Jérôme

The temperature sensor monitors top oil or winding temperature and provides input for alarms, cooling control, and protective shutdown. It helps prevent overheating, insulation degradation, and catastrophic transformer failure during abnormal operating conditions.

A transformer oil level indicator provides continuous or visual confirmation of oil volume inside the transformer tank or conservator. It helps operators detect oil loss due to leaks, overheating, or abnormal expansion. Maintaining proper oil level prevents air ingress, insulation exposure, and overheating, making the indicator a critical safety and reliability component in oil filled transformers.

The crackle test detects the presence of free or excessive moisture in transformer oil. When a small oil sample is heated, audible crackling or bubbling indicates water boiling off. This quick field test is qualitative and does not measure moisture concentration, but it helps identify urgent contamination risks. It is commonly used as a screening tool after leaks, breather failures, or sudden condition changes. Results must be confirmed with laboratory moisture testing such as Karl Fischer analysis.

Replacement is required when the transformer fails to produce adequate ignition voltage, shows insulation breakdown, excessive heating, cracked casing, oil leakage, or repeated ignition failure. Electrical tests revealing open windings or short circuits also indicate replacement. Persistent burner lockouts or weak spark are common symptoms. Replacement ensures reliable ignition and prevents unsafe operation of oil fired heating systems.

Laboratory testing uses controlled instruments and standard methods to measure moisture, acidity, interfacial tension, dissipation factor, resistivity, and dissolved gases. DGA is typically done by gas chromatography after extracting gases from the oil. Field kits focus on fast screening: portable BDV testers, moisture meters, and sometimes quick checks for acidity or dielectric loss. Field results support immediate decisions after maintenance or events, while lab results provide higher accuracy, broader parameters, and trending data used for long term condition assessment and asset management.