Research Papers in Physics and Astronomy


Microprocessor-Based Protective Relays Deliver More Information and Superior Reliability With Lower Maintenance Costs

Roger D. Kirby, University of Nebraska-Lincoln
Ron Schwartz, Schweitzer Engineering Laboratories

Document Type Article

Published ©2006 IEEE. Permission to use.


The benefits in performance (sensitivity and speed), reliability (security, selectivity, and dependability), availability, efficiency, economics, safety, compatibility, and capabilities of microprocessor multifunction protective relaying (MMPR) technology over the previous existing technologies, namely electromechanical and solid-state, are explored. The suggested typical values, quality measurements, and analysis of protective relaying performance, reliability, and unavailability are intended to be a recommendation of what could be used as a benchmark in our industry.

This paper will be useful to consulting engineers, industrial and commercial electric power plant engineers, and OEM engineers that are interested in doing reliability and unavailability predictions for industrial electric power distribution systems that employ MMPR equipment. Furthermore, this paper should assist those making MMPR technology cost-versus-reliability decisions when performing facilities studies to evaluate and improve the system reliability and/or capacity of an existing plant.