Quality of supply at the Portuguese Electricity Transmission Grid

Abstract

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.

Failure rates in distribution networks: Estimation methodology and application

“…If a lower number of expected faults in F1 is required, the proposed alternative border point location could be used to shorten feeder F1 at the cost of worsening F2, resulting in 1.909 and 1.712 failures/year respectively. With this methodology, the expected number of faults of a whole distribution network can be obtained and used to assess its quality of supply by estimating the System Average Interruption Frequency Index (SAIFI) during a period of time [3], [14].…”

“…To quantify these concepts, some international quality indexes are widely used, e.g. in [3], such as ENS, AIT, SAIFI, SAIDI, ASAI, and those in [4] - [5] . Other indexes such as TIEPI and NIEPI [6] are also used in countries as Spain.…”

Power Quality of Supply Characterization in the Portuguese Electricity Transmission Grid

“…It provides a public utility service in mainland Portugal, as the Transmission System Operator (TSO). It holds as main functions: the management of technical aspects of the National Electricity System (SEN); the transmission of electricity; the management of the interconnections with neighboring TSO; planning, design, construction, operation and maintenance of the RNT; the identification of needs of new power production centers; the study of potential sites for new generation centers; and the global management of the Electricity System of the Public Service (SEP) [1]. REN, as the concessionaire of RNT, has an important role in the electrical energy quality to the final customer.…”

Coordination and Selectivity of Protection Devices with Reliability Assessment in Distribution Systems

“…For the main current regulations, the concept of reliability in the distribution of electricity is linked to interruptions in energy supply, which may be temporary (momentary) or sustained (permanent) [19]. This can be considered a subgroup of the perturbations that affect the quality of energy, as shown in Figure 3.…”