Cable Applications Research Articles

A simple and portable add-on converter module for communication and measurements

This paper presents the development of a new versatile portable add-on converter module which can be used for analysing mobile communication and cable TV networks. Present testing techniques required separate test equipment for characterising electrical and optical networks. Here, we develop a new system work as an add-on module for electrical frequency domain reflectometer which can perform measurements in electrical as well as optical cable networks. Using this technique, millions of electrical cable analyser currently in use all over the world can be converted into the optical analyser. The same system can also be configured as a bidirectional communication system for a wide variety of applications like fibre to the antenna/fibre to the home, cable TV applications. We also show that the developed system has wideband performance over a frequency range from 800 MHz to 2.5 GHz and a dynamic range of 45 dB.

Influence of transport modes on AC loss characteristics of cylindrical single-layer conductors consisting of various HTS tapes

In high temperature superconducting (HTS) cable applications, AC loss is always a critical issue and an obstacle to the commercialization, and the cables are usually composed of conductors with cylindrical structure. To study the effect of the magnetic field distribution with noncircular shape on AC losses, four hexagonal single-layer conductors are prepared using BSCCO, YBCO, and YBCONiW tapes. Besides the BSCCO and YBCO conductors, conductors consisting of YBCONiW tape are tested with the Ni-W located in two positions that is the inside and the outside of the conductor. Moreover, we achieve the magnetic field of the noncircular shapes through various transport modes.The results show that AC losses of all conductors get a minimum in the simultaneous mode which means the six tapes of the conductor are energized together. For the BSCCO, YBCO, and NY conductor, the AC loss of the tape strongly depends on transport modes and the cylindrical configuration can obviously decrease AC loss. However for the YN conductor, the transport mode dependence is quite weak and the cylindrical configuration can hardly decrease AC loss. Furthermore, the AC losses of the YBCO conductor is optimal, and the AC loss of the YN conductor is the greatest because of the hysteresis loss of the NiW layers located outside of the conductor.

A Three-Phase Adaptive Reclosure Technology for Distribution Feeders Based on Parameter Identification

A scheme is proposed to improve the decreasing success rate of reclosing in a non-effectively grounded system with a wide application of cables. An inverter source is momentarily connected to the low-voltage side of a service transformer by controlled thyristors to apply a transient high voltage to the de-energized feeder before reclosing. Based on the idea of parameter identification, the internal structure of the de-energized feeder is investigated according to the frequency characteristics of the reference parameters to determine whether the feeder still experiences the fault. The influence of the firing angle on the strength of the frequency components in the transient waveforms is analyzed to determine its range for accurate measurement of feeder harmonic impedance. A sensitivity analysis on the fault property detection criterion is conducted, and the selection of the inverter source power impacted by the firing angle is provided. The results of the theoretical analysis, computer simulation, and lab experiments confirmed the effectiveness of the proposed scheme.

Degradation of unplasticised poly vinyl chloride based engineering products upon exposure to ultra violet radiation

Poly vinyl chloride (PVC) is considered as a widely used polymer for various applications. It is durable, inexpensive and resistant to heat, water and chemicals. Additives such as lubricants, heat stabilizers, plasticizers, impact modifiers, fillers and ultra violet (UV) stabilizers enhance its durability and make it suitable for a range of applications. PVC is used for automobile and other sectors in products ranging from piping and siding, blood bags and tubing, to wire and cable insulation applications. Poly vinyl chloride exhibits high sensitivity to UV rays and it is a life time deciding factor specially in outdoor applications. This study was conducted to analyse the degradation behavior of PVC under the UV environment. Commercially available 32mm PNT7 unplasticised poly vinyl chloride (uPVC) pipes were selected for this research. Initially, tensile strength, elongation, hardness and water absorption properties were analysed. Ultra violet ray exposure test was performed for PVC samples to evaluate the photo-degradation behavior at selected UV exposure time periods. Tensile strength, elongation, hardness, water absorption properties and visual inspection tests were performed after the UV exposure test. Scanning electron microscopic images and differential thermal analysis were also used to analyze the degradation behavior. It was indicated a slight reduction of tensile strength, percentage elongation and hardness of samples with increase of UV exposure time. Scanning electron microscopic images of products showed degraded features after UV exposure test. This study revealed that uPVC based products are resistant to photodegradation by UV rays.

СТРУКТУРНЫЙ АНАЛИЗ И КЛАССИФИКАЦИЯ РОБОТИЗИРОВАННЫХ СИСТЕМ С ПРИВОДНЫМИ МЕХАНИЗМАМИ НА ОСНОВЕ КАБЕЛЬНЫХ ЭЛЕМЕНТОВ

The mechanisms of the parallel structure are very diverse. Cable-driven robots that use cables instead of retractable rods to control the position of the output link are of particular interest. They have several advantages, such as large workspace, easy assembly, and disassembly, high mobility, but also there are disadvantages associated with controlling the movement of robot cables. The paper gives examples of some of the first cable robots, their purpose, and application. The article also considers Russian and foreign scientists who deal with these issues and analyzes their work. As a result of the structural analysis, the classification of cable robots is compiled and considered in detail: by the method of placing the reels, by the DOF number of the working body and the number of flexible links, by the application method, by the type of base, by the method of cable fastening. The cable robot structure for the movement of goods is given. However, there are still many areas open to theoretical research. In conclusion, the topics that need more research are considered. The most obvious area of research is control, also optimizing the workspace for different applications of these devices, finding and take advantage of all the benefits offered by cable devices.

Temperature dependent electrical properties of thermoplastic polypropylene nanocomposites for HVDC cable insulation

Polypropylene has been regarded as a potential recyclable insulation material for HVDC cable, which is beneficial to improve the working temperature and transmission capacity of HVDC cables. However, the electrical properties of polymeric insulation materials exhibit apparent temperature dependent characteristics. Temperature influences the generation and migration of charge carriers, thereby affecting the electrical properties. This paper focuses on the electrical properties of polypropylene nanocomposites at different temperatures, including volume resistivity, space charge and DC breakdown strength. The temperature dependent electrical properties of polypropylene are regulated by adding MgO nanoparticles. Based on the characterization of microstructure and trap characteristics, the mechanism of regulating the charge carrier transport process and the electrical properties of the nanocomposites by introducing MgO nanoparticles is explained. The polypropylene nanocomposites show decreased electrical conduction, suppressed space charge accumulation and increased DC breakdown strength, which are desirable for recyclable HVDC cable insulation application. This work may pave a way for tailoring the high temperature electrical properties of polymeric insulation material.

Augmented reality tracking registration and process visualization method for large spacecraft cable assembly

The new generation of spacecraft has the characteristics of large-scale structure and complicated cable assembly process. In order to meet the needs of the augmented reality process visualization technology in its further application exploration, the two aspects of augmented reality tracking registration and process visualization are now studied. In the large-scale spacecraft cable assembly application scenario, the augmented reality process guidance technology puts more stringent requirements on the continuous tracking range and virtual and real registration accuracy of large space. The 3D process visualization method for cable assembly is optimized to improve the accuracy, quality and efficiency of the operator in process interpretation and implementation.

Material progress toward recyclable insulation of power cables. Part 1: Polyethylene-based thermoplastic materials: Dedicated to the 80th birthday of professor Toshikatsu Tanaka

New catalyst, copolymerization, blending, nanotechnology, and additives have been used to improve the electrical properties of thermoplastic polyethylene for power cable insulation applications.

Performance analysis for aerial-towing system

The dynamics of open chain systems have been widely investigated as a result of its increased applications such as aerial towing system, submerged towed cable applications, robot manipulators, and bio-mechanical applications. In this study, a practical engineering system, Mine Clearing Line Charge MICLIC system is taken as an example for an open chain system with accelerated end and varying number of segments. To validate the proposed model, a comparison between two different finite segment methods namely Kane’s method and Riccati transfer matrix method of linear multibody system (Riccati-MS-TMM) have been performed for a large open chain system. Results show that computational speed of Riccati-MS-TMM outperforms Kane’s method due to its huge matrix size to be solved. Then, using a predefined rocket motor total impulse, a parametric study has been performed on MICLIC system to illustrate the impact of different rocket motor thrust profiles on the resulted flight performance including the missile range, flight time, maximum tension applied on the rocket towing bridle, and the missile stability.

Numerical study on critical current and AC loss for different structured stack slotted-core HTS cables

AC losses occur when high temperature superconducting (HTS) cables are connected by alternating current placed in alternating background magnetic field. The generation of AC loss will increase the load of cooling system, and deteriorate the overall performance of cables. Therefore, AC loss of high temperature superconducting cable is an important design parameter of large-scale power application. Up to now, AC loss characteristics of various HTS cables such as conductor on round core (CORC) cable, twisted stacked tape cable (TSTC), Roebel cable, quasi-isotropic strand and soldered-stacked-square-twisted (3S-T) wire have been extensively studied. AC loss characteristics of twisted-stack slotted-core cable, however, have not been studied. In this work, the self-field and in-field AC losses and critical currents of different structured stack slotted-core cables are studied numerically in two-dimensional. The critical current calculation using self-consistent model was based on the A-formulation and the H-formulations to assessment the AC losses. The numerical results are useful for the application of HTS cables.

Solution Modified Fumed Silica and Its Effect on Charge Trapping Behavior of PP/POE/Silica Nanodielectrics

Various dielectric nanocomposite materials are studied in the frame of the European Commission funded project GRIDABLE. This project has the aim to develop DC cable extruded insulation and medium and low voltage DC capacitor films exhibiting enhanced performance with respect to presently used materials. The nanocomposites intended for cable applications are polypropylene (PP)/polyolefin elastomer (POE) blends filled with surface modified nano-silica particles. The surface modification is carried out via the state-of-the-art solution method using a polar silane as the modifying agent. Thermally Stimulated Depolarization Current (TSDC) measurements were carried out in order to study the charge trapping behavior of the nanocomposite samples. TSDC results indicate that the addition of the treated nano-silica, for most cases, reduces the density of the deep traps significantly. The effect of the addition of silica nanoparticles - both modified and unmodified - on the crystallinity of the samples was studied using X-ray Diffraction (XRD). This is important as the charge trapping properties of the nanodielectrics can be affected by the degree of crystallinity. While more detailed studies are necessary, these results imply that the depth and the density of the deep trap states is profoundly influenced by the level of the silica modification i.e. the amount of the grafted silane on the silica surface.

Modeling-Driven Optimization of Mechanically Robust REBCO Tapes and Wires

The bending properties of RE-Ba-Cu-O (REBCO, RE = rare earth) coated conductors are a stringent constraint for coil and cable applications. While the use of thinner substrates reduces the stresses/strains in the REBCO layer, it is also possible to enhance the mechanical properties of these tapes by optimizing the stabilizer thickness in order to reduce the distance between the neutral axis and the REBCO layer. In this paper, we present both experimental and analytical results showing a significant improvement in the critical current (I c ) retention at small bend diameters (less than 2 mm) for tapes with various substrate thicknesses by using an optimized copper thickness on the REBCO side only. The presented analytical method accounts for the neutral axis shift caused by the progressive plastic deformation in the various layers (Hastelloy, silver, and copper). The Ic dependence of different substrate tapes on the thickness of single-sided electroplated copper stabilizer was measured at bending diameters ranging from 0.81 to 12.5 mm by means of a single-turn helical winding on a cylindrical former. The strains were then calculated and an optimized copper thickness is determined for the various configurations. Based on these results, an optimal design for ultra-small diameter REBCO wires is also presented.

Economic Evaluation of 23 kV Tri-Axial HTS Cable Application to Power System

Research on the development of a superconducting power cable for commercialization is currently underway across the world. Many demonstrations of superconducting power cables connected to real power grids have already been conducted with various designs depending on the voltage levels of the distribution and transmission lines. In Korea, the first commercial project for high temperature superconducting (HTS) power cables, “Shingal Project” which is fully funded by Korea Electric Power Corporation (KEPCO), is underway to connect two substations with a 23 kV HTS cable with a distance of 1 km. In addition, the KEPCO Research Center (KEPRI) initiated the project in 2017 to develop the 23-kV tri-axial HTS power cables, including a cooling system, for a distance of 3 km. In this paper, the recent progress and research activities related to the two 23-kV superconducting power cables projects are discussed. An economic evaluation of the HTS power cables for commercialization in consideration of their construction environments and social issues is also presented.

High thermal conductivity insulation and sheathing materials for electric vehicle cable application

Polymeric insulated cable with high ampacity and good thermal performance is the core of the new fast charging technology for electric vehicles (EVs). Advanced materials with both good thermal and electrical properties to improve the performance of EVs charging cable are proposed in this paper. Two sample cables were manufactured with ethylene-propylene-diene (EPDM) insulation and a chlorosulfonated polyethylene rubber (CSM) sheath. Both the insulation and sheathing materials were modified by hybrid boron nitride (BN) to improve the thermal conductivity (TC). The test results show that the modified EPDM insulation has good electrical and mechanical properties. For the temperature characteristics of these two cables, the adoption of high TC EPDM insulation and CSM sheath can improve the heat dissipation capability and the temperature distribution in the cable. In addition, the theoretical ampacity of the cable was calculated showing a significant improvement. The employment of high TC insulation and sheath appears to be of great benefit to the reduction of temperature and increase in ampacity of EV charging cables.

Longitudinal Magnetic Field Effects on (Y,Gd)Ba2Cu3O7−δ Coated Conductor With BaHfO3 Nanoparticles Fabricated by UTOC-MOD Method

To clarify the effects of longitudinal magnetic field (LMF) on Y0.77Gd0.23Ba2Cu3O7- δ coated conductors fabricated by the trifluoroacetic-acid based metal organic decomposition method with the ultra-thin-once-coating process (UTOC-MOD (Y,Gd)BCO-CCs), and to understand the contributions of BaHfO3 nanoparticles (BHO-NPs) to this, we investigated the critical current density J c under a wide range of temperature and magnetic field conditions. We found that J c in the LMF configuration increased compared to those in the in-plane transverse magnetic field configuration under whole conditions in samples both with (w/) and without (w/o) BHO-NPs. J c enhancement due to the LMF configuration was remarkable in the w/ BHO-NPs sample at higher temperatures, indicating that introduction of BHO-NPs to UTOC-MOD (Y,Gd)BCO-CC would be useful for LMF DC cable applications.

Improving Mechanical Properties and Reaction to Fire of EVA/LLDPE Blends for Cable Applications with Melamine Triazine and Bentonite Clay.

The high flame-retardant loading required for ethylene-vinyl acetate copolymer blends with polyethylene (EVA-PE) employed for insulation and sheathing of electric cables represents a significant limitation in processability and final mechanical properties. In this work, melamine triazine (TRZ) and modified bentonite clay have been investigated in combination with aluminum trihydroxide (ATH) for the production of EVA-PE composites with excellent fire safety and improved mechanical properties. Optimized formulations with only 120 parts per hundred resin (phr) of ATH can achieve self-extinguishing behavior according to the UL94 classification (V0 rating), as well as reduced combustion kinetics and smoke production. Mechanical property evaluation shows reduced stiffness and improved elongation at break with respect to commonly employed EVA-PE/ATH composites. The reduction in filler content also provides improved processability and cost reductions. The results presented here allow for a viable and halogen-free strategy for the preparation of high performing EVA-PE composites.

A short review of cable yarding applications in Australia

The current technology in Australia is mainly large swing tower yarder with grapple. These yarders operate under whole tree or cut-to-length methods in steep terrains of Victoria, Tasmania and South-East Queensland. Cable yarding is often applied in clear fell operations in pine or Eucalypt stands in Australia. Felling operations prior to yarding are carried out manually or using tracked feller-bunchers. Typical terrains for applying cable yarding have slope larger than 30°. There is currently a lack of small to medium size cable yarders that can efficiently operates under different circumstances. Medium size capacity yarders would be required to handle a wide range of situations under uphill and downhill extractions while small capacity highly mobile yarders will be needed for clean-up operations.

Novel thermoplastic vulcanizates by selectively dynamic cross-linking based on PVDF/PTW blends: structure and property

ABSTRACTA novel thermoplastic vulcanizate (TPV) based on poly (vinylidene fluoride)/poly (ethylene–butylacrylate–glycidyl methacrylate) (PVDF/PTW) (30/70 w/w) blends has been fabricated by dynamic vulcanization due to selective cross-linking of PTW by adding small amount of 3-(2-Aminoethylamino) propyldimethoxymethylsilane (KH602). The blends with KH602 had the solid-like behavior at low frequency and enhanced viscosities and dynamic modulus. The TPV exhibited a quasi co-continuous morphology with PVDF dispersed in PTW matrix, which was different from that of PVDF/PTW blend, exhibiting phase-separated morphology with PVDF dispersed in unvulcanized PTW matrix. The resulted TPVs displayed excellent mechanical properties, and excellent strain recovery, which will be a promising coating material, especially wire and cable applications.

Comparisons of different polypropylene copolymers as potential recyclable HVDC cable insulation materials

The potential recyclable thermoplastic materials represent the future trend of the HVDC cable insulation material to replace crosslinked polyethylene (XLPE). Polypropylene block copolymer (PPB) and polypropylene random copolymer (PPR) with different weight-averaged molecular weight (Mw) were used to investigate the influence of different structure on their properties. The morphology, thermal, mechanical and electrical properties of the PP copolymers were comprehensively studied. The results show that PPB has good thermal properties, but its poor mechanical properties of low breaking elongation and low DC breakdown strength make it not suitable for recyclable HVDC cable insulation application. While PPR has relatively good thermal properties, high breaking elongation and high breakdown strength, which is significantly higher than XLPE and its space charge behavior is much better than PPB and XLPE. So PPR is more potentially suitable for recyclable cable insulation application.

Experimental investigation on the noise reduction method of helical cables for a circular cylinder and tandem cylinders

Cylinder noise can be remarkably reduced when the surface is helically wrapped with cables along the cylinder span. In this paper, aeroacoustic and aerodynamic experiments are conducted to reveal the noise reduction mechanism of the helical-cable technique. With the application of helical cables on the single circular cylinder, three-dimensional flow is promoted into the cylinder near wake, leading to the suppression of two-dimensional vortex shedding process and flow fluctuations. Besides, the three-dimensional wake also destroys the in-phase relationship of flow fluctuations along the cylinder span, leading to the reduction of spanwise correlation length and noise radiation efficiency. These two effects together contribute to the cylinder noise reduction. Furthermore, this helical-cable technique is extended to tandem cylinders and the results show that it can also reduce the tandem cylinder noise effectively. Especially for the moderate and large spacing tandem cylinder configurations, the key of the noise reduction is the control on the upstream cylinder.