Quality of supply at the Portuguese Electricity Transmission Grid

The energy market's liberalization has contributed to an increase of responsibility on the transmission and distribution system operators to achieve the standards established by the respective regulatory entities in order to guarantee the highest quality of supply to the consumers. This paper describes the evolution of the Portuguese National Electricity Transmission Grid (RNT), the results achieved in the last years, the grid's reability and availability, and also some necessary measures taken in a perspective of quality of supply improvement.