1,721,084 research outputs found
Safe Working Procedures for Electric Vehicle Maintenance
Full text linkThe surge in Electric Vehicle (EV) adoption marks a crucial shift towards sustainable transportation solutions driven by environmental concerns. EVs offer various advantages, including reduced emissions, enhanced energy efficiency, and quieter operation. However, the EVs are also affected by faults and crashes, requiring personnel to repair them. Currently, no International, American, or European Standard is dedicated to work activities on EVs. This paper addresses the regulatory gap by examining the properties of the EVs, the risk sources, and the available standards related to generic electrical installations, or EV emergency scenarios. The study proposes suggestions for workshop setup, organizational procedures, and operational protocols to ensure safety during EV maintenance activities. Moreover, the processes of evaluating and managing the electric risks are presented for a real case study, in which technicians replace cells in a battery pack of an electric bus
Electric Vehicles Maintenance: Recommendations for a Safe Work
No full textThe surge in Electric Vehicle (EV) adoption marks a crucial shift towards sustainable transportation solutions driven by environmental concerns. EVs offer various advantages, including reduced emissions, enhanced energy efficiency, and quieter operation. However, also the EVs are affected by faults and crashes, and therefore require personnel to repair them. Currently, there is not an International or European Standard dedicated to work activities on EVs. This paper addresses the regulatory gap by examining the properties of the EVs, the risk sources, and the available standards related to generic electrical installations, or EV emergency scenarios. The study proposes suggestions for workshop setup, organizational procedures, and operational protocols to ensure safety during EV maintenance activities
An Analytical Procedure to Identify a Global Earthing System
Full text linkGlobal Earthing System (GES) is defined by international standards IEC 61936-1 and EN 50522 as an equivalent Earthing System (ES) created by the interconnection of local ESs. Thanks to this interconnection, just a percentage of the total fault current is injected to ground in a single ES, with a significantly reduction of touch voltages in case of fault. If a GES is officially certified, the procedure to verify the effectiveness of an ES can be simplified, with advantages in terms of time and money. Unfortunately, Standards do not provide any practical guidelines to identify a GES. In this work, a methodology is proposed for MV network with the neutral point isolated from ground. A practical example is provided
A Web-Based Georeferenced Model of the Urban Traction Electrification System in Turin
Full text linkTransport accounts for approximately 25% of Green House Gas emissions in Europe, with urban road transport being a major contributor to air pollution. Decarbonizing urban transport is essential, particularly as over 70% of Europeans reside in urban areas. Strengthening public transport, the most sustainable travel option for large populations, is a key strategy. This article focuses on urban tramways, formed by the urban traction electrification systems and electric public transport vehicles. A digital twin approach is proposed to improve the operational activities of tramways, aiming to optimize system design, enhance maintenance, improve reliability, and unlock unused infrastructure potential, such as using the tramway infrastructure for off-peak charging stations. This article presents the methodology adopted to develop the model of the tramway in Turin, Italy. This step is a milestone to implement the tramway digital twin. Moreover, this article presents the validation process of the model, which was carried out through a comparison with both simulated and field measurement data
Large N.G. explosion and fire involving several buried utility networks
Full text linkThis paper describes an accident (explosion and natural gas fire) that occurred in Turin (Italy), in which power distribution cables, tramway network feeding cables and a gas pipe were involved. The described accident is particularly interesting because it occurred in the town centre and lasted several hours, producing a very high risk for the population. Fortunately, nobody was injured, but 120 people were evacuated for 24 h. The sequence of events is described, the involved facilities are examined and the physical processes which led to the different top events are discussed. Actually, starting from a modest event (600 V electric cable loss of insulation), which most likely lasted for months, the aforementioned accident was reached in a crescendo of domino effects. This sequence has been represented by an ISD in which the failure of the different protection systems is highlighted. These protection systems were mostly based upon the strict respect of procedures both in the installation and in the following maintenance of the different utilities. These aspects have been also briefly devised in the light of Italian and foreign regulations concerning the problem of the coexistence of buried utilities
A perspective overview of topological approaches for vulnerability analysis of power transmission grids
Full text linkVulnerability analysis is a key issue in power systems since power transmission grids play a crucial role as a critical infrastructure. The power grid structure (number of nodes and lines, their connections, and their physical properties and operational constraints) is one of the main factors to assure power system security. Complex network theory as a promising topological approach for the structural vulnerability analysis has been widely used in many different fields. Recently, many complex network metrics have been proposed to assess the topological vulnerability of power transmission grids. However, these approaches are purely topological and fail in capturing the specific features of power systems. In this paper, an extended topological approach which incorporates electrical features such as flow path, line flow limits, etc., is presented. Three new metrics, net-ability, electrical betweenness and entropy degree are provided and used to assess structural vulnerability in power transmission grid
Extended Topological Metrics for the Analysis of Power Grid Vulnerability
Full text linkVulnerability analysis in power systems is a key issue in modern society and many efforts have contributed to the analysis. Recently, complex networks metrics, applied to assess the topological vulnerability of networked systems, have been used in power grids, such as the betweenness centrality. These metrics may be useful for analyzing the topological vulnerability of power systems because of a close link between their topological structure and physical behavior. However, a pure topological approach fails to capture the electrical specificity of power grids. For this reason, an extended topological method has been proposed by incorporating several electrical features, such as electrical distance, power transfer distribution, and line flow limits, into the pure topological metrics. Starting from the purely topological concept of complex networks, this paper defines an extended betweenness centrality which considers the characteristics of power grids and can measure the local importance of the elements in power grids. The line extended betweenness is compared with the topological betweenness and with the averaged power flow on each line over various operational states in the Italian power grid. The results show that the extended betweenness is superior to topological betweenness in the identification of critical components in power grids and at the same time could be a complementary tool to efficiently enhance vulnerability analysis based on electrical engineering method
Hazardous areas extension in explosive atmospheres caused by free gas jets
Full text linkThis paper regards the validation procedure of the Italian Guide CEI 31-35 formula, used to calculate the hazardous areas extensions in places where explosive gas atmospheres may be present. In industrial activity, a typical event which cause explosive atmosphere consists of damaging and leakage from unions, gaskets, valves of pipes and vessels. At this purpose, in this work it has been taken into account the accidental discharge of flammable gas into a quiescent atmosphere through an orifice. Validation has been performed by comparing calculated values with experimental data. Two gases have been taken into account: methane and hydrogen. Different scenarios have been analyzed, each one differing from the others in the gas release cross section and in the vessel pressure. Results show that the formula fits well not catastrophic industrial accident situation
Digital Twin Applications in the Energy Sector
No full textRecently, there has been a significant interest in the integration of engineering systems into digital formats. This trend has attracted considerable attention because of the numerous advantages it offers in terms of enhancing system performance and reducing costs. Within digitalization techniques, one approach that has gained prominence is the utilization of Digital Twins (DTs). DTs have emerged as a promising method for improving performance, reducing maintenance and operation expenses, and ensuring the safety of associated systems. This research provides an in-depth analysis of the key concepts and characteristics of existing studies on DTs applied in diverse energy systems areas. This study also illustrates the wide range of application areas where DT technology can be employed in power systems such as battery management systems, power monitoring systems, microgrid management, fault detection, and demand forecasting. Furthermore, the research aims to provide insights into future research directions that can facilitate the practical implementation of DTs in various domains
Analysis of the structural vulnerability of the interconnected power grid of continental Europe with the Integrated Power System and Unified Power System based on extended topological approach
Full text linkPower systems as one of the key infrastructures play a crucial role in any country's economy and social life. A large-scale blackout can affect all sectors in a society such as industrial, commercial, residential, and essential public services. However, the frequency of large-scale blackouts across the world is not being reduced, although advanced technology and huge investment have been applied into power systems. Given a single blackout, it is possible to analyze the causes with the traditional engineering methods. What we want to do is not to explain the causes of blackouts but to find what are the most critical elements of the power system to improve the resilience of the system itself. As blackout can happen in different load conditions, we do not want a method that depends on the load/generation level. We want a method independent from these factors: This is the structural perspective. When the interconnection between European and Russian power grids will create the largest interconnected power grid throughout the world in terms of the scale, transmission distance, and involved countries, analyzing the vulnerability of a large-scale power grid will be useful to maintain its reliable and secure operation. To analyze the vulnerability of the interconnected power grid, in this article, we first created the interconnected transmission network between continental Europe and the Commonwealth of Independent States (CIS) and Baltic countries; then, the structural vulnerability of the interconnected power grid was analyzed from a topological point of view using our proposed extended topological method, which incorporates some electrical engineering characteristics into complex network methodology. We found that these power grids of continental Europe, the Baltic states, and the CIS countries can benefit from the interconnection because the interconnected power grid can not only improve the overall network performance of these power grids in the Baltic states and the CIS countries but also increase their structural robustness
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