Demagnetization circuit for current transformers
US4456875A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 10, 1982 |
| Grant date | Jun 26, 1984 |
| Priority date | — |
| Expiry date | Feb 10, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R35/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to a method and a system for measuring residual flux in current transformers. The system comprises a controlled circuit for generating two voltage levels for switching the current flow in the transformer. The switching circuit is connected to one current transformer winding and causes the induction to vary from the residual flux level to a saturation level through successive switching of the current when the voltage is applied across the winding terminals. A processing unit receives a first signal delivered by the switching circuit, such signal being representative of the induction variation for a time corresponding to the time period of the voltage. The processing unit further receives a signal representative of the induction variation caused by the application of the voltage for a second time period. The unit determines saturation levels corresponding to a positive variation and a negative variation of the induction as a function of the residual flux and generates a signal which corresponds to the residual flux of the current transformer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.