Overvoltages provoked by faults in the distribution electrical network

The study of the overvoltages generated by faults in the transmission distribution electrical network comprised over 500 live tests of a single phase-to-earth fault in a 10 kV network. The influence of the neutral point grounding resistance on overvoltages in the network is researched. Different values of the resistor were used. Moreover the networks with an insulated neutral point were tested. A computer model of the cable network and the supply station was additionally developed. Overvoltages are reduced to relatively low values, mostly below the value of a double phase peak voltage, if the neutral point of the network 10(20) kV is grounded through the resistor. This is under a condition that the nominal resistor current is three times greater than the earth fault capacity current.