Approaches to generator protection schemes using numerical technology

Over the history of power system protection, improvements have continually been made to all aspects of protection equipment. The most important advances however have been made possible by the introduction of numerical technology. Multiple-function numerical protection relays are currently available from many protection equipment suppliers, providing user configurable inputs and outputs, substation control system interfaces, disturbance recording etc. Suppliers as well as users have always kept the general protection concepts in mind and have implemented the same philosophies with newer approaches containing more features and possibilities. This paper examines the use of these relays from a different point of view. The various approaches available can be adapted to suit the individual requirements of the plant in different ways, in accordance with the experience, philosophy or other factor important to the electric generator protection engineer.