You Do Need power plug adapter while traveling from Bulgaria 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 Bulgaria are C and F. This is how they look like.

Bulgaria

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

Type C

Type F

Greenland

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

Type C

Type E

Type F

Type K