Protection system for a three-phase distribution transformer insulated in a liquid dielectric
US5898556A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 3, 1997 |
| Grant date | Apr 27, 1999 |
| Priority date | — |
| Expiry date | Apr 3, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H5/08
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A protection system for a three-phase distribution transformer immersed in a liquid dielectric contained in a tank, at least two of the three phases being equipped on the high voltage side of the transformer with respective current-limiting fuses. On each of the two phases equipped with current-limiting fuses, a protective micro-fuse is also connected in series with the current-limiting fuses and which operates faster than the current-limiting fuse. In addition, each micro-fuse is associated with a striker which, in turn, is connected to a mechanical trigger system which causes a three-phase short-circuiting device connected across the three phases to close in the event of a micro-fuse operating. Furthermore, the system includes at least one fault detector detecting one of pressure in the tank or the level of the dielectric. In particular, the three-phase short-circuiting device is situated on the high voltage side of the transformer between the current-limiting fuses and the high voltage windings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.