Internal armature current monitoring in large three-phase generator
US4689546A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 1985 |
| Grant date | Aug 25, 1987 |
| Priority date | — |
| Expiry date | Dec 18, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K2203/09
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A three-phase generator includes an internal neutral junction to which one end of each of the windings of the generator is connected thereby forming a wye-connected generator. An air-core current transformer is disposed over each of the three conductors leading to the internal neutral junction for monitoring neutral current therein. A corresponding air-core current transformer is disposed over high-voltage terminals connected to the other ends of the generator windings. A shielded differential amplifier on the output of each air-core current transformer produces a signal corresponding to the difference between two bifilar half windings in its associated air-core current transformer. The difference currents from the neutral and high-voltage ends of each generator winding are compared, and, if their difference exceeds a predetermined threshold, a threshold circuit produces a trigger signal which is latched by a latching relay to produce a trip signal for use by the generator control system. Connectors are provided for isolating two of the three generator windings from the internal neutral junction to enable isolated testing of the three windings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.