Specific gravity — 0. The following tests can be adopted before using the insulating oil. The oil test in which spark occurs and the testing set trips is known as dielectric strength test of transformer oil. This test is performed in the oil testing set. Suitable oil testing sets, stationary as well as portable, are available for testing the oil under the specified conditions. A sample of the oil is drawn from the transformer and tested in the oil testing set.
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What is BDV Test in transformer? How to proceed the Dielectric Strength Test for transformer oil? Oct 20, 1. BDV Test is an very important testing procedure for the insulation oils in transformer. When the testing result shows a very low value, the oil has to be replaced or purified.
The transformer oil under test is subjected to an AC electric field with continuously increasing voltage till the oil breaks down. The test cell shall be of glass or plastic and transparent and non-absorbent Eg.
Methyl Methacrylate Vessel with effective volume between to ml. The electrodes must be Copper, Brass, Bronze or Stainless steel and well polished having spherical shape with dip It shall have a spherical front as shown in the figure.
The electrodes shall be mounted horizontally in the cell and the axis shall be immersed at a depth of approximately 40 mm, The electrode gap shall be 2.
Before carrying out the test the cell shall be cleaned by rinsing with the test oil. The sampling vessel containing the test oil shall be gently agitated to have homogeneous distribution of impurities and air bubbles to escape. The test kit will have provision for automatic switching off of the supply voltage within 0. The test shall be repeated six times on the same cell filling and the arithmetic mean of the under test six of in results is noted as the electric strength or BDV Break Down Voltage of the oil under test.
The test shall be conducted in a dry place free from dust and voltage applied every time after disappearance of any air bubbles. The time intervals shall be five minutes, if the disappearance of air bubble cannot be observed.
What is BDV Test in transformer? How to proceed the Dielectric Strength Test for transformer oil?
It is also called as dielectric strength value. It is the dielectric strength of transformer oil. If the value of BDV is higher then it indicates that the presence of contaminants is lower. The minimum value of breakdown voltage is 30 kV kV. It depends upon on the moisture present in transformer oil.
BDV Test in Transformer
It is done for checking the dielectric strength of the oil of the Transformer. Dielectric strength means the maximum capacity to withstand voltage of insulating oil. This test shows the dielectric strength of Transformer oil. In transformer oil has mainly two purposes, first for insulation, second as cooling of Transformer core and other winding.
Transformer oil testing
Thus, the dielectric quality of transformer oil is essential to secure operation of a transformer. Voltage breakdown during oil test On-site testing[ edit ] Recently time-consuming testing procedures in test labs have been replaced by on-site oil testing procedures. There are various manufacturers of portable oil testers. Some of them are even battery-powered and come with accessories.