Abstract: For a method of operating of a synchronous compensator including a rotating electric machine including a rotor and a stator with at least one winding with a solid insulation enclosing the electric field, relevant parameters for temperature conditions in the rotor are determined, and during over-excited operation, to temporarily enlarge the field of operation of the synchronous compensator, cooling of the rotor is forced depending on a rotor temperature value determined from the parameters. The synchronous compensator measures parameters relevant for the temperature conditions of the rotor. A mechanism is also provided to force the cooling of the rotor depending on rotor temperature values determined from the parameters during over-excited operation of the electric machine.

Abstract: For a method of operating of a synchronous compensator comprising a rotating electric machine comprising rotor (46) and stator (2) with at least one winding with a solid insulation enclosing the electric field, relevant parameters for the temperature conditions in the rotor are determined, and during over-excited operation in order to temporarily enlarge the field of operation of the synchronous compensator, the cooling of the rotor is forced depending on a rotor temperature value (TR) determined from said parameters. Such a synchronous compensator comprises measuring means for measuring parameters relevant for the temperature conditions of the rotor. Means (36, 38) are also provided to force the cooling of the rotor (46) depending on rotor temperature values (TR) determined from said parameters during over-excited operation of the electric machine.