Patent ID: 6842319

Claim:
A method for generating a trigger signal based on a current differential protection when a fault occurs on a section of an electrical power supply system, comprising: monitoring differential current values for a predetermined lower limit value of the differential current and stabilization current values weighted with a characteristic curve factor, and generating the trigger signal if the differential current values exceed the predetermined lower limit value and stabilization current values and are present simultaneously, calculating the differential current values and the stabilization current values with instantaneous values of the currents detected at the section of the electrical power supply system, forming and checking a first measurement quantity, which is proportional to a differential quotient of the stabilization current with respect to time, in an evaluation operation to determine whether the first measurement quantity exceeds the predetermined limit value of the differential quotient of the differential current with respect to time, forming and checking a second measurement quantity, which is proportional to a differential quotient of the differential current with respect to time, in another evaluation operation to determine whether the second measurement quantity exceeds the differential current quotient limit value, and generating the trigger signal if the forming and checking operations each produce a positive result at the same time as the two instances of monitoring.