Academic literature on the topic 'Overhead contact line'

An autonomous diagnostic measuring device, that allows to reduce expenses for the maintenance and the need for highly qualified personnel, is proposed in the article. The described algorithm of the work of the measuring system allows setting pre-failure conditions of an overhead contact line during exploitations of the software complex. The Installation scheme of the measuring complex on an overhead contact line equipment and the functional scheme of the software and hardware complex are described. The experimental dependence of the vibration frequency on the contact wire tension is defined for various overhead contact line spans. The limits of the variation of the vibration frequency for various combinations of overhead contact line parameters are defined.

Icing on the overhead contact line exclude the possibility of efficient current collection from the overhead contact line. The effects of icing can result in losses for carriers due to delay or cancellation of trains and also cases of damage to the traction infrastructure and pantographs. The existing methods of de-icing the traction network (mechanical, chemical and electrical) are currently ineffective. Therefore, it is necessary to develop a new electrical method that takes into account the detailed current fl ow in the over-head contact line. This article presents a model for calculating the current fl ow in the overhead contact line and the resistances of droppers, suspension elements, and distance holders measured on the basis of actual measurements. Keywords: simulation model, de-icing of the contact line, current flow in the contact line

The paper presents the computational model of the pantograph – overhead contact line (OCL), which uses the theory of cable vibrations and Lagrange – Ritz approximation method to derive equations of motion of the overhead contact line subjected to moving pantographs. The pantograph is modelled as a dynamic system of two degrees of freedom describing the motion of two masses replacing a collector head and an articulating frame. The overhead contact line is defined as a catenary system with continuously distributed mass. It consists of a multi-span cable characterized by a curvilinear route (catenary wire) and a straight cable (contact wire) connected with a catenary wire by elastic droppers. The main objective of the paper is to present principal ideas of the computational model, with a particular emphasis on formulating the equation of motion of a pre-tensioned multi-span cable with non-negligible static sag. Much attention is paid to the description of dynamic interaction between the pantograph and overhead contact line. The model allows computer simulation of catenary vibrations induced by two pantographs passing over the contact line, as well as a simulation of dynamic increments of the contact force.

There are no systematic studies reported on measuring model of dynamic contact force between pantograph and overhead line. Keep this in view, the high-speed measuring model of dynamic contact force between pantograph and overhead line is discussed in details in this article. Based on the analysis of forces acting on the pantograph, measuring model of dynamic contact force is constructed with the mass correction and aerodynamic compensation. The results of verifying running test are given in the end of article to show that the measuring model is effective practically.

Continuous co-phase traction power supply system is the major change of the traction power supply. It is important to analyze the transient response characteristics of overhead contact line for the traction substation feeder protection. This article introduces the main structure of continuous co-phase traction power supply system and the control strategy of traction substation. Meanwhile, transient responses of overhead contact line in the earth short circuit are studied, including metallic earth short circuit and non-metallic earth short circuit (high resistance ground). In the PSCAD/EMTDC electromagnetic transient simulation environment, the effects on the system and the recovery process are studied which the fault occurred in the output interface of traction substation and occurred in overhead contact line.

The paper presents the results of initial validation of the method for simulating the dynamic interaction between a pantograph and a overhead contact line. According to European Standard EN50318, the first step of validation was done, which consists of comparison of the simulation results with limit values given in European Standard for the reference model. The dynamic behaviour characteristics, in terms of TSI ENE, were calculated from simulated vibrations of the ten-span overhead contact line and the pantograph, and the rate of contact force change in time. Geometrical and mechanical parameters of the overhead contact line and the pantograph were based on the annex to European Standard EN50318. It was proved, that the part of the characteristics meets European Standard requirements and the other slightly exceed the limit values. Based on the analysis, the direction of further research was proposed.

The article tells about the problem of the railway infrastructure objects reliable, safe, and effective operation on an example of the overhead contact line operation mode rational selection. The overhead contact line operation mode modelling results are described. The model is considering exploitation and climatic conditions and is based on the clusterization, classification, and neuronal network modelling methods for predictive analysis of a large amount of data.

The developments of new types of conductors and increase of voltage level have driven the need to carry out research on evaluating overhead line acoustic noise. The surface potential gradient of a conductor is a critical design parameter for planning overhead lines, as it determines the level of corona loss (CL), radio interference (RI), and audible noise (AN). The majority of existing models for surface gradient calculation are based on analytical methods which restrict their application in simulating complex surface geometries. This thesis proposes a novel method which utilizes both analytical and numerical procedures to predict the surface gradient. Stranding shape, proximity of tower, protrusions and bundle arrangements are considered within this model. One of UK National Grid's transmission line configurations has been selected as an example to compare the results for different methods. The different stranding shapes are a key variable in determining dry surface fields. The dynamic behaviour of water droplets subject to AC electric fields is investigated by experiment and finite element modelling. The motion of a water droplet is considered on the surface of a metallic sphere. To understand the consequences of vibration, the FEA model is introduced to study the dynamics of a single droplet in terms of phase shift between vibration and exciting voltage. Moreover, the evolution of electric field within the whole cycle of vibration is investigated. The profile of the electric field and the characteristics of mechanical vibration are evaluated. Surprisingly the phase shift between these characteristics results in the maximum field occurring when the droplet is in a flattened profile rather than when it is ‘pointed’.Research work on audible noise emitted from overhead line conductors is reviewed, and a unique experimental set up employing a semi-anechoic chamber and corona cage is described. Acoustically, this facility isolates undesirable background noise and provides a free-field test space inside the anechoic chamber. Electrically, the corona cage simulates a 3 m section of 400 kV overhead line conductors by achieving the equivalent surface gradient. UV imaging, acoustic measurements and a partial discharge detection system are employed as instrumentation. The acoustic and electrical performance is demonstrated through a series of experiments. Results are discussed, and the mechanisms for acoustic noise are considered. A strategy for evaluating the noise emission level for overhead line conductors is developed. Comments are made on predicting acoustic noise from overhead lines. The technical achievements of this thesis are summarized in three aspects. First of all, an FEA model is developed to calculate the surface electric field for overhead line conductors and this has been demonstrated as an efficient tool for power utilities in computing surface electric field especially for dry condition. The second achievement is the droplet vibration study which describes the droplets' behaviour under rain conditions, such as the phase shift between the voltage and the vibration magnitude, the ejection phenomena and the electric field enhancement due to the shape change of droplets. The third contribution is the development of a standardized procedure in assessing noise emission level and the characteristics of noise emissions for various types of existing conductors in National Grid.

Problemstellung Im Rahmen des Zulassungsverfahrens für elektrische Schienenfahrzeuge werden oft Messungen bezüglich der Interaktion von Stromabnehmer und Oberleitung benötigt. Zu diesem Zweck werden meist Kontaktkraftmessungen durchgeführt. Dabei soll die dynamische Kraft zwischen Schleifleiste und Oberleitung bei Fahrzeughöchstgeschwindigkeit ermittelt werden. Beim Einsatz klassischer Messsysteme werden herkömmliche Kraftsensoren unter die Schleifleiste montiert. Daraus resultieren verschiedene Schwierigkeiten. Zum Einen muss der Sensor auf Hochspannungspotential mit elektrischer Energie versorgt und die Messdaten zum Erdpotential gesendet werden. Zum Anderen wirken hohe Massenträgheitskräfte oberhalb der Sensorik, welche die Messung höherfrequenter Schwingungen ausschließt. Diese Montage hat zudem den Nachteil, dass vagabundierende Kräfte und Momente ebenso über den Kraftsensor geleitet werden und so das Messergebnis beeinflussen können. Außerdem wirken aerodynamische Effekte, die die Messergebnisse zusätzlich verfälschen. Um geeignete Korrekturmaßnahmen anwenden zu können, müssen Versuche durchgeführt werden, bei denen es dauerhaft keinen Kontakt von Schleifleiste und Fahrdraht gibt. Wenn dieser Stromabnehmer der Einzige am Fahrzeug ist, stellt dies, neben den messtechnischen Herausforderungen, eine erhebliche betriebliche Einschränkung dar. Herangehensweise Nach einer Literatur- und Patentrecherche wurde die Problemstellung in zwei Unterthemen gegliedert. Zum Einen sollte von klassischen elektrischen Sensoren zu faseroptischer Messtechnik gewechselt werden. Dies hat den Vorteil, dass neben der Energie für den Sensor auch dessen Messsignale elegant über Potentialunterschiede hinweg übertragen werden können. Somit werden keinerlei elektrisch aktive Messinstrumente auf Hochspannungspotential benötigt. Als schöne Beigabe ist diese Sensorik auch gänzlich unempfindlich gegen elektromagnetische Störungen, die von der Oberleitung ausgehen. Zum Anderen sollte die gesamte Messtechnik nicht mehr unter, sondern in der Schleifleiste verbaut werden. Diese seit fast 40 Jahren bekannte Herangehensweise ist in einigen Publikationen schematisch dargestellt. Lediglich eine Veröffentlichung beschreibt die praktische Umsetzung. Allerdings sind in dieser Beschreibung andere Randbedingungen als für die hier vorgestellte Konstruktion dargelegt. So war diese Konstruktion als Messpalette für Fahrleitungsuntersuchungen und nicht als Einzelschleifleiste für Fahrzeugzulassungen ausgeführt. Die prinzipielle Funktion dieser Theorie wurde aber schon damals bewiesen. Um die Notwendigkeit der Verfahrensverbesserung mit Messwerten zu untermauern, wurden verschiedene Streckenversuche an verschiedenen Zügen durchgeführt. Mit dieser umfangreichen Statistik konnten Unzulänglichkeiten des klassischen Messverfahrens aufgezeigt werden. Die in dieser Arbeit entwickelte Konstruktion musste von Geometrie und Masse dem Original-Schleifstück entsprechen und sollte ebenso die komplette Traktionsenergie übertragen können, sowie die gleichen Kontaktbedingungen zur Oberleitung haben. Für den Einsatz sollten Fahrgeschwindigkeiten bis 400 km/h vorgesehen werden. Hinsichtlich der Festigkeit sollten mindestens die gleichen Werte wie für das Original-Schleifstück erreicht werden. Zudem sollte das Produkt einen Schlag, welcher durch einen herunterhängenden Ast oder Hänger ausgelöst werden kann, überstehen können. Aus messtechnischer Sichtweise sollte die Masse oberhalb der Sensorik so gering wie möglich gehalten werden um Masseträgheitseinflüße zu reduzieren. Außerdem sollten alle vagabundierenden Kräfte und Momente möglichst um den Sensor herum geleitet werden, um diesen nicht zu beeinflussen. Ein weiteres Ziel war, den Sensor geschützt einzuplanen, damit aerodynamische Kräfte ausgeschlossen werden. Lösung Aufgrund dieser Anforderungen wurde ein Sensorkörper entworfen auf dem Faser-Bragg-Gitter appliziert wurden. Nach einer mehrstufigen Entwicklung wurden Sensoren hergestellt, die seit über einem Jahr im Dauereinsatz sind und seither verlässlich Ergebnisse senden. Ein relevantes Ergebnis dieser Entwicklung war, dass derartige Sensorik einen minimalen Bauraum benötigt, der nicht unterschritten werden kann. Aufgrund dessen, musste auch die bis zu diesem Zeitpunkt auf einen sehr viel kleineren Sensortyp ausgerichtete Schleifleiste mit innenliegenden Sensoren entsprechend angepasst werden. In dieser Konstruktion wurde ein Sensor mit Pilzkopf vorgesehen, so dass nur die relevanten Kräfte über den Sensor geleitet und gemessen werden. Alle weiteren Kräfte und Momente werden über eine Lagerkonstruktion geleitet, die Kräfte in der Messrichtung nicht aufnimmt. Um die Masse oberhalb der Sensorik zu minimieren und das Gewicht der Lagerkonstruktion und des Sensors auszugleichen, wurde die Dicke der Schleifkohle erheblich reduziert. Eine gänzliche Substitution der Kohle war nicht möglich, da sonst veränderte Kontaktbedingungen zwischen Schleifleiste und Fahrdraht vorliegen würden. Im Original-Schleifstück wird ein Aluminium-Strangpressprofil verwendete, welches neben dem Stromfluß auch die Festigkeit gewährleistet. Dieses Profil konnte in erster Linie aus Bauraummangel nicht weiter verwendet werden. Deshalb wurde eine Leichtbaukonstruktion aus mehreren U-Profilen vorgesehen, die neben dem benötigten Bauraum auch noch eine Masseeinsparung, durch Nutzung von Faserverbundwerkstoffen, ermöglichte. In dieser Arbeit wurden sowohl die relevanten Festigkeitsberechnungen als auch eine Betrachtung der Erwärmung durch Stromfluss durchgeführt. Diese Handrechnungen wurden mittels Simulationsrechnung validiert. Im Anschluss wurden alle Fertigungsunterlagen erstellt. Die Fertigung wurde mit potentiellen Projektpartnern besprochen, wodurch Schwierigkeiten erkannt und deren Lösungen in den Entwurf eingepflegt wurden. In der wirtschaftlichen Betrachtung wurden Kosten und Nutzen bilanziert. In Summe wurde somit eine Schleifleiste mit modularer innenliegender faseroptischer Sensorik entwickelt. Um deren Vorteil in der Praxis nutzen zu können, wird empfohlen Diese zu fertigen.

In Deutschland und Europa ist im Zuge der Energiewende erforderlich, mehr Elektroenergie mit bestehenden Freileitungen zu transportieren. Eine technische Lösung, mit der dieses Ziel erreicht werden kann, ist das Umbeseilen der Freileitung mit Hochtemperatur-Leiterseilen mit geringem Durchhang (High Temperature Low Sag – HTLS conductors). Diese Leiterseile haben gegenüber konventionellen Leiterseilen (z. B. Aluminium/Stahl-Leiterseilen) höhere Bemessungsströme und temperaturen. Die stromführenden Verbindungen mit HTLS-Leiterseilen werden damit ebenfalls höher thermisch belastet. Diese sind für den zuverlässigen und sicheren Betrieb der Freileitung sehr wichtige Betriebsmittel. Neben anderen Verbindungstechnologien hat sich bei den stromführenden Verbindungen mit konventionellen Leiterseilen das Sechskantpressen seit Jahrzehnten bewährt. Aus der Literatur sind fast ausschließlich empirische Untersuchungen mit dieser Verbindungstechnologie bekannt. Das elektrische Kontaktverhalten von Pressverbindungen wurde bisher nur unzureichend untersucht. In dieser Arbeit wird dazu ein elektrisches Modell vorgestellt und weiterentwickelt, mit dem das elektrische Kontaktverhalten von Pressverbindungen genauer beschrieben werden kann. Weiterhin werden prinzipielle Zusammenhänge zwischen der Stromverteilung in den Kontaktpartnern und deren Einfluss auf den Verbindungswiderstand dargestellt. Als Ergebnis von theoretischen und experimentellen Untersuchungen konnten allgemeine Empfehlungen für das Dimensionieren von Pressverbindungen mit konventionellen und HTLS-Leiterseilen erarbeitet werden. Aus der prinzipiellen Funktionsweise einer Pressverbindung ist bekannt, dass der Form-, der Kraft- und der Stoffschluss in der Verbindung das elektrische Kontaktverhalten beeinflussen. Insbesondere der Kraftschluss wurde in der Literatur bislang nur näherungsweise berechnet. In den bekannten analytischen Modellen werden die Geometrie der Kontaktpartner sowie das Werkstoffverhalten vereinfacht und die mechanischen Belastungen beim Fügen der Verbindung nicht genau genug berücksichtigt. Aus den genannten Gründen wurde das Fügen von Pressverbindungen mit mehrdrähtigen Leiterseilen mit der Finite-Elemente-Methode (FEM) berechnet. Die Press- und Kontaktkräfte konnten damit für alle Kontaktflächen in einer Verbindung ermittelt werden. Es konnte gezeigt werden, dass insbesondere hohe Press- und Kontaktkräfte die Ursache für ein gutes elektrisches Kontaktverhalten einer Pressverbindung sind. Die physikalischen Ursachen dieses Zusammenhangs werden diskutiert. Das Langzeitverhalten von Pressverbindungen mit Verbund-Leiterseilen wurde experimentell untersucht. Die Ergebnisse der durchgeführten Langzeitversuche zeigen den Einfluss der Kontaktkraft im elektrischen Langzeitverhalten qualitativ auf. Bei den Pressverbindungen, für die nur sehr geringe Kontaktkräfte berechnet wurden, war das elektrische Langzeitverhalten weniger stabil
In Germany and in Europe it is due to the “Energiewende” necessary to transmit more electrical ener-gy with existing overhead transmission lines. One possible technical solution to reach this aim is the use of high temperature low sag conductors (HTLS-conductors). Compared to the common Aluminium Conductor Steel Reinforced (ACSR), HTLS-conductors have higher rated currents and rated tempera-tures. Thus the electrical connections for HTLS-conductors are stressed to higher temperatures too. These components are most important for the safe and reliable operation of an overhead transmission line. Besides other connection technologies, hexagonal compression connections with ordinary transmis-sion line conductors have proven themselves since decades. From the literature, mostly empirical stud-ies with electrical tests for compression connections are known. The electrical contact behaviour, i.e. the quality of the electrical contact after assembly, of these connections has been investigated insuffi-ciently. This work presents and enhances an electrical model of compression connections, so that the electrical contact behaviour can be determined more accurate. Based on this, principal considerations on the current distribution in the compression connection and its influence on the connection re-sistance are presented. As a result from the theoretical and the experimental work, recommendations for the design of hexagonal compression connections for transmission line conductors were devel-oped. Furthermore it is known from the functional principle of compression type connections, that the elec-trical contact behaviour can be influenced from their form fit, force fit and cold welding. In particular the forces in compression connections have been calculated up to now by approximation. The known ana-lytical calculations simplify the geometry and material behaviour and do not consider the correct me-chanical load during assembly. For these reasons the joining process of hexagonal compression con-nections with stranded overhead transmission line conductors was calculated with the finite element method. The compression forces and the residual contact forces were determined for all contacts be-tween barrel and conductor as well as between the wires of the conductor. It was shown, that high compression and residual contact forces are the main cause of good electrical contact behaviour. The physical relations are discussed. The electrical long-term behaviour was furthermore investigated in experiments. The results confirm the influence of the residual contact force on the long-term behaviour qualitatively. Those compression connections, which had only small residual contact forces, were less stable in the long-term tests

The voltage profile of the catenary between traction substations (TSSs) is affected by the trolleybus current intake and by its position with respect to the TSSs: the higher the current requested by the bus and the further the bus from the TSSs, the deeper the voltage drop. When the voltage drops below 500V, the trolleybus is forced to decrease its consumption by reducing its input current. This thesis deals with the analysis of the improvements that the installation of an BESS produces in the operation of a particularly loaded FS of the DC trolleybus network of the city of Bologna. The stationary BESS is charged by the TSSs during off-peak times and delivers the stored energy when the catenary is overloaded alleviating the load on the TSSs and reducing the voltage drops. Only IMC buses are considered in the prospect of a future disposal of all internal combustion engine vehicles. These trolleybuses cause deeper voltage drops because they absorb enough current to power their traction motor and recharge the on board battery. The control of the BESS aims to keep the catenary voltage within the admissible voltage range and makes sure that all physical limitations are met. A model of FS Marconi Trento Trieste is implemented in Simulink environment to simulate its daily operation and compare the behavior of the trolleybus network with and without BESS. From the simulation without BESS, the best location of the energy storage system is deduced, and the battery control is tuned. Furthermore, from the knowledge of the load curve and the battery control trans-characteristic, it is formulated a prediction of the voltage distribution at BESS connection point. The prediction is then compared with the simulation results to validate the Simulink model. The BESS allows to decrease the voltage drops along the catenary, the Joule losses and the current delivered by the TSSs, indicating that the BESS can be a solution to improve the operation of the trolleybus network.

Multi functional health monitoring wearable devices are quite prominent these days. Usually these devices are battery-operated and consequently are limited by their battery life (from few hours to a few weeks depending on the application). Of late, it was realized that these devices, which are currently being operated at fixed voltage and frequency, are capable of operating at multiple voltages and frequencies. By switching these voltages and frequencies to lower values based upon power requirements, these devices can achieve tremendous benefits in the form of energy savings. Dynamic Voltage and Frequency Scaling (DVFS) techniques have proven to be handy in this situation for an efficient trade-off between energy and timely behavior. Within imec, wearable devices make use of the indigenously developed MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). This system is optimized for efficient and accurate collection, processing, and transfer of data from multiple (health) sensors. MUSEIC v2 has limited means in controlling the voltage and frequency dynamically. In this thesis we explore how traditional DVFS techniques can be applied to the MUSEIC v2. Experiments were conducted to find out the optimum power modes to efficiently operate and also to scale up-down the supply voltage and frequency. Considering the overhead caused when switching voltage and frequency, transition analysis was also done. Real-time and non real-time benchmarks were implemented based on these techniques and their performance results were obtained and analyzed. In this process, several state of the art scheduling algorithms and scaling techniques were reviewed in identifying a suitable technique. Using our proposed scaling technique implementation, we have achieved 86.95% power reduction in average, in contrast to the conventional way of the MUSEIC v2 chip’s processor operating at a fixed voltage and frequency. Techniques that include light sleep and deep sleep mode were also studied and implemented, which tested the system’s capability in accommodating Dynamic Power Management (DPM) techniques that can achieve greater benefits. A novel approach for implementing the deep sleep mechanism was also proposed and found that it can obtain up to 71.54% power savings, when compared to a traditional way of executing deep sleep mode.
Nuförtiden så har multifunktionella bärbara hälsoenheter fått en betydande roll. Dessa enheter drivs vanligtvis av batterier och är därför begränsade av batteritiden (från ett par timmar till ett par veckor beroende på tillämpningen). På senaste tiden har det framkommit att dessa enheter som används vid en fast spänning och frekvens kan användas vid flera spänningar och frekvenser. Genom att byta till lägre spänning och frekvens på grund av effektbehov så kan enheterna få enorma fördelar när det kommer till energibesparing. Dynamisk skalning av spänning och frekvens-tekniker (såkallad Dynamic Voltage and Frequency Scaling, DVFS) har visat sig vara användbara i detta sammanhang för en effektiv avvägning mellan energi och beteende. Hos Imec så använder sig bärbara enheter av den internt utvecklade MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). Systemet är optimerat för effektiv och korrekt insamling, bearbetning och överföring av data från flera (hälso) sensorer. MUSEIC v2 har begränsad möjlighet att styra spänningen och frekvensen dynamiskt. I detta examensarbete undersöker vi hur traditionella DVFS-tekniker kan appliceras på MUSEIC v2. Experiment utfördes för att ta reda på de optimala effektlägena och för att effektivt kunna styra och även skala upp matningsspänningen och frekvensen. Eftersom att ”overhead” skapades vid växling av spänning och frekvens gjordes också en övergångsanalys. Realtidsoch icke-realtidskalkyler genomfördes baserat på dessa tekniker och resultaten sammanställdes och analyserades. I denna process granskades flera toppmoderna schemaläggningsalgoritmer och skalningstekniker för att hitta en lämplig teknik. Genom att använda vår föreslagna skalningsteknikimplementering har vi uppnått 86,95% effektreduktion i jämförelse med det konventionella sättet att MUSEIC v2-chipets processor arbetar med en fast spänning och frekvens. Tekniker som inkluderar lätt sömn och djupt sömnläge studerades och implementerades, vilket testade systemets förmåga att tillgodose DPM-tekniker (Dynamic Power Management) som kan uppnå ännu större fördelar. En ny metod för att genomföra den djupa sömnmekanismen föreslogs också och enligt erhållna resultat så kan den ge upp till 71,54% lägre energiförbrukning jämfört med det traditionella sättet att implementera djupt sömnläge.

In Deutschland und Europa ist im Zuge der Energiewende erforderlich, mehr Elektroenergie mit bestehenden Freileitungen zu transportieren. Eine technische Lösung, mit der dieses Ziel erreicht werden kann, ist das Umbeseilen der Freileitung mit Hochtemperatur-Leiterseilen mit geringem Durchhang (High Temperature Low Sag – HTLS conductors). Diese Leiterseile haben gegenüber konventionellen Leiterseilen (z. B. Aluminium/Stahl-Leiterseilen) höhere Bemessungsströme und temperaturen. Die stromführenden Verbindungen mit HTLS-Leiterseilen werden damit ebenfalls höher thermisch belastet. Diese sind für den zuverlässigen und sicheren Betrieb der Freileitung sehr wichtige Betriebsmittel. Neben anderen Verbindungstechnologien hat sich bei den stromführenden Verbindungen mit konventionellen Leiterseilen das Sechskantpressen seit Jahrzehnten bewährt. Aus der Literatur sind fast ausschließlich empirische Untersuchungen mit dieser Verbindungstechnologie bekannt. Das elektrische Kontaktverhalten von Pressverbindungen wurde bisher nur unzureichend untersucht. In dieser Arbeit wird dazu ein elektrisches Modell vorgestellt und weiterentwickelt, mit dem das elektrische Kontaktverhalten von Pressverbindungen genauer beschrieben werden kann. Weiterhin werden prinzipielle Zusammenhänge zwischen der Stromverteilung in den Kontaktpartnern und deren Einfluss auf den Verbindungswiderstand dargestellt. Als Ergebnis von theoretischen und experimentellen Untersuchungen konnten allgemeine Empfehlungen für das Dimensionieren von Pressverbindungen mit konventionellen und HTLS-Leiterseilen erarbeitet werden. Aus der prinzipiellen Funktionsweise einer Pressverbindung ist bekannt, dass der Form-, der Kraft- und der Stoffschluss in der Verbindung das elektrische Kontaktverhalten beeinflussen. Insbesondere der Kraftschluss wurde in der Literatur bislang nur näherungsweise berechnet. In den bekannten analytischen Modellen werden die Geometrie der Kontaktpartner sowie das Werkstoffverhalten vereinfacht und die mechanischen Belastungen beim Fügen der Verbindung nicht genau genug berücksichtigt. Aus den genannten Gründen wurde das Fügen von Pressverbindungen mit mehrdrähtigen Leiterseilen mit der Finite-Elemente-Methode (FEM) berechnet. Die Press- und Kontaktkräfte konnten damit für alle Kontaktflächen in einer Verbindung ermittelt werden. Es konnte gezeigt werden, dass insbesondere hohe Press- und Kontaktkräfte die Ursache für ein gutes elektrisches Kontaktverhalten einer Pressverbindung sind. Die physikalischen Ursachen dieses Zusammenhangs werden diskutiert. Das Langzeitverhalten von Pressverbindungen mit Verbund-Leiterseilen wurde experimentell untersucht. Die Ergebnisse der durchgeführten Langzeitversuche zeigen den Einfluss der Kontaktkraft im elektrischen Langzeitverhalten qualitativ auf. Bei den Pressverbindungen, für die nur sehr geringe Kontaktkräfte berechnet wurden, war das elektrische Langzeitverhalten weniger stabil.
In Germany and in Europe it is due to the “Energiewende” necessary to transmit more electrical ener-gy with existing overhead transmission lines. One possible technical solution to reach this aim is the use of high temperature low sag conductors (HTLS-conductors). Compared to the common Aluminium Conductor Steel Reinforced (ACSR), HTLS-conductors have higher rated currents and rated tempera-tures. Thus the electrical connections for HTLS-conductors are stressed to higher temperatures too. These components are most important for the safe and reliable operation of an overhead transmission line. Besides other connection technologies, hexagonal compression connections with ordinary transmis-sion line conductors have proven themselves since decades. From the literature, mostly empirical stud-ies with electrical tests for compression connections are known. The electrical contact behaviour, i.e. the quality of the electrical contact after assembly, of these connections has been investigated insuffi-ciently. This work presents and enhances an electrical model of compression connections, so that the electrical contact behaviour can be determined more accurate. Based on this, principal considerations on the current distribution in the compression connection and its influence on the connection re-sistance are presented. As a result from the theoretical and the experimental work, recommendations for the design of hexagonal compression connections for transmission line conductors were devel-oped. Furthermore it is known from the functional principle of compression type connections, that the elec-trical contact behaviour can be influenced from their form fit, force fit and cold welding. In particular the forces in compression connections have been calculated up to now by approximation. The known ana-lytical calculations simplify the geometry and material behaviour and do not consider the correct me-chanical load during assembly. For these reasons the joining process of hexagonal compression con-nections with stranded overhead transmission line conductors was calculated with the finite element method. The compression forces and the residual contact forces were determined for all contacts be-tween barrel and conductor as well as between the wires of the conductor. It was shown, that high compression and residual contact forces are the main cause of good electrical contact behaviour. The physical relations are discussed. The electrical long-term behaviour was furthermore investigated in experiments. The results confirm the influence of the residual contact force on the long-term behaviour qualitatively. Those compression connections, which had only small residual contact forces, were less stable in the long-term tests.

Nationalism: Past as Prologue began as a single volume being compiled by Ad Akande, a scholar from South Africa, who proposed it to me as co-author about two years ago. The original idea was to examine how the damaging roots of nationalism have been corroding political systems around the world, and creating dangerous obstacles for necessary international cooperation. Since I (Bruce E. Johansen) has written profusely about climate change (global warming, a.k.a. infrared forcing), I suggested a concerted effort in that direction. This is a worldwide existential threat that affects every living thing on Earth. It often compounds upon itself, so delays in reducing emissions of fossil fuels are shortening the amount of time remaining to eliminate the use of fossil fuels to preserve a livable planet. Nationalism often impedes solutions to this problem (among many others), as nations place their singular needs above the common good. Our initial proposal got around, and abstracts on many subjects arrived. Within a few weeks, we had enough good material for a 100,000-word book. The book then fattened to two moderate volumes and then to four two very hefty tomes. We tried several different titles as good submissions swelled. We also discovered that our best contributors were experts in their fields, which ranged the world. We settled on three stand-alone books:” 1/ nationalism and racial justice. Our first volume grew as the growth of Black Lives Matter following the brutal killing of George Floyd ignited protests over police brutality and other issues during 2020, following the police assassination of Floyd in Minneapolis. It is estimated that more people took part in protests of police brutality during the summer of 2020 than any other series of marches in United States history. This includes upheavals during the 1960s over racial issues and against the war in Southeast Asia (notably Vietnam). We choose a volume on racism because it is one of nationalism’s main motive forces. This volume provides a worldwide array of work on nationalism’s growth in various countries, usually by authors residing in them, or in the United States with ethnic ties to the nation being examined, often recent immigrants to the United States from them. Our roster of contributors comprises a small United Nations of insightful, well-written research and commentary from Indonesia, New Zealand, Australia, China, India, South Africa, France, Portugal, Estonia, Hungary, Russia, Poland, Kazakhstan, Georgia, and the United States. Volume 2 (this one) describes and analyzes nationalism, by country, around the world, except for the United States; and 3/material directly related to President Donald Trump, and the United States. The first volume is under consideration at the Texas A & M University Press. The other two are under contract to Nova Science Publishers (which includes social sciences). These three volumes may be used individually or as a set. Environmental material is taken up in appropriate places in each of the three books. * * * * * What became the United States of America has been strongly nationalist since the English of present-day Massachusetts and Jamestown first hit North America’s eastern shores. The country propelled itself across North America with the self-serving ideology of “manifest destiny” for four centuries before Donald Trump came along. Anyone who believes that a Trumpian affection for deportation of “illegals” is a new thing ought to take a look at immigration and deportation statistics in Adam Goodman’s The Deportation Machine: America’s Long History of Deporting Immigrants (Princeton University Press, 2020). Between 1920 and 2018, the United States deported 56.3 million people, compared with 51.7 million who were granted legal immigration status during the same dates. Nearly nine of ten deportees were Mexican (Nolan, 2020, 83). This kind of nationalism, has become an assassin of democracy as well as an impediment to solving global problems. Paul Krugman wrote in the New York Times (2019:A-25): that “In their 2018 book, How Democracies Die, the political scientists Steven Levitsky and Daniel Ziblatt documented how this process has played out in many countries, from Vladimir Putin’s Russia, to Recep Erdogan’s Turkey, to Viktor Orban’s Hungary. Add to these India’s Narendra Modi, China’s Xi Jinping, and the United States’ Donald Trump, among others. Bit by bit, the guardrails of democracy have been torn down, as institutions meant to serve the public became tools of ruling parties and self-serving ideologies, weaponized to punish and intimidate opposition parties’ opponents. On paper, these countries are still democracies; in practice, they have become one-party regimes….And it’s happening here [the United States] as we speak. If you are not worried about the future of American democracy, you aren’t paying attention” (Krugmam, 2019, A-25). We are reminded continuously that the late Carl Sagan, one of our most insightful scientific public intellectuals, had an interesting theory about highly developed civilizations. Given the number of stars and planets that must exist in the vast reaches of the universe, he said, there must be other highly developed and organized forms of life. Distance may keep us from making physical contact, but Sagan said that another reason we may never be on speaking terms with another intelligent race is (judging from our own example) could be their penchant for destroying themselves in relatively short order after reaching technological complexity. This book’s chapters, introduction, and conclusion examine the worldwide rise of partisan nationalism and the damage it has wrought on the worldwide pursuit of solutions for issues requiring worldwide scope, such scientific co-operation public health and others, mixing analysis of both. We use both historical description and analysis. This analysis concludes with a description of why we must avoid the isolating nature of nationalism that isolates people and encourages separation if we are to deal with issues of world-wide concern, and to maintain a sustainable, survivable Earth, placing the dominant political movement of our time against the Earth’s existential crises. Our contributors, all experts in their fields, each have assumed responsibility for a country, or two if they are related. This work entwines themes of worldwide concern with the political growth of nationalism because leaders with such a worldview are disinclined to co-operate internationally at a time when nations must find ways to solve common problems, such as the climate crisis. Inability to cooperate at this stage may doom everyone, eventually, to an overheated, stormy future plagued by droughts and deluges portending shortages of food and other essential commodities, meanwhile destroying large coastal urban areas because of rising sea levels. Future historians may look back at our time and wonder why as well as how our world succumbed to isolating nationalism at a time when time was so short for cooperative intervention which is crucial for survival of a sustainable earth. Pride in language and culture is salubrious to individuals’ sense of history and identity. Excess nationalism that prevents international co-operation on harmful worldwide maladies is quite another. As Pope Francis has pointed out: For all of our connectivity due to expansion of social media, ability to communicate can breed contempt as well as mutual trust. “For all our hyper-connectivity,” said Francis, “We witnessed a fragmentation that made it more difficult to resolve problems that affect us all” (Horowitz, 2020, A-12). The pope’s encyclical, titled “Brothers All,” also said: “The forces of myopic, extremist, resentful, and aggressive nationalism are on the rise.” The pope’s document also advocates support for migrants, as well as resistance to nationalist and tribal populism. Francis broadened his critique to the role of market capitalism, as well as nationalism has failed the peoples of the world when they need co-operation and solidarity in the face of the world-wide corona virus pandemic. Humankind needs to unite into “a new sense of the human family [Fratelli Tutti, “Brothers All”], that rejects war at all costs” (Pope, 2020, 6-A). Our journey takes us first to Russia, with the able eye and honed expertise of Richard D. Anderson, Jr. who teaches as UCLA and publishes on the subject of his chapter: “Putin, Russian identity, and Russia’s conduct at home and abroad.” Readers should find Dr. Anderson’s analysis fascinating because Vladimir Putin, the singular leader of Russian foreign and domestic policy these days (and perhaps for the rest of his life, given how malleable Russia’s Constitution has become) may be a short man physically, but has high ambitions. One of these involves restoring the old Russian (and Soviet) empire, which would involve re-subjugating a number of nations that broke off as the old order dissolved about 30 years ago. President (shall we say czar?) Putin also has international ambitions, notably by destabilizing the United States, where election meddling has become a specialty. The sight of Putin and U.S. president Donald Trump, two very rich men (Putin $70-$200 billion; Trump $2.5 billion), nuzzling in friendship would probably set Thomas Jefferson and Vladimir Lenin spinning in their graves. The road of history can take some unanticipated twists and turns. Consider Poland, from which we have an expert native analysis in chapter 2, Bartosz Hlebowicz, who is a Polish anthropologist and journalist. His piece is titled “Lawless and Unjust: How to Quickly Make Your Own Country a Puppet State Run by a Group of Hoodlums – the Hopeless Case of Poland (2015–2020).” When I visited Poland to teach and lecture twice between 2006 and 2008, most people seemed to be walking on air induced by freedom to conduct their own affairs to an unusual degree for a state usually squeezed between nationalists in Germany and Russia. What did the Poles then do in a couple of decades? Read Hlebowicz’ chapter and decide. It certainly isn’t soft-bellied liberalism. In Chapter 3, with Bruce E. Johansen, we visit China’s western provinces, the lands of Tibet as well as the Uighurs and other Muslims in the Xinjiang region, who would most assuredly resent being characterized as being possessed by the Chinese of the Han to the east. As a student of Native American history, I had never before thought of the Tibetans and Uighurs as Native peoples struggling against the Independence-minded peoples of a land that is called an adjunct of China on most of our maps. The random act of sitting next to a young woman on an Air India flight out of Hyderabad, bound for New Delhi taught me that the Tibetans had something to share with the Lakota, the Iroquois, and hundreds of other Native American states and nations in North America. Active resistance to Chinese rule lasted into the mid-nineteenth century, and continues today in a subversive manner, even in song, as I learned in 2018 when I acted as a foreign adjudicator on a Ph.D. dissertation by a Tibetan student at the University of Madras (in what is now in a city called Chennai), in southwestern India on resistance in song during Tibet’s recent history. Tibet is one of very few places on Earth where a young dissident can get shot to death for singing a song that troubles China’s Quest for Lebensraum. The situation in Xinjiang region, where close to a million Muslims have been interned in “reeducation” camps surrounded with brick walls and barbed wire. They sing, too. Come with us and hear the music. Back to Europe now, in Chapter 4, to Portugal and Spain, we find a break in the general pattern of nationalism. Portugal has been more progressive governmentally than most. Spain varies from a liberal majority to military coups, a pattern which has been exported to Latin America. A situation such as this can make use of the term “populism” problematic, because general usage in our time usually ties the word into a right-wing connotative straightjacket. “Populism” can be used to describe progressive (left-wing) insurgencies as well. José Pinto, who is native to Portugal and also researches and writes in Spanish as well as English, in “Populism in Portugal and Spain: a Real Neighbourhood?” provides insight into these historical paradoxes. Hungary shares some historical inclinations with Poland (above). Both emerged from Soviet dominance in an air of developing freedom and multicultural diversity after the Berlin Wall fell and the Soviet Union collapsed. Then, gradually at first, right wing-forces began to tighten up, stripping structures supporting popular freedom, from the courts, mass media, and other institutions. In Chapter 5, Bernard Tamas, in “From Youth Movement to Right-Liberal Wing Authoritarianism: The Rise of Fidesz and the Decline of Hungarian Democracy” puts the renewed growth of political and social repression into a context of worldwide nationalism. Tamas, an associate professor of political science at Valdosta State University, has been a postdoctoral fellow at Harvard University and a Fulbright scholar at the Central European University in Budapest, Hungary. His books include From Dissident to Party Politics: The Struggle for Democracy in Post-Communist Hungary (2007). Bear in mind that not everyone shares Orbán’s vision of what will make this nation great, again. On graffiti-covered walls in Budapest, Runes (traditional Hungarian script) has been found that read “Orbán is a motherfucker” (Mikanowski, 2019, 58). Also in Europe, in Chapter 6, Professor Ronan Le Coadic, of the University of Rennes, Rennes, France, in “Is There a Revival of French Nationalism?” Stating this title in the form of a question is quite appropriate because France’s nationalistic shift has built and ebbed several times during the last few decades. For a time after 2000, it came close to assuming the role of a substantial minority, only to ebb after that. In 2017, the candidate of the National Front reached the second round of the French presidential election. This was the second time this nationalist party reached the second round of the presidential election in the history of the Fifth Republic. In 2002, however, Jean-Marie Le Pen had only obtained 17.79% of the votes, while fifteen years later his daughter, Marine Le Pen, almost doubled her father's record, reaching 33.90% of the votes cast. Moreover, in the 2019 European elections, re-named Rassemblement National obtained the largest number of votes of all French political formations and can therefore boast of being "the leading party in France.” The brutality of oppressive nationalism may be expressed in personal relationships, such as child abuse. While Indonesia and Aotearoa [the Maoris’ name for New Zealand] hold very different ranks in the United Nations Human Development Programme assessments, where Indonesia is classified as a medium development country and Aotearoa New Zealand as a very high development country. In Chapter 7, “Domestic Violence Against Women in Indonesia and Aotearoa New Zealand: Making Sense of Differences and Similarities” co-authors, in Chapter 8, Mandy Morgan and Dr. Elli N. Hayati, from New Zealand and Indonesia respectively, found that despite their socio-economic differences, one in three women in each country experience physical or sexual intimate partner violence over their lifetime. In this chapter ther authors aim to deepen understandings of domestic violence through discussion of the socio-economic and demographic characteristics of theit countries to address domestic violence alongside studies of women’s attitudes to gender norms and experiences of intimate partner violence. One of the most surprising and upsetting scholarly journeys that a North American student may take involves Adolf Hitler’s comments on oppression of American Indians and Blacks as he imagined the construction of the Nazi state, a genesis of nationalism that is all but unknown in the United States of America, traced in this volume (Chapter 8) by co-editor Johansen. Beginning in Mein Kampf, during the 1920s, Hitler explicitly used the westward expansion of the United States across North America as a model and justification for Nazi conquest and anticipated colonization by Germans of what the Nazis called the “wild East” – the Slavic nations of Poland, the Baltic states, Ukraine, and Russia, most of which were under control of the Soviet Union. The Volga River (in Russia) was styled by Hitler as the Germans’ Mississippi, and covered wagons were readied for the German “manifest destiny” of imprisoning, eradicating, and replacing peoples the Nazis deemed inferior, all with direct references to events in North America during the previous century. At the same time, with no sense of contradiction, the Nazis partook of a long-standing German romanticism of Native Americans. One of Goebbels’ less propitious schemes was to confer honorary Aryan status on Native American tribes, in the hope that they would rise up against their oppressors. U.S. racial attitudes were “evidence [to the Nazis] that America was evolving in the right direction, despite its specious rhetoric about equality.” Ming Xie, originally from Beijing, in the People’s Republic of China, in Chapter 9, “News Coverage and Public Perceptions of the Social Credit System in China,” writes that The State Council of China in 2014 announced “that a nationwide social credit system would be established” in China. “Under this system, individuals, private companies, social organizations, and governmental agencies are assigned a score which will be calculated based on their trustworthiness and daily actions such as transaction history, professional conduct, obedience to law, corruption, tax evasion, and academic plagiarism.” The “nationalism” in this case is that of the state over the individual. China has 1.4 billion people; this system takes their measure for the purpose of state control. Once fully operational, control will be more subtle. People who are subject to it, through modern technology (most often smart phones) will prompt many people to self-censor. Orwell, modernized, might write: “Your smart phone is watching you.” Ming Xie holds two Ph.Ds, one in Public Administration from University of Nebraska at Omaha and another in Cultural Anthropology from the Chinese Academy of Social Sciences, Beijing, where she also worked for more than 10 years at a national think tank in the same institution. While there she summarized news from non-Chinese sources for senior members of the Chinese Communist Party. Ming is presently an assistant professor at the Department of Political Science and Criminal Justice, West Texas A&M University. In Chapter 10, analyzing native peoples and nationhood, Barbara Alice Mann, Professor of Honours at the University of Toledo, in “Divide, et Impera: The Self-Genocide Game” details ways in which European-American invaders deprive the conquered of their sense of nationhood as part of a subjugation system that amounts to genocide, rubbing out their languages and cultures -- and ultimately forcing the native peoples to assimilate on their own, for survival in a culture that is foreign to them. Mann is one of Native American Studies’ most acute critics of conquests’ contradictions, and an author who retrieves Native history with a powerful sense of voice and purpose, having authored roughly a dozen books and numerous book chapters, among many other works, who has traveled around the world lecturing and publishing on many subjects. Nalanda Roy and S. Mae Pedron in Chapter 11, “Understanding the Face of Humanity: The Rohingya Genocide.” describe one of the largest forced migrations in the history of the human race, the removal of 700,000 to 800,000 Muslims from Buddhist Myanmar to Bangladesh, which itself is already one of the most crowded and impoverished nations on Earth. With about 150 million people packed into an area the size of Nebraska and Iowa (population less than a tenth that of Bangladesh, a country that is losing land steadily to rising sea levels and erosion of the Ganges river delta. The Rohingyas’ refugee camp has been squeezed onto a gigantic, eroding, muddy slope that contains nearly no vegetation. However, Bangladesh is majority Muslim, so while the Rohingya may starve, they won’t be shot to death by marauding armies. Both authors of this exquisite (and excruciating) account teach at Georgia Southern University in Savannah, Georgia, Roy as an associate professor of International Studies and Asian politics, and Pedron as a graduate student; Roy originally hails from very eastern India, close to both Myanmar and Bangladesh, so he has special insight into the context of one of the most brutal genocides of our time, or any other. This is our case describing the problems that nationalism has and will pose for the sustainability of the Earth as our little blue-and-green orb becomes more crowded over time. The old ways, in which national arguments often end in devastating wars, are obsolete, given that the Earth and all the people, plants, and other animals that it sustains are faced with the existential threat of a climate crisis that within two centuries, more or less, will flood large parts of coastal cities, and endanger many species of plants and animals. To survive, we must listen to the Earth, and observe her travails, because they are increasingly our own.

AbstractIn Bangladesh, the peaking power plants that serve the peak time loads use conventional fossil fuels for power generation. These power stations remain idle for a good part of their operating life, which therefore results in a high overhead cost. Continuous integration of renewables into the grid is increasing the dependency on these, so far, feasibility of no other less-expensive options has been studied. In this context, this paper aims to analyze the financial feasibility of different alternative options. Three possible options were analyzed and the levelized cost of energy (LCOE) was compared with that of conventional peaking power plants. It was found that Battery-based storage systems are not financially feasible at this moment, while the nation’s lone hydro power plant promises financial feasibility if solar PV driven pumped hydro storage is implemented. We also report that if the nation continues to add solar PV power stations even with costly peaking power plants using traditional fuels, this hybrid option was counter intuitively found to be financially feasible.

The increasing complexity of modern ground vehicles is making crucial the role of control for improving energetic efficiency, comfort and performance. At the same time, the control software must be frequently updated in order to let the vehicle respond safely and efficiently within more sophisticated environments and to optimize the operations when new vehicle components are integrated. In this framework real-time hardware-in-the-loop simulations represent a fundamental tool for supporting the verification and validation processes of the control software and hardware. In this chapter a railway case study will be presented. The mathematical models of the most relevant electromechanical components of the vehicle powertrain are presented: the pantograph connected to an ideal overhead line with continuous voltage; the electrical components of a pre-charge circuit, the line filter and the braking chopper; the three-phase voltage source inverter and the induction motor; and, finally, the mechanical transmission system, including its interactions with the rail. Then the issues related to the real-time simulation of the locomotive components models are discussed, concentrating on challenges related to the stiff nature of the dynamic equations and on their numerical integration by combining field programmable gate array (FPGA) and central processing unit (CPU) boards. The usefulness of the real-time hardware-in-the-loop simulations for the analysis of railway control software will be demonstrated by considering the powertrains of two real metropolitan trains under complex scenarios, i.e., stator winding disconnection of the induction motor, pantograph missing contact, wheel-rail slipping phenomenon.

The instructor overhead is a major obstacle to visualization technologies. Visualization is highly effective in two and three dimensions, and these are the dimensions where computational geometry occurs in practice. The authors present a hypertext system which creates e-content for computational geometry teaching. Their hypertext system provides geometric and visualization libraries that allow the quick creation of interactive visualizations of computational geometry algorithms. Inquiry-based learning is promoted as the learners have the opportunity to observe, interact, and experiment with the produced animations. Their system utilizes the inherent expressiveness of the Python programming language, which permits coding programs that look like pseudo code, whilst easily making advanced low importance details transparent. This is crucial for pedagogical use in computational geometry courses where the focus should be on the geometric algorithmic aspects, with low level details made abstract.

Fostered by the emerging Knowledge Society, the enriched media is nowadays a very challenging research topic, be it considered either from academic or from industrial perspectives. In its largest acceptation, enriched media refers to all possible associations established between some original data (video, audio, 3D, …) and some metadata (textual, audio, video, executable codes, …). Such a new content may be further exploited for various applications, like interactive HDTV, computer games, or data mining, for instance. This chapter is meant to bring into evidence the role watermarking techniques may play in this new applicative field. Following the watermarking philosophy, the in-band enrichment supposed that the enrichment data are inserted into the very data to be enriched. Thus, three main advantages are ensured: backward compatibility, format coherence, and virtually no network overhead. The discussion is structured on both theoretical aspects (the accurate evaluation of the watermarking capacity in several real-life scenarios) and on applications developed under the framework of the R&D contracts conducted at the ARTEMIS Department, Institut TELECOM.

Lightning strikes are rare accidents but carry a 10% case fatality, killing 0.1–0.3 per million population each year. During thunderstorms, the risk is increased by sheltering under trees or by being on open water, on tractors, or in open fields or in outdoor activity. Lightning is considered to cause instant asystole. Immediate cardiopulmonary resuscitation is mandatory. Survivors might develop complications including pain syndromes and psychological sequelae. Burns are generally of minor consequence, unlike electrical injury. The most disabling consequences of the injury is generally the psychological sequelae. Meanwhile, electrocution is the fifth most common cause of workplace death, mainly affecting utilities, mining, and construction labourers. Domestic electrical accidents are common, where contact with overhead power lines, faulty power tools, and particularly using extension cords, are the most common causes, with metal ladders and antennae being particularly dangerous.

Mapmakers typically depict the aridlands of the world in colors like buff and buckskin, in contrast to the greens of wetter regions. Their choice is true to reality, for dry places usually produce scant vegetation, and the bare ground, baked by unobstructed sun, tends to wear a washed-out shade of dun, or one of its cousins. In the North American Southwest, you might add a touch of rust to reflect the widespread iron-rich geology. In many areas, oxides of iron produce the pinkish flesh tones that make it easy to think the landscape is alive. If you also brush in some piney greens and spruce black for upland woods and forests, and dab smaller areas white to represent high-country snowcaps, you have a fair start toward capturing the palette of the region. But you would still be missing the most definitive color of the Southwest, which is found not beneath the feet, but overhead. You can look up, straight up, almost any day of the year, and there it is: an intense, infinite blue, miles deep and beyond reach. It is not merely bluish, not the watery blue of Scandinavian eyes, not the black-mixed blue of dark seas or bachelor buttons, not the hazy blue of glacier ice or distant mountains, but an Ur-blue, an über-blue, a defining quintessence. It is to other blues as brandy is to wine: a distillation, pure and heady. It can be a little deflating to reflect that the ethereal blue of southwestern skies results from mundane forces, that it is the product of solar radiation and atmospheric gases interacting in an environment shaped by climate. If the air held more water vapor, the sky would whiten overhead, as it does at the horizons, where the light that reaches our eyes has more atmosphere and diffusing vapor to travel through.

In order to reduce maintenance labor of overhead contact lines (OCL), a contactless measurement device for OCL was developed. This device is mounted on a roof of a vehicle of a train and measures static three-dimensional positions of wires of OCL and detects positions of OCL fittings without touching the OCL while the train is running. We proposed hybrid sensing method that combines stereo measurement by image processing with structure measurement by laser range scanners and it realized to measure OCL geometry with high-precision even in sections with complicated OCL structure. In addition, we developed position detection method of the OCL fittings that can cope with changes in height and stagger of OCL by using machine learning. Measurement data of OCL contactless measurement device is static position of OCL without influence of a probe such as a pantograph. With this device, the OCL static position can be measured continuously instead of at each support point or dropper point. For maintenance of OCL, the criterion of OCL is defined as a static position. The device is utilizable for OCL maintenance and it sophisticate maintenance of OCL. For example, this device realize the height difference measurement of the crossing section, which has been conventionally measured by maintenance workers. In addition, the device are utilizable for OCL fittings inspection. Maintenance workers can check the image of OCL fittings without on foot into the field. Furthermore the static position data of OCL can be used to create simulation model of OCL dynamic behavior. Using this model, it is possible to know the dynamic response of cases where various pantographs pass at various speeds. Running tests was conducted on commercial line, and the performance of the device was verified when running at a speed of 130 km/h. The results shown that the repeated measurement accuracy is within 10 mm, and the OCL fitting detection rate is 90 % or more.

This study aims to create a numerical analysis model which can investigate the interaction between pantograph and overhead contact line used for railway vehicles, and validate the simulation results according to EN 50318 standards. Finite element analysis models of pantograph and overhead contact line are created using SAMCEF, a commercial FE analysis program, and mean, standard deviation, maximum and minimum values of contact forces are obtained. The simulation results are validated according to EN 50318, and the reliability of SAMCEF as an analysis solver of railway vehicle’s catenary system is discussed.

The evaluation of the contact loss of the catenary system is the highlight issue for the high-speed railway vehicle. In this paper, using the multibody dynamic analysis techniques including a flexible body, the simulation method of the catenary system is proposed. The pantograph and overhead contact line are developed by using rigid body and ANCF (Absolute Nodal Coordinate Formulation) beam elements, respectively. And relative motions are constrained by sliding joint. Using this analysis model, contact force and loss of contact are calculated according to vehicle speed. The results of the simulation are evaluated by EN 50318 that is the international standard with regard to validation of the dynamic interaction between pantograph and overhead contact line.

Overhead contact line or catenary is the structure composed of support elements and wires responsible for the power supply of the locomotive through sliding contact with the pantograph. This contact causes wear not only on the pantograph contact strips but also in the contact wire, which produces a reduction on its effective section and eventually its replacement, resulting in the stop of the railway traffic with its associate economical and operational drawbacks. For this reason, it is important for catenary designers to count with appropriate tools able to predict the contact wire wear behaviour for extending the service life of the system. This work proposes a strategy to simulate the long-term contact wire wear evolution considering the mutual influence between the dynamic behaviour and wear of the system. The method is based on two pillars: the efficient simulation of the catenary-pantograph dynamic interaction [1] and a heuristic wear model [2] which considers mechanical wear due to friction and electrical wear produced by Joule effect and electric arcs. With the proposed simulation tool, we analyse the effect on the long-term contact wire height irregularity caused by wear of different parameters such as the train speed, the pantograph uplift force or the presence of installation errors in the catenary.