**6. Conclusions**

This chapter proposes some solutions about the topics of unconventional backup structures used in smart microgrids. The issue is of interest particularly in connection with the problem of ensuring continuity in power supply. In this context, firstly the case of the switching to the backup power supply, in the case of a low-voltage symmetrical grid when using two frequency converters, one of which is alternately maintained in cold reserve, is presented. The only consumer is an asynchronous motor with a short-circuit rotor with nominal active power P = 22 kW. The logic of switching and electrifications is ensured by using an associated software of a microprogrammable automaton. Secondly, the switching to the backup power supply, in the case of low-voltage symmetrical smart microgrids using an electric generator set or using an electric generator set and the photovoltaic panels, in the case of modern residential buildings, is proposed. The microgrid is symmetrical and uses two identically transformers, T1 and T2, one of the transformers being alternately in hot reserve state. The users are divided into two categories: critical and noncritical ones. Finally, the implementation of recloser devices for autoconfiguration and automatic connecting/disconnecting decisions, in order to switch on the backup power supply, is presented. It is expected in the future realized the conversion of the public grids to active (distribution/using) grids that use high-tech smart devices like reclosers. The grouping together of these smart microgrids that have the auto-reconfiguration option through implementation of the recloser type devices is also considered in the development of smart grids. In this context the implementation of the recloser-type devices for switching on the backup power supply, for the case of a two radial structures of a public grid with isolated neutral, is presented.
