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Patent Searching and Data


Title:
DETECTING CIRCUIT FOR CURRENT OF PROTECTIVE RELAY
Document Type and Number:
Japanese Patent JPH0526908
Kind Code:
A
Abstract:

PURPOSE: To obtain a detecting circuit of a current of a protective relay which conducts detection of the current with high precision and, in addition, can make the whole processing operation fast by enabling execution of other arithmetic processings in the course of A/D conversion by sampling for detection of the current.

CONSTITUTION: A comparator circuit 11 provided with an amplitude determining circuit for an input signal and outputting an A/D conversion processing instruction signal to an arithmetic processing circuit 9 only when the input signal is larger than a prescribed value is interposed between an input terminal of an A/D conversion circuit 8 and the arithmetic processing circuit 9, and an input processing wherein execution of A/D conversion is controlled to be made or not according to an output value of the comparator circuit 11 and other arithmetic processings are executed within the time when an A/D conversion processing is not executed is conducted. An A/D converter of which the processing speed is low and which is inexpensive is used for the A/D converter 8 for inputting a current and the same high-speed processing as executed when high-speed A/D conversion is used is conducted, while the function of a protective relay can be improved.


Inventors:
BABA SADAAKI
Application Number:
JP1991000184602
Publication Date:
February 05, 1993
Filing Date:
July 24, 1991
Export Citation:
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Assignee:
MITSUBISHI ELECTRIC CORP
International Classes:
G01R19/00; G01R19/165; H02H3/02; H02H3/08; (IPC1-7): G01R19/00; G01R19/165; H02H3/02; H02H3/08
Attorney, Agent or Firm:
Mamoru Takada (1 person outside)