Method for detecting an isolated network
US8035369B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 9, 2008 |
| Grant date | Oct 11, 2011 |
| Priority date | — |
| Expiry date | Oct 7, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02J3/388
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The subject matter of the invention is a method for detecting an isolated network for an inverter (2) carrying a converter voltage that is adapted for connection in parallel with a grid (5) having a mains frequency and electric loads and that is decoupled from the grid (5) by a choke (3), a test signal being superimposed upon the converter voltage at a test frequency the frequency of which is smaller than the mains frequency, the amplitude of the test signal being much smaller than the nominal voltage amplitude of the mains voltage on the one side but still just large enough on the other side for changes in reactive power to be detectable as a result of the test signal, a reactive power share being determined, which oscillates with the test frequency, this share not being allowed to fall below an imposed minimum for an isolated operation to be reliably excluded.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.