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

Here is Why You Need An Adapter

The outlet and plug type used in Guinea are C, F and K 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

Guinea

In Guinea, outlets of type C, F and K are in use.

Type C

Type F

Type K