Title:
【発明の名称】電力ケーブルの絶縁劣化診断法
Document Type and Number:
Japanese Patent JP2742636
Kind Code:
B2
Abstract:
PURPOSE:To sense deterioration in the insulation of a power cable accurately and certainly. CONSTITUTION:The insulation of a cable 3 and an impedance Z3 for sensing the current are connected in series to an AC power supply 1, and a differential amplifier 6 determines the difference of the output of the impedance Z3 from the output from a phase adjuster 5 and a preamplifier 4 through which the output of a parallelly connected voltage divider 2 for sensing of voltage is passed, the result wherefrom gets rid of the fundamental wave by a removing filter 7, and the 3rd higher harmonic is extracted by a band pass filter 8, and indication is made with a voltometer 10 upon passing through an amplifier 9. The degree of amplification K of the preamplifier 4 is varied, and the output at the time of minimum presents the degree of deterioration.
Inventors:
Sakamoto Naka
Nakagawa Masayoshi
Nakagawa Masayoshi
Application Number:
JP27328791A
Publication Date:
April 22, 1998
Filing Date:
September 24, 1991
Export Citation:
Assignee:
Mitsubishi Cable Industries, Ltd.
International Classes:
G01R27/18; G01R31/02; G01R31/12; (IPC1-7): G01R31/12; G01R31/02
Domestic Patent References:
| JP3172777A | ||||
| JP62104170U |
Attorney, Agent or Firm:
Hibiya Masahiko