METHOD AND DETECTION DEVICE FOR DETECTING A HIGH-IMPEDANCE GROUND FAULT IN AN ELECTRICAL ENERGY SUPPLY NETWORK WITH A GROUNDED NEUTRAL POINT

摘要

Method and detection device for detecting a high-impedanceground fault in an electrical energy supply network with agrounded neutral pointThe invention relates to a method for detecting ahigh-impedance ground fault in an electrical energy supply network(12) with a grounded neutral point, in which a test signal isfed with a detection device (10) into the energy supply network(12), wherein the test signal has a frequency which differsfrom the network frequency of the energy supply network (12),and the presence of a high-impedance ground fault is inferredon the basis of a measuring signal produced by the test signal.In order to enable a reliable detection, with low equipmentcosts, of high-impedance ground faults in energy supplynetworks with a grounded neutral point, it is proposed that athree-phase test signal is fed into the phase conductors of theenergy supply network (12) as a test signal, a measuring signalwhich indicates the displacement voltage of the test signal isgenerated with the detection device (10), the displacementvoltage is compared with a threshold value using a test device(15) of the detection device (10), and the presence of ahigh-impedance ground fault is detected if the displacement voltageexceeds the threshold value.The invention also relates to a correspondingly designeddetection device (10).