Cable Simulation Research Articles

Research on the gas generation characteristics of power cables when heated

Abstract Power cable fires evolve through several stages. Initially, the fire’s early phase is characterized by an anomalous temperature in the outer sheath without considerable smoke generation. It progresses to a smoldering stage with significant smoke production, leading eventually to open flames, which persist until extinguished. Fault-induced high temperatures initiate the breakdown of chemical bonds in the polymer materials composing the cable’s outer sheath, resulting in specific pyrolysis gases that bear the cable’s temperature information. Investigating the heating and gas production properties of the cable can enhance our understanding of the gas phase characteristics at the onset of fires. This paper presents an experimental platform comprising a power cable overheating fault simulation device and chemical analysis instruments. It examines the gas production traits and sources in power cables under fault-induced, high-temperature conditions based on gas chromatography and infrared spectrum data.

Reference dynamic power cable of floating offshore wind turbine for thermal and simple fatigue evaluation

With the increased interest in floating offshore wind turbines, there is an increased focus on evaluating the lifetime of the auxiliary systems, such as the mooring lines and the dynamic power cables, because these systems are in-mature compared to bottom-mounted offshore wind farms. This paper proposes a conceptual reference dynamic power cable suitable for the 15 MW NREL reference turbine mounted on the UMaine floater installed at 82 m water depth. This provides a basis for discussing the life evaluation of dynamic cables obtained from aeroelastic simulation of the floating offshore wind turbine platform exposed to the environmental conditions of the South Brittany site in France. An electromagnetic-thermal finite element simulation is used to determine the current capacity of the cable and aeroelastic simulations are used for a simple assessment of the main failure modes as maximum cable tension, minimum bending radius and fatigue damage accumulation.

Fluid–structure interaction simulation and optical fibre stress analysis of submarine cables in vortex‐induced vibration

AbstractUnder the current scouring, submarine cables are prone to be exposed, suspended, and even vortex‐induced vibration (VIV), threatening their mechanical and electrical properties. In this contribution, a finite element simulation model of 110‐kV single‐core optical fibre composite submarine cable is established. The natural frequency and resonant frequency of the model are obtained through wet mode analysis and harmonic response analysis. Then the VIV is simulated by the fluid–structure coupling method. Moreover, the stress extraction method of the torsional optical fibre position under the VIV is proposed. The results show that when the reduced speed is 2.57, the submarine cable appears beating vibration, which is composed of two vibrations with similar frequencies. When the reduced speed is 7.08, the vibration frequency is about 7.813 Hz, causing a rapid increase in vibration amplitude. The stress distribution of the torsional optical fibre presents a mirror image relationship at two moments separated by half a vibration cycle. Also, the frequency of stress change is the same as the frequency of VIV, which can judge whether the VIV occurs. The VIV range and position can be determined by the location where the stress changes the most.

A Highly Distensible, Cable Loop-Driven Soft Robotic Gastric Simulator for Endoscopy Training

With the increased demand for endoscopic diagnosis in the upper gastrointestinal (GI) tract, gastric simulators have been developed for endoscopy training. However, most of them remain nonideal due to their static and nondistensible nature. This paper presents a new soft robotic gastric simulator, comprising mainly of a silicone-based stomach model that mimics the size and inner surface condition of a human stomach. It also features peristaltic effect on its stomach wall via five cable loop-driven mechanisms, sphincter mechanisms at two ends of the stomach model, and structural pathology phantoms that can be magnetically controlled for multi-location deployment. Finite element simulation of the stomach behavior was performed under different insufflation pressures to determine the cable loop mechanism design parameters. During the simulator evaluation, the performances of the sphincters and cable loop mechanisms were first characterized. The simulator was then actuated to provide sequential contraction across the stomach model at different contraction ratios, leading to intragastric pressures similar to those reported in the literature. Finally, a preliminary user study was performed to face validate the simulator in terms of its realism, usability, and usefulness for endoscopy training. It is envisioned that the soft robotic gastric simulator could be adopted in endoscopy training programs to replace the use of animal models.

Towards realistic nonlinear elastic bending behavior for cable simulation

AbstractThis contribution aims to characterize and model the nonlinear elastic behavior of cables for reliable simulations. To simulate the nonlinear elastic behavior of cables, we use an iterative method, where at each step, an algorithmic local bending stiffness constant is used and updated according to the current cable state. We also formulate an inverse problem to determine the properties of real cables. By solving the inverse problem, the nonlinear elastic behavior for given measurement data is identified, yielding a curvature‐dependent bending stiffness characteristic. In addition, we propose an alternative method based on the balance equations for rods in static equilibrium to identify the bending stiffness characteristic. We apply both methods to experimental data, and the results are compared and discussed.

Comparison of Rational Krylov and Vector Fitting in Transient Simulation of Transmission Lines and Cables

This paper presents stringent comparisons between Vector Fitting (VFIT), Relaxed Vector Fitting (R-VFIT) and Rational Krylov Fitting (RKFIT) techniques in the fitting of transmission line and cable functions to rational forms while accounting for the frequency dependence of electrical parameters. The fitting procedures encapsulate new solution strategies to improve fitting performance. Various case studies are presented to assess the performance of RKFIT in terms of model order reduction, passivity violation and computing times. In addition, the use of RKFIT in obtaining the frequency dependent cable model (FDCM) is demonstrated for the first time together with a resolved case study that showed unstable behavior with the universal line model (ULM) methodology.

Asymmetric Voltage Attenuation in Dendrites Can Enable Hierarchical Heterosynaptic Plasticity.

Long-term synaptic plasticity is mediated via cytosolic calcium concentrations ([Ca2+]). Using a synaptic model that implements calcium-based long-term plasticity via two sources of Ca2+ - NMDA receptors and voltage-gated calcium channels (VGCCs) - we show in dendritic cable simulations that the interplay between these two calcium sources can result in a diverse array of heterosynaptic effects. When spatially clustered synaptic input produces a local NMDA spike, the resulting dendritic depolarization can activate VGCCs at nonactivated spines, resulting in heterosynaptic plasticity. NMDA spike activation at a given dendritic location will tend to depolarize dendritic regions that are located distally to the input site more than dendritic sites that are proximal to it. This asymmetry can produce a hierarchical effect in branching dendrites, where an NMDA spike at a proximal branch can induce heterosynaptic plasticity primarily at branches that are distal to it. We also explored how simultaneously activated synaptic clusters located at different dendritic locations synergistically affect the plasticity at the active synapses, as well as the heterosynaptic plasticity of an inactive synapse "sandwiched" between them. We conclude that the inherent electrical asymmetry of dendritic trees enables sophisticated schemes for spatially targeted supervision of heterosynaptic plasticity.

Temperature and humidity sensor monitoring of directly buried cable based on temperature field distribution simulation of power cable

Power cable is a piece of major transmission equipment, and its operating temperature as a major factor determines whether the cable system can operate safely and reliably and the current-carrying capacity. Therefore, it is of great significance to master the real-time temperature and the distribution of the power cable core. During the aging of cable insulation, temperature, as a major factor, directly determines the aging rate. One of the basic parameters on the power cable is the ampacity. If the ampacity is high, the cable will be overloaded. In this paper, the thermal circuit method is used to construct and calculate the cable, and the whale algorithm is used to estimate the temperature of the cable conductor. The conductor is estimated accurately within the allowable error range. The results are compared with the results of finite element simulation to verify the effectiveness of the finite element method. Through the experimental analysis, the model is established according to the cable trench on the spot. The steady-state temperature field is calculated through parameter setting. The average packet loss rate is 0.066 %, and the relative error is 0.32 %, which proves that this study can optimize the communication mode of the network and achieve a better monitoring effect. The method realizes the real-time temperature rise prediction of the cable core conductor by using the temperature rise of the outer skin. It can provide a certain theoretical basis for the online monitoring and engineering practical application of the cable core temperature and has practical significance.

Common OECD/NEA FIRE and PRISME Cable Benchmark Exercise

This paper deals with the common OECD/NEA FIRE and PRISME Cable Benchmark Exercise conducted for a realistic cable fire scenario in an electrical system of a nuclear power plant. The major goal was to simulate a real cable fire event in order to assess the behaviour of fire models for a complex and real fire scenario with the current state of knowledge. Since a numerical Benchmark Exercise on a real fire event is quite challenging, a three-step methodology was adopted: (1) a calibration phase of the cable fire models, (2) a blind simulation of a cable fire test, and (3) the real cable fire event simulation. The selected fire event from the FIRE Database occurred in 2014 in a heater bay of a nuclear power plant. Thirteen institutions from nine NEA member countries participated in this Benchmark Exercise. Simulations were performed using computational fluid dynamics codes, a lumped parameter code, and zone codes. The simulations have provided a wide range of results which reflect the difficulty for fire simulation codes to correctly predict the development of the fire heat release rate over time of a cable tray fire, even under simple, open atmosphere conditions.

Data based constitutive modelling of rate independent inelastic effects in composite cables using Preisach hysteresis operators

AbstractThis contribution aims at introducing first steps to develop hysteresis operator type inelastic constitutive laws for Cosserat rods for the simulation of cables composed of complex interior components. Motivated by the basic elements of Cosserat rod theory, we develop a specific approach to constitutive modelling adapted for this application. Afterwards, we describe the hysteretical behaviour arising from cyclic bending experiments on cables by means of the Preisach operator. As shown in pure bending experiments, slender structures such as electric cables behave inelastically, and open hysteresis loops arise with noticeable difference between the first load cycle and the following ones. The Preisach operator plays an important role in describing the input-output relation in hysteresis behaviours, and it can be expressed as a superposition of relay operators. Hence, a mathematical formulation of the problem is introduced, and a first attempt is made to determine the hysteresis behaviour that describes the relation between curvature and bending moment. Therefore, a suitable kernel function is identified in a way that its integration over the Preisach plane results in the bending moment of the specimen, and a comparison between different kernel functions is performed.

Introducing energy into marine environments: A lab-scale static magnetic field submarine cable simulation and its effects on sperm and larval development on a reef forming serpulid

Non-chemical sources of anthropogenic environmental stress, such as artificial lights, noise and magnetic fields, are still an underestimate factor that may affect the wildlife. Marine environments are constantly subjected to these kinds of stress, especially nearby to urbanized coastal areas. In the present work, the effect of static magnetic fields, associated with submerged electric cables, was evaluated in gametes and early life stages of a serpulid polychaete, namely Ficopomatus enigmaticus. Specifically, biochemical/physiological impairments of sperm, fertilization rate inhibition and incorrect larval development were assessed. We evaluated differences between two selected magnetic field induction values (0.5 and 1 mT) along a range of exposure times (30 min–48 h), for a sound evaluation on this species. We found that a magnetic induction of 1 mT, a typical value that can be found at distance of tens of cm from a submerged cable, may be considered a biologically and ecologically relevant for sessile organisms and for coastal environments more generally. This value exerted statistically significant effects on membranes, DNA integrity, kinetic parameters and mitochondrial activity of sperm cells. Moreover, a significant reduction in fertilization rate was observed in sperm exposed to the same magnetic induction level (1 mT) for 3 h, compared to controls. Regarding early larval stages, 48-h exposure did not affect the correct development. Our results represent a starting point for a future focus of research on magnetic field effects on early life stages of aquatic invertebrates, using model species as representative for reef-forming/encrusting organisms and ecological indicators of soft sediment quality.

Efficient simulation of cables with anisotropic high‐order solid finite elements

AbstractCables are slender structures with a complex geometry, that can undergo large deformations during their installation or in dynamic environments. In combination with their complex inner structure they pose a challenging problem for finite element simulations. In this article a simplified approach is presented to model cables by using an effective material and a homogeneous cross‐section, which is anisotropic in the elastic and inelastic domain. For the high‐order hierarchic shape functions with quasi‐regional mapping, anisotropic ansatz spaces are applied in tension, torsion and bending simulations. The identification of material parameters is conducted based on experimental results for a tension and a torsion test using the particle swarm optimization algorithm. Finally, the identified parameters are validated for a combined load case with torsion and free bending, showing a promising approach regarding the simulation of cable structures.

ВЛИЯНИЕ РЕЗОНАНСНЫХ ЯВЛЕНИЙ НА ТЕХНИЧЕСКИЙ РЕСУРС АСИНХРОННЫХ ЭЛЕКТРОДВИГАТЕЛЕЙ ПРИ ИМПУЛЬСНЫХ ПЕРЕНАПРЯЖЕНИЯХ

The relevance The work is devoted to assessing the impulse overvoltages effect at the input of the supply cable on the asynchronous machines technical resource as a solution to the electrical equipment failure problem caused by the resource loss. Aim of research Reducing the asynchronous machines accident rate by monitoring their technical condition and the implementation of electrical equipment riskbased maintenance during impulse overvoltages. Research methods The asynchronous electric motor, a supply cable, lightning effects and surge arrestor simulation modeling was used; Fourier analysis was applied. Results The simulation model of electric motor supply system section with installed surge arrestors in transformer substation cells was developed. Spectral composition of input voltage and current of asynchronous machine depending on cable line length was obtained. Assessment of technical resource of asynchronous machine based on voltages and currents oscillograms on its input and the related value of energy transmitted to its insulation during impulse overvoltages was realized.

Measurement of Pyrolysis Properties for Fire Spread Simulation of Cables

The analysis and review of the thermal decomposition properties required for the fire spread simulation of cables composed of multiple materials were performed. Thus, a typical two-step pyrolysis reaction was identified independent of cable type. It is expected that the Kissinger and flynn–wall–ozawa (FWO) methods, which are calculated using various heating rates, more accurately predict fire spread than the input method that uses the and values calculated using a single heating rate. Consequently, in the case of flame-retardant cables (CLASS 1E and TFR-8), the Kissinger method is more likely to overestimate the fire spread rate than the FWO method. In the case of polyvinyl chloride (PVC) cables (vinyl cabtire power cable, VCTF), the fire spread rate may be underestimated.

Routing multiple flow channels for additive manufactured parts using iterative cable simulation

Many prior works highlight the potential of additive manufacturing (AM) for flow components. Examples include hydraulic manifolds with multiple crossing flow channels that guide separate fluid flows in a single part. Creating the 3D geometry of such complex parts can be challenging. Designers must consider functional requirements, such as minimizing the channels’ length, creating smooth channel paths, and preventing overlaps between channels for different fluid flows. Furthermore, designers must adhere to manufacturing restrictions specific to the chosen AM technology. Critical overhangs inside channels must be avoided for processes such as laser powder bed fusion by adapting the shape of channel cross-sections. However, such production-related design changes can cause overlaps between different channels and require re-adjusting the channel paths. Consequently, routing several flow channels is often challenging when manually designing parts for AM. This work aims to automate the routing of multiple channels considering the AM overhang restriction. The presented approach models flow channels as virtual cables defined by a chain of particles (connected by line segments) and collision spheres (located at the cable particles). The cable line segments describe the path or centerline of channels, while the cable collision spheres approximate the required space of each channel. The cables are initialized as straight lines between the channel inlets and outlets and iteratively subjected to geometric-based constraints, e.g., to minimize the cables’ length and smoothen their paths. The collision spheres are used to detect overlaps between channels for different flows and repel the affected cables from each other. The radii of the collision spheres are iteratively updated to consider the adaption of cross-sections for AM. After the iterative cable simulation convergences, the cable paths are used to generate a detailed 3D part design. A case study applies the approach to a hydraulic manifold fabricated using laser powder bed fusion of stainless steel. The study demonstrates the automated design and production of customized design variants.

Cable Steady-State Ampacity Correction Method based on Multi Physical Field Coupling Algorithm

The difference between the single air laying ampacity test value of medium voltage power cable and the system ampacity of three-phase laying and operation is a common problem in the industry. Based on the TICW-2012 standard, the single cable ampacity of medium voltage single core power cable is tested, and the COMSOL basic simulation model is debugged with the measured ampacity value. On the premise of correct single cable basic simulation model, the system ampacity under three-phase operation under different working conditions is calculated, including triangular laying, plane laying, single circuit and double circuit laying, The difference and correction coefficient between the test current carrying capacity and the of single air laying of medium voltage single core power cable are further analysed. Finally, the analytical formula is derived through the cable ampacity equivalent thermal circuit diagram, and the cable samples are theoretically analysed and calculated. According to the ampacity calculation results of single loop triangular laying and plane laying, the correctness of the simulation results is verified. This study provides a reference basis for the current carrying capacity test and correction of medium voltage power cable in the future, and also provides an effective method for the actual operation state analysis of medium voltage power cable.

Electrical stresses simulation of DC cable in ±10 kV distribution system

Electrical stresses simulation of DC cable in ±10 kV distribution system

Study of the Fire Behavior of Multilayer Cables in a Mine Tunnel

Fires caused by cables occur frequently in mines, which endanger the safety of workers. To explore the characteristics of a multilayer cable fire in a mine tunnel, multilayer cable fire simulations were carried out using the Fire Dynamics Simulator (FDS). The influence of cable tray spacing, ignition position, and tunnel ventilation speed on the characteristics of the fire were studied. The results showed that these factors change the amount of contact between the cable and air, the heat accumulation, and the heat transfer by the flame interaction between the cables. It was also noted that increasing the spacing or wind speed both made the peak of heat release rate (PHRR) initially increase and then decrease. The influence of wind speed on the cable burnout rate in the upstream and downstream sides of the fire source was not consistent, and the wind speed had a sensitive effect on the cable burn out rate in the upstream side of the fire source. The higher the ignition position was, the longer the arrival time of PHRR was and the slower the fire developed. There was a higher burn velocity close to the ceiling. The cable hooks obstructed the cable fire. This study provides a theoretical basis for cable fire prevention and control in mine tunnels.

Active Tendon Control of Stay Cable by a Giant Magnetostrictive Actuator Considering Time-Delay

Active control of a stay cable through changing its tension is an effective way to lower the vibration amplitude. In this paper, active tendon control of a stay cable using a giant magnetostrictive actuator (GMA), which can generate axial deformation in a short period (normally less than 10 ms) under magnetic fields, is studied considering the time-delay. The bilinear controlled state equation of the small-sag cable is established by employing the Lagrange formulation. The linearization method for the bilinear controlled state equation is proposed and validated by numerical simulations. A GMA is designed and manufactured to actively control a stay cable model and the relationship between the output force and the input voltage is obtained by experiments. Based on the phase-shifting method, a multi-mode control algorithm with the time-delay compensation is proposed, and the time-delay compensation matrix based on the state feedback control algorithm is obtained. Based on a 1:20 scaled cable model, simulations and experiments are conducted to investigate the control performance of the proposed method under different external loads including the free vibration, harmonic excitation and random excitation. The results show that the tendon control of cable vibration by a GMA may be invalid and even amplify the vibration amplitude when the compensation of time-delay is not considered. Moreover, the excellent control performance can be achieved by using the proposed time-delay compensation method.

Verification and Analysis of Lumped-Circuit Approximate Models of Twisted-Stranded Cables for High-Speed Railway Signaling Systems

To evaluate the transmission characteristics, anti-electromagnetic interference performance, and cable channel fault detection of multi-core twisted-stranded cables used in high-speed railway signaling systems, this study established a model for accurate twisted cable physical simulations. With the LEU-BSYYP cable, the finite element method (FME) software constructed a one twisted cycle length model and calculated the per-unit-length (pul) distribution parameters of the cable under high-frequency pulses. The purpose is to simulate long-distance twisted cables physically and analyze the factors affecting the transmission quality and transmission distance of high-frequency signals quantitatively by constructing a lumped equivalent circuit comprising cascaded T-type circuits. Additionally, by analyzing the relationship between the working frequency and the characteristic impedance error, where the characteristic impedance error is the difference in characteristic impedance between a lumped equivalent circuit and a lossy uniform transmission line, the number of T-type cascaded circuits that fulfill the accuracy requirements of the physical simulation is determined. Finally, the model output is compared with the measured waveforms using a 500 m LEU-BSYYP twisted pair cable as an example to verify the correctness of the equivalent modeling of the lumped circuit in the paper.