Why should the dielectric strength test be carried out regularly for insulating oil?

Transformer oil is widely used in substations in the power industry, and the dielectric strength is a composite index for transformer oil. Insulating oil dielectric strength tester,insulating oil breakdown voltage tester (Insulating oil BDV tester) is designed according to IEC156 international standard, using industrial single chip as a controller, suitable for large integrated circuits, new I/O interface, liquid crystal display, but also built-in printer and other IIJ-II transformer oil testing, combined with special testing and anti-interference technology, thereby greatly improving the performance of the tester.
In the transformer, oil circuit breaker, oil-filled cable, power capacitor and oil sleeve and other high-voltage electrical equipment running, insulating oil due to oxygen, high temperature, high humidity, sunlight, strong electric field and impurities, the performance will gradually deteriorate, resulting in it can not give full play to the insulation effect, for this reason must be regularly tested on the insulating oil to identify whether its performance has deteriorated. The quality of the insulating oil is closely related to the breakdown voltage.
Breakdown voltage is a measure of the ability of the dielectric withstand voltage without being destroyed, is one of the main indicators to test the performance of transformer oil, dry and clean oil has a fairly high breakdown voltage value. The main factors affecting the breakdown voltage of transformer oil are moisture, impurities, temperature, etc., the temperature has a complex relationship with the breakdown voltage, and the breakdown voltage of dry, impurity-free oil is maintained by the non-free nature of the neutral particles of the oil.
However, when the oil contains free water, dissolved water or solid contaminants, because these impurities have a greater conductivity and dielectric constant than the oil itself, they will form a conductive bridge under the action of the electric field and reduce the breakdown voltage of the oil. The dielectric strength tester of insulating oil can determine whether there is moisture, impurities and conductive particles in the oil, but it cannot determine whether there are acidic substances or sludge in the oil.

Generally, before the transformer oil is added to the transformer through vacuum filtration and degassing, its breakdown voltage can reach 70KV. Insulating oil is an important dielectric material in power electrical and industrial production, which is widely used in transformers and other power electrical equipment to play a role in cooling and insulation.