| 摘要 |
#CMT# #/CMT# The method involves carrying out local modification of temperature of an insulator (4) of a sub-assembly constituted of a section selected among an assembly of low insulation risk sections of an electrical coil, with respect to an ambient temperature of the coil. An electrical characteristic representing an insulation resistance of the coil assembly is measured during local modification of the temperature the sub-assembly. The measured characteristic is compared to a reference to obtain a difference representing presence of a degraded zone (2) located in the sub-assembly. #CMT#USE : #/CMT# Method for locating a degraded zone in an insulator e.g. oil impregnated paper based insulator, covering a conductor of an electrical coil in a rotating high-voltage electric machine e.g. high voltage alternator or motor, which is cooled by circulation of liquid e.g. water, and high voltage transformer (all claimed). Can also be used for an epoxy resin based composite insulator of a dry-type transformer. #CMT#ADVANTAGE : #/CMT# The method permits to rapidly and effectively locate the degraded zone in the insulator that covers the conductor of the electrical coil, and is applicable to different insulation technologies of the coil. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a schematic view of an end winding bar of a stator of a high voltage alternator cooled by water, with insulation of a coil of the stator carried out by a low insulation zone located on the bar. 1 : End winding bar 2 : Degraded zone 3 : Conductor 4 : Insulator 13 : Braze. |
