公开(公告)号：EP1159627A1

公开(公告)日：2001-12-05

申请号：EP99955172.4

申请日：1999-10-27

Applicant: ABB POWER T & D COMPANY INC.

Inventor： BACHMANN, Bernhard ,  HART, David, G. ,  HU, Yi ,  NOVOSEL, Damir ,  SAHA, Murari, M.

IPC: G01R31/08 ,  H02H3/16

CPC classification number: H02H3/40

Abstract: A reach-measurement method used in connection with a series-compensated line of a power system. The series-compensated line includes an installed series capacitance (20) having a bus side and a line side, and a non-linear protection device parallel the installed series capacitance (20). The series-compensated line and non-linear protection device have capacitance voltage thereacross equal the bus side voltage minus the line side voltage. A number of line current samples are measured, where such samples are representative of values of a line current waveform at successive instants of time on the series compensated line. Capacitance voltage values are computed based on measured line current samples in accordance with an equation which accounts for the non-linear protection device parallel to the installed series capacitance (20). A prescribed power system function is performed based on the computed capacitance voltage values.

公开(公告)号：EP1142076A1

公开(公告)日：2001-10-10

申请号：EP99972381.0

申请日：1999-10-27

Applicant: ABB POWER T & D COMPANY INC.

Inventor： BACHMANN, Bernhard ,  HART, David, G. ,  HU, Yi ,  NOVOSEL, Damir ,  SAHA, Murari, M.

IPC: H02H3/26

CPC classification number: H02H3/40 ,  H02H1/04

Abstract: An accurate impedance measurement method for a power system transmission line is disclosed for improving various protection functions, i.e., distance protection and/or fault location estimation. The method is less sensitive to harmonics and other transient problems introduced to power systems by series capacitance and the like, and is easily incorporated into existing protective relays. In the method, a number (n) of current and voltage samples (Ik, Vk) representative of values of current and voltage waveforms are measured, respectively, at successive instants of time on a conductor in a power system. The number n is an integer greater than l and the index k takes on values of 1 to n. Resistance (R) and inductance (L) values are computed in accordance with an equation in which R and L are related to sums of differences in values of successive current and voltage samples. A prescribed power system function is then performed based on the computed R and L values.