System for stabilizing a power supply system

Apparatus for stabilizing the voltage of a power supply system having at least one load connected thereto, said apparatus including a choke unit for connecting said power supply system to a mains power system and a converter system for stabilizing the power supply system voltage, said converter system comprising:

• a converter machine having a rotor and at least one three phase winding, one three phase winding of said converter machine being coupled to said power supply system;
• a voltage controller adapted to detect said power supply system voltage and control said converter machine to maintain said voltage at a predetermined value;
• a flywheel storage unit including a synchronous machine and a flywheel coupled thereto;
• a static converter unit coupling the synchronous machine of said flywheel unit and one three phase winding of said converter machine to exchange real power between the flywheel unit and converter machine by changing the speed of said flywheel;
• and
• a converter controller, responsive to at least one electric parameter of said power supply system and of said mains power system, to control said static converter unit such that the flywheel storage unit supports said converter machine in stabilizing the power supply system voltage by drawing real power from the converter machine or supplying real power to the converter machine.