Giacomo Petretto

Analysis of the Italian distribution system evolution through reference networks

This paper presents initial results of a three-year research project entitled ATLANTIDE, which is aimed at developing a comprehensive digital archive of reference models of Italian distribution networks, including forecasted load and generation development evolving towards future smart grid scenarios. Such reference network models and evolutionary scenarios should provide a useful benchmark for testing and comparing different control methodologies, distribution schemes and operation strategies for dealing with the new challenges caused by the envisaged widespread diffusion and integration of distributed generation, renewable generation and distribution storage devices. The paper focuses on the criteria adopted for defining a set of evolutionary scenarios for the reference networks, accounting for current drives and future trends, valuable to a wide range of the stakeholders of the distribution business.

Preliminary analysis of MV cable line models for high frequency harmonic penetration studies

The large penetration of distributed generation requires accurate line and cable models in a frequency range much wider than the classical interval, 0–2.5 kHz, used for traditional harmonic and interharmonic penetration studies. In the paper, the behavior of MV cable lines is considered in the frequency range from 0 to 100 kHz, with reference to a casestudy. Models base on the classical Π and Γ line equivalent circuits are considered. Reference is made to open and short circuited line input terminals conditions. A comparison of the performances of different complexity models, in terms of impedance magnitude accuracy at output terminal, is developed.

A Solid Oxide Fuel Cell model to investigate load following and stability issues in distribution networks

The increase of DG penetration in the distribution networks makes more and more interesting the investigation of security issues which are typical of the large transmission grids (transient stability, voltage stability and small signal stability) as well as the study of the DG responses to load changes in the grid. This paper presents the model of a Solid Oxide Fuel Cell (SOFC) dedicated to perform dynamic simulations on MV distribution networks. In particular in the present paper transient stability and load following issues are tackled. The first part of the paper is aimed at describing the model of the SOFC which is then used in the test system. As also a gas turbine is inserted into the test system, a brief look at the gas turbine model is mandatory. The aforementioned models include both the slow dynamics (GT prime mover, electrochemical system time constants for SOFC) necessary to study the DG response to load variations and the fast dynamics (e.g the power converter control and protection systems for SOFCs) necessary to study the transient stability related issues. The results of the analysis (carried out on a test MV distribution network) are reported and some conclusions are drawn.

Representative distribution network models for assessing the role of active distribution systems in bulk ancillary services markets

Nowadays, renewable energy sources feed significant shares of energy demand, resulting in a reduction of market energy price but also a significant increase of expenditures for ancillary services due to inherent not complete predictability and programmability. Thus loads and generation in the distribution network are more and more required to play an active role in supporting grid stability by participating to ancillary service markets, either directly or through aggregators. The paper presents a novel procedure to estimate distribution networks capabilities to support grid stability, by making use of synthetic representation of HV/MV substations and their relevant distribution networks with a GIS based clustering procedure. The impact of active distribution networks to the bulk ancillary service market is then evaluated by applications to the Italian electric system and by assuming different regulatory frameworks for transmission/distribution network market interactions.

Application of ATLANTIDE models to harmonic penetration studies

This paper presents some of the results of a three-year research project entitled ATLANTIDE, which is aimed at developing a comprehensive digital archive of reference models of Italian distribution networks, including forecasted load and generation development evolving towards future smart grid scenarios. The paper focuses on the models developed for harmonic penetration studies and on how the results of these models can be included in the multi-objective optimization approach used by the Distribution Management System model developed in ATLANTIDE.