Voltage Control in Active Distribution Grids: A Review and a New Set-Up Procedure for Local Control Laws

Planning, operation and control of active distribution grids by increasing the number of dispersed generators is becoming more important but also more complex. Hence, the importance of controlling the voltage is highlighted in many research papers. Traditionally, in passive distribution networks the voltage rise has been mitigated by network reinforcement. Nowadays, local voltage control, coordinated voltage control and centralized voltage control have been discussed for active networks in research papers. Although all the approaches have been proven to solve the problem of voltage rise in distribution grids, using plenty of sensors to gather huge number of measurement could cause complexity. This paper represents a literature review of different voltage control approaches in active distribution grids and proposes a new procedure to set up a local voltage control law devoted to properly manage the voltage profile (e.g. minimizing losses on MV feeders)

Distributed Storage for the Provision of Ancillary Services to the Main Grid: Project PRESTO

AbstractThis paper presents the three-year PRESTO research project (2013-2015). PRESTO is a self-funded project developed by the Department of Energy of Politecnico di Milano in cooperation with FIAMM Storage, Elvi Energy and MCM Energy Lab (an Italian spin-off). Within the project, experimental tests and numerical simulations were performed in order to evaluate the effectiveness of an Energy Storage System (ESS) in the provision of ancillary services to the main grid. This paper focuses specifically on the experimental and numerical analyses carried out in the project to develop an innovative control law for the primary frequency regulation, able to maximize the performances of the regulating service and effectively manage the ESS state of charge

Hosting Capacity Analysis: A Review and a New Evaluation Method in Case of Parameters Uncertainty and Multi-Generator

The rapid growth of distributed energy resources exploitation can cause voltage violations and overloading on distribution grids due to the uncontrolled and unprogrammable power injections associated with dispersed generators. To overcome these issues, distributed system operators have to evaluate the maximum generation that can be hosted by distribution grids without violating the technical constraints and find the ways to increase it. In this paper, different methodologies for hosting capacity evaluation are reviewed, and a novel model to determine the hosting capacity considering grid parameters uncertainties and multi-generator connection is proposed

MANAGEMENT OF ELECTRIC VEHICLES CHARGING PROCESSES IN A DSO CONTROL CENTER

ABSTRACT Today, it is well known that the Electri

Participation of Aggregated DERs to the Ancillary Services Market: A Monte Carlo Simulation-Based Heuristic Greedy-Indexing Model

In an effort to improve the stability and secure operation of the grid, regulatory bodies are opening Ancillary Services Markets participation to Distributed Energy Resources (DERs), energy storage systems, and demand response. Within this framework, this study proposes a model that simulates the coordinated operation of an aggregate of power plants, including non-dispatchable DERs and, as regulating units, Combined Heat and Power (CHP) generation and electrochemical energy storage systems. A Monte Carlo procedure is adopted to realistically create a population of aggregation scenarios. The real-time operation of the DER portfolio is managed through a Heuristic Greedy-Indexing logic, which allows the Aggregator to select the optimal control action to implement according to the technical and economic quantities characterizing the market and the grid. The techno-economic performance of the proposed algorithm is evaluated by simulating its interaction with the electricity markets. Finally, a sensitivity analysis is performed to analyze the profitability in different scenarios. The novel mathematical model proposed showed to be effective in managing a complex problem like the one at hand with an acceptable computational effort. The numerical results obtained confirmed that the aggregated participation in the market could provide interesting economic returns, especially if a CHP unit is involved as regulating unit, while the feasibility of the batteries adoption is still limited by the actual cost of the technology

Data-Driven Evaluation of Secondary- and Tertiary-Reserve Needs with High Renewables Penetration: The Italian Case

The diffusion of nonprogrammable power plants, together with the decommissioning of conventional, rotating generators, is increasing the need for flexible resources to always ensure the safe and secure operation of the European electric-power system. Beyond technological advances, policy aspects also play a fundamental role in the opening of electricity markets to new players; in this regard, System Operations Guideline EU 2017/1485 and Italian Regulatory Authority documents require the Italian transmission-system operator (TSO; Terna) to publish all exploited algorithms and methodologies for the management of market balancing. In this context, the present paper develops and presents a data-driven methodology to estimate secondary and tertiary reserve needs; a numerical real-life case study, focused on the North Italy geographical zone, is presented. Data for 2017, 2018, and 2019 on electricity consumption and production (forecasted and actual) were gathered. Following the European TSOs Organization (ENTSO-E) and the Italian TSO (Terna) prescriptions, methodology for the calculation of reserve needs was developed. Results are presented under graphical form and refer, among others, to spinning and nonspinning reserve duration curves, forecast error contribution to reserve calculation, and samples considered for analysis. While a comparison with available market observations is not very helpful, results suggest that the developed methodology could be useful for the evaluation of reserve needs in different control areas

Distribution networks' observability: A novel approach and its experimental test

The work presents an approach devoted to improving the observability of distribution systems with a high share of Renewable Energy Sources. The proposed method, developed according to the prescriptions of Italian Resolution 646/2015/R/eel, but designed to be applied in any modern power system, provides the delivery to the Transmission System Operator of real-time estimates of the overall generation downstream an HV/MV substation. The estimation process is based on the real-time monitoring of a limited set of power plants, completed by the acquisition of weather nowcast and energy measures collected on users through the standard Automatic Meter Reading infrastructure. The approach, tested on two real Italian distribution networks, and benchmarked against an Artificial Neural Network based approach, showed a good accuracy, allowing the provision of useful information to the TSO through a simple and easy to implement architecture

Power Systems' Resilience Against Ice Sleeves: An Assessment Methodology Tested in the Smart City Vizze Project

In recent years, climate changes caused an increase of violent and wide-ranging meteorological events, often with significant effects on the power systems continuity of service. Moreover, evolutions of users' habits and the increasing dependence on the electric energy carrier are motivating the request for a more and more reliable power supply. In this framework, the work presents a methodology aimed at evaluating the resilience of electric distribution grids against interruptions due to the ice and snow sleeves accretion on overhead lines. The approach proposed is applied to the MV network supplying the Vizze Valley, managed by the Italian DSO Edyna, and represents an essential step to perform a selection of the corrective actions to be implemented on the network according to their expected benefits and costs