METHOD FOR MONITORING INSULATION OF ROTATING MACHINE

摘要

PROBLEM TO BE SOLVED: To accurately monitor an insulation characteristic during driving by identifying an abnormality monitor level with taking influences of a voltage gradient applied to a stator winding during driving into consideration on the basis of a partial discharge intensity under one atmospheric pressure during halts. SOLUTION: A generator in which hydrogen is sealed as a cooling gas is driven with a pressure raised to 3-4 atm. A generated voltage is impressed to an insulator of a stator winding. A partial discharge is brought about by the generated voltage if an insulation performance of the winding is deteriorated. A range where a discharge start voltage when the partial discharge is started or a larger voltage is impressed is 1/a total number of windings. The partial discharge is smaller in size during driving. The partial discharge is generated by reflecting a defect because of the deterioration of the insulator. An abnormality can be detected by deriving an abnormality monitor level on the basis of an intensity of the partial discharge under 1 atm. during halts with influences of a spark generate voltage by a type of the cooling gas, effects of a pressure of the cooling gas and influences of a voltage gradient applied to the stator winding during driving being taken into consideration.