The only remaining criterion for this implementation is proper
sensitivity and selectivity of protection, and this must be
evaluated considering new recommended values of protective
earthings along the line which is supplied from 220/33kV grid
station or 33/11kV primary/package unit station. In AADC
technical specification, there is a sensitive E/F relay as part of
the 11kV OHL protection scheme, but it is not installed in all
existing OHL feeders and AADC is currently introducing this
protection for the same