Title:
DISTRIBUTION LINE REMOTE SUPERVISORY AND CONTROLLING EQUIPMENT
Document Type and Number:
Japanese Patent JPH01152932
Kind Code:
A
Abstract:
PURPOSE:To find faults early by detecting arc noises generated in the case of a contact fault in a switch. CONSTITUTION:Three phase voltage to ground is divided into phase voltage of a distribution line respectively by capacitors 1Ca-1Cc and 2Ca-2Cc, and three phase voltage is added by means of an adder '+' to obtain zero phase voltage V0. Based on the output V0 of the adder subtraction '-' between a signal through a BPF passing commercial frequency and a signal of the output V0 of the adder is made, and the commercial frequency component contained in the residual zero phase voltage of a system is removed. The output signal V1 of a subtractor '-' is an arc-noise component generated in the case of a contact fault in a power switch. A level decision of the subtractor output signal V1 is made by a level detection comparator C, and the noise detection output is obtained. In other words, at least one phase switch among three phase switches is detected to be in an incomplete contact fault.
Inventors:
SAKO EIZABURO
NAKAMURA MITSURU
MIYAZAKI TERUNOBU
NAKAMURA MITSURU
MIYAZAKI TERUNOBU
Application Number:
JP30963587A
Publication Date:
June 15, 1989
Filing Date:
December 09, 1987
Export Citation:
Assignee:
HITACHI LTD
International Classes:
H02J13/00; H02H7/00; H04B3/54; (IPC1-7): H02H7/00; H02J13/00; H04B3/54
Attorney, Agent or Firm:
Katsuo Ogawa (2 outside)
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