Application considerations of static overcurrent relays-a working group report

The technology of static overcurrent relays has developed very rapidly in the past few years. These developments have produced changes from electromechanical relays in the way they are applied, and further, offer many new features to provide greater utilization than possible previously. A Working Group of the Medium Voltage Subcommittee of the Power Systems Protection Committee began examining the impact of these developments several years ago. This report documents the results and describes the nature of the changes and the new areas of application. It is presented acknowledging the fact that this is really an interim report, since static relay technology is a very dynamic technology with many more innovations yet to be developed.