We design and manufacture insulatnig oil BDV tester according to international standard IEC**6, it is usedfor testing the dielectric strength of the insulating liquids of a high tension transformer. These insulating liquids must possess a high dielectric strength. The dielectric strength is measured by passing a very high voltage through them. If the insulating liquid fails in the test the device will show a spark between its two electrodes.The oil tester consist of different parts like H.T. transformer and oil test cell (with electrodes & gauge), LCD displayer, control panel and so on.