Multiconductor Cables Research Articles

Mathematical modelling of multi conductor cables

This paper proposes a formal justification of simplified 1D models for the propagation of electromagnetic waves in thin non-homogeneous lossy conductor cables. Our approach consists in deriving these models from an asymptotic analysis of 3D Maxwell's equations. In essence, we extend and complete previous results to the multi-wires case.

High-Frequency Behavioral Multiconductor Cable Modeling for EMI Simulations in Power Electronics

Computationally efficient high-frequency circuit models of long cables are necessary for accurate analysis of electromagnetic interference in power converter systems. A methodology for behavioral modeling of multiconductor power cables based on measurements is presented in this paper. The procedure is founded on and extended from the techniques developed and used for modeling very large scale integration interconnects and printed circuit board transmission lines in packaging and microwave engineering. The methodology accurately captures the frequency-dependent behavior in the conductive emission range, including dc, using a vector-fitting rational-function approximation and results in stable, causal, and passive equivalent circuits. The models are validated by comparing the results obtained using simulations with the measurements in both frequency and time domain.

Estimation of multi‐conductor powerline cable parameters for the modelling of transfer characteristics

The modelling of transfer characteristics of low-voltage power distribution networks for Power Line Communications requires the knowledge of the electrical parameters of the cables comprising these networks. In this study, a method is developed for characterising the power line cable parameters. In complement to many existing approaches, the authors estimate the cable parameters from a limited set of measurements. Measurement results can take into account fabrication tolerances, bending of the cables etc., which help to obtain more accurate results. A multi-conductor powerline cable has multiple, coupled propagation modes with corresponding primary parameters. Based on multi-conductor transmission line theory, the authors propose a practical measurement approach to derive the parameters separately. A previous analysis was made for four-conductor powerline cable. Here, it will also be generalised for three-conductor cables. With the parameters, the transfer function of the same kind of cable can be obtained easily. The approach is validated by comparing the deduced transfer function of a power line cable with the directly measured one.

Narrowband PLC SIMO-Based Interference Suppression With Zero-Forcing

A single-input multiple-output-based architecture is considered to support co-channel interference (CCI) suppression processing at the receiver, where narrowband (NB) outdoor power-line communications (PLC) in the 42-89 kHz frequency band are assumed. The phantom mode (PM) in a multiconductor power transmission cable is employed for transmission, and both the PM and the differential mode (DM) are used at the receiver. Transfer functions for the PM-PM and the PM-DM modes are modeled for short-range and long-range outdoor NB PLC topologies incorporating three-path propagation using a deterministic transmission-line modeling approach. An orthogonal frequency-division multiplexing (OFDM) waveform based on the PRIME standard is used for the desired and CCI signals. Interference suppression is achieved through a zero-forcing algorithm that leverages multichannel reception and requires channel state estimates for the interference signal. Stochastic network structures are further discussed to demonstrate the average interference suppression performance. Bit-error-rate performance is estimated in the presence of interference with and without zero-forcing suppression. Results indicate that the suppression algorithm leads to a more robust interference-tolerant receiver, particularly when the relative channel responses between modes for the desired signal and the interference signal are sufficiently different.

Accurate numerical method to evaluate the capacitances of multi-conductor power cables

This paper presents an accurate method to evaluate the capacitances of multi-conductor power cables. The method developed can also be applied to cables presenting multilayer dielectrics. Strips of charge are used to represent the electric charge distribution on conductors’ surface, as well as to characterize the polarization charge distribution on interfaces separating two different dielectrics. The advantage of using strips of charge is to preserve charge continuity along conductor surfaces and dielectric interfaces. This methodology is accurate since the proximity effects among conductors are taken into account. Validation of the method is performed comparing experimental, other software and analytical results with those obtained by using the proposed numerical method. A cylindrical non-concentric capacitor is used for the analytical validation and a three-phase power cable is used on experimental tests.

Microstructure of the elements of a superconducting Alloy Nb-Ti cable

The formation of a micro- and macrostructure in the Nb-Ti-based technical superconductors that are intended for the current-carrying elements in the magnetic system of the International Thermonu-clear Experimental Reactor and are subjected to deformation by drawing is considered. The deformation structure and microstructure of cable samples are studied by optical microscopy, atomic force microscopy, and scanning electron microscopy. The specific features of plastic flow localization at the sites of fracture of a multiconductor cable are revealed.

A full-space conformal mapping for the calculation of series impedance of overhead transmission lines and underground cables

This paper introduces a 2-dimensional conformal transformation scheme for the parameter extraction of an arbitrary overhead transmission line or underground cable in an unbounded lossy space. The quasi-magnetic Helmholtz equation is solved using the finite element method (FEM). A modified bilinear transformation is employed to transform the unbounded domain to a bounded domain that is more efficiently handled in FEM simulations. Due to conformality of the transformation, the magnetic stored energy, which is used to calculate the per-unit-length inductance matrix, L, is independent from the mapping factor while the longitudinal current and its corresponding dissipated energy, which is used to calculate the per-unit-length resistance matrix, R, are functions of the mapping factor. Numerical results for an overhead transmission line and a buried multiconductor cable are compared with those calculated using Carson's approximation and Wedepohl's formula from near DC to the high frequency range.

An MTL Theory Approach for the Simulation of MIMO Power-Line Communication Channels

We propose a bottom-up power-line communication (PLC) channel simulator for networks that deploy multiconductor cables and enable establishing a multiple-input multiple-output (MIMO) communication link between two nodes. We show that the fundamental multiconductor transmission-line (MTL) relations are a matrix form extension of the two-conductor transmission-line equations, and that they allow the application of the voltage ratio approach for the computation of the channel transfer function (CTF). Thus, any complex network can be remapped to obtain a simple representation in terms of MTL elementary units. Then, the MIMO CTF is computed as the product of the insertion loss of the units. We discuss the analytical computation of the per-unit-length (p.u.l.) parameters for two electrical cables, that we refer to as symmetric and ribbon. Further, we propose using an improved cable model for ribbon cables that accounts for the dielectric nonuniformity. We report the comparison between simulation and experimental measures for two test networks. The results are in good agreement. This validates the proposed MIMO PLC channel simulation approach.

Stochastic Analysis of Multiconductor Cables and Interconnects

This paper provides an effective solution for the simulation of cables and interconnects with the inclusion of the effects of parameter uncertainties. The problem formulation is based on the telegraphers equations with stochastic coefficients, whose solution requires an expansion of the unknown parameters in terms of orthogonal polynomials of random variables. The proposed method offers accuracy and improved efficiency in computing the parameter variability effects on system responses with respect to the conventional Monte Carlo approach. The approach is validated against results available in the literature, and applied to the stochastic analysis of a commercial multiconductor flat cable.

Robust Passivity Enforcement Scheme for Time-Domain Simulation of Multi-Conductor Transmission Lines and Cables

This paper proposes an algorithm to enforce passivity on the time-domain simulation model for a multi-conductor cable or transmission line. The model is first reformulated in a form which reduces the severity of passivity violations. The frequency sweep method is then used to identify any remaining passivity violating regions of the model's frequency response. These small passivity violations are then removed using a linear constrained least squares algorithm to perturb the diagonal elements of propagation matrix. The passivity enforcement algorithm is applied to the Universal Line Model (ULM), a widely used robust phase domain formulation implemented in many commercial electromagnetic transients simulation programs. Two examples of multi-conductor underground cable systems, one for ac and the other for HVDC transmission are presented to demonstrate the proposed approach.

10.1007/s11487-008-1004-8

A rigorous method is proposed for calculating the parameters of two-wire lines (twisted pairs) surrounded by a single metal shield and the mutual coupling between these lines. It is shown that coupling between the lines in multiconductor cables results in electromagnetic interference (crosstalk) in communications channels and that inphase currents in the lines are caused by the asymmetry of excitation and loads. The stray voltages induced across the impedances placed at the beginning and the end of an adjacent line are determined at a given power in the main line. The effect produced by the loads placed between the wires and the shield is considered. The proposed method allows generalization of the obtained results to the case of lossy multiconductor cables.

An Experimental Multi-disciplinary observatory (VENUS) at the Ryukyu Trench using the Guam-Okinawa Geophysical Submarine Cable

A MultiDisciplinary Ocean Bottom Observatory (MDOBO) was installed on VENUS (Versatile Eco-monitor- ing Network by Undersea-cable System) at a depth of 2170 m on the slope of the Ryukyu Trench. In this con- text, «Eco-»refers to both economic (e.g., earthquake hazard mitigation) and ecological motivation. The first step in this instillation was to insert a telemetry/power system into the submarine coaxial cable; this system could then service the MDOBO, which consists of seven major bottom sensor packages. During August-Sep- tember 1999, using a deep-towed unit and both manned and unmanned submersibles coupled with precise ship navigation, the MDOBO system and its attendant cables were deployed over a range of distances from 80 m to 1 km from the telemetry system, with several meters allowance for navigational uncertainty in positioning. The unmanned submersible then extended the multi-conductor extension cables from the instrument units toward the telemetry system and connected them to undersea mateable connectors on a junction box installed on the submarine cable. The MDOBO collected one and half months of continuous records. Several kinds of useful data were collected after installation, including an aftershock (Ms= 6.1) of the 1999 Chi-Chi earthquake (Ms= 7.7) in Taiwan.

The CO2SINK boreholes for geological CO2 -storage testing

This paper reports the well design, drilling and completion operation as well as the coring technique applied in the CO2SINK project. Three boreholes, one injection well and two observation wells have been drilled to a total depth of about 800 m. 200 m of recovered 6” core material has been real-time analysed in a research field lab. The wells have been completed as “smart” wells, containing a variety of permanently installed down-hole sensors for the continuous monitoring of the CO2 in the reservoir. All wells were cased with stainless final casings equipped with pre-perforated sand filters in the reservoir zone and wired on the outside with fiber-optical and multi-conductor copper cables. The reservoir casing section is externally coated with a fiber-glass-resin wrap for electrical insulation.

Two-way voice communication device having external acoustic noise reduction

A two-way voice communication device which provides a high-level of acoustic noise reduction is disclosed. A resilient ear tip provides acoustic isolation and secures the earphone within the ear canal of the user. The ability to rotate the earphone within the ear canal allows the user to easily position an attached microphone. The audio signals may be conveyed by an included radio frequency receiver and radio frequency transmitter, or the earphone may be connected to an electrical audio device using a multi-conductor cable. Audio signals may be conveyed to one or both ears of a user. A switch to mute the audio signal from the microphone, or for supporting a push-to-talk mode of operation, may be included in the earphone housing, or on the cable.

The Chinese nuclear tests, 1964–1996

A combination of intellectual rigor, technical sophistication, hard work, and intelligence gathering brought China into the world’s nuclear club in record-shattering time.

Calculation of Electrical Parameters of Two-Wire Lines in Multiconductor Cables

A rigorous method for the calculations of the characteristics of two-wire lines (twisted pairs) located in a metal shield is considered. In this paper, it is first shown that the mutual coupling between lines in multiconductor cables results in the appearance of electromagnetic interference (crosstalk) in communication channels; second, the asymmetry of excitation and loads results in the appearance of common-mode currents in the cable. The voltage values (interference) in the loads placed at the beginning and the end of the adjacent line are determined at a given power in the main line. The effect of loads connected between wires and shield is examined. The proposed method allows generalization of the obtained results in the case of multiconductor cables with losses.

Calculation of the characteristics of two-wire lines in multiconductor cables

A rigorous method is proposed for calculating the parameters of two-wire lines (twisted pairs) surrounded by a single metal shield and the mutual coupling between these lines. It is shown that coupling between the lines in multiconductor cables results in electromagnetic interference (crosstalk) in communications channels and that inphase currents in the lines are caused by the asymmetry of excitation and loads. The stray voltages induced across the impedances placed at the beginning and the end of an adjacent line are determined at a given power in the main line. The effect produced by the loads placed between the wires and the shield is considered. The proposed method allows generalization of the obtained results to the case of lossy multiconductor cables.

Verification of Multipair Copper-Cable Model by Measurements

Analysis, assessment, and design of advanced wireline transmission schemes over multipair copper cables require accurate knowledge of the channel properties. This paper investigates modeling of multiconductor cables based on interpair impedance measurements. A unified approach to the application of the model is introduced. The direct measurement approach of the underlying interpair impedances yields a good match with the alternative approach suggested in the recent study of Cioffi et al. Crosstalk coupling functions derived from the model exhibit a good match with the corresponding direct measurements in the case in which the modeled length is close to the length of the interpair impedance measurements. However, the prediction power of this model with respect to termination impedance is limited.

Deterministic modeling of the (shielded) outdoor power line channel based on the multiconductor transmission line equations

In this paper, a complete methodology is proposed for the deterministic modeling of the channel transfer functions associated with underground power line access networks, in the light of the Multiconductor Transmission Line Theory. Some multiconductor power line cables are analyzed in detail, and their fundamental propagation characteristics (definition of eigenmodes, phase velocity, characteristic impedance, lineic attenuation) are related to the geometry of the conductors and the material properties. A multidimensional scattering matrix formalism is then introduced to perform an accurate analysis of the global power line network including multiconductor cable segments, derivation points, and termination loads. An illustrative example of a power line access network with three types of cables (with different numbers of conductors), 20 derivations, and five remote terminals, is finally proposed.

Online calibration of high-frequency partial discharge signals in three-phase belted power cables

Partial discharge (PD) magnitudes from classical detection techniques are expressed in terms of apparent charges. Signals from HF/VHF/UHF techniques on substation components are often hard to express in this quantity because of complex signal excitation and propagation channels. A method to calibrate PD signals obtained during online inductive detection in medium voltage belted cables is described. online inductive detection implies that the impedances of components present in substations essentially determine the detected PD signal magnitude. The use of belted cables means, that the coupling of a PD event to the conductors not only depends on the PD site within the cross-section of the cable or cable accessory, but also becomes dependent on the momentary phase angle. In addition, during signal propagation the signal magnitude may alter according to the propagation modes of a multi-conductor cable. These aspects are studied quantitatively by the use of theoretical modelling in addition to offline and online experiments. PD diagnostic equipment including pulse injection capability allows online calibration with sufficient accuracy, irrespective of the actual substation arrangement.