Composite Cables Research Articles

On-line monitoring system of 110 kV submarine cable based on BOTDR

The submarine cable is large-scale and high cost, and at the same time, it locates at the bottom of the ocean, which leads to difficulties in its daily inspection and fault detection. At present, there is no effective real-time on-line monitoring system for it. To solve the problem, an on-line monitoring method based on the Brillouin optical time domain reflectometer (BOTDR) is proposed. The BOTDR technology can measure the temperature/strain distribution along the submarine cable with high accuracy, and the temperature and strain coefficients of the G.652 optical fiber are calibrated. On the basis of systematic investigations, the real-time on-line monitoring system based on BOTDR has been realized. A 110kV optical fiber composite submarine cable can be monitored by the established BOTDR system with a spatial resolution of 1m. The system is put into service in China, and runs well. The large amounts of data are acquired and analyzed, and the results reveal that currently, the three phases’ submarine cables function well. At the same time, the influence of the sea wave scouring and sediment migration is slight at the relatively flat area. However, the cable laying topography has a very close relationship with the measured data, that is, the steeper the topography, the larger the measured Brillouin frequency shift value. The monitoring system proposed in the paper provides a feasible scheme for the on-line monitoring of the submarine cable, which can ensure the safe operation of the submarine cable.

Development and Improvement of an Intelligent Cable Monitoring System for Underground Distribution Networks Using Distributed Temperature Sensing

With power systems switching to smart grids, real-time and on-line monitoring technologies for underground distribution power cables have become a priority. Most distribution components have been developed with self-diagnostic sensors to realize self-healing, one of the smart grid functions in a distribution network. Nonetheless, implementing a real-time and on-line monitoring system for underground distribution cables has been difficult because of high cost and low sensitivity. Nowadays, optical fiber composite power cables (OFCPCs) are being considered for communication and power delivery to cope with the increasing communication load in a distribution network. Therefore, the application of distributed temperature sensing (DTS) technology on OFCPCs used as underground distribution lines is studied for the real-time and on-line monitoring of the underground distribution power cables. Faults can be reduced and operating ampacity of the underground distribution system can be increased. This paper presents the development and improvement of an intelligent cable monitoring system for the underground distribution power system, using DTS technology and OFCPCs as the underground distribution lines in the field.

Continuous monitoring of mining induced strain in a road pavement using fiber Bragg grating sensors

This paper describes the application of fiber Bragg grating (FBG) based sensors for monitoring road pavement strains caused by mining induced ground subsidence as a result of underground longwall coal mining beneath a major highway in New South Wales, Australia. After a lengthy planning period, the risks to the highway pavement were successfully managed by the highway authority and the mining company through a technical committee. The technical committee comprised representatives of the mining company, the highway authority and specialists in the fields of pavement engineering, geotechnical engineering and subsidence. An important component of the management strategy is the installation of a total of 840 strain and temperature sensors in the highway pavement using FBG arrays encapsulated in glass-fiber composite cables. The sensors and associated demodulation equipment provide continuous strain measurements along the pavement, enabling on-going monitoring of the effects of mining subsidence on the pavement and timely implementation of planned mitigation and response measures to ensure the safety and serviceability of the highway throughout the mining period.

지중 배전계통 적용을 위한 광복합 케이블 실시간 감시시스템 개선

Since power system is switching to smart grid, on-line monitoring technology has become necessary for underground distribution power cable. Therefore, the application of DTS(Distributed Temperature Sensing) technology using OFCPC(Optical Fiber Composite Power Cable) capable of monitoring underground distribution power cables has been developed. These can bring about reductions in faults and increases in operating capacity of underground distribution system. To date, the test-bed of optical fiber composite power cable on-line monitoring system has been constructed. Then, matters to be improved have been drawn through verification experiments. This paper presents the improvement and experiment results of the optical fiber composite power cable on-line monitoring system to apply to underground distribution lines in the field.

Coastal seafloor observatory at Xiaoqushan in the East China Sea

The seafloor observation system is becoming an important infrastructure for marine research because it is transforming oceanic research from temporal investigation to long term observation. The East China Sea coastal seafloor observatory, located between 30°31′44″N, 122°15′12″E and 30°31′34″N, 122°14′40″E, is constructed near the Xiaoqushan Island outside the Hangzhou Bay on the inner continental shelf of the East China Sea. The observatory is connected by a submarine optical fiber composite power cable that is more than one kilometer long and consists of a special junction box that transmits power and communication signals to different instruments. The special junction box has a variety of waterproof plugs and connects to three different instruments installed in a trawl preventer. The submarine optical fiber composite power cable is landed on the platform by The East China Sea Branch, State Oceanic Administration and the power is continuously supplied by the solar panels and solar battery on the top of the platform. The real time data are directly sent through the cable to the platform and are transmitted by CDMA wireless to the receiver at the State Key Laboratory of Marine Geology of Tongji University. Measurements at the observatory have been taken since April 20, 2009 after installation and the results have been interpreted. The characteristics of the near bottom boundary are constrained by a sediment suspension model using portion of the observed data. In particular, discussion is provided on the sea surface height anomaly at Xiaoqushan Island influenced by the tsunami driven by the 2010 Earthquake in Chile. The successful establishment of the coastal seafloor observatory is the first step toward future development of seafloor observation systems in China. It not only accumulates experiences in technology and engineering, but also paves the way for performing important oceanic research using the long term continuous observation platform.

DTS를 활용한 광복합 지중 배전계통 실시간 감시시스템 개발 및 성능평가

Intelligent distribution equipment is inevitable to realize self-healing which is one of smart grid functions in distribution network. Therefore, most of distribution equipment have been developed with self diagnostic sensors. However, it is not effective to construct on-line monitoring system for underground distribution cable because of high cost and low sensitivity. Recently, optical fiber composite cable is being considered for communication and power delivery in order to cope with increasing communication in distribution network. This paper presents the design and performance assessment results of underground cable on-line monitoring system using DTS(Distributed Temperature Sensing) and optical fiber composite underground cable.

Research on Fully-Enclosed Composite Cable Made with CFRP and High-Tensile Steel Wire

In this paper, the proposed idea of producing fully-enclosed composite cable with CFRP coupling of high-tensile steel wires and the forming technology of the fully-enclosed composite cable body were introduced. The coordination mechanism of the fully-enclosed composite cable, the requirement of equal elastic modulus between high strength steel wire bundle and CFRP were investigated theoretically. We have come to the follwing conclusions: (1) Carbon fiber has the same strain with the high-tensile steel wire under the tension of whole anchorage. (2) The distribution of the force of the composite cable is in accordance with the axial stiffness between the carbon fiber with high-tensile steel wire. (3) To achieve a good synergy between the carbon fiber with high-tensile steel wire, similar or equivalent elastic modulus is required. (4) The stress ratio between carbon fiber and high-tensile steel wire in the fully-enclosed composite cable in engineering application should be controlled around 0.5.

Flexural Performance of Carbon Fiber-Reinforced Polymer Prestressed Concrete Side-by-Side Box Beam Bridge

The effect of varying transverse posttensioning levels and arrangements on the load response of a one-half scale 30° skewed seven box beam bridge model was investigated. The effective span of the bridge model was 9.45 m (31 ft) with a width of 3.35 m (11 ft) and depth of 355.6 mm (14 in.). The bridge model was prestressed and reinforced with carbon fiber composite cables (CFCCs). CFCCs were also used as shear reinforcement. The bridge model was provided with five transverse diaphragms equally spaced along the length of the bridge. The experimental investigation included load and strain distribution tests and a flexural ultimate load test. The load and strain distribution tests were conducted on the bridge model with and without full-depth longitudinal cracks at the shear-key locations. The investigation showed that the application of an adequate transverse posttensioning force was successful in restoring the load distribution of the bridge model with full-depth longitudinal deck cracks to that of the case without deck cracks. The ultimate load and the associated compression-controlled failure mode of the bridge model agreed well with that predicted according to ACI 440.4R-04 and numerical analysis. The behavior of the bonded pretensioned and reinforced CFCC strands was linear elastic and remained intact throughout the collapse of the bridge model. The unbonded transverse posttensioned CFCC strand also remained intact.

Development of a Super Slim Façade System for InHolland Polytechnic, Delft

The initial conceptual ‘wild idea’ for the INHolland project by architect Rijk Rietveld, New York, was elaborated through different design brainstorms towards a radical innovative system for ultra-slim glass facades. In this facade system insulated glass panels of a depth of maximum 50 mm are integrated with internal pre-stressed structural composite cables, stabilising the facade against wind forces. Dead weight to be taken over by vertical deadweight rods in between the vertical silicone seams between the panels. The insulated glass panels are sealed by composite spacer frames. Many different solitary tests were done with the sealing and the carbon fibre components, with adhesion of silicone sealant on the carbon fibre frames and on the perforation of the carbon fibre used through the frames. In the actual engineering phase structural analysis was performed and tests on several levels were executed. The composite frames were substituted by conventional metal frames. Due to the refusal by the glass panel manufacturer to supply a guarantee on inadequate number of tests with inadequate quality, the integrated system had to be changed into a duosystem with internal pre-stressed cables and integrated dead weight suspension rods. The facade had to keep in pace with the progress on site.

Hybrid composite cable with an increased specific strength for tensioned structures

High-strength hybrid composite cables with large specific strength based on such materials as carbon fiber reinforced plastics (CFRP), glass fiber reinforced plastics (GFRP), and Vectran are widely used in constructional practice. But use of a steel component enables to increase small relative elongation, decrease brittleness, and expand area of application of high-strength hybrid composite cables. In this paper, steel was investigated in combination with such materials as CFRP, GFRP, and Vectran. The behavior of hybrid composite cable was studied analytically and by experiment. Hybrid composite cables with increased specific strength were considered as materials of several cable groups for a prestressed saddle-shaped cable roof with dimensions 50×50 m. The opportunity to decrease displacements of composite saddle-shaped cable roof by using cable trusses, made from the hybrid composite cable with the increased specific strength was studied Rational geometric characteristics of the cable truss were determined by numerical experiment. It was shown that using hybrid composite cable enables to increase its specific strength up to 2.4 times. Rational components for composite cable with an increased specific strength were chosen by the numerical experiment.

Tension and fatigue behavior of silver-cored composite multi-strand cables used as implantable cables and electrodes

The mechanical behavior of a variety of cable architectures comprised of silver-cored wires was evaluated in uniaxial tension, and in cyclic strain-controlled fatigue with the use of a flex tester operated to provide fully reversed bending fatigue. The magnitude of cyclic strains imparted to each cable tested was controlled via the use of different diameter mandrels. Smaller diameter mandrels produced higher values of cyclic strain and lower fatigue life. Multiple samples were tested and analyzed via scanning electron microscopy. The fatigue results were analyzed via a Coffin–Manson–Basquin approach and compared to fatigue data obtained on 316LVM cables where testing was conducted in an identical manner. The effects of changes in wire diameter, cable architecture, and wire composition (i.e. silver-cored vs. 316LVM) are discussed.

Analysis of coupled electromagnetic-thermal effects in superconducting accelerator magnets

FAIR will built 5 magnet rings including two superconducting synchotrons. The SIS100 is the core component of the facility and will be equipped with 2 Tesla dipole magnets pulsed with 4 Tesla/s. The cable of the magnet coils is made of a hollow NbTi composite cable of about 7 mm outer diameter, cooled with two phase helium flow at 4.5 K. We calculate the heat load, the eddy and the hysteresis losses, investigate the impact of the ramping on the magnetic field, on the safety margin of the conductor and the required cooling for all different elements of the magnet including: the coil, the yoke, the bus bars and the beam pipe. This analysis is based on properties measured at cryogenic temperatures and fine detailed FEM models.

Mechanical Coil Structure of the FAIR SIS 100 Magnets

The SIS 100 magnets of the Nuclotron-type are fast- pulsed superferric cold iron magnets. The dipole coil is a double layer saddle-shaped coil with 16 turns. The cable is a hollow tube NbTi composite cable of about 7.2 mm outer diameter, cooled with two phase helium flow at 4.5 K. A 2D structural analysis of the dipole cross section has been performed to determine the stress levels in the components of the coil package and to suggest an appropriate support structure for the conductor. Different design proposals with the focus on limiting stress in the CuNi cooling tubes and on feasibility of industrial manufacturing procedures have been conceived and analysed. The chosen coil support structure (substrate or comb), together with new insulation and modification of the winding scheme, seems to be an appropriate way to stabilize the coil better and offers important advantages like precise positioning of the conductor, more uniform distribution of loads on the CuNi tubes, an easier winding process on a guiding support, and simplified production procedures. Samples of the new coil structure were produced and tested. The obtained results are presented and discussed.

Aging and condition monitoring studies of composite insulation cables used in nuclear power plants

Five composite ethylene propylene rubber/chlorosulfonated polyethylene (EPR/CSPE) insulated cables, a single composite cable with EPR/Neoprene, and a single Kerite insulated cable used in US nuclear power plants (NPP's) were evaluated. All of the cables had a CSPE outer jacket. To study the rate of degradation these cables were thermally aged at 110 and 120 degC until embrittlement of the composite insulation and/or outer jacket occurred. The degradation of the composite insulation and outer jackets was assessed by measuring elongation at break and indenter modulus. Both the indenter modulus and elongation values of the composite insulation and outer jacket exhibited excellent superposition when shifted using the time-temperature superposition principle. Regardless of whether or not the EPR insulation was bonded or non-bonded to the CSPE or Neoprene composite jacket thermal induced hardening and fusion of the composite jacket with EPR insulation was the cause for loss of flexibility of the composite wires. The aging rate of the composite insulated wires were not affected by the aging mode, namely, whether the composite wires were aged as a complete cable or with the jacket removed. However, the aging rate of the composite insulation and the outer jacket varied between different cables. Threshold indenter modulus values for successful loss of coolant accident (LOCA) performance for each of the composite insulation and outer jacket was correlated with the thermal aging periods of the studies available in the literature. Close correlation was found between the thermal aging periods used for satisfactory LOCA performance and the time to reach 50% elongation of the composite insulation. Indenter modulus values of the composite insulation and outer jacket when the composite insulation decreases to 50% elongation is also provided

More heat, less sag [power cable upgrades

This paper reports on the development of new high voltage cables that don't sag nearly as much as the power lines they would replace. By replacing the steel core that gives the cable its strength with novel composite materials, heat is reduced thereby minimizing sagging. One such low-sag, composite core transmission cable has been developed by the CA-based Composite Technology Corp. (CTC). Called aluminum composite conductor core (ACCC), the strength and resilience of these new cables are derived from fiberglass-encased carbon fiber. In addition to less sag, ACCC have more current carrying capacity than a typical cable with the same overall thickness. A similar low-sag cable, called aluminum conductor composite reinforced (ACCR) cable, has also been developed by 3M Co. except that it is made from a matrix of aluminum oxide fibers embedded in pure aluminum surrounded by wires made of hardened aluminum doped with zirconium for strength. Although these new cables are more expensive than steel-core cables, the economics of using them are attractive because of their greater current carrying capacity

New Design for the SIS100/300 Magnet Cooling

Two superconducting synchrotrons, SIS100 and SIS300, are planned for the new International Accelerator Facility of Antiprotons and Heavy Ions (FAIR) at GSI, Darmstadt. These accelerator rings, operating at liquid helium temperatures, are placed in one tunnel of 1100 m length. The SIS100 structural superferric dipoles and quadrupoles are based on the Nuclotron-type hollow NbTi composite multi wire cable and cooled in parallel with two-phase helium flows. The peak operating mode for the SIS100 dipoles corresponds to B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> =2 T, dB/dt=4 T/s, f=1 Hz. Fast-ramped dipoles ( dB/dtap1 T/s, fap0.05 Hz) with a field strength of 4 T and above are required for the SIS300 ring. A 4.5 T, costhetas-style, curved magnet with a coil made of a high current hollow cable cooled with two-phase helium flow is proposed for SIS300. The necessary modifications of the magnet cooling scheme are presented and discussed. General optimization of the SIS100/300 cryogenic system namely cooling with three refrigerators, the number of parallel channels, the length of helium transfer lines, and a closed nitrogen loop for the heat shield cooling is considered. The new design will make it possible to reduce the FAIR project cost

Rehabilitation of Masonry Walls Using Unobtrusive FRP Techniques for Enhanced Out-of-Plane Seismic Resistance

Earthquake damage to unreinforced masonry buildings has shown the vulnerability of perimeter walls to out-of-plane failure. This paper describes a study that was carried out to develop and test innovative fiber reinforced polymer (FRP) rehabilitation techniques that meet the stringent requirements for strengthening historical buildings and to be cost-effective alternatives applicable to other existing masonry structures. Unobtrusive FRP rehabilitation techniques that utilize flexible carbon fiber composite cables, mounted near the surface of the facade walls in epoxy-filled grooves in the bed and head joints, were developed. Ten full size walls were constructed of clay bricks and retrofitted using the developed FRP rehabilitation techniques. The test results demonstrated the high efficiency of the rehabilitation techniques under both monotonic and quasistatic cyclic loadings. Significant increases in ultimate capacities, energy absorption, and deformability were achieved for various reinforcing schemes co...

RRR behavior in NbTi superconducting cable due to fatigue damage

In order to investigate the effect of fatigue damage on the residual resistivity ratio (RRR) behavior in the nine strand Cu–Ni/NbTi/Cu composite superconducting cable, in this study, fatigue tests at room temperature and residual resistivity measurement tests at 12 K were carried out. Through fatigue tests of NbTi composite cables, a conventional S–N curve could be obtained even though there existed a possibility of fretting among strands in the cable. From the electrical resistivity measurement for NbTi strands after fatigue test, it was found that the RRR for the virgin strand from the annealed cable was three times larger than that for as-received one. With increased fatigue cycles at a stress amplitude level, the RRR decreased until 10 3 cycles, which was resulted from the accumulation of damage such as lattice defects and dislocation density in the Cu stabilizer.

Fast cycling superconducting magnets: new design for ion synchrotrons

A new option of a superconducting dipole magnet for a fast cycling ( f=1 Hz) synchrotron is presented. The magnet is based on cos θ-type geometry, but its cold mass ( T=4.5 K) consisting of SC-coil and a reinforcing shell is separated from the iron yoke ( T=50–80 K) by a small vacuum gap. The arc-type one layer SC-coil is made of a hollow NbTi composite cable.

DYNAMICS OF MOORING CABLES IN RANDOM SEAS

The dynamic analysis of a catenary mooring cable due to random motion of an offshore platform is performed in the frequency domain. The nonlinear fluid-drag force is linearized using the statistical linearization technique. A previously developed numerical procedure based on converting a boundary value problem to an equivalent set of initial value problems is utilized to solve the problem, which avoids the need for modal analysis. The method is found to be versatile for the determination of spatially varying drag and the analysis of composite cables in a unified manner. The influence of current on drag damping has also been investigated. The effect of seabed friction damping has also been incorporated in the linearized analysis.