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Title:
GROUND PHASE DETECTOR
Document Type and Number:
Japanese Patent JPH04331413
Kind Code:
A
Abstract:

PURPOSE: To provide a highly reliable ground phase which an arithmetic processing can detector easily be conducted in that can decides a ground phase accurately even if a phase of a zero-phase voltage changes due to an earth resistance at the time of grounding.

CONSTITUTION: This device is provided with line voltage generating devices 33-35 which find line voltages Vbc, Vca and Vab respectively from each of three phase voltages Va-Vc and shift the specified amount of the line voltage and then output it, calculating devices 45-47 which calculate a scalar product of each of the line voltages Vbc, Vca, Vab and a zero-phase voltage Vo, and a comparing device 48 which compares the outputs obtained from the calculating devices 45-47 and decides the practically largest phase is an earth phase.


Inventors:
MORISHITA KAZUO
MATSUMURA KOICHI
ISHIBASHI KOJI
SHIRAISHI KIICHI
Application Number:
JP9882991A
Publication Date:
November 19, 1992
Filing Date:
April 30, 1991
Export Citation:
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Assignee:
TOHOKU DENKI SEIZO KK
TOHOKU ELECTRIC POWER CO
International Classes:
G01R29/00; H01H83/02; H02H3/16; H02H3/34; (IPC1-7): G01R29/00; H01H83/02; H02H3/16; H02H3/34
Domestic Patent References:
JPS6439301A1989-02-09
Attorney, Agent or Firm:
Takehiko Suzue