Patent Number: 6,297,645

Title: Device for sensing partial discharges in test objects, preferably a cable joint

Abstract: A device for sensing discharges in a test object (1) with two electric connection conductors (1a, 1b, 1c, 1d), preferably a cable joint, comprises at least one first and one second sensor (2a, 2b) and evaluation equipment (EVU). Each one of the sensors generates and supplies to the evaluation equipment sensor signals in dependence on current pulses through the connection conductors and the direction thereof, the first sensor a first sensor signal (v1) and the second sensor a second sensor signal (v2). The evaluation equipment generates in dependence on received sensor signals an indication signal (IND), indicating a partial discharge in the test object. The device comprises a first tuning unit (T1) associated with the first sensor and a second tuning unit (T2) associated with the second sensor, each unit, in dependence on the respective sensor signal, forming a first filter signal (SF1) and a second filter signal (SF2), respectively, periodically oscillating with a preselected period (TP), as well as a multiplying member (MU), which is supplied with, and in dependence on said filter signals, forms a product signal (SP), whereby the evaluation equipment forms the indication signal in dependence on the product signal.

Inventors: Eriksson; Thomas (Uppsala, SE), Johansson; Kenneth (Vaster.ang.s, SE)

Assignee: ABB Research Ltd.

International Classification: G01R 31/12 (20060101); H01H 031/12 ()

Expiration Date: 10/02/2018