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Ac Impedance Measurements Used to Locate Faults in Mining Power Cables.

Authors
Hammer-R; Conroy-GJ
Source
NTIS: PB 275 815 :19 pages
Link
NIOSHTIC No.
10001158
Abstract
Various alternating current (ac) methods can localize faults in mining power cables. Several methods considered by the Bureau of Mines in this report are the murray loop for short circuits, wherein a bridge provides proportional distance to the fault; capacitance measurements for open conductors; inductance measurements for shorted conductors; phase comparison, high speed recordings of voltage and current in the faulted state are compared with normal voltage and current with the difference being a function of impedance change and impedance change being a function of fault location; and standing wave measurements, detecting the resonance of the length of cable to a fault (either short or open). Portable capacitance bridges are presently available for the second method, and the fourth method is well developed for use on large power distribution systems. Because it utilizes pulses rather than ac, the time domain reflectometer (tdr) method of fault locating was not included in this investigation. However, a comparative evaluation between this versatile method and the murray loop might prove advantageous in locating high resistance faults.
Publication Date
19770101
Document Type
IH; Report of Investigations
Fiscal Year
1977
NTIS Accession No.
PB-275815
NTIS Price
A03
Identifying No.
RI 8257
NIOSH Division
PRC;
Source Name
NTIS: PB 275 815
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