Carrier Migration Characteristics of Oil-impregnated Insulating Pressboard under the Combined Action of Electric and Thermal Fields

As the main insulation structure of the converter transformer, the insulation design of oil-paper insulation is crucial. Carrier mobility is one of the key parameters in insulation simulation design and has a significant impact on simulation results. However, the carrier mobility in the simulation model is mostly an empirical value, and there is a lack of actual measurement results under different temperatures and electric field strengths. In order to explore the effects of electric field strength and temperature on the carrier migration characteristics of oil-paper insulation, this paper built a variable temperature surface potential decay (SPD) measurement platform and used this platform to measure the carrier mobility of different oil-impregnated insulating Press-board under different electric field strength and temperature. The effects of electric field strength and temperature on carrier mobility were analyzed. It provides a theoretical basis for the design optimization of oil-paper insulation structure in transformers.