Papers by Alfredo Vaccaro
Smart Grids and Sustainable Energy
The integration of low carbon technologies and more efficient power system operation are key comp... more The integration of low carbon technologies and more efficient power system operation are key components in the transition to a sustainable future. To support this, power system operators are leveraging data from an ever-expanding network of sensors. Due to their ability to measure several different physical parameters, fiber optic sensors are recognized as an important enabling technology and offer many interesting opportunities to improve situational awareness in power systems. This paper presents an extensive overview of fiber optic sensors in power system applications, with particular focus on the needs of the power system sector and how these may change as the system continues to evolve. The intention is to provide the reader with a review that clearly discusses the current and future trends in power system sensors applications and connect these to the most recent developments in fiber optic sensor technology.
2022 AEIT International Annual Conference (AEIT), Oct 3, 2022
Energies
The growing attention to environmental issues is leading to an increasing integration of renewabl... more The growing attention to environmental issues is leading to an increasing integration of renewable energy sources into electrical grids. This integration process could contribute to power system decarbonization, supporting the diversification of primary energy sources and enhancing the security of energy supply, which is threatened by the uncertain costs of conventional energy sources. Despite these environmental and economical benefits, many technological and regulatory problems should be fixed in order to significantly increase the level of penetration of renewable power generators, which are connected to power transmission and distribution systems via power electronic interfaces. Indeed, these converter-interfaced generators (CIGs) perturb grid operation, especially those fueled by non-programmable energy sources (e.g., wind and solar generators), affecting the system stability and making power systems more vulnerable to dynamic perturbations. To face these issues, the convention...
2019 IEEE Milan PowerTech
This paper presents a novel optimal power flow (OPF) based approach for post-contingency manageme... more This paper presents a novel optimal power flow (OPF) based approach for post-contingency management of severe congestions, aimed at maximizing lead time available to the network operators before the next contingency occurs. The approach first computes the maximum allowed overloading times for the congested transmission lines and transformers, using their dynamic thermal models. Afterwards, the OPF analysis is performed to identify the maximum lead time available to the network operator for managing post-contingency constraints and for devising and implementing the most efficient corrective actions. The corresponding OPF problem is modelled as a mixed-integer nonlinear optimization problem and solved using mixed-discrete particle swarm optimization (MDPSO) approach. The approach is illustrated on a modified IEEE 14-bus network and obtained results demonstrate that presented approach can manage considered constraints within the available lead time.
SSRN Electronic Journal
Rising wind energy integration, accompanied by a decreasing level of system inertia, requires add... more Rising wind energy integration, accompanied by a decreasing level of system inertia, requires additional sources of ancillary services. Wind turbines based on doubly fed induction generators (DFIG) can provide inertial and primary frequency support, when equipped with specific controls. This paper investigates the effect of frequency support provision by DFIGs on the small-signal stability of power systems. To this end, a modified version of the Kundur two-area test system is employed to analyze different scenarios. Wind energy generation is either added to the existing system or displaces part of the synchronous generation. Simulations show that primary frequency support tends to improve the damping of electromechanical oscillations and deteriorate it for converter control-based ones. On the other hand, inertial response may be either beneficial, detrimental or negligible to damping, depending on the tuning of control parameters.
2017 IEEE Manchester PowerTech, 2017
Optimal power flow (OPF) and security-constrained OPF (SCOPF) studies are important tools for bot... more Optimal power flow (OPF) and security-constrained OPF (SCOPF) studies are important tools for both planning and operation of power supply systems. Conventional gradient-based SCOPF methods are commonly used for that purpose, but when analysed system is overstressed with severe multiple contingencies, conventional SCOPF methods may fail to converge. In such cases, meta-heuristic SCOPF methods can be used to identify “critical constraints” and help the convergency of conventional methods. As the time available for devising emergency control actions is typically limited, the paper first evaluates computational performance of used meta-heuristic SCOPF method (particle swarm optimization method) and then demonstrates how a suitable handling of constraints, i.e. penalization of objective function, can improve efficiency and practical value of the solutions found by the meta-heuristic SCOPF method. This approach is denoted as “time-constrained SCOPF analysis” and is illustrated by consider...
IEEE Transactions on Sustainable Energy, 2021
Wind energy is one of the most promising resources for the mitigation of greenhouse gas emissions... more Wind energy is one of the most promising resources for the mitigation of greenhouse gas emissions that contribute to anthropogenic global warming. However, the large proliferation of wind power generators is causing several critical issues in power systems due to their variable power generated profiles. For this reason, a large number of learning techniques, e.g. integrating Vector Auto-Regressive and Neural Network-based models, were proposed in the literature for mitigating wind power uncertainty issues. Unfortunately, these methodologies show several limitations, e.g. the huge number of parameters and/or the heavy computational cost, which hinder their deployment in modern power system operation, where prompt and reliable wide-area wind power generation forecasts are requested for supporting time-critical decision making on several time horizons. To try addressing this issue, this paper proposes the Dynamic Adaptive Feature-based Temporal Ensemble (DAFT-E) forecasting approach, which relies on an extensive feature engineering, a fast feature selection step and an ensemble of computationally inexpensive models to reduce the computational complexity of the forecasting task, while still preserving predictive accuracy. The experimental results, which benchmark DAFT-E against multivariate (VAR and deep learning) alternatives on two real case studies, show that the proposed approach outperforms state-of-the-art and representation learning models according to several forecasting accuracy metrics.
2016 AEIT International Annual Conference (AEIT), 2016
Cyber Physical Power System (CPPS) has been recognized as the most promising enabling technology ... more Cyber Physical Power System (CPPS) has been recognized as the most promising enabling technology for integrating and coordinating computing, networking, and physical processes according to a holistic vision of the transmission system. In CPPS, the network components and the computing entities cooperate in order to collect pervasive electrical and meteorological data, identifying suitable control actions, and adapting the grid controllers parameters. In solving these critical issues, meteorological and lighting forecasting represents a relevant issue to address, as they allow a reduction of outages and disturbances in the power system. Armed with such a vision, in this paper an autonomic CPPS framework, which explicitly integrates dynamic thermal models, adaptive estimation techniques, and weather forecasting algorithms is conceptualized. Validity and effectiveness of the proposed framework is experimentally assessed on a real-life 150 kV equivalent section of the Italian power system.
2021 AEIT International Annual Conference (AEIT), 2021
The main purpose of the Working Package 5 of the H2020 Optimal System-Mix of flexibility Solution... more The main purpose of the Working Package 5 of the H2020 Optimal System-Mix of flexibility Solutions for European electricity (Osmose) project is to develop an advanced Energy Management System (EMS), which allows the Transmission System Operators (TSOs) to reliably manage distributed Renewable Energy Sources (RES) and grid congestions, by properly coordinating innovative flexibility resources which include Dynamic Thermal Rating (DTR) and Demand Side Response (DSR). In this context, Ensiel, a consortium of Italian universities active in power systems research, developed a new DTR solution, which is based on a self-organizing sensor network composed by cooperative smart nodes deployed along the line route, having as final output the loadability curve of the line. This paper presents the first experimental results obtained by deploying this new DTR method on a real operation scenario, demonstrating the improved performance and effectiveness of the proposed method.
2020 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe), 2020
This paper presents a multi-stage optimal power flow (OPF) approach for efficient management of c... more This paper presents a multi-stage optimal power flow (OPF) approach for efficient management of contingencies, in which dynamic thermal models of overhead lines and power transformers are used to evaluate maximum lead time (MLT) available to network operators to resolve violated post-contingency constraints. At the first stage, optimal settings of volt-var controls, such as transformers with on-load tap changers and shunt capacitors, are selected, taking into account voltage-dependent load models. The second stage provides optimal generation re-dispatch, including fast-start generators. At the final third stage, optimal load shedding is implemented to clear all remaining constraint violations. The OPF problem is solved by a hybrid metaheuristics method and illustrated on a modified IEEE 14-bus network. Obtained results demonstrate that presented method can help network operators to efficiently resolve all violated constraints within the available MLT.
He is presently with VIT University as an associate professor. He is a Senior Member-IEEE with 31... more He is presently with VIT University as an associate professor. He is a Senior Member-IEEE with 31 published articles in peer-reviewed journals and 77 works in national and international conferences. His area of interest includes deregulation and restructured power systems under smart grid environments, electric vehicles, and issues related to distribution system studies.
International Journal of Electrical Power & Energy Systems, 2021
An electric arc-furnace is a complex industry which demands high levels of electrical energy in o... more An electric arc-furnace is a complex industry which demands high levels of electrical energy in order to heat iron materials and other additives needed for the production of cast iron and/or steelmaking. The cost of the electrical energy demanded by the factory during the production can be greater than 20% of the overall cost. This kind of arc-furnace allows the production of steel with levels of scrap metal feedstock up to 100%. From an electrical point of view, the factory size in terms of its maximum apparent power demanded from the grid is designed to make use of the static capacity of the transmission line that supplies the energy. In that case, it is not possible to increase the power of the factory above the static rating by adding new facilites without installing new transmission infrastructures. This paper presents a methodology that allows an increase in net power of an arc-furnace factory without installing new transmission lines. The novelty of the proposed solution is based on a mix strategy that combines Demand-Side Management (DSM) methodologies and the use of ampacity techniques according IEEE 738 and CIGRE TB601. The application of DSM methodologies provides an improvement in the sustainability of not only the industrial customer but also in the overall grid. As a secondary effect, it reduces operational costs and the greenhouse gas emissions. The proposed methodology has been tested in an arc-furnace factory located in the North of Spain.
The Journal of Engineering, 2019
The large penetration of wind generators in existing electrical grids induces critical issues tha... more The large penetration of wind generators in existing electrical grids induces critical issues that are pushing the system operators to improve several critical operation functions, such as the security analysis and the spinning reserve assessment, with the purpose of mitigating the effects induced by the injected power profiles, which are ruled by the intermittent and notprogrammable wind dynamics. Although numerous forecasting tools have been proposed in the literature to predict the generated power profiles in function of the estimated wind speed, further and more complex phenomena need to be investigated in order to take into account the effects of the forecasting uncertainty on power system operation. In order to deal with this issue, this paper proposes a probabilistic model based on Markov chains, which predicts the wind power profiles injected into the grid, considering the real generator model and the effects of the power curtailments imposed by the grid operator. Experimental results obtained on a real case study are presented and discussed in order to prove the effectiveness of the proposed method.
Electric Power Systems Research, 2019
Large-scale integration of variable and unpredictable renewable-based generation systems poses si... more Large-scale integration of variable and unpredictable renewable-based generation systems poses significant challenges to the secure and reliable operation of transmission networks. Application of dynamic thermal rating (DTR) allows for a higher utilisation of transmission lines and effectively avoids high-cost upgrading and/or reinforcing of transmission system infrastructure. In order to efficiently handle ranges of uncertainties introduced by the variations of both wind energy sources and system loads, this paper introduces a novel optimization model, which combines affine arithmetic (AA) and probabilistic optimal power flow (P-OPF) for DTR-based analysis of transmission networks. The proposed method allows for the improved analysis of underlying uncertainties on the supply, transmission and demand sides, which are expressed in the form of probability distributions (e.g. for wind speeds, wind directions, wind power generation and demand variations) and related interval values. The paper presents a combined AA-P-OPF method, which can provide important information to transmission system operators for evaluating the trade-off between security and costs at a planning stage, as well as for selecting optimal controls at operational stage. The AA-P-OPF methodology is illustrated for a day-ahead planning, using a case study of a real transmission network and a medium size test distribution network.
Electric Power Systems Research, 2017
In the last years, dynamic thermal rating assessment of overhead lines has gained a critical impo... more In the last years, dynamic thermal rating assessment of overhead lines has gained a critical importance in power system operation, since it allows transmission system operators to reliably increase the exploitation of existing infrastructures, avoiding the construction of new transmission assets, and increasing the hosting capacity of renewable power generators. Amongst the possible approaches that can be adopted to solve the thermal estimation problem, the one based on synchrophasor data processing is considered as one of the most promising enabling technologies, since it does not require the need for deploying dedicated sensing technologies distributed along the line route, but only the availability of synchronized measurements already available in the control centers for supporting wide area power system applications. Anyway, the deployment of this technology in real operation conditions is still at its infancy, and several open problems need to be addressed, such as the accuracy drop in low loading conditions, and the need for properly representing and managing the data uncertainties in the thermal estimation process. In trying to address these issues, this paper presents a comprehensive analysis of the most promising solution methods proposed in the literature, evaluating their performances on a real case-study based on a thermally constrained power transmission line located in the north of Italy.
Wide area monitoring, protection and control systems: the enabler for smarter grids
Smart grids are considered as one of the most effective answers to the need of reliable, economic... more Smart grids are considered as one of the most effective answers to the need of reliable, economic, and sustainable electricity services. The smart grids are conceived as a fusion of the energy, information, and communication infrastructures, which is obtained by designing integrated management and protection tools, able to handle heterogeneous and complex problems ranging from network optimization to security issues. In particular, issues such as grid efficiency improvement, flexible load supply, demand side management, emission control, and optimal network regulation can be addressed by a smart management system, which aims at acquiring and processing the available set of information describing the actual smart grid operation state. As easily understandable, this computing process is a very complex and time-intensive task, since it requires the periodic estimation of the power system state, the analysis of the massive data streams generated by the grid sensors and the repetitive solution of large-scale optimization problems, which are complex, nonlinear, and NP-hard problems. Moreover, in order to provide the grid operators with updated information to better understand and reduce the impact of system uncertainties associated with load and generation variations (e.g., in solar and wind power sources), the required computation times should be fast enough [1].
IEEE Transactions on Industrial Informatics, 2016
Synchronized sensing offered by wide area measurement systems (WAMSs) enables advanced investigat... more Synchronized sensing offered by wide area measurement systems (WAMSs) enables advanced investigations on modern electrical power systems not performable before their advent. One of them is overhead lines (OHL) temperature monitoring, which can be implemented in WAMS industrial domains thanks to the availability of newly accessible sensing information provided by phasor measurement units (PMUs). To accomplish this task, a proper sensing-based integrated intellectualization is necessary in order to face with the major WAMS issues and challenges. In line with these considerations, this paper proposes an advanced computing framework for real-time conductor temperature monitoring of fully transposed OHLs that is able to overcome the aforementioned challenges and issues. The validity and effectiveness of the conceptualized solution is verified via field tests on an Italian transmission line currently in operation. The obtained outcomes led the Italian Transmission System Operator (TSO) to equip its own Energy Management System (EMS) with the deployed solution.
2015 IEEE 1st International Forum on Research and Technologies for Society and Industry Leveraging a better tomorrow (RTSI), 2015
The paper addresses the problem of Dynamic Line Rating (DLR) estimation for OverHead transmission... more The paper addresses the problem of Dynamic Line Rating (DLR) estimation for OverHead transmission Lines (OHLs) in the context of Wide Area Monitoring Systems (WAMSs). DLR is universally recognized by experts from academia and industry as one of the most viable solution for a reliable exploitation of the real power systems thermal loadability margins. In this domain, the large quantity of synchronized data acquired by WAMSs allows to design effective solution frameworks for DLR assessment. To address this issue, various technical challenges, and many open problems, mainly deriving by the non-idealities characterizing the real working domain, should be fixed. Armed with such a vision, this paper, starting from a comprehensive analysis of the role of synchronized data in OHL DLR estimation, proposes practical and viable solutions aimed at addressing some of the open problems in WAMS based DLR. Experimental findings obtained from in-field investigations on a real life OHL, are presented and discussed in order to prove the effectiveness of the proposed techniques.
2015 AEIT International Annual Conference (AEIT), 2015
In this paper a computational paradigm based on self-organizing smart sensor networks is proposed... more In this paper a computational paradigm based on self-organizing smart sensor networks is proposed for addressing the problem of dynamic thermal rating prediction of overhead lines. The main idea is to decentralize the entire set of thermal rating processing and synchronization functions on a network of interactive smart sensors. The resulting computing architecture is expected to exhibit several advantages over traditional paradigms as far as built-in synchronization features, "in field" processing capabilities, less hardware complexities, less communication network requirements, easy to extend and reconfigure are concerned. Detailed results obtained on a real overhead line currently operating in the Italian power system are presented and discussed in order to prove the effectiveness of the proposed methodology.
Renewable and Sustainable Energy Reviews, 2016
Pakistan is among the naturally gifted countries that are rich in conventional and renewable ener... more Pakistan is among the naturally gifted countries that are rich in conventional and renewable energy resources. Despite the massive potential of energy resources, Pakistan is still an energy deficient country and have to import petroleum products to barely accomplish its energy demand. Geothermal energy is still one of the unexplored energy resources for electric power generation in Pakistan. Pakistan can overcome the energy shortage to a significant level by harnessing renewable energy resources, such as, geothermal energy. Majority of the geothermal hot springs and mud volcanoes exists within the seismic belt of Pakistan. Therefore, the country has viable geothermal energy manifestations. Several hot springs in Gilgit and Hunza region are originated due to the collision of Indian Plate with Eurasian Plate. Similarly, various geothermal reservoirs exist in Northeast to Southeast narrow belt along Indus basin margin. The survey discusses the current energy crisis in Pakistan and addresses the role of geothermal energy for the economic development of Pakistan. We served the manifestation and geographies of geologically active zones of Pakistan, like fault lines, plate tectonics, belt, and tectonic thrust, cleanest, base load, reliable, renewable, and sustainable geothermal energy resources. In our work, the hot springs and mud volcanoes of geologically active areas in maps are enlisted in Tables with potential features. The schemes used for extraction of geothermal energy for electric power generation are also investigated. The global electric power production from geothermal energy is visualized and discussed. Moreover, the suitable moderate temperature Binary Cycle Geothermal Power Plant for electric power generation in Pakistan is also described in detail. Furthermore, geothermal plants are experimentally summarized in different case studies. Finally the performance of geothermal and conventional thermal plants is critically analysed.
Uploads
Papers by Alfredo Vaccaro