Stefano Lauria

Stefano Lauria
Sapienza University of Rome | la sapienza · Department of Astronautics, Electrical and Energetics Engineering DIAEE

PhD

About

135
Publications
52,499
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1,480
Citations
Additional affiliations
November 2000 - present
Sapienza University of Rome
Position
  • Professor (Assistant)

Publications

Publications (135)
Article
Meshed HV subtransmission networks are subject to undesirable parallel (unscheduled) active power flows from the EHV system. The phenomenon is worsened by conversion of HV overhead lines to underground cables (UGCs), which increases parallel flows through the HV network because of the attendant reduction in HV line reactance; the effect increase wi...
Article
Full-text available
A growing interest in offshore wind energy in the Mediterranean Sea has been recently observed thanks to the potential for scale-up and recent advances in floating technologies and dynamic cables: in the Italian panorama, the offshore wind connection requests to the National Transmission Grid (NTG) reached almost 84 GW at the end of September 2024....
Article
The paper proposes an analytical approach to evaluate the effects of series compensation of an overhead transmission line (OHL) concerning the increase of (1) loadability and (2) practical loading of the line. The first part of the paper focuses only on the line characteristics, and proposes an analytical approach to determine the loadability curve...
Article
This paper investigates the reduction of Cross-Country-Faults currents in medium voltage (MV) cable networks in order to decrease thermal stress of cable screens, especially inside joints. Four methods are analyzed: 1) disconnection of cable screens from the earth electrode of primary substation (PS); 2) buried ground wire laid near the cable lines...
Article
Full-text available
In recent years, the explosion of renewable energy sources, the increase in the demand for electrical energy, and several improvements in related technologies have fostered research in many relevant areas of interest [...]
Article
The paper investigates the use of the Clarke transform in time-domain simulations, namely the evaluation of transient overvoltages in medium voltage (MV) distribution networks. A simplified Clarke equivalent circuit can be set up using readily available symmetrical components data used in steady-state studies, such as line series impedances and the...
Article
The paper presents a technical/economic feasibility study of the adequacy of a 100% renewable power system. The study relies on a hybrid nodal/zonal linear DCOPF formulation, developed by the authors in order to study years-long time frames of power system operation on an hourly basis. The formulation sizes and operates a 100% renewable generation...
Article
The successful application of the Single-Pole Autoreclosure (SPAR) to Extra-High Voltage (EHV) overhead lines (OHLs), as well as to the overhead portion of EHV mixed cable-overhead lines (MLs), significantly improves system stability. SPAR success requires that the secondary arc self-extinguishes during the dead time: according to the literature, s...
Article
This paper investigates a real complex power system supplied by a 100% renewable generation, focusing on the primary frequency regulation. The grid and the power production park are represented by means of an electro-mechanical model in a free open-source environment. The lack of synchronous generators in the grid, due to the conventional power pla...
Article
MV distribution networks with ungrounded or grounded neutral by compensating impedance are exposed to Cross-Country-Faults (CCFs). If CCFs occur in cable lines, fault current value can reach that of line-to-line fault current. This is because the large part of the fault current flows through cable screens and only a small amount through grounding s...
Preprint
Full-text available
In this letter we propose a generalized branch model to be used in DC optimal power flow (DCOPF) applications. Besides AC lines and transformers, the formulation allows for representing variable susceptance branches, phase shifting transformers, HVDC lines, zero impedance lines and open branches. The possibility to model branches with concurrently...
Article
Full-text available
A significant majority of overhead transmission lines’ (OHLs) outages is due to backflashovers caused by direct lightning strikes: the realistic assessment of the lightning performance is thus an important task. The paper presents the analysis of the lightning performance of an existing 150 kV Italian OHL, namely, its backflashover rate (BFOR), car...
Article
The use of diesel generators to supply electricity to small remote islands is both costly and environmentally troublesome. On the other hand, small island networks pose peculiar stability and reliability problems when renewable energy sources are added. The paper regards the installation of an hybrid power plant (phortovoltaic, PV, plus lithium bat...
Conference Paper
Full-text available
BOLOGNA 2016 2 SUMMARY The paper deals with the comparison of the estimated lightning performances of a typical 132 kV overhead line in a flat zone of Northern Italy, using different ground flash data from different LLSs and from the former Italian (CEI 81-3:1999) database, which was partly based on thunderstorm days, and different lightning parame...
Article
Full-text available
A Cross-Country Fault (CCF) is the simultaneous occurrence of a couple of Line-to-Ground Faults (LGFs), affecting different phases of same feeder or of two distinct ones, at different fault locations. CCFs are not uncommon in medium voltage (MV) public distribution networks operated with ungrounded or high-impedance neutral: despite the relatively...
Article
This paper deals with the arc-flash hazard calculation in large energy storage systems (ESSs), with specific reference to battery energy storage systems (BESSs) and supercapacitor energy storage systems (SESSs). Due to the lack of international harmonized standards and the growing use of large ESSs, the evaluation of arc-flash hazard associated wit...
Conference Paper
Full-text available
The paper deals with the protective relaying of MV rings recently introduced by e-distribuzione, the largest Italian Distribution System Operator (DSO). The paper refers to an existing MV distribution system which includes a loop line. Attention is focused on CrossCountry Faults (CCFs), i.e. two Line-to-Ground Faults simultaneously occurring in two...
Technical Report
Full-text available
The aim of this comprehensive Technical Brochure is to be a valuable document for reference by any Utility, Government agency or Investor looking to put in an underground system in lieu of an overhead line, or a long length of submarine cable, particularly in terms of appreciating what can be done or has been done.
Article
Reliability and quality analyses play an important role in defining the structural and operative characteristics of the system and in setting reliability and maintainability specifications, which could assure that service quality requirements will be met. The paper illustrates a methodology for the prediction of service quality of a high-speed rail...
Article
Full-text available
This paper presents an experimental application of LiFePO4 battery energy storage systems (BESSs) to primary frequency control, currently being performed by Terna, the Italian transmission system operator (TSO). BESS performance in the primary frequency control role was evaluated by means of a simplified electrical-thermal circuit model, taking int...
Conference Paper
The paper addresses the statistical simulation of the backflashover performance of an Italian 150 kV–50 Hz mixed overhead-cable subtransmission line, focusing on direct lightning strokes to the overhead-cable transition tower. An ATP-EMTP-based Monte Carlo procedure, developed by the authors, has been applied to assess the backflashover rate (BFR)...
Article
The paper presents the study of the behaviour of a real MV public distribution network in a mid-size in Italy, characterized by a very large amount of distributed generation (DG), reaching 100% of supplied network load. A parametric steady-state analysis of operating regimes was carried out, considering different load and DG scenarios (maximum and...
Article
The paper deals with train traffic operation in degraded conditions due to failure events of transportation systems components. An optimization algorithm, implemented in a computer procedure, able to minimize delays in case of scheduled constant train headways is first illustrated. The procedure can be applied for simulating and optimizing railway...
Conference Paper
Full-text available
The recently commissioned Malta-Sicily interconnector is at present time the longest (120 km) HV ac cable line (CL) in the world. The 245 kV-50 Hz XLPE insulated cable line includes a 19.1 km long underground stretch in Sicily, connecting the Ragusa terminal station to the landfall in Marina di Ragusa, and a 99.5 km submarine cable to the Maghtab t...
Conference Paper
Full-text available
In the last years, high penetration of distributed generation (DG) has strongly affected public MV networks. In order to improve their reliability and availability, loop operation is being tested. This solution requires the installation of new line protection devices and the identification of appropriate settings against phase-to-phase and ground f...
Conference Paper
The paper reports a voltage quality studies about integrate power system architectures in an all-electric ship. Two layout are considered: a medium voltage AC system and a “Hybrid” system which includes DC subnetworks. All-electric military vessels are characterized by a high power electric propulsion and high penetration of non-linear and impulsiv...
Article
This study presents a cost comparison between commercially available high-voltage DC (HVDC) and extra highvoltage AC shore connection (±320 kV voltage source converter and 420 kV-50 Hz single-core and three-core cables), for a 1 GW offshore wind farm cluster, considering transmission distances up to 400 km. The HVDC system is a point-to-point conne...
Article
Full-text available
The paper deals with the impact of subsequent strokes on the backflashover rate (BFOR) of HV overhead transmission lines (OHLs), assessed by means of an ATP-EMTP Monte Carlo procedure. The application to a typical 150 kV Italian OHL is discussed, simulating three different tower grounding system arrangements. Subsequent strokes parameters are added...
Article
The undergrounding of HV subtransmission networks in urban/suburban areas is bound to increase fault currents, especially for ground faults if system neutral is solidly grounded. A parametric fault analysis based on symmetrical components is applied to a sample HV system with three lines and two EHV points of supply, based on a simple meshed Italia...
Article
Fast charging station will play a key role in the widespread diffusion of electric vehicles in large cities. Large public parking areas, such as park-and-ride or commercial centres equipped with fast recharge infrastructure will require dedicated grid connections to the HV transmission grid, due to the significant installed power. The interaction b...
Article
This paper presents a technical/economic comparison between remedial measures aimed at improving the lightning performance of an existing Italian 3-phase 150 kV overhead line. The line is characterized by a very high backflashover rate (BFOR), due to large grounding resistance values. Two countermeasures are proposed: grounding system improvement w...
Conference Paper
The overall efficiency of battery electrical storage systems (BESSs) strongly depends on auxiliary loads, usually disregarded in studies concerning BESS integration in power systems. In this paper, detailed electrical-thermal battery models have been developed and implemented in order to assess a realistic evaluation of the efficiency of NaS and Li...
Conference Paper
Prediction of the potential threats due to direct lightning strokes of sensitive targets, e.g., overhead power-line towers, substations or buildings, requires accurate modeling of the transient impedance of grounding systems. When large-scale simulations are needed, detailed and computationally intensive models are hardly viable, although they usua...
Conference Paper
HVDC technology is a key driver for the integration of renewable energy sources (RES) in large transmission systems. However, the displacement of conventional thermoelectric power plants due to RES development can hinder safe operation of LCC-HVDC converters, especially during inverter operation, mainly due to the reduction of short circuit power o...
Conference Paper
A double-circuit line using commercially available 400 kV-50 Hz three-core XLPE-insulated submarine cables is considered for the evacuation of up to 1 GW offshore wind generation. Three transmission distances are studied, namely 80 km, 100 km and 160 km, evaluating conventional (line-end) as well as mid-line shunt compensation. Operating envelopes...
Conference Paper
The paper deals with the integration of ATP-EMTP models representing grounding system nonlinearities and corona effect in a wider overhead line (OHL) model, for the main purpose of backflashover (BFO) transient simulations. All towers of the simulated 10 km stretch (25 spans) of a typical 150 kV - 50 Hz Italian OHL have been equipped with a pi-type...
Article
The paper presents the application of an ATP-EMTP Monte Carlo procedure for backflashover rate (BFOR) evaluations to HV overhead lines (OHL), equipped with three different types of spatially extended and/or geometrically involved tower grounding systems. The ATP-EMTP circuit model of the OHL includes detailed line insulation and lightning represent...
Article
The paper presents a new approach to optimal exploitation and reactive power control of long inhomogeneous HV ac cable lines, such as submarine interconnectors including significant land cable stretches. Voltage and reactive power profiles are discussed, highlighting the requirements for full exploitation of power transmission capacity, and giving...
Conference Paper
Full-text available
An innovative design of a device embedding the functions of both power transformer and shunt reactor is presented. The device is thought for installation onboard substation platforms of long HV/EHV AC cable connected off-shore wind plants. The compact design saves much space on the hosting offshore platform, which can be sized smaller and cheaper....
Conference Paper
The recent availability of XLPE-insulated, 400 kV-50 Hz submarine cables, in single- or three-core construction, suggests to investigate the ac shore connection of GW-sized offshore wind-farm (OWF) clusters. The paper discusses some basic features of a 200 km long 400 kV-50 Hz cable system, connecting to the grid three large OWFs with 2 GW total ca...
Conference Paper
The paper describes the design and implementation of a new protection system consisting of a permissive overreach (PO) pilot relaying scheme with directional overcurrent relays for both phase and ground faults supporting closed-loop operation in MV network; attention is focused on ground fault relaying of loop networks operated with ungrounded or c...
Article
Il crescente interesse nelle interconnessioni tra stati e nelle centrali eoliche offshore ha portato a significativi miglioramenti nella tecnologia dei cavi sottomarini ad alta tensione. L’articolo tratta le caratteristiche tecnologiche e le problematiche di sistema tipiche dei collegamenti elettrico sottomarini nel mare Mediterraneo, esaminando i...
Article
The paper deals with the steady-state operation of a radial EHVAC cable transmission system with multiple power injection points, e.g. offshore wind farms, and variable shunt compensation. Generator voltages and variable compensation settings are determined by means of a power flow-based algorithm, aiming at symmetrical current magnitude profiles a...
Conference Paper
The growing interest in international interconnection lines as well as offshore-located energy generation has led to the improvement of high voltage submarine transmission technology. The paper deals with the technology and system challenges typical of submarine cable links in the Mediterranean Sea. Recent developments in HVDC converters technology...
Article
Due to the increasing public resistance against erection of new overhead lines, transmission utilities have to consider installation of large number of HV/EHV AC cable lines in their networks. Some of these cable lines are of very long length, even in the range of 100 km. Such long cables most likely require installation of reactive power compensat...
Conference Paper
Full-text available
Operational experience with extruded HV and EHV cable systems is now more than 15 years. In recent years the amount of cables in transmission networks is experiencing a fast growth [1] due to the increasing number of submarine interconnections (i.e. offshore windfarms) or because of environmental constraints. Cable modelling is an actual task in el...