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Title:
DIFFERENTIAL PROTECTIVE RELAY SYSTEM
Document Type and Number:
Japanese Patent JP2004304915
Kind Code:
A
Abstract:

To detect a cable failure without installing a device that requires an insulating current transformer or a controlling power supply at an intermediate connecting portion that connects an aerial line and a cable line, and to make easy a harmonious operation with a differential relay for protecting a transmission line.

This system is constituted of a first differential protective relay 11 that obtains a differential quantity by bringing in current signals each obtained at both terminals of a transmission line TL and protects the transmission line, an optical sensor 6 that converts the current signals each obtained from a terminal of the cable line 2 and the intermediate connecting portion into optical signals and outputs the signals, an optical transmission line 7 that transmits the outputs of the optical sensor in cascade, a photoelectric transducing means 15 that outputs the differential quantity of electrical signal out of the optical signals transmitted through the optical transmission line, and a second differential protective relay 12 that protects the cable line by bring in the differential quantity outputted from the photoelectric transducing means.


Inventors:
SAWAI KOICHI
TERAI KIYOHISA
HORI MASAO
TAKAHASHI MASAO
SASAKI KINICHI
Application Number:
JP2003000094893
Publication Date:
October 28, 2004
Filing Date:
March 31, 2003
Export Citation:
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Assignee:
TM T & D KK
TD SYSTEM TECHNOLOGY CORP
International Classes:
H02H3/28; H02G13/00; H02H3/30; (IPC1-7): H02H3/28; H02G13/00; H02H3/30
Domestic Patent References:
JPS49105943A1974-10-07
JP2001050988A2001-02-23
JPH0410533U1992-01-29
JP2002315180A2002-10-25
Attorney, Agent or Firm:
猪股 祥晃
菊池 治
猪股 弘子