Generator characteristics and their influence on relaying

This paper describes the design constants of large generators and their influence on protective relaying. The detailed nature of machine impedances, fault currents, the phasor diagrams for round-rotor and salient pole machines, saturation curves and the causes of overvoltage. The aggravated influence of unbalanced currents, and the relationship of the connected system to the generator grounding scheme are reviewed. Also, unique schemes for detecting stator and field grounds are described.