Study on the Noise Characteristics of 10kV Vegetable Insulating Oil Transformer

The noise emitted from distribution transformer often disturbs the normal life of people around it, hence it is necessary to research the noise characteristics of the vegetable insulating oil transformer. The characteristic of noise emitted by the 10KV vegetable insulating oil transformer under the condition with no load and different loads were tested in a spacious HV testing hall. As a comparison, the vegetable insulating oil in transformer was replaced by mineral insulating oil, and the noise of the transformer filled with mineral oil has also been measured in the same environment. The experiment results demonstrated that A-weighted sound pressure level of noise emitted from the transformer filled with vegetable insulating oil is about 5~6dB lower than that of noise emitted from the transformer filled with mineral insulating oil. Combined with the characteristics of insulating oil and the classical calculation formula of absorption coefficient, the sound absorption coefficient calculating formula of insulating oil has been derived. Though the calculation, it was found that the sound absorption coefficient of FR3 is about 2 times higher than that of mineral insulating oil. Thus vegetable insulating oil FR3 can reduce the transformer noise better than mineral insulating oil.