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The deepening penetration of distributed energy resources into distribution networks (DNs) is causing relevant issues to be addressed by distribution system operators (DSOs), such as quality of service, security and safety, both at medium-voltage and low-voltage distribution levels. This paper presents how Unareti SpA, an Italian DSO, has addressed those challenges launching a set of research activities in different areas of distribution automation. Results collected during field experiences have been used to design the reference model of the next generation of DN secondary substations. [ABSTRACT FROM PUBLISHER]

This paper presents the problem of power penetration of photovoltaic (PV) systems in urban networks. After a qualitative problem description, two different environments for PV systems have been analyzed: rural and urban networks. Concerning the rural network, a single line has been simulated in order to evaluate the relation between the number of PV systems installed along the line and the maximum PV power installable. In the second part of this paper, possible problems due to power penetration have been examined concerning a clustered PV system that will be installed in the city of Torino (Italy) within the ambit of the EU project called POLYCITY. [ABSTRACT FROM AUTHOR]

This paper deals with power system restoration and discusses the connection of pumped storage loads to restoration paths. This new strategy allows avoiding any disturbance to customers during field tests of restoration paths and improves as well the reliability of restoration plans. The first application of the new strategy concerned the field test of a new path in central Italy. This paper reports the test and analyzes the main novel features of the considered path: complete separation from subtransmission and distribution networks and use of pumped storage loads during its energization. These aspects and their consequences are discussed with reference to both field testing of restoration paths and effectiveness of system restoration. [ABSTRACT FROM AUTHOR]

The Italian regulatory authority is working toward the introduction of voltage-quality regulation. To this end, it initiated a power-quality measuring campaign and a study of customer costs. This paper summarizes the main results of these activities and provides evidence that economic losses due to very short interruptions and voltage dips can be very relevant for several sensitive industrial sectors in Italy. Despite the fact that these losses present an uneven distribution over the national economy, their magnitude justifies the intervention of a regulatory authority to limit the number of the most severe events. Nonetheless, the identification of severe events (those that fall under the responsibility of the network operator) is a difficult task. Using the available data, we test the classification table proposed in the latest version of the European Standard EN 50160 and confirm, albeit preliminarily, the usefulness of this classification for regulatory purposes. [ABSTRACT FROM AUTHOR]

In the analysis of reliability performance of distribution utilities, as well as in continuity of supply regulation, criteria are needed for separating normal operation data from exceptional events. In recent years a number of statistical methodologies has been proposed for this purpose. We present here the new methodology that was adopted by the Italian regulatory authority at the beginning of 2008. The decision is supported by a statistical analysis of the number of faults on the medium voltage (MV) and low voltage (LV) networks, for each six-hour time interval in a three year time span, for different provinces and distribution companies. The new methodology is employed in the reward and penalty mechanisms that regulate the SAIDI, SAIFI, and MAIFI indicators and, with some original provisions, also in the Guaranteed Standard on maximum restoration times. [ABSTRACT FROM AUTHOR]