Cable Conductor Research Articles

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.

Features of measuring deformations of load-bearing structures of buildings during their field and laboratory tests under the action of static and dynamic loads

The peculiarities of measuring the deformations of load-bearing structures of buildings during their field and laboratory tests using strain gauge-based sensors are considered. An overview of various problematic issues that arise in the process of conducting experimental tests and affect the measurement results is given. The most common, which affect the accuracy of measurements, are the effects of temperature, humidity, and vibration; the difficulty of calibrating and mounting strain gauges on different surfaces of elements; complexity of measurement data processing; combination of high-quality work of strain gauges, cable conductors, measuring equipment, data collection and processing system; the selection of the connection scheme of tensor resistors in the Wheatstone bridge. The peculiarities of the organization of the experiment for testing the load-bearing structures of the building, namely pile foundations, are considered, and the main problematic issues when using strain gauges as strain gauges of building elements are given. The use of strain gauges to measure deformations of load-bearing structures of buildings is one of the common methods, which has many advantages, which are discussed in detail in the work. Strain gauges can be used to measure deformations of elements that are mechanically connected to them. They have high measurement accuracy, sensitivity to element deformation, and a wide variable measurement range. The advantages of using the Wheatstone bridge to measure the change in electrical resistance are highlighted, as this method allows measuring very small values of the change in resistance. Methods of connecting tensor resistors according to the Wheatstone scheme are considered, the choice of which depends on the purpose of the study and the required accuracy. One of the easiest ways is to connect just one strain gauge to a current or voltage source and measure the change in resistance. But this method has low sensitivity and does not compensate for the effect of temperature. A more accurate way is to connect two or four tensor resistors in the Wheatstone bridge circuit, which allows you to measure the voltage change on the diagonal of the bridge. The bridge circuit has a high sensitivity and can compensate for the effect of temperature if the tensor resistors have the same coefficient of temperature dependence of the resistance. An algorithm for measuring the deformations of a metal pipe working under compression using strain gauges has been developed.

Adapter for the Impedance Measurement of Power Cable With an Impedance Analyzer

Performing accurate measurements of power cables input impedance can be useful for many applications, e.g., identify the cable parameters for electromagnetic interference modeling, locate faults along the cable, etc. However, performing a transparent connection between a power cable of large dimensions and an impedance analyzer is challenging. This article proposes an input impedance measurement adapter designed for a power cable, specifically the cable Nexans 12G6. This is a shielded cable with 12 conductors of cross section <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${6 \, \text{mm}^{2}}$</tex-math></inline-formula> . The impedance measurement is performed with the Keysight E4990 A impedance analyzer. The adapter is removable, and allows the connection between the cable conductors and an impedance analyzer without changing the cable geometry nor denuding its conductors. The compensation of the measurement circuit is performed at the measurement plane. The impedance measurement results are given, as well as and the cable parameters obtained from them. The uncertainty of the impedance measurements is estimated with a stochastic analysis. The adapter mitigates systematic errors linked to the measurement circuit and provides reproducible impedance measurements.

Planning and Design of Building Electricity Based on Spatial Distribution Model

Electrical equipment is ubiquitous in modern buildings, which not only provides great convenience but also produces a lot of energy consumption, which is contrary to the current purpose of energy saving and emission reduction. Under this background, the planning and design of building electricity based on a spatial distribution model are studied. In this study, BIM software is applied to build a building spatial distribution model. On this basis, the power supply and distribution system is re-planned, including the reasonable selection of transformer specifications and models, the selection and laying of cable conductors, and the improvement of the power factor. With the minimum energy consumption as the planning objective, the genetic algorithm is adopted to plan the operation scheme of the lighting electrical system and HVAC electrical system. The results verify that, according to the building electrical planning scheme based on the spatial distribution model, the energy consumption of the building is less in 15 hours, which illustrates the rationality of the planning scheme.

Fretting wear and fatigue in submarine power cable conductors for floating offshore wind energy

Multi-strand, copper conductors in submarine power cables (SPCs) for offshore wind are susceptible to fretting wear and fatigue, due to multiplicity and complexity of contacts, subjected to potentially severe dynamic loading. This paper presents (i) a global-local methodology for coupled hydro-aero-elastic dynamic loading of a representative SPC for identification of local inter-wire fretting-related conditions, (ii) fretting wear characterisation of copper conductor material, and (iii) local fretting multiaxial wear-fatigue finite element models for fretting fatigue life assessment of SPC copper conductor contacts. Predicted fretting fatigue lives are shown to be consistent with previously published bending fatigue test data on SPC copper conductors. Fretting fatigue life is shown to be significantly affected by aero-hydrodynamic loading, wear, slip regime and wire diameter.

Особенности моделирования воздушных и кабельных участков линий электропередачи 110–750 кВ при использовании фазного координатного базиса

Power system steady state and transient analysis require correct modeling of overhead transmission lines and cables operating at 110–750 kV. The key difficulties to model sections of overhead and cable lines are caused by complex conductor geometry, their transposition, as well as grounding schemes of ground wires of overhead lines and screens of underground cables. The paper covers various aspects of 110–750 overhead line and cable modeling that must be taken into consideration to obtain a reliable mathematical model in a phase domain. Modern software does not provide a universal solution to determine line parameters. The 110–500 kV cable line modeling issues have not been worked out properly and require careful analysis of specialized foreign literature. Thus, the task to develop the algorithms of calculating the parameters of overhead and cable power lines is relevant, taking into account the various configuration options of these lines which are possible in operational practice. To derive overhead transmission line and cable line models, electric circuit theory and matrix algebra methods have been used. The ATP/ATPDraw and MATLAB/Simulink software environment has been used to investigate what tools are available to determine line parameters, as well as to verify some of the calculation results. Analysis has been carried out to reveal the options available in the ATP/ATPDraw and MATLAB/Simulink software to compute line parameters in a phase domain. An algorithm has been developed and verified to calculate overhead line parameters regardless of the number of parallel circuits. The key features of the calculation of the matrix of linear resistances of overhead power transmission lines are outlined. The main features of modern cable lines operating at 110–500 kV are also described. The paper presents various cable layouts possible in real-field conditions, as well as provides expressions that allow obtaining correct impedances and admittances for a system of cable line conductors. Study of the options of various software tools dedicated to overhead line parameter calculation in a phase domain has revealed that these tools cannot be deemed universal to represent an overhead line of whatever configuration. However, the developed algorithm is universal as it allows computing line parameters regardless the ground wire grounding approach. The expressions presented in this paper consider various layouts of 110–500 kV cable lines that could be encountered in the Russian power system.

Investigation and Simulation of Technical Power Losses on 33/11kv Distribution Feeders Based on Gauss-Seidel Iterative Approach

Loss of technical performance is one of the main causes of energy shortages and inefficient operation of electrical machines in energy systems. In this study, an analysis of power losses for six selected 33/11 kV distribution feeders was presented. (Kakoba, Ntare, Karamurani, Ishaka MbararaNorth1 and Mbarara North 2) at Mbarara Central Substation Network of UMEME Electricity Distribution Company in Uganda. Data such as cable type, conductor resistance, conductor reactance, and route length were obtained from energy suppliers. From this data, the Gauss-Seidel method was used to determine the total active power and associated reactive power of the entire substation system. The findings showed that the substation is profitable due to the small calculated total power losses. Although it is possible to reduce the total loss to at least 9-12%. Losses were due to old substations, overloaded transformers, and copper losses core losses in lengthy feeder routes. To improve the performance of power distribution networks, it was recommended to replace old conductors to reduce losses.

MODELING AND ANALYZING THE EFFECT OF CONNECTION TO THE NETWORK OF A HARMONIC SOURCE HAVING VARIOUS TOTAL HARMONIC DISTORTION FACTORS ON LOAD SIGNAL WAVEFORMS

This article examines the effect of a network connected source of harmonics having a total harmonic distortion factor varying from 5% to 15% on load voltage and current waveforms. When a source of higher harmonics is connected to the network, both in the network and in the load, the effective values of voltage and current increase, that can negatively affect the cable line insulation, accelerating its destruction and aging.&#x0D; To analyze the consequences of a power quality deterioration, a 20 kV network was simulated, consisting of a 20 kV symmetrical generator, an XRUHAKXS-20(1x120/50) power cable line 20 km long, a step-down transformer 20/0.4 kV with a power of 2 MVA, with windings connected in delta-star, and a three-phase symmetrical load.&#x0D; The values of the currents flowing through the cable conductor, obtained as the result of simulation were used to calculate the voltage drop between the cable conductor and its shield. Results obtained show that the connection of a harmonic distortion source to a network leads to a magnification of a current flowing through the cable conductor by more than 2%. The model proposed in the article can be used further for a more detailed study of solar photovoltaic plants connection to the grid.&#x0D; One of the biggest problems regarding solar power plants is that its electricity generation is intermittent. Thus, future efforts should be focused on modeling and studying the higher harmonics generation during switching on and off of the solar photovoltaic plants.

Fast Computation Method of Energization Overvoltage in Cable Lines Based on Numerical Inverse Laplace Transform

Currently, the research on the energization overvoltage in cable lines is mainly realized through simulation calculation. However, the operation process is complex and the computation speed is slow when using the simulation software to calculate the energization overvoltage in the whole line. This paper presents a numerical calculation method of energization overvoltage in the entire cable line, which can greatly improve the calculation speed, simplify the operation process and have accurate calculation results. The method is based on transmission line theory, modal theory, transmission line equation’s complex frequency domain solution and Numerical Inverse Laplace Transform (NILT). This method first performs phase-to-mode conversion on the cable line and converts the mutually coupled cable conductors into mutually independent propagation modes. Furthermore, each independent propagation mode is conducted by Laplace Transform to obtain the complex frequency domain of its voltage. Finally, after the NILT is performed on the voltage complex frequency domain solution of each propagation mode and the time domain solution is obtained, the energization overvoltage of the full cable is obtained through the inverse phase-to-mode conversion. This method is applied to a 330kV cable line, and the calculation speed is significantly improved. The overvoltage calculation results have a small error compared to the obtained results using the simulation software, indicating that the method has high accuracy.

Novel processing, testing and characterization of copper/carbon nanotube (Cu/CNT) yarn composite conductor

AbstractSustainable electrified aircraft propulsion (EAP) is likely to lead to an increase in the electrical wiring contained within a single aircraft. Since the electrical resistance and mass of copper (Cu) conductors are associated with power losses, it is desirable to design high‐conductivity lightweight conductor materials, thus reducing the mass of components like motor windings, low‐voltage signal cables, and transmission cables for data and power to improve the overall energy efficiency. This paper describes a unique framework for manufacturing metalized carbon nanotube (CNT) composite conductors, measuring their electrical conductivity and strength, and modeling the overall conductivity and current sharing within such composites. Tensile testing was conducted on the processed composite conductor cables with the use of acoustic emission and electrical resistivity to determine stress‐dependent‐failure mechanisms while monitoring the electrical conductivity. The average of measured electrical conductivities of annealed Cu/CNT samples from batch 5 was greater than theoretical predictions by 9.8 percent and was also greater than the conductivity of pure annealed Cu by 4.8 percent and had comparable ultimate tensile strengths. Additionally, those Cu/CNT samples provide a 13.5% weight saving over current state of the art copper wires. Theories explaining improved intrinsic conductivity are discussed.

Cable conductor of cabling and wiring products based on composite materials for transport systems

The article deals with the issues of working out the technology of manufacturing cabling and wiring products that are used in railway transport systems. A cable conductor for a cable product, made on the basis of composite materials, was adopted as the object of research. The technology of production of composite billets and wire for cable products for subsequent drawing, as well as ways of obtaining them, is covered in detail. Special attention is paid to the problems of operation in railway transport, power transmission systems, which confirms the relevance of the research. The increase in the cost of the finished product is due to the violation of the technology, which is associated with the structural diversity of the layers of the composite long-length billet, determines the need to maintain the constancy of its plastic properties along the entire length. By means of a generalized mathematical model of the drawing process and on the basis of reference data, calculated parmeters of technological extracts were obtained for the layers of the composite billet to be drawn. The results of the research work made it possible to develop a methodology for calculating the technological modes of operation of the drawing machine and to determine the optimal technological parameters of the technological equipment.

Wideband Noncontact Voltage Measurement for EMC Applications: Design and Implementation

A methodology of amplitude and phase compensation for non-contact voltage measurements, which can be applied to wideband signal and noise observation in the EMC application, is presented. The non-contact techniques are based on a small amount of coupling capacitance between probe electrode and cable conductor where the observed signal is induced. In this case, a main technical issue to be overcome is the amplitude and phase error introduced by stray capacitance of the internal circuit, which needs to be resolved for application of the wideband EMC measurements. Herein, a design and implementation of phase compensation with inverting OpA configuration are discussed. Moreover, by introducing a system calibration with numerical process, validity for recovering the frequency response at 100 Hz ~ 100 MHz is indicated. In the calibration process, frequency compensation for dielectric dispersion of the PVC cable is also discussed. As for the time-domain measurement, the evaluation result of the fast transient impulsive noise of tr/tf: 10 ns emitted from a commercial power supply module is also discussed.

Determining the actual reduction factor of distribution cable lines with applied cross-bonding

The considered problem appears as the consequence of the fact that many metal installations surrounding power lines in urban areas are situated under the surface of the ground and cannot be visually determined or verified. This paper presents the methodological version that enables solving the problem in the case of cable lines with cross-bonding, but it can also be applied with higher accuracy to cable lines with no applied cross-bonding than the existing one. It is based on the test measurement of currents appearing in two cable line phase conductors during a simulated ground fault in the supplied HV substation. By using the here-presented methodology it is possible to put the grounding problem of high-voltage distribution substations into realistic frameworks. Its application in practice shows that the actual conditions for solving this problem are much more favorable than was considered before.

Electromechanical behaviour of REBCO coated conductor toroidal field coils for ultra-high-field magnetic-confinement plasma devices

The development of rare-earth barium copper oxide (REBCO) coated conductors with an extremely high critical current density under ultra-high fields opens up a high-field path towards large-scale fusion. The latest technology has inspired cable-in-conduit conductors such as conductor on round core wires, twisted stacked tape conductor cables and Rutherford cables with outstanding current-carrying capacities. In order to realise an inductance balance and decrease magnetic diffusion, these cables have been twisted or folded to a certain extent, thus breaking the mechanical behaviour of the ceramic superconductor and limiting their potential for ultra-high-field applications. One possible solution is to employ a non-twisted cable, which offers maximum protection of its mechanical properties and enables a parallel orientation of the toroidal field vector to the surface of REBCO coated conductors, and at the same time decreases the influence of perpendicular fields on the critical current of REBCO cables. However, the applied physics community’s attitude towards using non-twisted, parallel REBCO stacked-tape cables is one of scepticism, the main argument being that the nonlinear E–J behaviour associated with screening current in the parallel stack might lead to a field distortion and reduce the performance of superconductivity. Recent analyses have demonstrated that the effect of screening current decreases significantly owing to a wavelike magnetic field distribution along the cable. The authors obtained similar results using H-formulation and T–A formulation based finite element methods and demonstrated that the non-twisted cable may be feasible for DC current transmission toroidal field coils in magnetic-confinement devices. Furthermore, the electromechanical behaviour of toroidal field coils has been evaluated via the Maxwell stress, solved by using an A–V formulation. It was discovered that the stress generated by the toroidal field coils is within the stress tolerance of the REBCO coated conductor, something which is of great significance in promoting the application of REBCO coated conductors for ultra-high-field magnetic-confinement plasma devices.

THE WINDER DANCER POSITION CONTROL MODEL USING DIFFERENT PID CONTROL STRUCTURES AND MICROLOGIX PLC

In the cable industry, improper regulation of the winding speed of the conductor cable, i.e. the position of the tensioner (dancer) leads to improper stretching of the conductor, which significantly affects the characteristics of the final product. Winding speed control is directly related to tensioning which is an additional problem. This paper presents a system for control a cable winding device using a linear PID controller with and without control signal limitation. The system parameters were determined using integral time-weighted absolute error (ITAE) criteria and realized using a conventional PLC controller.

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.

All-Electric NASA N3-X Aircraft Electric Power Systems

In this article, turboelectric NASA N3-X aircraft is fully electrified for the first time; engines are removed and the all-electric NASA N3-X aircraft electric power system (EPS) is introduced, supplied by four electrochemical energy units (EEUs), including batteries, fuel cells, and supercapacitors. In this regard, three medium-voltage direct current (MVdc), ±5 kVdc, bipolar EPS architectures are proposed for the aircraft and discussed and analyzed in detail by a performing power flow (PF) analysis. The proposed architectures are also considered as three-phase ac, 10 kVac, EPSs and discussed and analyzed in detail for comparison. To perform the PF analysis for the proposed MVdc EPSs, two PF solvers for dc networks under constant power generations and loads are also modified and developed. Potential cable conductors are selected and hints are provided to choose final conductors; to assess the performance of selected conductors, dimensions of the aircraft are estimated and cable parameters are calculated based on the presented dimensions. The proposed EPS architectures meet power system planning criteria under normal condition as well as all n −1 contingencies. This article aims to assess newly designed EPSs and, therefore, assumptions are made about EEUs and propulsion motors to the extent whereby PF analysis is affected.

Fatigue Fracture of Aluminum Wires in High-Voltage Electrical Cables in Alaska

Several wires in aluminum conductor cables fractured within 5–8 years of, service in Alaskan tundra. The cables were comprised of 19-wire strands; the wires were aluminum alloy 6201-T81. Visual and metallographic examinations of the cold-upset pressure weld joints in the wires established that the fractures were caused by fatigue loading attributable to wind/thermal factors at the joints. The grain flow at the joints was transverse to the wire axis, rendering the notches of the joints sensitive to fatigue loading. An additional contributory factor was intergranular corrosion, which assisted fatigue crack initiation/propagation. The failure was attributed to the departure of conductor quality from the requirements of ASTM B 398 and B 399, which specify that “no joints shall be made during final drawing or in the finished wire” and that the joints should not be closer than 15 m (50 ft). The failed cable did not meet either criterion. It was recommended that the replacement cable be inspected for strict compliance to ASTM requirements.

A Brief Review on the Electrical Resistivity Of Aluminium Alloy and its Nanoparticles at Low Temperature

The objective of this review article is to study the resistivity of aluminium alloy at low temperatures. Various articles have been thoroughly studied for this review. Alloys that contain Al as dominant metal are termed as Al alloys. The first conventional Al alloy was prepared A6160 whose major constituents are Si and Mg. Al metal in its pure form has very high electrical conductivity but it is soft. Foils and conductor cables are made of Al. For advanced applications, Al is alloyed. The review has briefly explained the physical background of electrical resistivity and analysis of chosen material, aluminium alloy. Furthermore it has also discussed the resistivity of nanoparticles of Aluminium alloy.Keywords: Aluminium alloys, electrical resistivity, temperature, impurity.

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.