Process for operating a fuel cell stack at high temperature

Process for operating a cell stack of solid oxide high temperature, the process comprising the following steps: a) connecting the stack of solid oxide cells in parallel to a drive power supply at a temperature and / or voltage Predefined of the cell stack and fuel, b) applying a voltage from the unit fuel supply between 700 and 1500 mV for solid oxide cell through the stack of solid oxide cells independently of the electromotive force of the cell stack solid oxide, so that the drive power supply drives electrons towards the anode of the stack of fuel cells, c) heating the stack of solid oxide cells from a predetermined temperature to an operating temperature, maintaining time the voltage solid oxide cell from the power supply unit, d) holding the stack of solid oxide cells at or above a predetermined operating temperature and / or above a predetermined voltage until the stack of solid oxide cells should be operated, e) supplying fuel to the stack of solid oxide cells, f) disconnecting the power supply unit followed by g) disconnecting a load requiring power to the cell stack of solid oxide.