Mill benefits from upgrading generator protective relaying

Electrical generation at paper mills is becoming an increasingly critical asset and should be well protected from faults, system upsets and abnormal operating conditions. The loss of a major generating unit for an extended period would result in very costly replacement power and repair costs for any paper mill. This paper presents the reasons why mill generator owners should consider upgrading the electrical protection of their generators to meet today's standards. It specifically outlines the risks assumed in protection areas where 20 plus-year-old generator protection is inadequate. The paper relates the experience of completed protection upgrade projects at Westvaco's Luke, Maryland mill where 1960-vintage electromechanical relays were replaced with modern digital protection. The paper points out the advantages of this technology versus conventional electromechanical protection, and also discusses the unique application considerations in applying digital protection.