You Do Need power plug adapter while traveling from Papua New Guinea to Cape Verde.

Here is Why You Need An Adapter

The outlet and plug type used in Cape Verde are C and F and in Papua New Guinea is I. This is how they look like.

Papua New Guinea

In Papua New Guinea, outlets of type I are in use.

Type I

Cape Verde

In Cape Verde, outlets of type C and F are in use.

Type C

Type F