Det här projektet har utförts på Scania och är en förstudie till en standardbeskrivning där olika bindemedel i ledningsnät studerats för att kunna användas i olika miljöer i lastbilen så som hytt chassi och drivlina. Olika krav som temperatur, kemikaliebeständighet och fuktresistans ställs för de olika miljöerna. Bindemedlet ska hålla kablarna på plast i en skyddsslang och samtidigt fungera som tätning. De limtyper som har studerats i den här rapporten är ett epoxilim, ett epoxy-cyanoacrylate hybrid lim, ett smältlim av polyamid och två siliconlim. De har limmats på några av de platser som används i lastbilen och sedan utsatts för dragtester, kemikalietester, åldring- och klimattest. Inget av de testade limmerna klarade alla testerna men den limgrupp som klarade testen bäst var de av silicon. / This project has been performed at Scania and it is a pre-study for a standard description of binders in cables harness in different environments in the truck. The different environmental zones are the cab, chassis and power train. Different zones in the truck have different requirements such as temperature, chemicals and moister resistance. The function of the binder is to glue cables into a protective hose of plastic and also act as a seal. The different types of adhesives that have been study in this report is epoxy adhesive, epoxy-hybrid cyanoacrylate adhesive, hot melt by polyamide and two types of silicon glue. They have been glued to some of the different plastics that the cables are made of in the truck and then they have been exposed to tensile tests, chemical tests, aging and climate tests. None of the tested adhesives passed all the tests, but silicon glue passed most of the tests.

This research is focused on the multi-stress aging phenomena and lifetime estimation of 15 kV EPR cable. In order to gain the suitable parameters for the lifetime estimation, the aging study on the EPR cable samples as well as on the cable layers’ dielectrics samples was carried out at the High Voltage Laboratory of Mississippi State University. During the multi-stress aging study of 15 kV EPR cable samples, the EPR cable samples underwent electrical stress, thermal stress, and environmental effects. The aging time for the EPR cables varied from 650 hrs to 1300 hrs. An empirical aging model describing the cables’ lifetime was derived from the partial discharge measurements results. The aging study on the EPR cable layers’ dielectrics was achieved as well. The EPR insulation material samples were aged by combined electrical and thermal stress, while the material samples of inner semi-conducting layer, outer semi-conducting layer, and outer low-density polyethylene (LDPE) jacket were aged by thermal stress. The measurement data was used for the newly proposed lifetime estimation method. A new lifetime estimation method was introduced for the EPR cables. The method assumed that the failures of cables results from the expansion of voids/cavities initiated from the defects in the EPR insulation layer. The proposed lifetime estimation method applied the finite element method (FEM) to solve the electric field distribution inside the EPR cable with the existence of voids/cavities. The parameters were derived from the aging study on the EPR insulation material samples. Assuming the voids/cavities would expand in the direction of the maximum electric field stress, the lifetime of the EPR cables was then estimated through the iteration. The introduced method helped to establish a relationship between the aging study of insulation material samples and the aging of EPR cable samples, which was long missing in the past studies. It also provided a new way to assess the reliability of the EPR cable.

No description available.

When a rope quickly transfers from a slack state to a taut state, a snapping action occurs and produces a large tensile force which is known as a snap load. Energy is dissipated during this snap load, and it is proposed to use synthetic fiber ropes as a type of passive earthquake damper in order to take advantage of this phenomenon. This thesis is the second phase of a multi-stage research project whose goal is to investigate and develop what will be known as Snapping-Cable Energy Dissipators (SCEDs). The experimental data that was collected in the Master'­s Thesis of Nicholas Pearson was organized and analyzed as a part of this research in order to evaluate the behavior of the ropes during the snapping action. Additional tests were also conducted for this project under more controlled conditions in order to better understand how the ropes change throughout a sequence of similar snap loadings and also to determine the amount of energy that is dissipated. The data from both projects was then used as input parameters for a mathematical model that was developed to characterize the behavior of the ropes during a snap load. This model will be utilized in subsequent research involving the finite element analysis of the seismic response of structural frames containing SCEDs. / Master of Science

Energy is lost when a rope transfers from a slack state to a taut state. This transfer is called a snap load and can be very violent. It is proposed to use synthetic fiber ropes as a type of passive control device in new or existing structures to mitigate seismic response. Experimental static and snap load (dynamic) tests were conducted on various synthetic fiber ropes. An eleven-foot-tall drop tower was built in the Virginia Tech Structures and Materials Laboratory in order to conduct these tests. Force and acceleration of the drop plate, which slides vertically within the drop tower, were measured with respect to time for all dynamic tests. Acceleration data was integrated using the trapezoidal or midpoint rule to obtain velocity and displacement values. Plots were made for each test in order to give a better representation of the results. These plots include representations of force and acceleration vs. time, force vs. absolute displacement, force vs. velocity, and force, acceleration, velocity, and displacement vs. time (during the initial taut phase only). Test results show that energy was dissipated in all of the dynamic drop tests, which was expected. Also, the displacement of each rope did not return to zero at the same time that the force returned to zero after the initial snap load. This proves that the ropes undergo some permanent elongation under load. The stiffness of each rope increased with continuous testing. As more tests are conducted on each rope, the strands are pulled tighter into the braided configuration, which causes the rope to become stiffer. / Master of Science

Marine cables often comprise an integral part of a larger structural system, such as an offshore drilling platform. They are also used to support marker buoys, as well as anchored or towed instrument arrays. Consequently, the resonant flow-induced oscillation of these cables, caused by vortex shedding, is extremely undesirable because of the associated damaging phenomena. The present study, which employs hot wire anemometry as the principal investigative tool, was undertaken to examine the behavior in the near wake of a flexible, helically wound, high aspect ratio (L/d = 107) marine cable in a linear shear flow (steepness parameter β = 0.0053) at centerline Reynolds numbers between 2.0 x 10³ ≤ Re_c ≤ 4.2 x 10⁴. Particular attention was paid to lock-on or “synchronization” related changes associated with uniform and sheared flow past the cable when it was forced to vibrate in the first mode. The study was extended to include an analysis of the effects on vortex shedding synchronization phenomena generated by placing spherical bluff bodies along the cable span. The frequency and reduced velocity boundaries of the lock-on regions, for both the cable and sphere-cable combination, as a function of vibration amplitude up to a/d = 0.322, were measured, plotted and analyzed. The critical reduced velocity of the vibrating cable was U*ᵣ = 5.50, and for the sphere-cable combination U*ᵣ = 3. 39. A sudden increase in the vortex formation length in the near wake of the vibrating cable occurred during perfect synchronization (U*ᵣ = 5.50). Shortly thereafter, the formation length returned to stationary cable values. At Re_c = 2.96 x 10³, the spanwise vortex shedding frequencies behind the stationary and vibrating cable in a linear shear flow (with and without the presence of spherical bluff bodies) were measured, plotted and the results coup a red. A stable cellular vortex shedding frequency structure, strengthened by the synchronous vibration, existed along the span of the cable. The presence of and spacing between the spherical bodies along the cable span significantly affected the sparwise character of the near wake cellular structure. The length of the locked-on region was substantially increased (almost doubled) when the spherical bodies were present along the span of the cable. / Ph. D.

[pt] Nos últimos anos a protensão externa tem sido empregada tanto na recuperação e reforço de estruturas existentes quanto na concepção de novas estruturas. A protensão externa pode ser feita com cabos de aço ou com cabos sintéticos. Dentre esses, podem-se destacar os cabos Parafil, cujo núcleo é constituído de fibras kevlar. Essas fibras têm alta resistência (3700MPa), alto módulo de elasticidade (126000MPa) e excelente resistência à corrosão. Neste trabalho é feito um estudo do comportamento de vigas protendidas com cabos externos tipo Parafil, onde se identificam os principais fatores que influenciam a resistência à flexão através de um estudo paramétrico, utilizando um modelo computacional desenvolvido por Krüger (1989) e Campos (1993). Foram ensaiadas experimentalmente cinco vigas protendidas com dois cabos externos, considerando a taxa de armadura passiva e o tipo de carregamento como principais variáveis. Os resultados mostram que a taxa de armadura passiva, o tipo de carregamento, o módulo de elasticidade do reforço, a resistência do concreto e o nível de protensão inicial (protensão efetiva) têm um efeito significante sobre a resistência à flexão das vigas. Os resultados teóricos obtidos através de equações desenvolvidas para o caso de cabos de aço, mostram, de um modo geral, bons resultados para o caso de cabos Parafil. / [en] External prestressing has been used either in new structures or in the repair and rehabilitation of existing ones. The use of steel tendons has been the most usual solution, but synthetic cables have also been used over the last years. One example of these cables is a parallel-lay rope known as Parafil, which is made from the high strength (3700 MPa), high modulus (126000 MPa) and corrosion resistant fiber commercially known as Kevlar. An investigation on the behavior of beams prestressed with external Parafil tendons is conducted with the purpose of studying the flexural strength of these beams. The main variables which affect the behavior of the beams are firstly identified through a parametric analysis using an existing computational model based on the finite element method. Secondly, an experimental investigation of five simple supported beams, in which the non-prestressed reinforcement and type of loading are the main variables, is presented. The results show that the non-prestressed reinforcement, type of loading, elastic modulus of the tendons, effective prestressing force level and concrete strength have a significant affect on the flexural strength of the beams. The comparison between the experimental results and those obtained from equations developed for steel tendons, shows that these equations could also be used for beams prestressed with synthetic cables. / [es] En los últimos años la protensión externa há sido empleada tanto en la recuperación y refuerzo de extructuras existentes como en la concepción de nuevas extructuras. La protensión externa puede ser realizada con cables de acero o con cables sintéticos. Dentro de estos, se pueden destacar los cables Parafil, cuyo núcleo está constituido de fibras kevlar. Esas fibras tienen alta resistencia (3700MPa), alto módulo de elasticidad (126000MPa) y excelente resistencia a la corrosión. En este trabajo se realiza un estudio del comportamientode vigas protendidas con cables externos tipo Parafil, donde se identifican los principales factores que tienen influencia sobre la resistencia a la flexión, a través de un estudio paramétrico, utilizando un modelo computacional desarrollado por Krüger (1989) y Campos (1993). Fueron ensayadas cinco vigas protendidas con dos cables externos, considerando como principales variables la tasa de armadura pasiva y el tipo de carga. Los resultados muestran que la tasa de armadura pasiva, el tipo de carga, el módulo de elasticidad del refuerzo, la resistencia del concreto y el nível de protensión inicial (protensión efectiva) tienen un efecto significativo sobre la resistencia a la flexión de las vigas. Los resultados teóricos obtenidos a través de las ecuaciones desarrolladas para el caso de cables de acero, muestran, de un modo general, buenos resultados para el caso de cables Parafil.

Pasados los 80’s el incremento en la demanda del ancho de banda por el uso de Internet, así como las comunicaciones internacionales privadas de la industria de las Telecomunicaciones, han ocasionado que las redes basados en Satélites colapsen, ya que esta tecnología no podía brindar la tecnología (ancho de banda) que se necesitaba y otro, su costo es significativamente mayor. Razón por el cual, se inicio el uso de las redes por cable submarino aumentando considerablemente su demanda, hasta que el día la mayoría de las comunicaciones internacionales se hacen a través de este medio. Los grandes cables submarinos en las telecomunicaciones, tiene la misión de unir los continentes entre si a través de los océanos y soportan el 90% del tráfico de la red, trasmitiendo hasta más de 7 Terabits por segundo (Tbps); es decir, más de siete billones de bits cada segundo. El uso de este medio de transmisión tiende a ser vulnerable por el medio ambiente, los daños y el uso inadecuado que se le brinde; es por eso que, la Operación y Mantenimiento de una Red de Cable Submarino es de suma importancia para prevenir y actuar al momento que se presente algún deterioro o rotura, esto es un problema que conlleva perdida económica, por cuanto la rotura de sólo un cable afectaría a millones de usuarios, Para fines de mantenimiento preventivo y correctivo es necesario realizar mediciones y enviar órdenes a los repetidores que están bajo el mar. Esto se realiza variando levemente (sobre-modulando) la señal luminosa de acuerdo a la señal de datos de baja velocidad que contiene los mensajes enviados o recibidos hacia o desde los repetidores.

D’ençà que el polietilè reticulat (XLPE) es va començar a utilitzar com aïllament elèctric per cables de subministrament elèctric, s’han destinat molts esforços a l’estudi de les propietats dielèctriques del polietilè i l’efecte que la càrrega d’espai té sobre el seu comportament. En aquest sentit, les corrents de despolarització estimulades tèrmicament (TSDC) s’han utilitzat extensament per estudiar les relaxacions de càrrega d’espai. Aquesta tècnica ha demostrat tenir prou resolució per distingir diferències en aïllaments de XLPE amb composicions o processos de fabricació diferents. En aquesta tesi, els mecanismes de conducció dels aïllaments XLPE de cables de mitjana tensió (MV) han estat estudiats per TSDC i diverses tècniques complementàries, com l’anàlisi dinàmica elèctrica (DEA), les corrents d’absorció/resorció (ARC), el pols electroacústic (PEA) i les corrents de despolarització isotèrmiques (IDC). Altres tècniques, com l’espectroscòpia d’infrarojos (FTIR) o la difracció de raigs X, han estat també utilitzades per caracteritzar el material. S’han obtingut espectres TSDC per diferents mostres de cable, les quals en condicions de servei treballen en un rang de tensió AC de 12 a 20kV i a temperatures al voltant dels 90ºC. D’altra banda, s’han realitzat mesures de la conductivitat per ARC i DEA en mostres de cable, en cilindres de XLPE i en films. Les mesures s’han dut a terme a temperatures pertanyents al rang de fusió del XLPE (50–110ºC), en mostres sotmeses a aquestes temperatures durant diferents períodes de temps. Els resultats mostren diferències importants entre el comportament de les propietats conductives de les mostres de cable amb pantalles semiconductores (SC) i sense (cilindres de XLPE). El comportament observat ha estat explicat mitjançant la coexistència de dos mecanismes de conducció. La difusió d’impureses des de les pantalles SC determina el comportament d’una d’aquestes contribucions a mig i llarg termini. Els resultats obtinguts per FTIR són consistents amb aquest model. Respecte la microestructura, tant les mesures DSC com la difracció per raigs X mostren que existeixen processos de recristal•lització quan les mostres són sotmeses a temperatures ubicades dins del rang de fusió. Els electrets formats mitjançant el mètode de la polarització per finestres (WP) mostren una descàrrega TSDC amb un ample pic heteropolar en el rang de fusió, amb el màxim al voltant dels 105ºC. En treballs previs, aquest pic es va associar a la fusió de la fracció cristal•lina. Tanmateix, en lloc de decréixer quan la temperatura de polarització augmenta, el pic presenta una temperatura de polarització òptima al voltant de 90-95ºC. Aquest comportament ha estat explicat tenint en compte els processos de recristal•lització que es produeixen quan el material es polaritza isotèrmicament. Durant la recristal•lització, una nova fracció cristal•lina creix en un estat polaritzat degut el camp aplicat, i origina una corrent de despolarització quan es fon durant la mesura TSDC. Amb l’objectiu de determinar l’origen d’altres pics que apareixen en l’espectre TSDC del XLPE, s’han emprat les IDC com a tècnica complementària. Les corrents IDC obtingudes de mostres no tractades es poden representar com la combinació de dues contribucions diferenciades: un terme que és una funció potencial del temps i un d’exponencial. La segona relaxació es correspon amb un pic TSDC que apareix a 95ºC. D’aquesta manera s’ha pogut determinar l’origen dipolar del pic. Finalment, mitjançant la tècnica PEA s’ha obtingut la distribució de la càrrega d’espai en mostres polaritzades que havien estat sotmeses a diferents tractaments tèrmics. S’ha observat un comportament transitori tant per PEA com per TSDC. Tanmateix no s’ha pogut establir cap relació directa entre les descàrregues TSDC i mesures PEA. En conseqüència, s’ha proposat una explicació per les corbes TSDC que considera mecanismes que no són detectables en els perfils de càrrega obtinguts per PEA / Since cross-linked polyethylene (XLPE) started to be used as electrical insulation for power cables, much research has been focused on polyethylene dielectric properties and the effect of the space charge on its behavior. In this sense, thermally stimulated depolarization currents (TSDC) have been widely used to study space charge relaxation. This technique has proved to have enough resolution to determine differences in charge trapping properties among XLPE insulations with different composition and manufacturing processes. In this thesis work, the conduction mechanisms of medium voltage (MV) cable XLPE insulation have been studied by TSDC and several complementary techniques, such as dynamic electrical analysis (DEA), absorption/resorption currents (ARC), pulsed electroacoustic (PEA) and isothermal depolarization currents (IDC). Other techniques, like Fourier transform infrared (FTIR) spectroscopy or X-ray diffractometry, have been used to characterize the material. TSDC spectra have been obtained for different cable samples, which in service conditions work under AC voltages ranging from 12 to 20kV and at temperatures around 90ºC. On the other hand, conductivity measurements by ARC and DEA have been performed in cable samples and in XLPE cylinders, as well as XLPE films. Measurements have been carried out at temperatures within the melting temperature range of XLPE (50–110ºC) on samples annealed at such temperatures during several annealing times. Results show significant differences in the behavior of the conductive properties of XLPE cable samples with semiconducting (SC) screens and without them (XLPE cylinders). The observed behavior has been explained by the coexistence of two conduction mechanisms. Diffusion of impurities from SC screens determines the medium and long-term behavior of one of these contributions and, hence, of cable conductivity. FTIR results are consistent with this model. With respect to microstructure, DSC and X-ray diffractometry results show that recrystallization processes exist when samples are annealed in the melting range of temperatures. Electrets formed by means of the windowing polarization method (WP) showed a TSDC discharge with a wide heteropolar peak in the melting temperature range, and with the maximum at about 105ºC. This peak was associated with the melting of the crystalline fraction in previous works. However, in spite of decreasing with the temperature of polarization, an optimal polarization temperature around 90–95ºC is found. This behavior has been explained by taking into account recrystallization processes when the insulation is isothermally polarized. During recrystallization, the new crystalline fraction grows in a polarized state due to the applied electric field, and it causes the depolarization current when it melts during the TSDC measurement. Results obtained from different experiments are consistent with this assumption. With the aim to find out the origin of other TSDC peaks present in the spectrum of XLPE cable samples, IDC has been used as complementary technique. IDC currents obtained from as-received cable samples at temperatures close to service conditions can be considered as the combination of two different contributions: a power law current and a stretched exponential contribution. The last relaxation process has been successfully associated with with a TSDC peak found at 95ºC. By this way the dipolar origin of the peak has been determined. Finally, PEA measurements have provided the space charge distribution profiles of polarized samples with different annealings. A transient behavior has been observed in both PEA and TSDC measurements. However, no straightforward relation between TSDC discharges and space charge detected by PEA can be established. Therefore, an explanation for TSDC curves has been proposed, which considers mechanisms that are not noticeable in charge profiles obtained by PEA.

Examensarbete utfördes hos konsultföretaget WSP Group- Stockholm med syftet att identifiera och hitta förläggningsmetoder som underlättar förläggning av kablar idag och i framtiden. Examensarbetet fokuserar bara på regionnät och lokalnät i storstäder men med inslag av stamnät. Detta examensarbete bygger på informationssamling från standarder EBR KJ41:15 kabelförläggning max 145 kV, SS-EN 424 14 37 och Stockholm stad tekniska handbok. Som komplettering till standarderna användes handböcker från olika företag samt gamla examensarbeten. Svar på frågeställningar är baserad på intervjuer med olika aktörer inom branschen så som nätägare, konsuler, och entreprenörer. Genom intervjuerna kom man fram till att rör används i första hand inte för att skydda kablar utan för att kunna passera genom en väg, rör leder till att värmeavledningsförmågan försämras vilket innebär att temperaturen på kabeln stiger och i värsta fall förkortar livslängden på kabeln. Att gå upp i ledararea för kablar är inte möjligt eftersom det är trångt i marken och det krävs mycket plats. Bentonitfyllning är ingen bra metod eftersom det inte finns data på vad som kan hända med bentoniten efter 5 år eller 20 år, och det är svårt att komma åt kablarna och reparera de eftersom bentoniten måste spolas ur. Om bentoniten stelnar kan det bli svårt att komma åt kabeln. Det visade sig att grävning är den enda metoden som används i storstäder eftersom andra metoder kan orsaka skador på befintliga ledningar som ligger i marken. De vanligaste kabelfelen är gräv skador på kablar, det är väldigt lätt att man kommer åt markkablarna vid schaktarbetet. För att kunna bygga ut nätet i framtiden kan man förlägga kablar med större ledningar för att täcka framtida behovet. I de områden där man vet att nätet inte behöver förstärkas kan man förlägga i rör för att underlätta underhållsarbetet i framtiden. Staden måste vara mer tydliga med sina planeringar och säga till att hålla sig till det. Staden måste också ansvara för sin mark och inte låta någon annan ta hand om nätet. Ledningsägarna måste bli bättre på att samförlägga och agera snabbt med att komma ut med detaljer på vart man vill samförlägga för att slippa schakta och störa markägaren flera gånger. Det kommer bli ännu trängre i marken i framtiden och det låter som att man kommer behöva bygga tunnlar. Tunnlar är en dyr infrastruktur och ifall flera aktörer väljer att samförlägga kan kostnaderna för tunnelbyggnation fördelas mellan olika aktörer. OPI kanalisation är också en annan typ av lösning och det är väldigt bra om flera aktörer också kan samförlägga. Idag är man ganska dålig på att samförlägga och det är något som man måste bli bättre på. / The thesis work was carried out at the consulting company WSP Group- Stockholm, with the purpose of identifying and finding installation methods that facilitate the placement of cables today and in the future. The thesis focuses only on regional and local grids but with elements of main grids in major cities. This degree project is based on information gathering from standards EBR KJ41: 15 cabling max 145 kV, SS-EN 424 14 37 and Stockholm City Technical Manual and the differences between them. As a supplement to the standards, different manuals were used by different companies and also past thesis work. Answers to main question and subquery are based on interviews with various actors in the industry such as grid owners, consultants, and entrepreneurs.  The interviews revealed that pipes are used primarily not to protect cables, but to pass through a road. Pipes Installation lead to deterioration of heat dissipation in cables, which means that the temperature of the cable rises and, in the worst case, shortens the life of cable. Walking up the cable wiring area is not possible because it is crowded in the ground and requires a lot of space. Bentonite filling is not a good method because there is no data on what can happen with the bentonite after 5 years or 20 years. It would be difficult to access the cables and repair them because the bentonite must be flushed out. If the bentonite is stiff, it can be difficult to access the cable. It turned out that excavation is the only method used in metropolitan areas because other methods can cause damage to existing wires lying in the ground. The most common cable damages are digging in cables, it is very easy to access the ground cables at the installation work. In order to expand the network in the future, cables with larger wires can be placed to cover future needs. In areas where you know that the network does not need to be strengthened, pipes can be placed to facilitate maintenance work in the future. The city needs to be clear about where the future constructions will be and develop a plan and stick to it. The city must also be responsible for its land and not let anyone else take care of the network. Management owners need to be better at co-ordinating and acting quickly to come up with details on where to co-ordinate to avoid bottleneck and disturbing landowners several times. It seems that tunnels will be a way to go in the future. Tunnels is an expensive infrastructure and if several actors choose to collaborate, the costs of tunnel construction can be divided between different actors. OPI channelization is also another type of solution and it is very good if several players can also collaborate / <p>Godkänd</p>