What We Did

Overview

Our team was appointed to carry out a complete oil change on a distribution transformer after routine sampling revealed elevated moisture levels within the insulating oil. Moisture contamination is one of the most common causes of reduced dielectric strength and accelerated ageing in transformers. Left untreated, it can lead to partial discharge, insulation breakdown, and potentially catastrophic failure.

Acting quickly allowed us to restore the transformer to a safe operating condition and extend its service life significantly.

Issue Identified

During scheduled maintenance, an oil sample was taken from the transformer and tested. The results showed moisture levels above the acceptable thresholds for safe operation. Visual inspection also indicated a slight haze in the oil—one of the early indicators of water contamination.

Work Completed

• Isolation & Safety Preparation
• Draining of Contaminated Oil
• Internal Inspection
• Filling with New Transformer Oil
• Testing & Commissioning

Outcome

The successful oil change restored the transformer’s insulating properties and removed the risk of moisture‑related faults. The client now benefits from:

• Improved reliability and performance
• Extended transformer lifespan
• Reduced likelihood of unplanned outages
• Full compliance with maintenance standards

Our proactive approach ensured minimal downtime and delivered a safe, efficient solution supported by comprehensive testing.

Recommendations

• Continue routine annual oil sampling
• Replace breather media whenever colour change indicates saturation
• Maintain a regular transformer maintenance schedule to prevent future contamination