Electric circuit arrangement for standard insulation monitoring with emergency shut-down for an ungrounded power supply system upon detection of a ground fault

Abstract

The invention relates to an electric circuit arrangement () for standard insulation monitoring with emergency shut-down for an ungrounded power supply system () upon detection of a ground fault, having a standard insulation monitoring device () which is coupled to an active conductor (L, L, L) of the power supply system () on the network side via a coupling branch () each or to a neutral point (S) of the power supply system () via a coupling branch () and is connected to ground (PE) on the ground side via a ground connection branch (). The electric circuit arrangement () comprises an AC/DC sensitive measuring current transformer () which detects a fault current on the network side at the active conductors (L, L, L) in the coupling branches () or at the neutral point (S) in the coupling branch () or on the ground side in the ground connection branch () of the insulation monitoring device (); an evaluator () for evaluating the fault current with regard to a fault current threshold being exceeded; and a trip device () for shutting down the power supply system ().