Trip unit providing short circuit zone location detection, electrical switching apparatus and system including the same
US8514531B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2012 |
| Grant date | Aug 20, 2013 |
| Priority date | — |
| Expiry date | Mar 21, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H1/0076
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A trip unit includes a current sensor to sense a value of current flowing through a conductor, a circuit to receive first frequency pulses having a number of first frequencies from the conductor, a transmitter to transmit second frequency pulses having a second frequency different than the first frequencies to the conductor, and a processor having a routine. The routine inputs the sensed value of current from the current sensor, determines if the sensed value of current exceeds a predetermined value and responsively causes the transmitter to transmit the second frequency pulses having the second frequency to the conductor, monitors within a predetermined time after determining that the sensed value of current exceeds the predetermined value if a number of the first frequency pulses having the number of first frequencies is received by the circuit, and responsively delays outputting a trip signal, and, otherwise, immediately outputs the trip signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.