Transformer Oil Breakdown Voltage Testing Services

To assess the insulating property of dielectric transformer oil, a sample of the transformer oil is taken and its break down voltage is measured. The lower the resulting breakdown voltage, the poorer the quality of the transformer oil.

• The transformer oil is filled in the vessel of the testing device. Two standard-compliant test electrodes with a typical clearance of 2.5 mm are surrounded by the dielectric oil.
• A test voltage is applied to the electrodes and is continuously increased up to the breakdown voltage.
• At a certain voltage level breakdown occurs in an electric arc, leading to a collapse of the test voltage.
• An instant after ignition of the arc, the test voltage is switched off automatically by the testing device.
• The transformer oil testing device measures and reports the root mean square value of the breakdown voltage.
• After the transformer oil test is completed, the insulation oil is stirred automatically and the test sequence is performed repeatedly: typically 5 repetitions, depending on the standard.
• As a result the breakdown voltage is calculated as mean value of the individual measurements.