Background. At the present time, a great number of methods of distant single phase to earth fault localization (DSPEFL) have been developed for 6–10 kV distribution cable networks. These methods are based on the analysis of operating parameters both during stable single phase to earth faults (SFEFs) and transient processes that occur during SFEFs. However, the accuracy of single phase to earth fault localization is low, which determines the lack of their widespread implementation. A promising direction in this area is to determine the distance to the place of single phase to earth fault based on the calculation of the passive parameters of the phase-to-earth loop which is formed by the phase conductors of the cable and its sheath.
Materials and methods. Simulation study in PSCAD, Matlab and also in COMSOL Multiphysics software has been carried out to study transient and steady-state modes during SFEFs, and to assess the stability of the functioning of the proposed DSPEFL methods.
Results. The author has proposed a DSPEFL method, which is based on the calculation and subsequent analysis of the passive parameters of the phase-to-earth loop in 6–10 kV cable networks with an isolated neutral point. An assessment of the applicability of the fundamental harmonic component (50 Hz) for DSPEFL is made. The frequency range of higher harmonic components in transient current and voltage during SFEF is indicated, in which the proposed method (and other similar methods) will be functional and will allow reliably calculate the passive parameters of the phase-to-earth circuit.
Conclusions. The developed method of DSPEFL based on measuring the parameters of transient processes during SFEF allows us to determine with sufficient accuracy the distance to single phase to earth fault localization during both stable and short-term SFEFs. It is based on recording the instantaneous values of fault current and voltage in the network under study, which makes it possible to use it in cable networks with resonant-grounded neutral point.