For precise calculation of doubl-ground fault current in meshed networks, it is necessary to take into account precise values of all emf in the network. For this purpose those parts of the network scheme which form active triangle must be transformed into active star and vice versa. These transformations as well as other more simple must be carried out so long till original network is reduced to a single active star or active triangle which comprise only two emf notwithstanding the number of sources in the original network scheme. Further, calculating the current, the corresponding to these figures formulas must be applied. The active star renders more simple formulas for double-ground fault current calculation than active triangle. But in some cases the active triangle is more convenient. These cases could be: when one source supplies energy via two parallel lines as well as when in the network is only two energy sources. For radial network canonical star must be used.