Many electric utilities use computer databases to store their relay data. The database naturally gives access to many users, coordinates modifications, and generates the necessary reports for different purposes. The relay database must accommodate a wide variety of protective devices. Users of a relay database include relay engineers, relay technicians, system operators, and other field personnel. Information wanted by these users takes the form of setting sheets, test forms, and substation reports. We conducted an informal survey of relay databases in use at different utilities and found that the readability of the forms and reports varies greatly from one database to another. The term readability here refers to the ease with which the relay information can be viewed and updated by humans and by computer programs. The readability and effectiveness of a relay database hinge on the underlying data organization. This article describes several existing relay database designs and their advantages and disadvantages, and features a new database model that has proven to be flexible and easy to use and can accommodate a wide variety of relay types. >