcing in the transformer.

5. Ethane (C2H6): Propane (C3H8), and Propylene (C3H6): These gases are produced due to more severe faults like localized overheating, arcing, or breakdown of oil.

6. Carbon Monoxide (CO) and Carbon Dioxide (CO2): The presence of these gases can provide insights into the severity of the fault and the degree of decomposition occurring in the oil.

7. Oxygen (O2): Oxygen is not a fault gas but its presence indicates possible oil oxidation.

Monitoring the levels of these gases over time and comparing them to established limits and trends helps in identifying potential transformer faults and allows for timely maintenance and preventive measures. DGA is a valuable tool for condition monitoring and early detection of issues in power transformers, helping to prevent major failures and costly downtime.