Cable Applications Research Articles

Application study on the first cable-stayed bridge with CFRP cables in China

In order to push forward the development of CFRP cable-stayed bridge and accumulate experiences, the study on the application of the first cable-stayed bridge with CFRP cables in China was carried out. The design essentials of main components of the bridge were introduced and its integral performances, including static properties, dynamic properties and seismic response were analyzed using finite element method. A new bond-type anchorage was developed and the processes of fabricating and installing CFRP cables were elaborated. Based on the results of construction simulation, a tension scheme for bridge was propound. During constructing, the stresses and displacement of girder and pylon, as well as the forces and stresses of cables, were tested. The results indicate that all sections of the bridge could meet the requirements of the ultimate bearing capacity and normal service; the performance of the anchorage is good and the stresses in each cable system are similar; the tested values accord well with the calculated values. Further, creep deformation of the resin in anchorages under service load is not obvious. All these results demonstrate that the first application of CFRP cables in the cable-stayed bridge in China is successful.

Low-Field-Orientation Effect on REBCO Tape Performance and Its Power Cable Application

Low field characteristics, including field orientation dependence relations for four different commercially available REBCO tapes, were investigated in an external field of up to 0.3 T at 77 K. A design method of the performance of a twisted stacked-tape conductor (TSTC) has been developed for a power transmission line. Cable critical current is obtained from an averaged self-field distributed over the cable cross section and the minimum critical current obtained from the field orientation dependence in transverse fields experimentally measured for the single tapes. The performance of three types of TSTCs, i.e., single-, double-, and triple-channel configurations, has been assessed for the four REBCO tapes.

Evaluation of polypropylene/polyolefin elastomer blends for potential recyclable HVDC cable insulation applications

This paper evaluates the microstructure and properties of polypropylene/polyolefin elastomer (PP/POE) blends for potential recyclable HVDC cable insulation applications. PP/POE blends with different POE content were prepared by melt mixing. The introduction of POE results in a slight decrease of the melting points but improves the flexibility of PP. Compared with PP, the volume resistivity of the blends shows a decrease at low loading of POE and starts to increase when the POE loading is higher than 15 wt%. After the introduction of POE, the DC breakdown strength is slightly decreased and the hetero space charge accumulation is enhanced. Although the electrical properties of the PP/POE blends are inferior to those of the pure PP, the enhanced flexibility, high volume resistivity, high breakdown strength as well as the excellent thermal properties make the PP/POE blends have the potential for HVDC cable application. The hetero space charge accumulation is still an issue, and further modification of the blends should be considered for suppressing the space charges.

Effect of zinc borate on mechanical and dielectric properties of metallocene linear low-density polyethylene/rubbers/magnesium oxide composite for wire and cable applications

The effect of zinc borate (ZB) quantity on the mechanical and dielectric properties of 20 phr magnesium oxide/10 % rubbers (9/1 NR/ENR-50)/metallocene linear low-density polyethylene (mLLDPE) in the presence of N,N-m-phenylene bismaleimide (HVA-2) compatibilizer was investigated for wire and cable applications. With the increase in ZB loading, the tensile strength and the elongation-at-break of the composites decreased while the tensile modulus increased. In all composites, the strain-induced crystallization phenomenon at 200 % elongation was being observed in the stress–strain curves. Moreover, the dielectric strength, dielectric loss, permittivity and volume resistivity at frequency of 50 Hz were investigated. The permittivity of all composites increased with a rise in the voltage within the range of 1–5 kV. The loading of ZB in the composites improved the permittivity and volume resistivity as compared to the neat mLLDPE. The dielectric loss increased and 2 phr ZB composite displayed the highest dielectric loss among all other composites. On the other hand, the breakdown decreased with increasing ZB loading and the highest breakdown was observed in the 6 phr ZB composite. It was concluded that all composites are suitable for wire and cable application and the best result based on dielectric properties was observed in the 6 phr ZB composite.

Analysis and Mitigation of Resonance Propagation in Grid-Connected and Islanding Microgrids

The application of underground cables and shunt capacitor banks may introduce power distribution system resonances. In this paper, the impacts of voltage-controlled and current-controlled distributed generation (DG) units to microgrid resonance propagation are compared. It can be seen that a conventional voltage-controlled DG unit with an LC filter has a short-circuit feature at the selected harmonic frequencies, while a current-controlled DG unit presents an open-circuit characteristic. Due to different behaviors at harmonic frequencies, specific harmonic mitigation methods shall be developed for current-controlled and voltage-controlled DG units, respectively. This paper also focuses on developing a voltage-controlled DG unit-based active harmonic damping method for grid-connected and islanding microgrid systems. An improved virtual impedance control method with a virtual damping resistor and a nonlinear virtual capacitor is proposed. The nonlinear virtual capacitor is used to compensate the harmonic voltage drop on the grid-side inductor of a DG unit LCL filter. The virtual resistor is mainly responsible for microgrid resonance damping. The effectiveness of the proposed damping method is examined using both a single DG unit and multiple parallel DG units.

Cable Tension Preslack Method Construction Simulation and Engineering Application for a Prestressed Suspended Dome

To solve the shortage of traditional construction simulation methods for suspended dome structures, based on friction elements, node coupling technology, and local cooling, the cable tension preslack method is proposed in this paper, which is suitable for the whole process construction simulation of a suspended dome. This method was used to simulate the construction process of a large-span suspended dome case study. The effects on the simulation results of location deviation of joints, construction temperature, construction temporary supports, and friction of the cable-support joints were analyzed. The cable tension preslack method was demonstrated by comparing the data from the construction simulation with measured results, providing the control cable tension and the control standards for construction acceptance. The analysis demonstrated that the position deviation of the joint has little effect on the control value; the construction temperature and the friction of the cable-support joint significantly affect the control cable tension. The construction temperature, the temporary construction supports, and the friction of the cable-support joints all affect the internal force and deflection in the tensioned state but do not significantly affect the structural bearing characteristics at the load state. The forces should be primarily controlled in tensioned construction, while the deflections are controlled secondarily.

Thioxanthone derivatives as stabilizers against electrical breakdown in cross-linked polyethylene for high voltage cable applications

In the search of voltage stabilizers for high voltage underground cables the chemical synthesis and electrical tree inhibiting effect of a series of thioxanthone derivatives in cross-linked low-density polyethylene (XLPE) is reported. The strongest increase in electrical tree initiation field under high-voltage alternating current (HVAC) conditions was 55% compared to reference XLPE after the addition of 0.3 wt% 9-oxo-9H-thioxanthen-2-yl methacrylate. Thermal analysis, small angle X-ray scattering and gel content measurements showed that the addition of the stabilizers did not significantly influence the microstructure and gel fraction of XLPE. A comparison between the stabilizing effects of the thioxanthone derivatives and previously reported photophysical properties revealed that a short lifetime of the triplet excited state can be related to a good voltage-stabilizing effect.

Three-dimensional characterization of BaHfO3 precipitates in GdBa2Cu3O7-y flim using STEM tomography.

IntroductionSince the discovery of REBa2Cu3O7-y (RE: Rare Earth element, REBCO) superconductors, they have been expected as the best candidates for the power cable application due to its high critical temperature (Tc) and critical current density (Jc). Among those REBCO superconductors, GdBa2Cu3O7-y (GdBCO) have been receiving great interest because they have higher Tc and Jc than YBa2Cu3O7-y [1].GdBCO with various types of precipitates as artificial pinning centers (APCs) have been proposed to minimize the anisotropy of Jc characteristics under the magnetic field. Among those precipitates, BaHfO3 (BHO) was found most effective precipitates as APCs in GdBCO film prepared by pulsed laser deposition (PLD) method [2]. It is therefore necessary to investigate not only the morphologies but also the dispersion of BHO precipitates within the GdBCO, to understand the role of BHO for the superconducting characteristics. In this study, morphologies and dispersions of BHO precipitates were characterized three-dimensional by scanning transmission electron tomography ExperimentalBHO dispersed GdBCO films were fabricated on Hastelloy C-276TM substrates with buffer layers of CeO2/LaMnO3/MgO/ Gd2ZrO7 by PLD method.To observe microstructure of GdBCO film with BHO precipitates, cross-section TEM specimens were prepared by FIB method using Quanta 3D-200 (FEI, USA) with acceleration voltage from 2 to 30 kV. Three-dimensional information such as morphology and dispersion, of BHO precipitates were characterized by electron tomography using STEM-HAADF. Result and discussionFigure1 shows three-dimensional reconstructed volume of BHO precipitates in GdBCO, which revealed that fine BHO precipitates have rod- and plate-like morphologies with homogeneous dispersion in GdBCO. In addition, growth directions of these precipitates were found with wide angular distributions from growth direction of GdBCO. Anisotropy of Jc in the magnetic fields was probably enhanced by various growth directions and homogeneous dispersion of nanosized BHO within GdBCO.jmicro;63/suppl_1/i26/DFU080F1F1DFU080F1Fig. 1.Three-dimensional reconstructed volume of BHO.

Electron Beam Irradiation of LDPE Filled with Calcium Carbonate and Metal Hydroxides

This article deals with the effect of electron beam irradiation and flame-retardant loading on the performances of LDPE-based formulations for wire and cable applications. In this study the influence of electron beam irradiation on different blends of low density polyethylene (LDPE) filled with aluminum trihydrate (ATH), magnesium hydroxide (MH), and calcium carbonate (CaCO3) were studied. The mechanical, thermal, and burning properties of the resulting polymer networks have been analyzed and discussed. Addition of all non-halogenated fillers to LDPE deteriorated the mechanical properties. Addition of MH to LDPE presented a significant increase on adhesion forces inside polymer matrices and acted more efficiently than similar ATH/LDPE and CaCO3/LDPE compounds. LDPE flame retardancy improved significantly by a carbonaceous, non-flammable coating formation with high plasticity of CaCO3 addition at high temperature. The resulting MH blends were more efficient thermally and burned more stably than similar ATH blends. It was also concluded that electron beam irradiation had improved effects on thermal stability and mechanical properties for all the polymeric samples in this research.

Semi-active control of forced oscillations in power transmission lines via optimum tuneable vibration absorbers: With review on linear dynamic aspects

Due to flexibility, relatively small weight and low energy-dissipative characteristics of cables, they are vulnerable to external excitations such as wind, wind–rain, earthquake and traffic loadings. Among them, galloping phenomenon is one of the most important sources of electrical/mechanical failures in power transmission lines. In this paper, tuneable vibration absorbers (TVAs) are used to suppress galloping forced vibrations (as a semi-active control approach). Using mode summation technique, mathematical model of the hybrid problem including the transmission line and an arbitrary number of absorbers is presented. Developing a sophisticated multi-loops optimization algorithm, best values of the absorbers׳ parameters (their location and stiffness, not necessarily symmetric) are found such that the transmission line deflection is minimized. Simulation results are presented in time and frequency domains. According to the results, designed TVAs act efficiently in suppressing galloping forced vibrations, especially under resonance conditions. Finally, global optimum design of TVAs is presented through a lookup diagram for a wide range of harmonic excitations. Since the optimal algorithm is developed in an extensive and general user-friendly manner, TVAs design can be accomplished for other industrial applications of flexible cables; under various excitations.

Reserve Power Arrangements in Rural Area Underground Cable Networks

The popularity of underground cables to replace overhead lines is increasing. This is partly a consequence of the requirement for better reliability and supply security. In some countries, the authorities have set maximum interruption durations for distribution system operators to steer the operators to avoid the use of overhead lines. However, although faults are typically of a rare occurrence in underground cable networks, they cannot be completely avoided. Since the fault repair process in an underground cable network is time consuming, the distribution network should be meshed, and the rate of disconnecting switches should be high enough. However, this is not always possible or economically feasible and, therefore, other opportunities to restore the electricity supply should also be considered. This is especially the case for branch lines without a backup option. Yet, the power should be restored in a reasonable amount of time, which emphasizes the significance of an appropriate switch placement strategy and reserve power planning. This paper proposes a methodology to analyze the costs of different reserve power strategies and to optimize the reserve power arrangements. The reserve power strategies under consideration are the application of reserve power cables and reserve power generators and looping of the existing branch lines.

Использование канатных анкеров при креплении выработок в условиях слоистых пород

Использование канатных анкеров при креплении выработок в условиях слоистых пород

Evidence of surface accumulation of fillers during the photo-oxidation of flame retardant ATH filled EVA used for cable applications

Abstract This paper is devoted to the photo-oxidation of a fire retardant polymer used for cable jacketing and an emphasis was put on understanding how highly filled composites (Ethylene-Vinyl Acetate filled with Aluminium Tri-Hydroxide) behave under UV irradiation. Samples have been irradiated during several thousand hours and the degradation has been studied at the surface but also within the polymer bulk. The degradation of the polymer part, because of a massive chain scissions process, leads to a progressive enrichment of the inorganic part at the surface which then acts as a screen for the bulk. Thus, the degradation is very heterogeneous along the polymer thickness and the degradation profiles well correlate with the evolutions of the mechanical properties (i.e. mechanical properties are not influenced if the degradation profile remains small compared with the total sample thickness).

Misalignment tolerance analysis and fabrication for highly efficient parallel optical-electrical convertor module

A compact, highly efficient, and passively assembled parallel optical-electrical convertor module (POECM) for active optical cable application is proposed. This paper presents our POECM structure, optical design simulation results, fabrication process, and data transmission test results, in sequence. The POECM has a compact size of $$18.5\hbox {mm} \times 10\hbox {mm} \times 2.8\hbox {mm}$$ . We confirm a data rate of total throughput at 21.6 Gbps ( $$5.4\hbox {Gbps} \times 4$$ channels) with a bit error rate of less than $$10^{-12}$$ .

Improvement and application of load-dispersing anchor cable

Improvement and application of load-dispersing anchor cable

Modular Femoral Tapered Revision Stems in Total Hip Arthroplasty

Background: Modular component options can assist the surgeon in addressing complex femoral reconstructions in total hip arthroplasty by allowing for customization of version control and proximal to distal sizing. We review the early clinical results of a single modular femoral revision system that offers 3 proximal body types, 5 distal stem geometries, and a wide range of offset, sizing and auxiliary options.Methods: A query of our practice’s arthroplasty registry revealed 60 patients (61 hips) who signed an IRB-approved general research consent allowing retrospective review, and underwent total hip arthroplasty performed with the modular femoral revision system between December 2009 and April 2012. There were 35 men (58%) and 25 women (42%). Mean age was 65.1 years (range, 35-94) and BMI was 31.3 kg.m2 (range, 14-53). Procedures were complex primary in 1 hip, conversion in 6 (10%), revision in 32 (53%), and two-staged exchange for infection in 22 (33%). Two-thirds of procedures included complete acetabular revision (n=40), while 31% (19) involved liner change only and 2 were isolated femoral revisions.Results: At an average follow-up of 1.5 years (maximum: 3.7 years) there have been no revisions or failures of the femoral component. Average Harris hip scores (0 to 100 possible) improved from 44.2 preoperatively to 66.0 at most recent evaluation, while the pain component (0 to 44 possible) improved from 15.8 to 31.2. Complications requiring surgical intervention included intraoperative periprosthetic femur fracture in one patient returned to the operating suite same day for open reduction internal fixation, which further required incision and debridement for superficial infection at 1 year postoperative; and two patients with dislocation and fracture of the greater trochanter treated with open reduction, revision of the head and liner, and application of cerclage cables, one of which required removal of a migrated claw 10 months later followed 2 weeks subsequently with incision and debridement for a non-healing wound. Postoperative radiographs were available for review for 59 THA in 58 patients. Analysis of the femoral component revealed satisfactory findings in 50 hips (85%) while 9 had radiographic changes that included bone deficit, osteolysis, or radiolucency in one or more zones.Conclusions: The early results of this modular femoral revision system are promising for the treatment of the deficient femur in complex primary and revision total hip arthroplasty. Patients with radiographic changes are advised to return for regular clinical and radiographic follow-up. Survival of the modular femoral component in this series was 100% at mean follow-up of 1.5 years and up to 3.7 years. While HHS clinical and pain scores were somewhat low at most recent evaluation, they were significantly improved over preoperative levels.

A combined experimental–numerical rheometric and mechanical characterization of EPM/EPDM rubber for medium voltage cable applications vulcanized with peroxides

ABSTRACTThe vulcanization of medium and high voltage (M‐H V) cables is an important industrial application where manufacturers use principally EPM/EPDM, crosslinked polyethylene (XLPE) and now also thermoplastic rubbers. In the present article, an EPDM compound for medium voltage cables—normally distributed to producers in pellets and ready to be cured—is considered and several experimental tests (rheometer curves and mechanical characterizations) are conducted changing controlled curing temperature, peroxide type and peroxide concentration. In particular, tests are replicated in a temperature range between 160 and 200°C, with data provided every 20°C, using two different peroxides, a mixture of three commercial peroxides at five different concentrations. A huge amount of experimental data (cure curves) is obtained (one for each temperature, peroxide used and concentration) and results are critically compared one each other, to have a quantitative insight into the most effective temperature and peroxide to be used during this kind of vulcanization, with the aim of maximizing vulcanization velocity, final torque reached and mechanical properties of cured rubber. The comprehensive experimental study proposed is finally assessed from a numerical point of view, utilizing a complex kinetic scheme constituted by reactions occurring in series and parallel, which allows estimating numerically the vulcanization degree by means of a single second order nonlinear differential equation, with unknown parameters determined through non‐linear least squares fitting, with target data represented by experimental rheoemeter curves. The experimental fitting is almost perfect for all the cases analyzed and is aimed at predicting (without an expensive experimentation) the most suitable production parameters (e.g., curing time and temperature) to guarantee improved mechanical properties and a good aging resistance of the items. In addition, the numerical approach could allow finding the most suitable recipe, also in presence of mixtures of peroxides, able to provide items with a uniform vulcanization level. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40075.

Influence of carbon black in polychloroprene organoclay nanocomposite with improved mechanical, electrical and morphology characteristics

The effect of carbon black on nanoclay filled polychloroprene (CR) composites has been investigated. The nanoclay loading is fixed at 5 part per hundred rubbers (phr), and carbon black loading varied from 5 to 20 phr in rubber compounds. The rubber nanocomposites are prepared in laboratory by mixing in two-roll mill. The addition of nanoclay enhances mechanical properties especially tear strength and decreases water absorption without change in electrical properties compared to gum rubber vulcanisates. Wide angle X-ray diffraction and transmission electron microscopy are used to study the microstructure of CR nanocomposites. The addition of 5 parts of nanoclay to 15 phr carbon black filled samples shows synergistic effect between the fillers and suggests that the reinforcement is due to a more developed filler network formation in hybrid filler system than that in single phase filler. Significant improvement in mechanical, electrical and low water absorption properties has been obtained with these nanoclay and carbon black filled rubber nanocomposites. The paper concludes that nanocomposites containing a mixture of organoclay and carbon black in right proportion can be a substitute for rubber components used in underwater cable and device encapsulation applications.

Design of Solder Alloy Composition for Semi-Flexible Coaxial Cable Holistic Tin-Plating Application

Holistic tin-plating on the outer conductor is one of the key processes in the manufacture of semi-flexible coaxial cable. In this study, a tin-based solder alloy was developed for this special tin-plating process. For this new solder alloy, the molten solder's antioxidant performance, the morphology of inter-metallic compounds (IMCs) at the solder/copper interface and the dissolution rate of outer conductor during tin-plating process were studied. The results indicate that when the addition of P element in the pure tin solder up to 35ppm, the static oxidation rate of pure tin decreased to 12.1g/m2 from 26.5g/m2, while the dynamic oxidation rate decreased from 8.9g/m2 to 5.6g/m2, which can significantly reduce the amounts of the oxidized slag from tinned tank during the continuous operating; By adding 0.1%Co, 0.05%Ni, the morphology of IMCs changed from scallop-shape to a uniform plate-shape, which can improve the interfacial bonding strength and flexibility; Adding 0.7%Cu can reduce the dissolution of the outer copper conductor during tin-plating process.

Application of Non-Adhesive Pre-Stressed Anchor Cables in the Treatment of the Crack of Dam

Mass concrete ,such as dam concrete will appear vertical and horizon cracks due to various reasons. and these cracks will threat the safe operation and limit the economic benefits of the dam. pre-stressed anchor cables have been widely used as a main reinforcement method. the paper focuses on the cable construction technique and describes its effective reinforcement capabilities combined with the reinforcement of Panjiakou dam.The horizontal crack of Panjiakou concrete gravity dam is an activity crack, which varies with season and temperature change. Results of many years of test and research showed that the application of "combining caulking with draining and pre-stressed Anchorage" in the treatment of the crack was effective.At present, reinforcement construction has been completed, and the project operates well.