A study of loss-of-excitation relaying and stability of a 595-MVA generator on the Detroit Edison system

This paper describes the investigation and evaluation of relationships between loss-of-excitation/field (LOF) relaying and stability of a 595-MVA generator on the Detroit Edison system. Need for the formulation of a plan of action to promote a reliable application of LOF relays is made evident. Operating guidelines are suggested which will safeguard the generator and system from damage during unstable swings while avoiding inadvertent generator tripping during stable swings. In addition, an examination of operating characteristics of a loss-of-field relay in response to changes in voltage and frequency is presented.