Abstract: Low temperature switching oil and transformer oil were compared in terms of standard and product properties. The results show that the paraffin content in low temperature switching oil is higher than transformer oil, dehydrogenation is easy to occur for the switching oil in a strong electric field, generating small molecules and hydrogen, this feature is extremely advantageous to the arc extinguishing; Switching oil has excellent thermal conductivity, therefore, the cooling of oil is more effective. Switching oil has low viscosity, resulting in faster flow, so it's good for the on-off and off. Switching oil has low flash point, so it has higher gas rate and evaporation rate, which improves the arc extinguishing ability.

Key words: switching oil, transformer oil, composition