Adaptation of the Duval Triangle for Enhanced Dissolved Gas Analysis and Diagnosis of Dielectric Nanofluids

For many years, mineral oil-filled transformers have successfully used dissolved gas analysis (DGA) as a fault diagnosis and condition monitoring tool. Amid continuous technological advancements, and with the proposed use of alternative dielectric liquids, such as nanofluids, it is essential to assess whether and how this diagnostic technique can be effectively adapted and optimized for use with these advanced insulating systems. This study investigates the dissolved gas generation patterns of mineral oil and nanofluids under thermal and electrical fault conditions. These faults were conducted on oil samples using specialized test cells to simulate realistic fault scenarios. Subsequently, the traditional Duval (Triangle 1/Pentagon 1) methods were applied to assess their suitability for analyzing dielectric nanofluid oils. The high rate of total dissolved combustible gas production in nanofluids caused fault misclassifications with Duval Triangle 1, indicating a need for adjusted zone boundaries. Consequently, a proposed modified version of Duval Triangle that is suitable for use with dielectric nanofluids has been introduced.