Under the pressure of the ecological transition, electricity is more and more crucial for the sustainable economic and social development of cities. Energy flows are increasing in city distribution networks, and Distribution Systems Operators (DSOs) are constantly looking for new solutions to meet customer demands. Local flexibility services based on Distributed Energy Resources (DERs), including Electric Vehicles (EVs) have emerged as a possible solution in recent years. The paper presents a study focused on the EVs charging hub of Unareti SpA, the DSO of the city of Milan. The aim of this study was to determine the hub's possible role and contribution to the Demand Response (DR) services of the elctricity network. The impact of the charging load, the potential services and a possible energy optimization are evaluated and discussed in detail, based on real data measured during two summer months.
In this paper, the problem of upgrading an electric urban distribution network is considered. Although network planning has attracted considerable attention in the field of power systems since the early 1970s, the urban distribution network of Milano (Italy) shows significant and challenging peculiarities. Due to historical reasons, there are two separate distribution networks, previously operated by two different companies, which grew up independently and in an uncoordinated way. Therefore, this paper will present a MILP approach for planning a new network configuration, called H-shaped layout, which optimally integrates the two networks already in place. In order to validate the mathematical model, computational results using a part of the whole distribution network is presented in this paper.
Electrical distribution networks are going through a phase of significant changes from both technical and regulatory points of view. For example, load and coincidence factors change due to the high penetration of distributed generators and loads such as electric vehicles, heating, ventilation, and air conditioning systems, induction stoves, and customer behavior changes. Furthermore, many countries are introducing performance-based regulations, pushing distribution system operators to be more aware of selecting investments to improve the system efficiency and the quality of service for customers. In order to do that, distribution network planners should find best practices to evaluate ex-ante the main critical issues and periodically update the status and benefits of investments. In this paper, a risk index is proposed to estimate the reliability of distribution grids. Using a suited algorithm, automatic calculation of the index has been carried out on Milano's medium voltage distribution network, a city in the north of Italy, showing its correlation with the traditional reliability indices. Moreover, benchmark values for the index are given as well as some suggestions for reliability improvement.
Electric power systems are moving toward more decentralized models, where energy generation is performed by small and distributed power plants, often from renewables. With the gradual phase out from fossil fuels, however, Distribution Energy Resources (DERs) are expected to take over in the provision of all regulation services required to operate the grid. To this purpose, the opening of national Ancillary Service Markets (ASMs) to DERs is considered an essential passage. In order to allow this transition to happen, current opportunities and barriers to market participation of DERs must be clearly identified. In this work, a comprehensive review is provided of the state-of-the-art of research on DER integration into ASMs. The topic at hand is analyzed from different perspectives. First, the current situation and main trends regarding the reformation processes of national ASMs are analyzed to get a clear picture of the evolutions expected and adjustment required in the future, according to the scientific community. Then, the focus is moved to the strategies to be adopted by aggregators for the effective control and coordination of DERs, exploring the challenges posed by the uncertainties affecting the problem. Coordination schemes between transmission and distribution system operators, and the implications on the grid infrastructure operation and planning, are also investigated. Finally, the review deepens the control capabilities required for DER technologies to perform the needed control actions.
Access to electricity is nowadays considered a necessity to health and human dignity. Most of the people who do not have access to electricity are located in remote rural areas, where electrification costs are often prohibitively high. Due to the relevant investments, planning and operation require new strategies and tools to be developed capable to manage effectively the problem's specificity. Geographic Information Systems (GIS) have significant potential for contributing to the necessary geospatial analyses and visualization methods for awareness-building and decision support for distribution networks planning and operation. Using a real study case in the municipality of Chacas, Peru, the paper presents the valuable advantages of using GIS systems in the DSO's daily tasks. On the one hand, GIS is valuable for developing accurate databases, improving internal efficiency in power supply monitoring, commercial and customer services. On the other hand, GIS is handy for essential functions like network analysis, facility management, load management, theft detection. In particular, the paper details the Chacas distribution network conversion procedure from traditional support to the GIS model and some network analysis examples to highlight the benefits of the GIS-based models in power systems.
The local environmental concerns and the decarbonization process favored by European and national policymakers drive the spread of new technologies, such as electric heating/cooling systems, residential photovoltaic generators, and electric mobility. Since these new equipment are mostly connected to the MV and LV levels of the electricity network, their widespread implementation will substantially impact electric distribution systems planning an operation. The analysis of future development scenarios and the impact of new control techniques are, therefore, preparatory for the evolution of the planning and operation of electric networks, specifically the distribution networks. The simulations reported in this paper integrates the network data, including a georeferenced description of the distribution network, with external public databases information. Thanks to the proposed approach, the impact of the new equipment can be studied considering different scenario hypotheses investigating the evolution of the distribution network in detail. In particular, the methodology is applied to the distribution network of Brescia, a city in Northern Italy.
Nowadays, Distributed System Operators (DSOs) are facing more and more difficult challenges in meeting the user needs with an increasing overall power demand, at the same time guaranteeing the required level of reliability. A possible solutions is offered by the Demand Response (DR) management, aiming to reduce the total load demand of the distribution system during peak periods in order to maintain the integrity of the network and stability of the whole system. The paper analyses different scenarios based on real data from the distribution grid of Milan (Italy), evaluating benefits and costs of DR implementation in three different plants, to solve problems related to feeders congestion, power losses, and voltage drops, through either the scheduling or remote control of distributed resources. Moreover, load shape considerations suggests the possibility to integrate in the system a higher share of photovoltaic (PV) generation, of which the effects on DR are also evaluated in the paper.
The growing demand for improved quality of service increases the importance of network automation. This allows improving the fault isolation and reconfiguration time and therefore increasing the system quality of service. Since the investment in remote-controlled switch (RCS) devices comes at a cost, this study proposes a heuristic approach to solve the problem of optimal siting RCS devices in distribution systems. For doing that, RCS devices are located to improve the reliability of the system based on the optimal open ties deriving from the distribution network (DN) reconfiguration problem. A Genetic Algorithm has been developed to optimise the radial layout of the DN taking into account the reliability of the system. As a measure of the system reliability, the authors use a risk index which is expected to well estimate, based on the statistical data available, the system average interruption frequency index. The risk index is based on two parameters: the length of the feeders, which measures the failure probability, and the number of customers, which measures the failure impact. The solution approach has been tested on a real distribution subsystem of Milano.
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