Application

The differential function offers a high sensitivity for

low-level internal faults. The unique and innovative

sensitive differential protection feature of the

RET670 provides the best possible coverage for

winding internal turn-to-turn faults, based on well

known theory of symmetrical components .

Low impedance restricted earth-fault protection

functions are available as complimentary sensitive

and fast main protection against winding earth

faults. This function includes a directional zero

sequence current criterion for additional security.

Additionally a high impedance differential function

is available.