Abstract:
This paper conducts an experimental exploration about the breakdown in transformer oil under the action of impulse voltages for the insulation of the transformer in the field may be endangered to the lightning and switching overvoltage. There is a lack of research on the influences of AC and DC mixed voltage on the oil- insulation characteristics. In this paper a needle-plate electrode model is designed, and different values of AC, DC and transient voltage are levied on the oil surrounded needle-plate electrode model to learn the differences of breakdown characteristics. Liquid Insulation that is mineral oil is taken for AC, DC voltage profile and measured transient voltage breakdown strength of lightning impulse for both positive and negative polarity. After that mineral oil with Nano particle is prepared using TIo2 and surfactant as CTAB. The AC, DC and lightning impulse breakdown strength are measured for both mineral oil and Nano oil which results have been compared. It is observed that the corona inception voltage (CIV) in Lightning impulse having high break down strength when compared to AC and DC. The CIV was measured and the magnitude of discharged particles high in Nano mineral oil increases the breakdown voltage of transformer oil.
