You Do Need power plug adapter while traveling from Ethiopia 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 Ethiopia are C, F and G. This is how they look like.

Ethiopia

In Ethiopia, outlets of type C, F and G are in use.

Type C

Type F

Type G

South Sudan

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

Type C

Type D