Introduction

Power transformers are among the most critical and expensive assets in an electrical network. Their failure not only results in high repair costs but also leads to operational downtime, safety risks, and revenue losses. To prevent such incidents, it’s essential to detect early warning signs before a failure occurs. One of the most powerful tools for transformer condition monitoring is Dissolved Gas Analysis (DGA).

DGA is often called the “blood test” of transformers, capable of detecting hidden faults well before they become catastrophic. In this blog post, we explore what DGA is, why it’s important, how it works, and how Tru-FIL Ltd’s intelligent ERP-integrated testing process makes this diagnostic even more valuable.

What Is Dissolved Gas Analysis?

DGA is a laboratory method used to detect and measure the types and concentrations of gases that have dissolved in transformer insulating oil. These gases are generated as a result of internal faults or degradation processes such as overheating, partial discharges, arcing, and insulation breakdown.

Over time, the insulating oil absorbs these gases. By analyzing them, experts can determine not only the type of fault but also its severity and progression.

What Causes Gases to Form?

When a transformer experiences internal stress — whether due to electrical faults, overheating, or chemical reactions — the organic compounds in the oil and solid insulation begin to break down. This breakdown produces gases such as:

• Hydrogen (H₂) – Associated with partial discharges

• Methane (CH₄) and Ethane (C₂H₆) – Linked to low-energy overheating

• Acetylene (C₂H₂) – A clear indicator of high-energy arcing

• Carbon Monoxide (CO) and Carbon Dioxide (CO₂) – Generated from cellulose (paper insulation) degradation

The type and ratio of these gases tell a diagnostic story that experienced lab analysts — and now, intelligent software — can interpret.