Cable Design Research Articles

A probabilistic approach for power cable cross section area selection: Most economic design by computer aided

This study presents a practical computer-based design program for a power cable network called “Power Cables Graphical User Interface” (PCGUI). This program is mainly for academic education, consulting electrical designers, primary engineers, and technical personnel with open-source code and a simple user interface. As a low/medium-voltage cable selection program, PCGUI will represent an essential part of the design for any electrical system, including different and complex analytic procedures based on various international standards (“IEEE, IEC, BS, NEC, NPFA 70, and local applied country standards.”). A MATLAB PCGUI program gives a new method to analyze and identify the optimized cable design depending on huge numbers of MATLAB script files and data appropriate for different factors and conditions. These factors and conditions include the type of insulation, temperature factor, grouping factor, accepted voltage drop, cable lifetime costs, etc. PCGUI is easily accomplished with the least effort and provides a fast and economical design with very high accuracy through limited manual input steps. After executing the program, the obtained results will contain the complete economic cable design, the circuit breaker standard rating and type, the actual cable current loading, the actual voltage drop, and the primary and the most economic cable cross-section area “CSA” based on the cost analysis.

Research on Methods of Increasing Current Carrying Capacity of 110 kV Single Core Cable

Power cables have been used more frequently in planning and designing the urban power grid. With the rapid development of power grid engineering, the power grid’s capacity is increasing, and the transmission capacity of the cable is also growing. Therefore, it is of great significance to improve the cable carrying capacity. This paper puts forward some methods to enhance the current-carrying capacity of the cable, taking a 110 kV cable as an example, including adopting a reasonable cable arrangement, adopting proper grounding mode and segment length, and reducing the external thermal resistance of the cable and adopting reasonable laying mode. The above methods are calculated and analyzed, and the influence degree of the above methods on the current carrying capacity of the cable is counted, which provides a reference and basis for the design and selection of power cables in the future. Combined with the theoretical calculation and engineering practice of the current carrying capacity of the cable, the cable diameter is reasonably selected, the engineering investment is reduced, and the urban power grid is well constructed to provide a stable power guarantee for urban construction.

Experimental methods for studying heat transfer in cable penetrations in case of fire

An experimental technique for studying the processes of heat transfer in cable penetrations under the thermal effects of fire is proposed. To study the influence of the design of cable penetrations on cable heating processes, three most common types of penetrations were selected. New experimental data on the dependence of the temperature of the structural elements of the cable and the penetration on time have been obtained. It is shown that the conductive core of the cable is the main element involved in the propagation of heat. The presence of an air space or a material that promotes intensive heat exchange in the cable penetration design leads to an increase in its fire resistance limit. It is determined that the cable penetration with the filling of the internal space with fire-fighting foam based on polyurethane foam is most susceptible to rapid heating and loss of fire resistance. Studies have shown that when assessing the fire resistance limits of cable penetrations, it is necessary to take into account the thermophysical characteristics of cables, their number, as well as the design features of cable penetrations.

Sizing of Superconducting Cables for Turbo-ElectricDistributed Propulsion Aircraft Using a Particle Swarm Optimization Approach

Superconducting electrical power systems are proposed to meet high specific power densities required for turbo-electric distributed propulsion aircraft. Superconducting materials have unique thermal and electrical requirements for maintaining the superconducting state, which is critical to their normal operation. Electrical system faults can lead to this state being lost for all network assets in the electrical fault path. The resulting temperature rise can prevent the superconducting state from being immediately resumed following fault clearance, requiring disconnection of nonfaulted equipment. Undersized cables experience a higher temperature rise under faulted conditions and disconnect from the system more readily. Oversized cables are heavier and more costly. Therefore, there is a need to optimize the cable size, preventing disconnection of equipment due to temperature rise following a fault while minimizing the weight and cost penalty. This article proposes a system parameter-driven methodology, using particle swarm optimization, to identify fault-tolerant cable designs, which deliver minimum through-life costs. This facilitates high-value, quantifiable design trade studies incorporating system parameters. Key observations drawn are that the choice between improving fault ride-through capability of a superconducting cable by increasing the amount of either superconducting material or conventional former material strongly depends on acceptable system operating temperature and voltage.

Electric Field Calculation During Voltage Transients in HVDC Cables: Contribution of Polarization Processes

The simulation of electric field transients in HVDC cables can be a fundamental tool to support insulation system design when operation dynamics, which includes voltage polarity inversions and load variation, becomes significant during the expected cable life. The field behavior during voltage and temperature transients is associated with intrinsic and extrinsic ageing processes that can affect the cable design life. Traditional models employed for electric field simulations consider only the non–linear, steady–state dependence of conductivity on temperature and field magnitude, but they neglect the transient behavior of permittivity and conductivity, that is, polarization and charge trapping phenomena. These processes impact on the duration of the field transient and thus ageing. This paper discusses the numerical implementation of an electro–quasistatic model that can be used to perform transient simulations of electric fields in HVDC cables insulation. With respect to the model traditionally employed, the presented one is extended with Debye's equations for dielectric polarization processes. The model is implemented numerically using finite differences, or the Occhini equivalent circuit: this paper demonstrates that the two approaches are equivalent. Numerical simulations show that, during transients, polarization processes slow down the electric field dynamics and reduce its maximum intensity.

Numerical Analysis on Performances of Critical Current for Rutherford Cable Made From HTS Quasi-Isotropic Strands

2G high temperature superconducting (HTS) tapes are frequently cabled into strands that can be assembled as conductors in cables with various layouts and thus potentially employed in large-scale superconducting magnets with high magnetic fields and large transport currents. One option meeting the requirements for manufacturing high-current cables is the Rutherford cable configuration. This article proposes a flat Rutherford cable with a copper core made up of 12 quasi-isotropic strands. The critical current characteristics of the Rutherford cable are numerically analyzed at 77, 20, and 4.2 K by using the finite element method and a self-consistent model in self-field and applied magnetic fields with different magnitudes and orientations, respectively. Additionally, the simulated results of the Rutherford cable are compared with those of a directly stacked conductor. The results show that the proposed Rutherford cable can attain critical currents in the hundreds of kA range at 20 and 4.2 K in high fields. This Rutherford cable design is a potential and prospective solution for high-current superconducting cables in power transmissions and large-scale magnets with a high magnetic field.

Dependence of dynamic resistances in high-temperature semiconducting quasi-isotropic strands on magnitude and orientation of AC magnetic field

The dynamic resistance of a superconductor appears if it carries a direct current (DC) current and is simultaneously exposed to alternative current (AC) magnetic fields if its amplitude is higher than its full penetrated field. Due to its strong anisotropy, the dynamic resistance of high-temperature superconducting (HTS) tape is not only affected by the magnitude of AC magnetic fields but also their orientations. In particular, the dynamic resistance has considerable effect on the current distribution in HTS cables (except for Roebel cables) and even cable-in-conduit conductors made from those HTS cables, except for dissipative loss. This paper presents the behavior of dynamic resistance in an HTS quasi-isotropic strand (Q-IS), which consists of four sub-stacked 2G HTS tapes proposed by our group at North China Electric Power University, while it carries a DC current and simultaneously experiences an AC magnetic field with different magnitudes and orientations. An angular dependence of dynamic resistance in a single 2G HTS tape in an AC magnetic field with various orientations is first performed in simulations and experiments, respectively. The experimental results are in good agreement with the simulated ones, which shows that the dynamic resistance of a Q-IS also exhibits quasi-isotropic characteristics and has an important effect on the distribution of DC transport current. The related results are promising for the design and application of other DC HTS cables, feeders and magnets.

Optimum Design and Performance Analysis of Superconducting Cable with Different Conductor Layout

Compared with the traditional cable, the high-temperature superconducting (HTS) cable has the advantages of low loss and large capacity transmission. At present, the research on HTS cables mainly focuses on the calculation of AC loss, the performance under specific working conditions and cooling system design. Relatively little research has been carried out on the basic design and overall layout optimization of the cables. In this paper, an HTS cable with a rated current of 4 kA was designed. Firstly, according to the selected superconducting cable parameters, the body design of cables with different structures was carried out and the corresponding finite element models were built. Then, the performance analysis of HTS cables with different layouts was carried out based on the proposed cable performance evaluation indicators and the CORC double-layer structure was determined as the scheme of this cable. Finally, the AC loss of the cable with this topology was calculated to be 9.81 J/m under rated conditions. The cooling system can ensure the safe operation of the cable in the rated temperature range.

The Construction and Components Analysis of The Aizhai Bridge

The Aizhai bridge was constructed in a mountainous area and across a large canyon, a bridge that bears immense importance to the development of the nearby areas, according to the China Hunan Roads Development III Project. This study analyzes the structure, construction, materials, and components of the Aizhai Bridge, and discusses their advantages and drawbacks. Some novel construction techniques for the suspension bridge include aerial spinning and steel truss gliding method. Results show that the structural design is unique to the project, adapting to specific conditions such as complex geology, extreme weather, and large interval by implementing the design of tower-girder separation for the bridge alongside the design of the suspender cables and the materials implemented in the bridge, comparisons of carbon emissions due to materials are made with other bridges demonstrate the high effectiveness of the bridge design. Although the essence of the structure follows that of a traditional suspension bridge, the new design of the tower-girder separation structure has made the bridge much more environmentally friendly and safe.

Structural Mechanics Analysis of Multi-row Cable Drum of Port Machinery Based on ANSYS Workbench

Single row cable reels are often used in the study of cable reels by heavy port machinery equipment, but there are problems of less cable capacity and larger circumferential space. In the design of the traditional heavy machinery cable drum design concept principle as the basis, on the basis of the drum structure optimization and strength check. According to the design of cable parameters, it is concluded that the winding of drum occupies less space, the cable is arranged in a regular order and can accommodate a large amount of cable. In this paper, Ansys Workbench is used for structural mechanical analysis of the drum body, and the final results show that the maximum stress of the drum under the working load is far less than the allowable stress value. By analyzing the mechanical state under the working condition, the effect of cable capacity increase is obvious, and the relative mass is reduced, and the stability of the drum structure meets the requirements.

Comparison of Two 2.45 GHz Microwave Ablation Devices with Respect to Ablation Zone Volume in Relation to Applied Energy in Patients with Malignant Liver Tumours.

(i) to compare two 2.45 GHz MWA devices with respect to AZV in relation to the applied energy after MWA in patients with hepatocellular carcinoma (HCC) or colorectal liver metastasis (CRLM) and (ii) to identify potential confounders for this relationship. In total, 102 tumours, 65 CRLM and 37 HCC were included in this retrospective analysis. Tumours were treated with Emprint (n = 71) or Neuwave (n = 31) MWA devices. Ablation treatment setting were recorded and applied energy was calculated. AZV and tumour volumes were segmented on the contrast-enhanced CT scans obtained 1 week after treatment. The AZV to applied energy R(AZV:E) ratios were calculated for each tumour treatment and compared between both MWA devices and tumour types. R(AZV:E)EMPRINT was 0.41 and R(AZV:E)NEUWAVE was 0.81, p < 0.001. Moderate correlation between AZV and applied energy was found for Emprint (r = 0.57, R2 = 0.32, p < 0.001) and strong correlation was found for Neuwave (r = 0.78, R2 = 0.61, p < 0.001). R(AZV:E)CRLM was 0.45 and R(AZV:E)HCC was 0.52, p = 0.270. This study confirms the unpredictability of AZVs based on the applied output energy for HCC and CRLM. No significant differences in R(AZV:E) were observed between CRLM and HCC. Significantly lower R(AZV:E) was found for Emprint devices compared to Neuwave; however, reflected energy due to cable and antenna design remains unclear and might contribute to these differences.

Analysis method for the design of long submarine cables

The recent push for renewable electrical energy sources has resulted in a significant increase in the installation of the offshore wind farms. These farms become much bigger than their earlier counterparts and the generated power is much larger. This puts additional performance requirements on the export cables. Long submarine export cables are not only subjected to changing laying conditions along the route, including depth and seabed material variations, but also the loading patterns vary significantly over time. Additionally, applied reactive power compensation measures and the time-dependent grid situation change the distribution of the current along the route. These unique features of long submarine power cables necessitate a new type of approach to their design and construction optimization. This paper introduces a new approach for ampacity calculations of long submarine power cables. As the ampacity calculations form a basis for the design of a cable route, it is of paramount importance that they are performed as accurately as possible. The approach can be applied to general-purpose circuit solvers, and this paper describes how to implement it using the ATP-EMTP software, which is extended to the consideration of concurrent electrical and thermal effects. The approach permits considering all the important local and time-dependent parameters of the analysis simultaneously. In particular, the approach allows simultaneous analysis of the varying laying conditions along the route including changes in the depth of burial and thermal resistivity of the soil together with the temporal variations of the cable loading. Additionally, current characteristics in long AC cable conductors are strongly affected by the reactive power flow, which in turn depends on the location of the reactive power compensation, the reactive power demand for grid operation, and the wind farm voltage reactive power control strategy. Such analysis cannot be performed with any existing analytical tool. Also, numerical tools cannot handle such problems because a 3-dimensional time-dependent analysis of a cable route which is 100 km long would encounter convergence problems as the size of such model would be prohibitive. Hence, at present, the proposed approach is the only one available to solve this complex electro-thermal problem. Several numerical examples illustrate an application of the proposed methodology.

Driving cable design for a cylindrical deployable mechanism based on depth first search

Cables are utilized widely to drive deployable mechanism for the advantages of light weight and wide range of arrangement. This paper proposes a novel driving cable design method based on depth first search, which can achieve the optimal cable route to drive a cylindrical deployable mechanism. A deployable mechanism using Bennett linkages which can approximate a given cylindrical surface is constructed. Kinematic model of the mechanism is established to obtain the position of the links and joints during the deployment and retraction process. Principles of driving cable design, which should be followed in the design of driving cable route, are presented. A driving cable route design method based on depth first search algorithm is proposed to find all possible cable routes. Considering the length of cable and installation of pulleys, an integrated evaluation function is introduced to assess the cable route. The optimal deploying and folding driving cable routes of the cylindrical mechanism are obtained with the proposed method. A prototype is fabricated and experiments are conducted to verify the feasibility of the design. The proposed method can be applied in the driving cable route design of other deployable mechanisms.

Magnetization loss of CORC cables under axial tensile loading

As a highly flexible and fully isotropic cable structure, CORC (Conductor on Round Core) cable wound with high-temperature superconducting (HTS) tapes has promise for giant magnets, including fusion magnets, high-energy accelerator magnets, and nuclear magnetic resonance. CORC cables are subjected to mechanical, thermal, and electromagnetic loadings during preparation and operation. Axial tension is one of the basic deformation modes of CORC cables. To investigate the impact of axial tension loads on the electromagnetic performance of CORC cables, a mechanical-electromagnetic model is created in this study. A comparison of numerical simulations and experiments was first performed for single straight tape and single-layer CORC cables to verify the model's reliability, with particular attention to the critical current reduction and the variation of magnetization loss during axial tension. The model developed in this paper may evaluate electromagnetic performance under applied AC magnetic fields with small amplitudes and mechanical response to axial tension loads. On this basis, the strain distribution of CORC cables under axial tension and their magnetization loss characteristics under various strain states are presented. The effects of different cable design parameters on the critical current and magnetization loss are discussed. The results show that the strain affects the magnetization loss of CORC cable significantly, especially for ones with larger winding angles. The magnetization loss can be reduced by choosing a narrower tape, a smaller winding angle, or a cable core material with a higher Poisson ratio. This study can provide a theoretical basis for the structure optimization design and practical application of CORC cables.

GA based algorithms for offshore wind farm collector cable optimization

In the capital-intensive offshore wind farm industry, the collector cable optimization problem arises primarily due to electric infrastructure expense contributing high rate of initial investment cost. In this study, a multistage solution was developed for optimal locations, the number of offshore substations (OSSs), and inter-array cable routing determination. In the first, a novel GA method picks up the initial OSSs number and location from the candidate site list, then capacities minimum span tree (CMST) is applied to identify valid cable routings. Finally, optimal OSSs location, quantity, and cable paths are obtained through an iterative process. The results of a library real wind farms case are introduced in paper proves the feasibility of the proposed method and showed this study can apply on real practice for optimal decision in OWF cable design.

Ultrahigh Fiber Count and High-Density Cables, Deployments, and Systems

Since the 1980s, the single-core optical fiber cable has been the essential data transmission wiring media, with ongoing increases in deployments. Its use case has broadened, with transmission distances ranging from meters to 10000s km, including intrabuilding, fiber-to-the-home (FTTH), terrestrial, and even submarine trunk lines. Currently, optical fiber cable deployment is strongly driven by cloud-based storage, X as a Service (XaaS), and worldwide data center (DC) functionality with the optical interconnection of massive servers on DC campuses. Hence, it is quite natural that the optical fiber cable industry has developed ultrahigh fiber count, high density, and small diameter optical fiber cable, e.g., 6912-fiber-count cable. With high-density cables, massive data capacity can be installed at one time while saving limited space in an underground duct. High-density cable designs have been developed not just by cable structure optimization but through the process of bundling fibers and the use of high-grade optical fibers. Moreover, many enabling technologies have been developed to support the deployment of ultrahigh fiber count cables, such as fiber identification, connectors, mass fusion splicing, and storage systems for fusion splicing points. In this article, state-of-the-art technologies and prospects for ultrahigh-count and ultrahigh-density optical fiber cables and enabling technologies are explained.

Temperature effect on cable force of a special-shaped tied-arch bridge

In this study, on-site monitoring was used to obtain the temperature field distribution and cable force values of the bridge at various times, the temperature change pattern of the bridge elements, the temperature sensitivity of the cable force of different parts of the bridge, and the trend of the cable force under temperature load were all analyzed. The static response of the wires was studied under various operating circumstances. The total cable force of the bridge is inversely related to the temperature rise and fall, and the temperature sensitivity of the cable force in different parts of the bridge is different under the same temperature effect. The change in cable force is uneven. They vary according to the loading circumstances. This project's cable force changes are the most substantial and consistent with observed circumstances and should be appropriately considered in comparable projects. Thermal impacts must be addressed in strand cable safety design.

Stay cable vibration mitigation: A review

Stay cables in cable-stayed bridges are subjected to various types of dynamic excitation mechanisms under environmental loads. The excited vibrations can have a large amplitude because of low vibration frequencies and small inherent damping of cables. As cables become longer (the longest cables are around 600 m in cable-stayed bridges with a main span of 1000 m), more modes are vulnerable to wind and rain-wind induced vibrations, posing challenges to vibration mitigation. This paper presents a comprehensive review of recent advances in stay cable vibration mitigation, including theoretical modeling of cable damping system and techniques for enhancing multimode damping. Recent results on cable damping measurements, understanding of cable vibrations, and relevant aerodynamic countermeasures are also recalled. The reflections can provide guidance for cable vibration control design of cable-supported bridges and for the maintenance/upgrade of cable vibration mitigation system of existing bridges.

Influence analysis of different compaction degrees on the fatigue performance for stranded copper power conductors

ABSTRACT The influence of compaction degrees of 120 mm2 stranded copper conductors on their fatigue performance was investigated. Conductors with two different compaction degrees were fatigue tested in tension-tension loading and the fatigue data for the two sets of conductors seemed not to fell within the same scatter band. Wires of stranded copper conductors were deformed due to the compaction procedure applied during fabrication. The fatigue data were adjusted considering the stress concentrations due to the deformation and the adjusted data fell within the same scatter band. Then the influence analysis of compaction degrees was performed. The compaction procedure was simulated by using finite element method and the results were compared with real conductors. A simplified fitting formula was proposed to describe the quantitative relationship between fatigue life and compaction degrees of copper conductors and a predicted fatigue life table was concluded which is helpful for cable design.

Investigating the effect of transverse compressive loads on the electromagnetic performance of superconducting CORC® cables

High-temperature superconductor (Re)Ba2Cu3O x (ReBCO) conductor on round core cable (CORC®) has a large current carrying capacity for high field magnets. Lorentz forces acting on CORC conductors, cause a reduction of the critical current, or even permanent degradation of their performance when exceeding critical values. Transverse compressive stress is one of the principal mechanical stresses when CORC cables are bundled to cable-in-conduit conductors (CICC) conductors capable of operating at currents up to 100 kA in magnetic fields of up to 20 T. In this research, a mechanical-electromagnetic model is developed to study the effect of transverse compressive loads on the electromagnetic performance of CORC cables. A mechanical transverse load on the cable is implemented to simulate the electromagnetic force. A comparison of numerical simulations with experiments for a three-layer CORC cable is first performed to validate the model’s reliability, with particular attention to critical current reduction during the transverse compression process. A novel feature of this paper is that the model developed can analyze both mechanical response under transverse compressive loads and electromagnetic performance under applied AC magnetic fields with low amplitudes. On this basis, the model investigates the effects of winding parameters on the axial strain and critical current reduction of the ReBCO layer in a single-layer CORC cable. The numerical analysis shows that increasing the winding angle can reduce the axial strain and critical current reduction of the ReBCO layer in the contact area. Subsequently, a detailed comparative study is carried out studying the axial strain of the ReBCO layer in the non-contact area with and without taking the winding core into account. In addition, a sudden increase in the magnetization loss is explained when the transverse compressive load reaches a certain level. Finally, a six-layer CORC cable’s electromagnetic analysis is performed, and each tape layer’s critical current reduction is investigated and discussed. The comparison of magnetization loss and current density between six- and single-layer CORC cables in the no-strain case is also given. This finite element model can guide optimizing a cable design for specific application conditions.