1. INTRODUCTION 1.1 Scope Determine system and equipment data requirements and discuss suitable data base structures for protection engineering design and steady-state analysis of high-voltage transmission systems, distribution systems, and plant auxiliary power systems. 1.2 Description Computer programs are increasingly being used to organize the data needed for various protection engineering activities and for analyzing, setting, and coordinating protection systems. The working group studied the data required to represent the power network, input sources such as CTs and VTs, and protective devices such as relays, fuses, reclosers, and sectionalizers for the purposes of modeling of equipment and devices. Better modeling will result in improved computer methods for analyzing the protection systems for typical engineering tasks such as application, setting, coordination, and post-mortem analysis of the devices in a protection system. Identifying the detailed data needed to model protective devices and other equipment will help manufacturers to provide all the needed model data, which may otherwise not be available in their catalogs and technical brochures. From a utility point of view, data identification will pave the way for migrating from a "paper-based" protection system and catalog data to a computerized data bank. Once the data gathering is completed, the data will be organized in an orderly structure that would allow a data base expert to design a full-fledged data base for the protection system. With the current state of data base technology, both the Relational and the Object-Oriented models appear to be promising choices for implementation of a protection system database. 1.3 Design Considerations A protective device database can be a very powerful tool for the protection engineer. The design of such a database must take into account several factors. The first consideration is the large number of different protective devices available to perform specified protection functions. A certain type of device may include several models to provide for variations in operating characteristics. In addition, the increased use of microprocessors adds a class of devices to be considered, which includes a large number of functions offered to provide great flexibility in use. Another important concern is for the planned uses of the database. Obviously, having a database as a means of cataloging the device settings is important; but requirements such as standard reports, device placement within the power system, and the need to keep maintenance and other historical data need to be considered also. There are a number of computer programs which serve to assist in the setting calculation, operation checking, or coordination graphics related to protective device coordination work. A database should have a means of interacting with these programs. During the design of a protective device database, the careful consideration of the requirements due to the large variety of protective devices, the eventual uses of the database, and the interaction with other protection computer programs will lead to a highly flexible and powerful design. The information in this publication will assist in this database design.