Study on the Method of Hot-Line Measuring the High Insulation Resistance of Medium-Voltage XLPE Cable by the DC Superimposition Bridge Method

DOI Web Site Web Site 5 References

Bibliographic Information

Other Title
  • 直流重畳ブリッジ法による高圧 CV ケーブルの高活線絶縁抵抗測定の検討
  • チョクリュウ チョウジョウ ブリッジホウ ニ ヨル コウアツ CV ケーブル

Search this article

Description

The measurement of insulation resistance by superimposing the DC voltage has a large possibility as a means of detecting insulation deterioration. Deterioration signal current in the insulation can be detected from the cable-shield grounding wire, but the earth-current from a cable sheath also flows into that grounding wire as a noise. To detect the deterioration signal current properly, therefore, it is necessary to separate the earth-current from the sheath. On the other hand, to improve detection sensitivity, it is desirable to super-impose the highest possible DC voltage. In this case, provision must be made so that no adverse effects are caused on GPT.<br> With attention paid to the method of measuring high insulation resistance by configuring the bridge, therefore, the authors conducted study on how to detect the insulation deterioration signal with a high accuracy and sensitivity without impairing the functions of GPT. As a result, the following points were identified and, in this paper, the results of these achievements are reported.<br> (1) It is possible to measure insulation resistance as high as 100, 000 MΩ by superimposing DC 50 V through GPT after canceling earth-current and by configuring a bridge for determining insulation resistance from voltage ratio.<br> (2) Even if DC 50 V is superimposed through GPT, it is possible to prevent the magnetic saturation of GPT if the injection current caused by such superimposition is limited (e. g. below max. 5 mA).<br> (3) Provision of a bridge in which variable DC voltage supply is employed in place of variable resistor consequently requires no mechanically driven part, thus making it possible to realize a fully automatic monitoring system.

Journal

References(5)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top