Cable Geometry Research Articles

Approximate calculation of the static analysis of a lifted stay cable in super-long span cable-stayed bridges

The sag effect of long stay cables is one of the key factors restricting further increase in the span of cable-stayed bridges. Based on the formerly proposed concept of long stay cables lifted by an auxiliary suspension cable in cross-strait cable-stayed bridges, corresponding static approximate calculations and analytical theory based on catenary and parabolic cable configurations are established. Taking a main span 1400 m cable-stayed bridge as the research object, three typical lifting conditions and the whole process of auxiliary cable lifting are analyzed and discussed. The results show that the sag effect is effectively reduced. The support efficiency is only improved when the cables are lifted above the original cable chord. Reduction of the horizontal component force of the cable is limited. The equivalent elastic modulus and the vertical support stiffness of the lifted cables are significantly increased with increased horizontal projection length and not sensitive to the change of the lifting point position. The scheme of lifting the cable to the chord midpoint is more economical because of the less steel required for the auxiliary suspension cable, but its effect on improving the vertical support efficiency is limited. The support efficiency is better when the cable is lifted to the cable end tangential to the original cable chord, but the lifting force and the cross-sectional area of the auxiliary suspension cable are doubled. The approximate calculation results of the lifted cables are very close to the numerical analysis results, which verifies the applicability of the approximation method proposed in this study. The results of parabolic approximation calculations are approximately equal to that of catenary cable geometry. As the parabolic approximation analysis theory of lifted cables is more convenient in mathematical processing, it is feasible to use parabolic approximation analysis theory as the analytical method for the conceptual design of lifted cables of super-long span cable-stayed bridges.

Skyline Tensile Forces in Cable Logging

Skyline tensile forces have been shown to frequently exceed the recommended safety limits during ordinary cable logging operations. Several models for skyline engineering analyses have been proposed. Although skyline tensile forces assume a dynamic behaviour, practical solutions are based on a static approach without consideration of the dynamic nature of the cable systems.The aim of this study was to compare field data of skyline tensile forces with the static calculations derived by dedicated available software such as SkylineXL. To overcome the limitation of static calculation, this work also aimed to simulate the actual response of the tensile fluctuations measured in the real environment by mean of a finite element model (FEM).Field observations of skyline tensile forces included 103 work cycles, recorded over four different cable lines in standing skyline configuration. Payload estimations, carriages positions, and time study of the logging operations were also collected in the field. The ground profiles and the cable line geometries were analysed using digital elevation models. The field data were then used to simulate the work cycles in SkylineXL. The dynamic response of six fully-suspended loads in a single-span cable line was also simulated by a dedicated FEM built through ANSYS®. The observed data and the software calculations were then compared.SkylineXL resulted particularly reliable in the prediction of the actual tensile forces, with RMSE ranging between 7.5 and 13.5 KN, linked to an average CV(RMSE) of 7.24%. The reliability in predicting the peak tensile forces was lower, reporting CV(RMSE) of 10.12%, but still not likely resulting in a safety or performance problem. If properly set-up and used, thus, SkylineXL could be considered appropriate for operational and practical purposes. This work, however, showed that finite element models could be successfully used for detailed analysis and simulation of the skyline tensile forces, including the dynamic oscillations due to the motion of the carriage and payload along the cable line. Further developments of this technique could also lead to the physical simulation and analysis of the log-to-ground interaction and the investigation of the breakout force during lateral skidding.

Extraction of High-Frequency Power Cable Transmission Characteristics From Impedance Spectroscopy

This study develops a technique to extract the wave propagation properties of power cables from impedance spectroscopy. This method extracts the propagation constant, characteristic impedance, phase velocity, and RLGC Telegrapher's Equation parameters. The current study first proposes an initial method to extract high-frequency cable transmission characteristics by the impedance spectroscopy of open- and short-ended cables. Using this method, the propagation constant and phase velocity can be extracted accurately. However, the initial method is still problematic. The waveform of characteristic impedance is distorted due to the additional impedance of connection wire between measuring devices and the tested cable. Therefore, this study proposes a modified method, which can eliminate the influence of additional impedance and acquire the high-frequency cable transmission characteristics accurately. By obtaining the series impedance from cable geometry parameters and getting the propagation constant from impedance spectroscopy, the modified method can obtain the characteristic impedance by combining the series impedance and the propagation constant. The extraction is demonstrated for a YJV-8.7/15 kV-1*35 XLPE cable in the frequency range 300 kHz-100 MHz.

Modelling the DAS Response for Offshore CO2 Storage Sites

Using fiber-optic cables as distributed sensors to monitor the subsurface is one of the fastest growing acquisition technologies in the hydrocarbon energy sector. Since the first exploration and production downhole field trial of a Distributed Acoustic Sensing (DAS) system for seismic monitoring in 2009, the technology has boomed. It has already proven to be an effective tool for acquiring vertical seismic profiles (VSP), performing passive interferometric measurements, and monitoring of microseismic earthquakes. DAS cables record seismo-acoustic wavefields and ground motions because ground-motion-induced changes in strain on the fiber affect the phase of back-scattered light in the fiber. Commercially available systems already provide sub-meter spatial resolution in sensing fibers up to 50 km in length with a frequency response up to several kHz. This exceeds the frequency range and spatial coverage of conventional seismic sensors. As a result, surface and borehole monitoring with DAS in addition to traditional sensors will most likely form a central component of future Measurement, Monitoring and Verification (MMV) systems for CO2 storage. DAS, however, does possess some key disadvantages in that it only provides a single component measurement which is most sensitive to motions in line with the fiber. DAS also measures linear strain rather than particle motion, meaning the recorded signals are not directly comparable to conventional sensors. In order to better understand the response of DAS it is therefore necessary to understand the seismic source, path, site and instrument effects. The ACT DIGIMON project aims to develop and demonstrate an affordable, flexible and societally embedded Digital Monitoring early-warning system, for monitoring CO2 storage sites. Within the DIGIMON concept fiber-optic monitoring will form a key component, therefore a thorough understanding of the response of DAS systems, including the transfer function, is a fundamental issue to be addressed. In this paper we present our modeling approach for the DAS response for a fictive CO2 storage site. The workflow exploits geometrical models of different complexity which in the end are representative of North Sea geology. Using ray tracing techniques and the seismic waveform modelling packages: SW4 and SPECFEM3D, we were able to analyze and compare these modeling approaches in relation to the response of a DAS system. With varying model complexity, we accurately capture and analyze the DAS response for realistic cable geometries. These geometries represent both vertical and horizontal deployments, which replicate fiber placed in wells and deployed on the seabed and or in shallow trenches.

Optimal Geometry for Cable Wrapping to Minimize Dynamic Impacts on Cable-Harnessed Beam Structures

Abstract Power and cable carrier systems have been shown to significantly impact the dynamic behavior of lightweight space structures. The goal of this paper is to obtain an optimal cable placement geometry for cable-harnessed beam structures by minimizing the impact of added cables on the system dynamics. The cable is harnessed to the beam in a periodic pattern, which forms several repeating fundamental elements within the structure. An analytical model for the cable-harnessed beam, using an energy-equivalence homogenization method, is employed for the purpose of optimization. The natural frequencies of the cable-harnessed beam are then matched with the bare beam (when no cables attached) using an optimization algorithm to find the optimal cable placement solution for the given system parameters. Subsequently, the system parameters’ effects on the optimal solutions are investigated and discussed. Experimental modal analysis is then performed to further validate the optimal solutions found using the model. The test results further validate findings from the model, and the frequency response functions from the bare and optimally wrapped beams align really well.

Effect of cable surface characteristics and flow turbulence on the aerodynamic behaviour of stay cables in dry conditions

This article describes a wind-tunnel study to evaluate the aerodynamic behaviour of stay cables of a bridge with various surface geometries in dry conditions. Nine cable models were fabricated and tested. Aerodynamic forces acting on the static models were measured for different wind speeds, cable-wind angles and cable axial rotation angles, in smooth and turbulent flow. The aerodynamic forces of bare, round cable models with different roughness levels were used as a baseline to compare the aerodynamic loading of the cables with surface geometry features. A comprehensive database of existing and emerging cable geometries in a wide range of flow conditions and cable-wind angles was generated. The trends exhibited by models with geometric features are similar to results available in the open literature. The aerodynamic drag coefficient was largely affected by the presence of cable surface geometry. The model with helical strakes had the lowest drag coefficient throughout the range of Reynolds numbers that was evaluated. It was observed that turbulence had a similar effect on all models, resulting in a reduction of the drag coefficient at lower Reynolds numbers and an earlier increase in drag that is associated with the supercritical Reynolds number regime. The presence of turbulent flow resulted in higher drag coefficients at high Reynolds numbers. An important secondary finding was that models fabricated with the Selective Laser Sintering (SLS) technique have a higher surface roughness than high-density polyethylene (HDPE) stay cable sleeves but when printed, they have a similar surface roughness.

Preload Characterization of Short Models of MQXF the Nb3Sn Low-β Quadrupole for the Hi-Lumi LHC

MQXF is the Nb3Sn Low-β Quadrupole magnet that the HL-LHC project is planning to install in the LHC interaction regions in 2026 as part of an upgrade to increase the LHC integrated luminosity by about a factor of ten. The magnet will be fabricated in two different lengths: 4.2 m for MQXFA, built in the US by the Accelerator Upgrade Project (AUP), and 7.15 m for MQXFB, fabricated by CERN. In order to qualify the magnet design and characterize its performance with different conductors, cable geometries and pre-load configuration, five short model magnets, called MQXFS, were fabricated, assembled and tested. The latest model, MQXFS6, uses a new powder-in-tube (PIT) superconducting wire, featuring a bundle barrier surrounding the filaments. The coil and the support structure were equipped with strain gauges and optical fibres to monitor strain during assembly, cool-down and excitation. In this paper we further develop the conventional azimuthal preload analysis and introduce a new set of tools for MQXF coil pack characterization which we use to analyse the behaviour of MQXFS6 room temperature preload and to reanalyse all the short models tested at CERN. A comparison is made between all the studied magnets revealing new characterizing preload parameters.

Modeling the electric field at interfaces and surfaces in high-voltage cable systems

PurposeIn high-voltage direct current (HVDC) cable systems, space charges accumulate because of the constant applied voltage and the nonlinear electric conductivity of the insulating material. The change in the charge distribution results in a slowly time-varying electric field. Space charges accumulate within the insulation bulk and at interfaces. With an operation time of several years of HVDC systems, typically the stationary electric field is of interest. The purpose of this study is to investigate the influence of interfaces on the stationary electric field stress and space charge density.Design/methodology/approachAn analytic description of the stationary electric field inside cable insulation is developed and numerical simulations of a cable joint geometry are applied, considering spatial variations of the conductivity in the vicinity of the electrodes and interfaces.FindingsWith increasing conductivity values toward the electrodes, the resulting field stress decreases, whereas a decreasing conductivity results in an increasing electric field. The increased electric field may cause partial discharge, resulting in accelerated aging of the insulation material. Thus, interfaces and surfaces are characterized as critical areas for the reliability of HVDC cable systems.Research limitations/implicationsThis study is restricted to stationary electric field and temperature distributions. The electric field variations during a polarity reversal or a time-varying temperature may result in an increased electric conductivity and electric field at interfaces and surfaces.Originality/valueAn analytical description of the electric field, considering surface effects, is developed. The used conductivity model is applicable for cable and cable-joint insulations, where homo- and hetero-charge effects are simulated. These simulations compare well against measurements.

Strain microseismics: Radiation patterns, synthetics, and moment tensor resolvability with distributed acoustic sensing in isotropic media

We have derived analytical formulations for the strain field produced by a moment tensor source in homogeneous isotropic media. Such formulations are important for microseismic projects that increasingly are monitored with fiber-optic distributed acoustic sensing (DAS) systems. We find that the spatial derivative of displacement produces new terms in strain proportional to [Formula: see text] with [Formula: see text]. In viscoelastic media, the derivative also produces an additional far-field term that is scaled by a frequency-dependent factor. When comparing with full wavefield synthetic data, we observe that the new terms proportional to [Formula: see text] can be considered part of a near-field in strain, similar to the practice with the displacement formulation. Analyses of moment tensor resolvability show that full moment tensors are resolvable with P-wave information from two or more noncoplanar vertical DAS cable geometries if intermediate- and far-field terms are considered and that S-wave information alone cannot constrain full moment tensors using only vertical wells. These results mirror previous observations made with displacement measurements. Furthermore, the addition of the new terms proportional to [Formula: see text] in strain improves the moment tensor resolvability but only in the case of a single vertical array. In the case of a single deviated/horizontal well, we can, in theory, resolve a full moment tensor but a case-by-case analysis is necessary to identify regions of full constraint around the well and the necessary noise conditions to guarantee reliable solutions. Real DAS measurements also are affected by the gauge length and interrogator details. In the case of the gauge length, we observe that this operator does not change the resolvability of the problem but it does affect inversion stability. The results derived here represent theoretical limits or in some cases specific examples. Practical implementations require analyses of conditioning, noise, coupling, and the effect of gauge length on a case-by-case basis.

Choice and justification of the optimum cooling temperature for HTS cable

At the first stage of designing a high-temperature superconducting (HTS) cable and its cryogenic refrigeration system (CRS), it is necessary to choose the optimum cooling temperature. The operating temperature is selected not only according to the critical parameters of the HTS conductor, but also taking into account other design and operational characteristics - geometry, length, operating current and the need to have subcooled nitrogen to prevent the occurrence of steam inclusions. Normally the range of cooling temperatures is limited by the critical temperature of the HTS conductor (THTS≤ 104К) and the triple point temperature of nitrogen (TLN≥ 63.15K). The choice of a certain temperature value will enable us to approximately evaluate the parameters of the CRS and overall characteristics of the cable. The article presents an analysis of the dependence of the electric power magnitude consumed by the CRS on the choice of the cooling temperature value and cable geometry. The analysis may be useful for determining the characteristics of the HTS cable operating at different temperature levels.

Cooperative Transport of a Slung Load Using Load-Leading Control

A system for cooperative transport of a slung load by a team of autonomous rotorcraft is described. The method described here is hierarchical and centralized, with the payload defined as the leader (here denoted as load-leading control): the payload uses knowledge of its current state and its desired trajectory to determine the net force and moment acting upon its center of gravity required to follow the desired trajectory. Using knowledge of the cable attachment geometry, the required cable forces are computed and transmitted to the rotorcraft. The cable force optimization problem is defined and shown to be nonconvex; constraints that make the problem convex are introduced. Cable forces computed using both the convex and nonconvex formulations are compared. Controllers for both payload and rotorcraft trajectory tracking are designed. Hardware implementation that uses small single-board computers carried onboard the payload and rotorcraft is described. Flight demonstrations conducted in an indoor motion capture studio using preplanned trajectories as well as human-in-the-loop control of the payload are described to show trajectory following and rejection of impulse disturbances. An outdoor flight test showing coordinated transport in the presence of light winds is described. All calculations are hosted on the computers carried on the payload and rotorcraft, and the system is shown to be capable of real-time control and path following both for fixed and in-flight changing formations.

Parameter Identification for Digital Fabrication: A Gaussian Process Learning Approach

Tensioned cable nets can be used as supporting structures for the efficient construction of lightweight building elements, such as thin concrete shell structures. To guarantee important mechanical properties of the latter, the tolerances on deviations of the tensioned cable net geometry from the desired target form are very tight. Therefore, the form needs to be readjusted on the construction site. In order to employ model-based optimization techniques, the precise identification of important uncertain model parameters of the cable net system is required. This paper proposes the use of Gaussian process regression to learn the function that maps the cable net geometry to the uncertain parameters. In contrast to previously proposed methods, this approach requires only a single form measurement for the identification of the cable net model parameters. This is beneficial since measurements of the cable net form on the construction site are very expensive. For the training of the Gaussian processes, simulated data is efficiently computed via convex programming. The effectiveness of the proposed method and the impact of the precise identification of the parameters on the form of the cable net are demonstrated in numerical experiments on a quarter-scale prototype of a roof structure.

An Approach for Impedance Matrix Computation Considering Phase Transposition on Distribution Lines

A renewed interest in phase frame analysis of distribution systems has surfaced in recent literature due to rapid expansion of grid-integrated distributed generation and non-linear loads, whose grid imbalance-increasing effects require more detailed analysis and modeling of distribution systems for their proper assessment. In this paper, under motivation of such recent usage of phase frame components, we propose analytical equations for N-phase neutral-equipped line admittance matrix under transposition assumption. By using the proposed equations, we evaluate precision losses caused by using the transposition assumption for modeling three-phase four-wire distribution lines. Moreover, differently from previous works, we validate the transposition assumption and the admittance matrix values obtained for various combinations of cable type and line geometry. A relevant reason for analyzing transposition assumption in more detail is the fact that it may be useful in distribution system computations, due to its advantageous decoupling of symmetrical components. In this sense, the present work provides additional discussion and illustrative evaluations of the line transposition assumption, which may be useful for analyzing its applicability under different circumstances.

Partial Discharge Localization on Power Cables Using On-Line Transfer Function

An on-line method is proposed for cable transfer function (TF) identification. For a cable's TF identification with this method, no knowledge about the cable geometry and material specification is needed. Moreover, it does not require that the cable system go out of service. An identification signal is injected through a high-frequency current transformer (HFCT) to the shield of the cable. By measuring the injected signal via HFCTs clamped on the shield at two distinct locations along the cable, the TF of the cable can be identified. A novel partial discharge (PD) localization method is also introduced, which is based on asynchronous PD measurements. In this method, travel distance of the signal is estimated by the reconstruction of a reference signal from the measured signals, using the obtained cable TF. Reference signal refers to the typical waveform of PD signal at its source location. Both the cable identification and PD localization methods are validated using two experimental setups to simulate a diverse range of PD source distance. The test cables are a 666-m long, single-core, low-voltage (2 kV) signal cable with PE insulation, and a 51-km long, single-core, medium-voltage (24 kV) power cable with XLPE insulation.

Simultaneous EEG-fMRI: Evaluating the Effect of the EEG Cap-Cabling Configuration on the Gradient Artifact.

Electroencephalography (EEG) data recorded during simultaneous EEG-fMRI experiments are contaminated by large gradient artifacts (GA). The amplitude of the GA depends on the area of the wire loops formed by the EEG leads, as well as on the rate of switching of the magnetic field gradients, which are essential for MR imaging. Average artifact subtraction (AAS), the most commonly used method for GA correction, relies on the EEG amplifier having a large enough dynamic range to characterize the artifact voltages. Low-pass filtering (250 Hz cut-off) is generally used to attenuate the high-frequency voltage fluctuations of the GA, but even with this precaution channel saturation can occur, particularly during acquisition of high spatial resolution MRI data. Previous work has shown that the ribbon cable, used to connect the EEG cap and amplifier, makes a significant contribution to the GA, since the cable geometry produces large effective wire-loop areas. However, by appropriately connecting the wires of the ribbon cable to the EEG cap it should be possible to minimize the overall range and root mean square (RMS) amplitude of the GA by producing partial cancelation of the cap and cable contributions. Here by modifying the connections of the EEG cap to a 1 m ribbon cable we were able to reduce the range of the GA for a high-resolution coronal echo planar Imaging (EPI) acquisition by a factor of ∼ 1.6 and by a factor of ∼ 1.15 for a standard axial EPI acquisition. These changes could potentially be translated into a reduction in the required dynamic range, an increase in the EEG bandwidth or an increase in the achievable image resolution without saturation, all of which could be beneficially exploited in EEG-fMRI studies. The re-wiring could also prevent the system from saturating when small subject movements occur using the standard recording bandwidth.

Skyline tensile force monitoring of mobile tower yarders operating in the Italian Alps

This study analysed the skyline tensile forces in 502 complete work cycles during ordinary cable logging operations on 12 different cable lines in the Italian Alps. The objectives of the research were to quantify the frequency of exceeding the recommended safe working limits and to determine the skyline peak tensile forces and dynamic amplifications, as well as their explanatory variables. Data collection was based on skyline tensile force monitoring synchronized with the video recording of the logging operations and the monitoring of the carriage positions. The load volumes were measured at the landing, and the total loads were estimated for each cycle. The results showed 55% of the work cycles exceeding the safe working load. The highest peak tensile forces were often recorded while starting the load moving during lateral skid. High-peak tensile forces were also recorded during inhaul, where the tensile forces were amplified by the cyclic load behaviour. It appears that some operators underestimate the effects of pretension, payload, and cable line geometry on the magnitude of the skyline tensile force. The complexity in identifying reliable theoretical models inclusive of dynamic amplifications and the inefficacy of the load limiters installed on the machines highlighted the need to improve the best practices within the operators, and to adopt technical solutions for the continuous skyline tensile force monitoring during ordinary cable logging operations.

Modelling and experimental validation of EM wave propagation due to PDs in XLPE cables

Monitoring of electromagnetic (EM) waves due to partial discharge (PD) is a promising tool for condition monitoring of cables. This study presents the development of a modelling scheme for simulation of EM wave propagation due to PDs occurring at cavities in the cross-linked polyethylene (XLPE) insulation. Simulation models for generation and propagation of PD pulses through the cable geometry are developed. A finite element method (FEM)-based model is developed to simulate the PD current along cylindrical voids in the cable insulation. The initial fields due to the PD currents in the voids are simulated by an FEM model. The propagated EM fields inside and outside the cable surface due to PD's occurring inside the voids are analysed by a finite-difference time-domain model. The analysis of propagated EM fields due to a Gaussian-shaped PD pulse identifies the dominant components of propagated electric and magnetic fields along the cable geometry. Furthermore, the propagated EM fields at the cable sheath due to different void dimensions are simulated and experimental validation of the propagated magnetic field is conducted with measurement by an high-frequency current transformer sensor installed around an earth wire from the sheath of an 11 kV XLPE cable.

Design optimization and evaluation of the 3 kA MgB2 cable at 4.3 K for the superconducting link project at CERN

High-current superconducting links (SC links) are being developed at CERN for powering the superconducting magnets of the High-Luminosity Large Hadron Collider upgrade. The links contain MgB2 cables, each about 100 m long, rated at currents of up to 18 kA. The assembly of the cables is carried out with reacted wires; cable geometry and cabling processes take into account the mechanical properties of the reacted MgB2 conductor. The production of the cables as well as their final installation requires good mechanical stability, flexibility and electrical performance. The superconductor should have good mechanical strength in view of the stresses during cabling (tension and bending), operation at cryogenic temperatures (Lorentz forces and thermal contraction) and handling installation (tension and bending) at room temperature. Moreover, the electrical integrity of the MgB2 wire (IC degradation ≤5%) should be ensured after the cabling process for the SC links. Therefore, the study of the mechanical properties of the MgB2 wire and the definition of the cable design parameters are crucial for the project. In the present work we report on the optimization and validation of the design of the 18-strand, 3 kA MgB2 cable by assessing the electromechanical behaviour of 3 kA MgB2 superconducting cables produced with different cabling parameters. The critical current (IC) of the MgB2 wires was measured after triple bending and axial tensile load, and strands extracted from the cables were tested to quantify the critical current degradation. Electrical measurements of two, 2 m long, 18-strand MgB2 cables were carried out in the FRESCA test facility at CERN and no degradation was observed. Cabling parameters such as the bending radius and the twist pitch were evaluated, and the most appropriate geometries for the MgB2 18-strand cables have been selected. Numerical simulations were performed to allow a detailed study of the strains developed in the MgB2 strands due to the mechanical loading. The present results have been successfully transferred to industry for the first industrial production in the framework of the SC Link project.

Control of an Architectural Cable Net Geometry

Tensioned cable nets can be used as a lightweight supporting formwork in the construction of thin concrete architectural shells. Meeting the structural and mechanical specifications of such shells requires precise positioning of the nodes of the cable net. We develop and experimentally verify a control strategy that uses measurements of the nodal positions to identify model parameters and calculate adjustments to the boundary cable lengths to achieve the desired form. As cable net lengths adjustments on the construction site are time-consuming, the number of control adjustments is minimized via a sparsity-promoting optimization-based method.

Modelling of ampacity and temperature of MV cables in presence of harmonic currents due to EVs charging in electrical distribution networks

To meet the rapidly growing electric vehicle (EV) charging demand, it is important to determine maximum ampacity and avoid overloading of Medium Voltage (MV) cables in power distribution systems. Previous works on modelling and analysis of relationship between the load demand of MV cables and EV penetration level did not consider the contribution of harmonic currents. This paper presents a methodology for modelling and analysis of the impact of EV charging loads on cable ampacity and temperature in presence of different levels harmonic currents under two typical scenarios of EV charging modes, i.e., uncontrolled domestic charging scenario and uncontrolled off-peak domestic charging. The proposed method determines the ampacity and temperature of three-core cable taking account for cable geometry, harmonic levels, stochastic nature of the charging power, start time of individual charging, seasonal temperature under different EV penetrations. A generic urban distribution network with residential load ratio of 0.7, which is representative of urban residential distribution network in China, is adopted as an example. Results show that the ampacity of a 400 mm2 10 kV cross-linked polyethylene (XLPE) cable decreased by 10.79 A and 2.03% when the harmonic level is at the maximum allowed limit as given in IEC 61000-3-2. Meanwhile, the ampacity decreased by 23.34 A and 4.09% at the maximum limit given in IEC 61000-3-4. In presence of 36.15% and 41.66% total harmonic distortion current which are the most serious harmonic distortion in the example network with 30% EV penetration, cable ampacity decreased by 42.86 A, 8.06% and 61.35 A, 11.35% respectively.