Method for initializing short time and groundfault protection heat index accumulators in a trip unit
US6097192A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 1998 |
| Grant date | Aug 1, 2000 |
| Priority date | — |
| Expiry date | Mar 5, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H6/005
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method of initializing short time and groundfault protection heat index accumulators to compensate for current flow during the time interval between the application of phase current and application of current measurement and protection algorithms in an electronic trip unit is presented. The electronic trip unit includes a microcontroller and associated ROM having trip unit application code, e.g., main functionality firmware, including initializing parameters, and boot code, stored therein and EEPROM having operational parameter code, e.g., encoded enumerations for parameters such as 50/60 Hz., UL/ANSI/IEC, etc., stored therein. The time internal comprises first and second time components. The first time component is the time between the instant phase currents are applied and the instant the microcontroller is initialized and the second time component is the time between the instant the microcontroller is initialized and the instant the microcontroller begins execution of short time and groundfault algorithms (i.e., protection algorithms). The first time component is approximated by applying an initial current measurement to index a calibrator. The second time component is measure…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.