Management experiences from digital relay information and its treatment in the Protection Analysis Center

In recent years many commercial applications of microprocessor-based digital relays have appeared. On 1988 Iberdrola (a Spanish power utility) decided to make some technical specifications about a digital overcurrent relay and a digital distance relay. According to those specifications one type of overcurrent relay and two different distance relays were selected and installed in field. One of the main conclusions after this experience is the need of a dedicated system for the management of the information collected from the digital relays and other equipment (disturbance and event recorder). The results of experiences with the relays in field and the basic features and structure of the system for the automatic treatment of information in the Protection Analysis Center are presented by the authors