Maintaining correct oil levels is vital to avoid overheating, insulation breakdown, and potential fire risks. Regular inspection for leaks, corrosion, and seal integrity is part of best practice maintenance programs.

Transformer oil levels can fluctuate due to temperature changes, load variations, and normal operating conditions. In addition, removing oil during routine sampling and laboratory analysis can withdraw up to approximately 2 litres per sample. Over several years, repeated sampling may gradually reduce the total oil volume in a transformer if not properly managed. Accurate monitoring and timely top-ups help ensures units remain within safe operating ranges and helps prevent over-pressurization or thermal stress.

The oil level device uses ultrasound in order to detect the presence of a liquid. In order to do this, the main unit sends a strong electrical signal to the sensor, which then emits a high energy pulse of ultrasound into the transformer wall. The ultrasound is conducted through the solid walls of the transformer and then interacts with the contents. After the sensor stops, emitting ultrasound, it starts listening for the returning echos of the signal. If no liquid is present, the echos will not be returned. This process allows the device to detect the presence or absence of transformer oil where the sensor is placed.