Transformer Oil Breakdown Voltage Test System

Transformer Oil BDV kit are used for dielectric breakdown voltage test. It is an important test as it determines the withstanding capacity of any insulating oil or liquid. Transformer oil degrades due to ingress of moisture and other impurities in it. Thus the dielectric strength or inshort the insulating capability of the oil degrades. Hence to test the dielectric strength of these oils “Break Down Voltage” (BDV) test is conducted. It is the very first and most preferred test of any insulating liquid as it requires very less time and also it is a precursor to its condition before any extensive test is carried out. Transformer oil BDV kit is used to conduct this test on transformers insulating oil. We offer high quality and most accurate transformer oil BDV test kits for you to ensure better health and protection of your transformer by periodical testing and maintenance.

Dielectric Strength of Transformer Oil

Oil has been used for a long time as an insulating medium in Transformers, HV Capacitors, XLPE Cables and Switchgear. It is also an effective coolant and transfer medium of various impurities from windings and paper insulation. It is necessary for Oil to be a perfect insulator as it was intended to be at the time of manufacture, for the HV equipment to function satisfactorily. Oil suffers from electrical and mechanical stresses while a electrical equipment is in operation. In addition contaminations caused due to chemical interactions with windings and other solid insulations, catalyzed by high operating temperature.

As a result the original chemical properties of Oil changes gradually, rendering it ineffective for its intended purpose after many years. Hence this oil has to be periodically tested to ascertain its basic electrical properties, and make sure it is suitable for further use, or necessary filtration has to be done. The most common and easiest test of these is finding out the dielectric strength of the oil.

transformer oil bdv kit
Transformer Oil BDV test kits

The dielectric strength of transformer oil is also known as the breakdown voltage (BDV) of transformer oil. Breakdown voltage is measured by observing at what voltage, sparking strands between two electrodes immersed in the oil, separated by a specific gap. A low value of BDV indicates presence of moisture content and conducting substances in the oil.

For measuring BDV of transformer oil, portable BDV measuring kit is used such as PE-AOBDV-MXXX or PE-LOBDV-MXXX. In these kits, oil is kept in a pot/chamber in which one pair of electrodes are fixed with a gap of 2.5 mm (in some kit it 4mm) between them. Then slowly rising voltage is applied between the electrodes. The rate of rising voltage is controlled and observed at which sparking starts between the electrodes. That means at which voltage dielectric strength of transformer oil between the electrodes has been broken down.

This measurement is taken 3 to 6 times in the same sample of oil, and we take the average value of these readings. BDV is an important and popular test of transformer oil, as it is the primary indicator of the health of oil and it can be easily carried out at the site.

Dry and clean oil gives BDV results, better than the oil with moisture content and other conducting impurities. Minimum breakdown voltage of transformer oil or dielectric strength of transformer oil at which this oil can safely be used in transformer, is considered as 30 KV.

oil cup
Oil Pot/Chamber with electrodes