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

Here is Why You Need An Adapter

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

Greenland

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

Type C

Type E

Type F

Type K