公开(公告)号：US20210048470A1

公开(公告)日：2021-02-18

申请号：US16991637

申请日：2020-08-12

Applicant: ABB Schweiz AG

Inventor： Zoran Gajic

IPC: G01R31/08 ,  G01R31/52 ,  H02H1/00

Abstract: A method for determining direction of an earth fault (EF) in a feeder of a high impedance grounded power system can be performed by an Intelligent Electronic Device (IED). The method includes obtaining a measure of a first order harmonic active current component derived from residual voltage and current of the feeder when the EF occurred in the feeder, obtaining a measure of a higher order harmonic reactive current component derived from the residual voltage and current of the feeder when the EF occurred in the feeder, and determining the direction of the EF in the feeder based on a combination of the first order harmonic active current component and the higher order harmonic reactive current component.

公开(公告)号：US10962604B2

公开(公告)日：2021-03-30

申请号：US16528076

申请日：2019-07-31

Applicant: ABB Schweiz AG

Inventor： Stefan Roxenborg ,  Zoran Gajic ,  Tord Bengtsson ,  Mikael Sehlstedt

IPC: G01R31/50 ,  G01R27/18 ,  G01R31/34 ,  H02H1/00 ,  H02H3/17 ,  H02H7/06

Abstract: An arrangement for injection-based ground fault protection handling including a number of stator windings of an electric machine that are connected to a neutral point, a first transformer including at least one primary winding connected to at least one measurement point of the stator windings and at least one secondary winding for measuring an electrical quantity of the machine at the measurement point. There is also a second transformer having a primary winding connected between the neutral point and a ground potential and a secondary winding for connection to a signal generation and detection unit in order to inject a signal into the neutral point and receive a response. The impedance of the second transformer is in the range of the impedance of the machine.

公开(公告)号：US10254155B2

公开(公告)日：2019-04-09

申请号：US15509156

申请日：2014-09-05

Applicant: ABB Schweiz AG

Inventor： Tord Bengtsson ,  Zoran Gajic ,  Stefan Roxenborg

IPC: G01H1/00 ,  G01R31/34 ,  G01M15/12 ,  G01M15/14 ,  G01H1/10

Abstract: A monitoring device and a method for detecting mechanical torsional oscillations in a rotor shaft of a turbine-generator system. Specifically, the monitoring device and a method for detecting mechanical torsional oscillations in a turbine-generator system having a plurality of, such as two, three, four, five, six or more, turbines that are interconnected by means of a common turbine shaft.