Polypropylene（PP） blended with polyolefin elastomer（POE） has been considered as a potential choice to replace XLPE as HVDC cable insulating material. During the process of fabrication

installation

and operation

the cable insulating material may be exposed to mechanical stress. In order to study the effect of mechanical stretching on the safe operation of cables

PP/POE blends were prepared and stretched to different ratios

and the space charge behaviors were measured by a pulsed electro-acoustic（PEA） method. Besides

the trap distribution was obtained based on the surface potential decay test. The results indicate that mechanical stretching can promote the space charge accumulation and migration in PP/POE blends. With the elongation ratio increasing from 1 to 1.2

the density of shallow traps increases

while both the depth and density of deep traps decrease. However

an opposite phenomenon can be observed when the elongation ratio increases from 1.2 to 1.4. The microstructure changes of the PP/POE blend due to mechanical stretching is considered to be responsible for the change in space charge behaviors and trap distributions.