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

Here is Why You Need An Adapter

The outlet and plug type used in Yemen are A, D and G and in South Sudan are C and D. This is how they look like.

South Sudan

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

Type C

Type D

Yemen

In Yemen, outlets of type A, D and G are in use.

Type A

Type D

Type G