A power supply apparatus for an X-ray imaging apparatus includes grid connection device(s) to connect to a power grid providing an AC input voltage, including circuit protection arrangement(s) to not trip below a safety current; an actively actuatable transformer arrangement to transform the AC input voltage into a DC output voltage as a supply voltage for the X-ray imaging apparatus; an electrical energy storage system; and a control apparatus to actuate the transformer arrangement to limit power consumption from the electric power grid as a function of the safety current and make up for a deficiency of a power requirement for the X-ray imaging apparatus from the energy storage system. The control apparatus is configured to actuate the transformer arrangement for time-dependent limitation of power consumption from the power grid according to a current/time profile, the current/time profile being deduced from a time-based trip profile of the circuit protection arrangement.