Service continuity indices for the Brazilian main transmission network

Power quality has been gaining increasing interest among the different customers in the Brazilian electrical sector. As a consequence one of the many goals fostered by the exclusive and independent system operator in Brazil (ONS - Operador Nacional do Sistema Eletrico) is seeing that the energy supplied at the customer's connection of the transmission network meets the established standards of service. In this context, resolution 024 of the Brazilian electricity regulatory agency (ANEEL - Agenda Nacional de Energia Eletrica), dated January 2000, establishes standard quality indices related to the continuity of electric power supplied by distribution utilities to customer groups. The resolution also establishes continuity indices for the delivery points of the Brazilian main transmission network (connections to distribution and generation utilities, free consumers and international interconnections), which must be registered and published by ONS. The purpose of this paper is to present the main activities coordinated by the ONS in the power quality field with relation to definition, criteria for indices and implementation of the monitoring procedures. The indices used to report the number of interruptions in the period between July 2000 and December 2003 will also be presented.