Line Differential Relay

The I diff min setting must take into account the cable charging current which is a function of the voltage, frequency, unit length capacitance, and length of the cable. this current accounts for the difference in current on either end and 1.5 times this value will give a safety margin for transient increases in charging current attributed to transient overvoltage conditions (if appicable). the ct's of course must be suitable for diff i.e. class X.