Method and apparatus for the detection of short circuits
US3978374A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 6, 1974 |
| Grant date | Aug 31, 1976 |
| Priority date | — |
| Expiry date | Dec 6, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/268
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method for the detection of short circuits in electrical installations, in particular on railway contact wires, comprising generating a measuring signal dependent on the derivative with respect to time of the monitored current, comparing the measuring signal with at least one limit value, determining the time for which the measuring signal exceeds a limit value, comparing the time with a preset time interval, initiating indication of a short circuit when the time for which the measuring signal exceeds the limit value also exceeds the time interval, checking the measuring signal on the occurrence of a decrease following an initial increase and on the occurrence of a subsequent increase, and generating a blocking signal inhibiting indication of a short circuit as a function of the occurrence of such a subsequent increase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.