Diagnostic method for oil-filled electrical device, diagnostic device for implementing the diagnostic method, and oil-filled electrical device provided with the diagnostic device

摘要

An object of the invention is to provide a diagnostic method for an oil-filled electrical device that considers a temperature distribution in the oil-filled electrical device and enables accurate diagnosis to be conducted even when the method is applied to diagnosis of an actually operating device, and further provide a method with which such diagnosis of an oil-filled electrical device can be conducted from a component analysis value of an insulating oil in the oil-filled electrical device. The invention is a diagnostic method for an oil-filled electrical device including in an insulating oil a metal part wrapped with insulating paper, and determines that a time when a surface resistivity of a maximum precipitation site where metal sulfide is most precipitated on the insulating paper reaches a preset surface resistivity management value is a time of occurrence of an abnormality.

主权项

1. A method for diagnosing an oil-filled electrical device including a transformer and a metal part wrapped with insulating paper in insulating oil, said diagnostic method comprising:
a) storing a preset surface resistivity management value; b) receiving a surface resistivity measurement value from a sensor, wherein the sensor is placed at a maximum precipitation site where metal sulfide is most precipitated on the insulating paper; c) comparing the surface resistivity measurement value to the preset resistivity management value; d) determining that the oil-filled electrical device is in an abnormal condition when the surface resistivity value is less than or equal to the preset surface resistivity management value; and determining that the oil-filled electrical device is in a normal condition when the surface resistivity value is greater than the preset surface resistivity management value, wherein steps b, c and d are performed while the oil-filled electrical device is operating.