Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4878142 | High resistance ground fault protection | Sten Bergman | 1989-10-31 |
| 4864453 | Protective relay with selective phase selection for double lines | Sten Bergman | 1989-09-05 |
| 4855861 | Longitudinal differential protection | Sten Bergman | 1989-08-08 |