Buzzing on laptop, stove and other electrical devices in Canary Islands
I am in the Canaries at the moment and their attitude to electricity supply and grounding is cavalier to say the least. There is no clear standard as to what is live and what is neutral. The plugs and sockets (Spanish) do normally have a connection for ground but what it is connected to is usually a mystery.

If she is there for a while I would suggest getting a long piece of rebar (2m+) and hammering it into the ground close to the building (diagonally will do if there is rock below). Make the earth connection to this.