Upgrading and Retrofitting Utility Protective Relaying Systems Benefits of Upgrading Protective Relaying Systems

A large number of old protection and control (PC maintenance practices and records; obsolescence; visual inspection; industry experience with certain relay types; in-house knowledge; and criticality of failure. However, it is not easy to justify relay upgrades entirely based on age. Reluctance to upgrade to microprocessor relays is further emphasized by complexity associated with increased functionality (e.g. settings), need for firmware upgrades, short life span of computer technology, and overall need to change the protection system philosophy and design. In addition, while digital relays provide wealth of data, utilities may be faced with data overload. It is often the case that even data already available are not used. As the number of old electromechanical relays in the US has passed their useful lifetime, most of the utilities are doing upgrades. Cost justification for comprehensive protection and control upgrade programs comes from combination of various benefits. Those benefits do not result only from replacing relays, but deploying an integrated system using enterprise IT