Upgrading the protection of industrial-sized generators using digital technology

This paper presents the reasons why industrial generator owners should consider upgrading the electrical protection of their generators to meet today's standards. It specifically outlines the risks assumed in five functional areas where 20/sup +/-year-old generator protection is inadequate. These areas include negative sequence (unbalanced current) protection, sensitive stator ground-fault protection, sensitive overexcitation protection, inadvertent (accidental) generator energizing, and VT fuse loss protection. It also outlines the need to provide generator oscillographic monitoring. The paper discusses the advantages of digital versus conventional technology for such an upgrade program.