In this Learning-Doc the learner should be able
describe use of the one-line diagram, functionality of the protective relays
and how the generator may be at risk.
Discussions include discussions of the information contained on a
one-line diagram, use of the R-X diagram, and shutdown considerations. Abnormal conditions described include stator
over-current, over voltage, a stator ground, phase-to-phase fault protection,
volts-per-hertz protection, field over-excitation, field ground, loss of
excitation, negative phase sequence currents, loss of synchronism, abnormal
frequency operation, inadvertent energization, reverse power, and use of a
distance relay. Each abnormal condition
description includes the risk to the generator, instrumentation used, description
of the protective relay function, and actions to be taken.