Audio frequency interface for differential relays
US4878241A · kind A · utility
1Cited by
3References
3Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 3, 1988 |
| Grant date | Oct 31, 1989 |
| Priority date | — |
| Expiry date | Oct 3, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H1/0084
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention interfaces a two-wire 60 Hz circuit to two circuits, each unidirectional, sending and receiving, and carrying frequency modulated audio tones containing the amplitude and phase of the 60 Hz voltage impressed on the 60 Hz circuit. The invention is used to interface differential relays used by electric utilities to detect power transmission line faults to a four-wire voice band communication line.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.