How to Determine the Condition of Transformer Oil?

Transformer oil testing typically evaluates the following key parameters:

1). Moisture Content

2). Dielectric Strength (Breakdown Voltage)

3). Acid Number (Neutralization Number)

4). Interfacial Tension (IFT)

5). Viscosity

6). Pour Point

7). Flash Point

8). Dissolved Gas Analysis (DGA)

9). Particle Count

10). Color and Appearance

11). Oxidation Stability

12). Furan Content

1). Moisture Content

Water in oil, expressed in the concentration of ppm (parts per million) or % (percent).

2). Dielectric Strength (Breakdown Voltage)

An assessment of the extent of oils resistance to electric stress as measured in kV (kilovolts).

3). Acid Number (Neutralization Number)

Acid Number (Neutralization Number) shows how acidic oil is and is usually expressed in unit of mg KOH/g (milligrams of potassium hydroxide per gram).

4). Interfacial Tension (IFT)

Interfacial Tension (IFT) describes the efficiency of how the oil has separated from water as indicated by dynes of centimeter (dyne cm-1).

5). Viscosity

Viscosity reflects oil’s ability to flow and its smoothness, as measured in mm² / s (millimeters squared per second).

6). Pour Point

The temperature at which provided oil loses its ability to flow due to viscosity in degree Celsius.

7). Flash Point

Temperature at which oil catch fire or burn, and is in degree Celsius.

8). Dissolved Gas Analysis (DGA)

Dissolved Gas Analysis (DGA) observes levels of gases that may be dissolved in crude oil including hydrogen, methane and carbon monoxide.

9). Particle Count

Measures oil’s particulate contamination, in particles per milliliter (p/mL).

10). Color and Appearance

The sight and appearance of the oil, specifically; the color of the oil and its clarity.

11). Oxidation Stability

Quantitatively determines the resistance of oil to oxidation with values given in terms of hours or days.

12). Furan Content

Quantifies oil’s degradation products and the measurements are given in mg/L (milligrams per litre).

These parameters enable determination of conditions of transformer oil, identification of existing problems and requirements for the transformer.