Three-Dimensional Features of Streamers in Natural Ester Insulating Oil Under Lightning Impulse Voltage

Due to its high fire point, degradability, and excellent electrical properties, natural ester (NE) insulating oils provide an alternative to mineral insulating oils in electrical equipment. At present, the streamer discharge system of NE insulating oil is being increasingly studied, but the 3-D characteristics of the streamer discharge of NE insulating oil are not investigated. In this article, a dual light path observation platform for streamers in insulating oil is built. The 3-D features of streamers in NE insulating oil under lightning impulse voltage are extracted, and the 3-D features of streamers initiation and grow in NE insulating oil are studied. Experimental results show that high viscosity insulating oil streamer has a larger cross-sectional area and branching angle. Streamer channels under positive and negative polarity lightning impulse voltage exhibit different morphologies. This article is important for studying streamers mechanism in NE insulating oil and guiding the manufacturing of NE insulating oil power equipment.