Integrated metering and protective relay systems-large drive motor applications

Fully microprocessor based multifunction protective relay systems, which can improve the quality of classical protection functions and reduce the cost per function, are discussed. The feasibility and reliability of such units is demonstrated through full-scale testing with saturated circuits and through operating experience with field installations. The author covers distribution fault records, relay performance with extremely saturated low-ratio circuits, and advanced methods of protecting high-inertia drive motors.<<ETX>>