Discharge Streamer Development Mmorphology in Multi-element Mixed Insulation Oil Considering Ionization Energy Effect

In this study, considering the influence of oil chemical composition on oil ionization energy and the variation law of oil ionization energy with electric field intensity, an improved discharge streamer simulation model was established to reveal the influence mechanism of lightning impact breakdown characteristics of multi-element mixed insulating oil. The simulation results show that the larger the applied positive voltage, the earlier the surge time of the multi-element mixed insulation oil discharge stream appears. With the decrease of the oil gap distance between the pin-plate electrode, the discharge stream of the multi-element mixed insulation oil develops more violently under the same voltage. Compared with the development characteristics of mineral oil, soya-based natural ester, palm-based natural ester and isooctyl stearate, the mixed-balance effect of oil composition dominated the development of multi-element insulating oil discharge stream.