Transformer Dissolved Gas Analysis (DGA) and Partial Discharge (PD) Analysis are two essential techniques used in power transformer risk management. Both methods provide valuable information about the condition of the transformer, enabling proactive maintenance and preventing costly failures.
- Transformer Dissolved Gas Analysis (DGA): DGA is a diagnostic tool used to analyze the composition and concentration of gases dissolved in the insulating oil of a power transformer. The analysis focuses on the identification and quantification of specific gases that are generated as a result of various internal faults within the transformer. By monitoring and interpreting the gas concentrations, DGA helps in detecting and diagnosing potential problems, including:
a) Thermal Faults: Overheating of transformer components, such as winding hotspots or insulation breakdown, produces gases like methane (CH4), ethane (C2H6), ethylene (C2H4), and acetylene (C2H2).
b) Electrical Faults: Arcing or sparking within the transformer can generate gases like hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), and various hydrocarbons.
c) Partial Discharges: Partial discharges, which indicate localized insulation degradation, can produce gases like methane (CH4), ethane (C2H6), and ethylene (C2H4).
By analyzing the types and concentrations of these gases, DGA can provide valuable insights into the condition of the transformer, identify the type of fault, estimate fault severity, and predict potential failures. Regular DGA monitoring allows for the early detection of problems, enabling timely maintenance or repairs before a catastrophic failure occurs.
- Partial Discharge (PD) Analysis: Partial discharge is a localized breakdown of insulation within a transformer that occurs due to various factors such as voids, contamination, or insulation degradation. PDs can lead to progressive deterioration of the insulation system and eventually result in a complete breakdown. PD analysis involves monitoring and measuring the magnitude, frequency, and patterns of these discharges to assess the insulation condition and identify potential risks.
PD analysis is typically performed using specialized sensors installed within the transformer or its associated equipment. By monitoring PD activity, it is possible to identify early signs of insulation degradation and take appropriate actions to prevent further deterioration. PD analysis provides the following benefits:
a) Early Warning: PD activity can be detected before visible damage occurs, allowing for timely maintenance and preventing major failures.
b) Insulation Condition Assessment: PD patterns and characteristics help assess the condition of the insulation system, identify potential weaknesses, and determine the remaining insulation life.
c) Maintenance Planning: By monitoring PD activity over time, trends can be established, enabling predictive maintenance planning and optimizing the lifespan of the transformer.
Combining DGA and PD Analysis: Both DGA and PD analysis provide complementary information about the condition of a power transformer. While DGA focuses on identifying and quantifying fault gases, PD analysis assesses the integrity of the insulation system. By combining the results of both analyses, a more comprehensive understanding of the transformer’s health can be obtained. The integration of DGA and PD analysis in transformer risk management allows for early fault detection, timely maintenance, and proactive asset management, ultimately improving the reliability and lifespan of power transformers.
Energy Risk Engineering Insights 
Great article.! It’s very important that each test searches different issues, but the same goal. Be saved in the operation of an transformers. How to anticipate, as much as we can, an catastrophic failure. It’s a great article, guys! Well done!
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