Patent ID: 7145760
Filing Date: 2006-12-05
Classification: G01R,H01F,H01H

Abstract:
1. A diagnosing method for a tap changer having an insulating liquid, the method comprising: performing a switching action of said tap changer; registering pressure in said insulating liquid as a function of time for a period of time comprising the time in which said switching action is carried through; and extracting switching-related information from said registered pressure function, said extracting comprising identifying a first pressure peak in said registered pressure function; relating quantities from said first pressure peak to quantities of a first arcing of said switching action; relating said quantities of said first arcing to breaking a first contact of a diverter switch in said tap changer during said switching action; and diagnosing a switching condition associated with said first contact, the switching condition being an error condition when quantities are outside a predetermined interval.