FAULT CURRENT AND DIFFERENTIAL CURRENT DETECTION SYSTEM CAPABLE OF PREVENTING SPURIOUS TRIGGERING OF A PROTECTION SYSTEM DUE TO TRANSIENT INTERFERENCE PULSES

摘要

This invention relates to a method in a system controller for detecting fault or differential current in an electronic device. The method comprises the steps of determining if a detected current generated on a conductor is greater than or equal to a first predetermined current thereshold based on a detection signal corrresponding to said detected current;refrainning from outputting a control signal for a predetermined delay period after said detected current is greater than or equal to said first predetermined thereshold; determining if said detected current is greater than or equal to a second predetermined current threshold after said predetermined delay period is over; determining if said detected current is a fault or differential current after said detected current is greater than or equal to said second predeterminded current therehold; and when said detected current is said fault or differential current, outputting said control signal at least indirectly to a swich to instruct said switch to isolate said fault current from an electric device connected to said conductor.