Difference Between Earth Fault Relay and Earth Leakage Relay?

Assuming you are refering to MV switchgear and not the "relay" you find on a DB in a home

Earth Fault Relay - Detects ground faults on a feeder

Earth Leakage/Frame leakage - This is a type of busbar protection. The switchboard must be fully isolated from earth (including cable glands and station earth). The switchgear is also installed on top of an insulation material. A single earth connection is then taken from the board to the station earth and is monitored by a relay (frame leakage protection relay) via a CT.

Basic difference: Earth fault relay = Feeder protection; Earth/Frame Leakage relay = unit protection (busbar)

Basically both are same.......earth leakage relay are sensitive earth fault relay. both
are working same principle residual current method.first
one is we r using CBCT second one is ordinary CT.

Hope this would help!!!!!!!!!

Earth fault is when a phase conductor makes contact with the neutral (for earthed system) or ground potential. Earth leakage is when there is a fault current from Live to the Earth. Most recent installation uses Residual Current Breaker(RCB) which detect leakage current directly disconnects the circuit whenever it detects that the electric current is not balanced between the energized conductor and the returning neutral conductor.Read more about Earth leakage relay and earth fault relay