Estimation of Earth-Faults in Insulated Neutral Networks by Earth-Fault initiation's character

The initial earth-faults cause high frequency swings that are moulded by three different frequency processes. Dangerous overvoltages are formed during transients, and they influence the insulation in the whole galvanically connected network. The registration of initial processes and examination of these registrations by special algorithms enables to find a weak insulation spots. Special algorithms are used for the analysis of the recorded registrations and they enable to detect spots of variable earth-faults and to increase the reliability of distribution network. This paper presents the result of the analysis of registered initiations of multiple earth-faults in healthy network phases. The digital model is worked out to examine the mentioned registered processes.