Electronic trip device that detects an imminent drop of the power system voltage and comprises a numerical processing circuit and a thermal memory
US5850330A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1997 |
| Grant date | Dec 15, 1998 |
| Priority date | — |
| Expiry date | Jul 29, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H1/06
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The electronic trip device with a thermal memory including a capacitor and a charging resistor arranged in parallel. In normal operation, the capacitor is permanently charged by a supply voltage supplied by the power system to be protected. The trip device includes a processing circuit which performs tripping functions after calculation of a thermal value representative of the thermal state of the power system and detects an imminent drop of the supply voltage. When such a drop is detected, the processing circuit orders discharging of the capacitor until the voltage at the terminals of the capacitor is representative of the calculated numerical value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.