Method and apparatus for pin-pointing faults in electric power lines
US5608328A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 18, 1994 |
| Grant date | Mar 4, 1997 |
| Priority date | — |
| Expiry date | Nov 18, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R31/085
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
When a fault in an energized power distribution cable flashes over, the surge draws charge from both sides of the line. The fault thus produces a pair of current surges that propagate from the fault in opposite directions along the line. These oppositely-directed current surges create pulsed electromagnetic fields of different directions which, in turn, induce voltages of different polarities in a receiving antenna positioned along the line. The polarity of the first such voltage pulse induced in the antenna indicates the direction from the antenna to the fault. In one embodiment, the line is repeatedly "thumped," causing flashovers to recur at the fault. By moving the antenna along the line until the polarity of the initial received pulse inverts, the precise location of the fault can be determined. In another embodiment, direction-indicating fault current indicators according to the present invention are permanently placed at numerous locations in an operating AC power distribution system, in anticipation of a fault. When a fault occurs, the polarity of the first received electromagnetic fault pulse at each device indicates the respective direction from the device to the fault.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.