Port bow turned on changeable current (5)
I believe the answer is:
accra
'port' is the definition.
(capital of Ghana)
'bow turned on changeable current' is the wordplay.
'bow' becomes 'arc' (both can mean a curve).
'turned' shows that the letters should be reversed in order.
'on' means one lot of letters go next to another.
'changeable current' becomes 'ac' (alternating current. I am not sure about the 'changeable' bit.).
'arc' backwards is 'cra'.
'cra' put after 'ac' is 'ACCRA'.
Can you help me to learn more?
(Other definitions for accra that I've seen before include "African city" , "Main city of Ghana" , "West Africa capital" , "Ghanaian capital" , "Ghana's capital" .)