کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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705125 | 891305 | 2008 | 6 صفحه PDF | دانلود رایگان |

The ground wire on top of a H.V. transmission line poses a unique problem when measuring the resistance of pole footings. With a multimeter most of the current is diverted away from the footing and a simple clamp-on type current meter is impractical for poles ranging in diameter from 8 to 32 in. In addition, clamp-on meters typically fail below a few milliamperes but sub-milliampere measurements are required for accurate monitoring of pole footing resistance. A correlator-based sub-milliampere current measurement system using giant magneto-resistive (GMR) magnetic field sensors is reported in this paper. A correlator-based phase insensitive algorithm was used with injected currents at 94 Hz. Experiments conducted on a pole in the laboratory indicate measurement of current values exceeding 1 mA with a standard deviation of less than 2%. Measurements were also performed with current values as low as 0.2 mA with a standard deviation of 16%. Details of the system, correlator algorithm, and results are presented in this paper.
Journal: Electric Power Systems Research - Volume 78, Issue 11, November 2008, Pages 1850–1855