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

Here is Why You Need An Adapter

The outlet and plug type used in Congo are C, D and E and in Sudan are C and D. This is how they look like.

Sudan

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

Type C

Type D

Congo

In Congo, outlets of type C, D and E are in use.

Type C

Type D

Type E