Third phase reconstruction from a two current transformer sensor with three-phase true RMS and phase loss determination capabilities
US5777835A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 30, 1997 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Jun 30, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H3/083
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and apparatus are disclosed to reconstruct a third phase for a three phase sensing system in which only two current transformers sense all three phases. Two phases of the three phase system are used as a single primary winding for each current transformer such that each current transformer produces a voltage representation of a sum of two phase currents. The present invention is directed toward reconstructing the third phase from the two discrete signals produced so that true RMS characteristics can be determined, as well as indicating any phase loss. Since all three phases can then be represented, this technique offers precise phase imbalance protection as well.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.