公开(公告)号：EP0787304A1

公开(公告)日：1997-08-06

申请号：EP95935716.0

申请日：1995-10-12

申请人： ABB POWER T & D COMPANY INC.

发明人： CALERO, Fernando

IPC分类号： G06F7 ,  G01R19 ,  G01R25 ,  G01R31 ,  G06F1 ,  H02H3 ,  G01R21

CPC分类号： G01R19/0038 ,  G01R19/25 ,  G01R19/2513 ,  G01R21/133 ,  G01R25/00 ,  G01R31/02 ,  H02H3/003 ,  H02H3/38 ,  H02H3/382 ,  H02H3/385 ,  H02H3/402

摘要： A numerical comparator (20) is disclosed. The numerical comparator (20) employs numerical techniques based upon the behavior of the cylinder unit (18) to compare phasors in real time. In one application of this invention, the torque signal generated by the numerical comparator, Mk+1, is employed to determine whether a fault has occurred in a transmission line. Another application involves employing the output Mk+1 to determine the direction of power flow in the transmission line. In yet another application, the output Mk+1 is used to determine whether a voltage or current has exceeded a predetermined threshold.