Ground fault monitoring device for an electrical power distribution system

摘要

The monitoring device comprises a measuring channel of the ground fault voltage, a measuring channel of the ground fault current, and a digital processing circuit whose role is to search for and indicate the presence of a ground fault. The processing circuit determines the fundamental parts of the ground fault current and voltage to compute the phase difference phi between the two parts and the cos phi value. The evolution of this phase difference is representative of a fault.