Study on the space charge characteristics of different types of oils and papers

Oil immersed paper insulation is widely used in converter transformers for its good electrical and mechanical properties. Under high DC voltage, space charge accumulates in oil-paper insulation, leads to the electric field distortion, and eventually enormously affects its performance. Large amounts of research were published on the space charge characteristics of oil-paper insulation under different conditions including temperature, temperature gradient and polarity reversal, however there was little report on the influence of composition of oil and paper on the space charge characteristics. In this article the space charge characteristics of different combination of transformer oils (Karamay 25# oil, Nytro Libra oil) and papers (Type I from XD factory, ? imported from France) were studied…