It is of great significance to study the effect of electrode/insulating material interface roughness on space charge characteristics under high temperature and high electric field. Therefore

taking the epoxy resin (EP)

the main insulating material commonly used in electric equipment

as the research object

we prepared EP samples with different surface roughness. The space charge distribution of EP under different temperatures

different electric fields and different electrode/epoxy resin interface roughness was measured by a pulse electro-acoustic measurement system. Besides

based on the DC conduction current experiments and electric field simulation

the space charge mechanism of EP under different electrode/epoxy resin interface roughness was explored. The space charge experimental results show that

under the high temperature and high electric field

with the increase of electrode/epoxy resin interface roughness

the accumulated space charge density in EP increases

in which the maximum average space charge density is 3.68 C/m3. Due to the larger accumulated space charge density

the electric field distortion is more serious

and the maximum value is 57.07%. The further mechanism study shows that the electrode/epoxy resin interface roughness will greatly increase the surface electric field of EP and lead to the larger amount of field-assisted charge injection

further resulting in the more severe space charge accumulation in epoxy resin. This study explains the influence of electrode/epoxy resin interface roughness on space charge characteristics of insulating materials

which provides a theoretical support for structural optimization design and improvement of production process of DC electric equipment.