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

Here is Why You Need An Adapter

The outlet and plug type used in South Africa are C, M and N 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

South Africa

In South Africa, outlets of type C, M and N are in use.

Type C

Type M

Type N