Detection device for directional detection of ground fault in e.g. insulated neutral balanced three-phase network, has location module including evaluation unit of phase shift between homopolar voltage and homopolar current derivative

摘要

The device has a first module (20) to provide a signal representative of homopolar voltage (V0) of a set of phases. A second module (40) provides a signal representative of derivative with respect to a time of homopolar current (I0). An activation unit activates the second module according to a detection signal (D) of occurrence of a ground fault in a multiphase medium voltage network. A location module (50) includes an evaluation unit to evaluate a phase shift between the homopolar voltage and the derivative of the homopolar current provided by the second module with respect to pi. Independent claims are also included for the following: (1) an indicator for indicating passage of ground fault (2) a relay for protecting a current line against ground fault (3) a method for directional detection of a ground fault in a multiphase medium voltage network (4) a method for protecting a current line during occurrence of a ground fault.