Simplified conservative testing method of touch and step voltages by multiple auxiliary electrodes at reduced distance

Grounding systems (GSs) must be tested periodically in order to maintain the touch voltage (TV) and step voltage (SV) below a safe value in all of the zones of the installation. Measurements of the ground resistance and of the TV and SV are typically done by the fall-of-potential (FoP) method, locating the auxiliary current electrode at remote distance to test the effective behavior of the GS. In urban areas, it could be very complicated or impossible to install the auxiliary current electrode as required, not having area around with sufficient accessibility. At this aim, this paper describes a methodology of using multiple current electrodes at short distances, modifying the classic FoP practice, so that the measurements of TV and SV are always conservative. The adequacy of a GS is verified if the values of the TV and SV, tested inside and in the vicinity of the GS, are below the permissible limits, regardless if they are true or conservatively increased. Thus, the measured TV and SV by the suggested method, always conservative, allow verifying the adequacy of GSs, in the cases where it is impossible to locate the remote auxiliary electrode

Inferring Anomaly Situation from Multiple Data Sources in Cyber Physical Systems

AbstractCyber physical systems are becoming ubiquitous devices in many fields thus creating the need for effective security measures. We propose to exploit their intrinsic dependency on the environment in which they are deployed to detect and mitigate anomalies. To do so, sensor measurements, network metrics, and contextual information are fused in a unified security architecture. In this paper, the model of the proposed framework is presented and a first proof of concept involving a telecommunication infrastructure case study is provided

A unifying orchestration operating platform for 5G

5G will revolutionize the way ICT and Telecommunications infrastructures work. Indeed, businesses can greatly benefit from innovation introduced by 5G and exploit the new deep integration between ICT and networking capabilities to generate new value-added services. Although a plethora of solutions for virtual resources and infrastructures management and orchestration already exists (e.g., OpenDaylight, ONOS, OpenStack, Apache Mesos, Open Source MANO, Docker Swarm, LXD/LXC, etc.), they are still not properly integrated to match the 5G requirements. In this paper, we present the 5G Operating Platform (5G-OP) which has been conceived to fill in this gap and integrate management, control and orchestration of computing, storage and networking resources down to the end-user devices and terminals (e.g., smart phone, machines, robots, drones, autonomous vehicles, etc.). The 5G-OP is an overarching framework capable to provide agnostic interfaces and a universal set of abstractions in order to implement seamless 5G infrastructure control and orchestration. The functional structure of the 5G-OP, including the horizontal and vertical interworking of functions in it, has been designed to allow Network Operators and Service Providers to exploit diverse roles and business strategies. Moreover, the functional decoupling of the 5G-OP from the underneath management, control and orchestration solutions allows pursuing faster innovation cycles, being ready for the emergence of new service models

A unifying operating platform for 5G end-to-end and multi-layer orchestration

Heterogeneity of current software solutions for 5G is heading for complex and costly situations, with high fragmentation, which in turn creates uncertainty and the risk of delaying 5G innovations. This context motivated the definition of a novel Operating Platform for 5G (5G-OP), a unifying reference functional framework supporting end-to-end and multi-layer orchestration. 5G-OP aims at integrated management, control and orchestration of computing, storage, memory, networking core and edge resources up to the end-user devices and terminals (e.g., robots and smart vehicles). 5G-OP is an overarching architecture, with agnostic interfaces and well-defined abstractions, offering the seamless integration of current and future infrastructure control and orchestration solutions (e.g., OpenDaylight, ONOS, OpenStack, Apache Mesos, OpenSource MANO, Docker, LXC, etc.) The paper provides also the description of a prototype that can be seen as a simplified version of a 5G-OP, whose feasibility has been demonstrated in Focus Group IMT2020 of ITU-T

Time-Domain Shielding Performance of Enclosures: A Comparison of Different Global Approaches

The analysis of the shielding performance is conducted on the basis of the classical IEEE Standard 299, which is typically a local and frequency-domain approach, may be not sufficient for the thorough appraisal of protection levels achievable through actual enclosures in the presence of transient electromagnetic fields. Stemming from a victim point of view, a new, global approach is proposed for the assessment of average and minimum guaranteed shielding performance directly in the time domain, in the presence of either near fields or plane waves. The method is suitable for the analysis of all the typical transient EMI phenomena and recommended for the analysis of protection levels of mission-critical devices or systems. An elementary statistical analysis of performance data is also presented

A global approach to time-domain shielding problems

The local and frequency-domain approach to shielding performance analysis of classical IEEE Std. 299 may be not sufficient for the thorough appraisal of protection levels achievable through actual enclosures in the presence of transient electromagnetic fields. Stemming from a victim point of view, a new, global approach is proposed for the assessment of average and minimum guaranteed shielding performance directly in the time domain. The method is suitable and recommended for the analysis of protection levels of mission-critical devices or systems

Tower Models for Power Systems Transients: A Review

Fast-front transients play an important role in the insulation design of any power system. When a stroke hits the shield wire or the tower of high-voltage overhead power lines, flashover may occur either along the span or across tower insulators, depending on the relevant voltages and insulation strength. As a result, backflashover may take place from the tower structure to the phase conductor whenever a huge impulse current flows along the tower towards considerably high footing impedances. For these reasons, tower modeling for transients studies is an important step in the insulation design, and also for lower voltage applications, where indirect lightning effects may play a predominant role. However, after decades of research on tower modeling, starting from the 1930s with the first model proposed by Jordan, no consensus has been reached neither on a widely accepted tower model nor on the quantitative effect of the tower models on insulation design. Moreover, the fundamental mechanisms at the base of the transient response of towers and the definition of some fundamental parameters have not been totally clarified yet. The aim of this review is to present the available tower models developed through the years in the power community, focussing mainly on lumped/distributed circuit models, and to help the reader to obtain a deeper understanding of them