Emergency island grids with small hydro power stations

This article focuses on alternative islands powered from small hydro power stations as an emergency power source for specific communities. Grids under consideration should backup regions of small communities. These areas are usually connected to main grid, but are provisionally disconnected from the grid due to some unexpected situations in the main grid. Mentioned small local grids in island mode are not capable to cover entire energy demand in the community, but it has probably the capacity to power main crucial facilities in the community (hospitals, public buildings, traffic lights, street lighting, water stations, broadcasting systems, etc.). Specific sequential coupling to or shut-off from the local grid must be defined. The main task is to discuss and define features of the local island, operating conditions, proper local power sources and particular source cooperation in dependency on the local power capacity, energy demand and duration of main grid outage. Although the complete research deals with particular types of small or distributed power sources, this article focuses mainly on hydro power plants from the category small hydro and thus utilization of adequate hydroengineering structures