You Do Need power plug adapter while traveling from Western Sahara to South Sudan.

Here is Why You Need An Adapter

The outlet and plug type used in South Sudan are C and D and in Western Sahara are C and E. This is how they look like.

Western Sahara

In Western Sahara, outlets of type C and E are in use.

Type C

Type E

South Sudan

In South Sudan, outlets of type C and D are in use.

Type C

Type D