Single-conductor Cables Research Articles

Electric Field Investigations of a Compact Superconducting Three-Phase Single Conductor Cable Assembly

A new compact cable design was investigated using only liquid nitrogen (LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ), general used as coolant of superconductors, as sole electric insulation. First, it was analyzed which conductor arrangement is better suited in terms of maximum electric field strength to withstand the applied voltage of 123 kV. It was found that a three-phase single conductor arrangement with a maximum electric field strength of 10.5 kV/mm is more suitable than a triaxial arrangement with a maximum field strength of 16.5 kV/mm. Furthermore, a corresponding supporting insulator was developed to provide the highest possible mechanical and electrical withstand. A major focus was on selecting the most appropriate material and its permittivity in combination with the surrounding LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (ϵ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> = 1.43) to reduce the electric field strength to its possible minimum. The best relative permittivity for the supporting insulator is in the range between 1.4 and 3.4.

Design, Modeling &amp; Simulation of Analysis of coupling to Cables due to Electromagnetic Pulse (EMP)

This paper is to analyze the EMP coupling to cables using 3D EM Modeling and Simulation Analysis. Bounded wave transmission line structure as per MIL-STD 461, RS105 EMP requirement in terms of peak electric field of 50KV/m with rise time-2.3ns and pulse width-25ns was developed. Single conductor cable, RF Coaxial cable were modeled. EMP Coupling to cables was carried out by placing the cable under generated EMP field in terms of induced voltage and currents due to EMP fields. EMP coupling to active line with matched termination also analyzed.

Determination of the Rated Current Loads of Cable Lines with Distributive Parameters

The power transfer capacity of cable lines is substantially affected by the conditions of cable laying. The laying of power cables at a rated ac voltage of 10 kV and frequency of 50 Hz with an aluminum multiwire compacted current-carrying conductor with a cross section of 240 mm2 and XLPE insulation in a cable channel, which is placed into the ground and filled with air, has been considered. The suggested technique to determine rated current loads of cables in the cable channel with the distributive parameters is based on the solving the problem of steady-state heat conduction and allows one to eliminate the problem of convective heat exchange. The numerical implementation of this problem is divided into two stages. At the first stage, when determining the current loads of cables, the dependence of mean air temperature in the cable channel on the power of an internal heat source is determined. At the second stage, the rated current loads of cables are calculated taking into account the obtained air temperature distribution in the cable channel. In this case the problems of steady-state conduction are solved at both stages using the ANSYS software. The rated current loads of cable lines are selected by the iteration procedure taking into account the admissible insulation and shell temperatures. The performance characteristics of single conductor cables laid in the same plane and three-conductor cables with sector-shaped conductors in the cable channel have been studied.

Arrangement Optimization of Power Cables in Harmonic Currents to Achieve the Maximum Ampacity Using ICA

In this article, a new electro-thermal optimization algorithm is proposed to determine the parallel power cables arrangement to obtain the maximum ampacity. The optimization procedure is based on the imperialist competitive algorithm (ICA). Electrical calculations are performed using the sub-conductors method and consideration of the skin and proximity effects. FEM thermal model and electrical calculations are coupled with optimization procedure to determine the ampacity in the optimization algorithm. Optimized arrangements are determined under sinusoidal and harmonic load currents conditions. Furthermore, the effects of different boundary conditions of the ground surface such as isothermal and convective heat flux are evaluated. The underground single conductor cables with solid bonded metallic sheaths and existing of circulating currents are considered. Cables are considered to be installed adjacent to each other in different rows above each other in flat formations. Also, the artificial bee colony (ABC) optimization algorithm is performed to validate the ICA procedure. Experimental measurement of a case study is carried out for simulation confirmation and the results show good agreement.

Methodology for the selection of long‐medium‐voltage power cable configurations

Single conductor cables are widely used in several types of installations over the last years, including the interconnection of wind parks to the power grid. Owing to the complexity of cable installations each configuration must be treated individually, regarding the use of sheath cross-bonding, the influence of grounding resistances and the use of sheath voltage limiters. In this study, a systematic investigation of the performance of a long-medium-voltage cable configuration is presented. Sheath voltages and currents are calculated during steady-state and short-circuit conditions for varying sheath arrangements using the ATP/EMTP software. Results are validated by field measurements. The analysis is also extended to include the investigation of overvoltages in the installation, during slow and fast transients, according to the basic insulation level for the cable system.

Current Distribution in Parallel Single-Core Cables on Metal Tray

Parallel single-core (single-conductor) cables are employed in the backbone of building distribution systems. As power consumption in buildings grows continuously, overheating problems associated with such a cable installation have become a concern. This paper investigates the current distribution among parallel single-core cables installed on metal tray in a multiphase distribution system. A general prediction method of current distribution is introduced and is validated experimentally. To analyze the current distribution under different cable arrangements, empirical formulas of cable impedance are presented. The current distribution associated with the local practice of parallel cable installations is evaluated, and recommendations for the design and installation are presented.

Modeling the effects of distance in single-conductor power cables in a three-phase power system

Single-conductor power cables are widely used in cable lines in Armenia and provide greater current conduction and reliability than triple-conductor cables. In this paper, the optimal distance between single-conductor power cables in a three-phase power system for a given arrangement (horizontal in the plane or triangular) and ambient (ground) temperature are determined. The results for single-conductor cable arrangements are presented in graphical form.

Impedance of a double submarine cable circuit using different types of cables within a single circuit

The interconnection between the Upper and Lower Peninsulas of Michigan has recently been upgraded from a single 138 kV circuit to a double 138 kV submarine power cable circuit. The original circuit consisted of four single-conductor cables, the fourth cable serving as a spare phase conductor. The second circuit was formed by adding two new single conductor cables and combining them with the spare cable from the original circuit. The use of two different types of cables in one circuit causes that circuit to be unbalanced. The series impedance and shunt admittance matrices of the circuits were studied to investigate the degree to which they were unbalanced, so that the impedance relays protecting the cable could be properly set. Measurements were made on the cables after they were installed and these were compared to calculations made with the ATP EMTP Cable Constants program. >

A new electronic system for the rectangular midwater trawl (RMT)

This paper describes a modified modern version of the original rectangular midwater trawl (RMT) manufactured by the Institute of Oceanographic Sciences (IOS). The shipboard acoustic transducer and the underwater RMT-monitor were replaced by an electronic interface box was while the data transfer, realized by a single-conductor cable. Using frequency shift keying (FSK) signal transmission, a PC-controlled system onboard handles data acquisition and control as well as real time monitoring of the haul. The volume of water filtered by the net is calculated based on the online readings of a net-angle sensor. The new RMT-system was successfully used in the Antarctic during the European Polarstern Study (EPOS) from October 1988 to March 1989. Fifty-seven tows to a maximum depth of 1000 m in open waters and in ice covered areas were performed.

Single-Conductor Cables in Parallel

The effect of the unbalanced current in a single-conductor cable circuit could have more adverse impact on the low voltage system than on the medium voltage system. This is because a low voltage cable circuit is generally sized to match the load requirement closely, whereas a medium voltage cable circuit is often determined by the system short circuit consideration. However, the adverse impact of the unbalanced current can be minimized if single conductor cables are arranged in a symmetrical configuration, or arranged in a triangular configuration (for Canadian practice only), if three, five, or six cables are needed in each phase.

A History of Well Logging In Canada

Early History The history of well logging in Canada begins in 1937, a mere 10 years after the very first electric log was run in the Pechelbronn oilfield in France on September 5th 1927. A quote from the official Schlumberger history tells the story: "In another part of the country, a young engineer named Bill Gillingham was attempting to raise some interest in electric logging in the Bradford, Pennsylvannia area. The response was not immediately tremendous. A trainee under Gillingham, R.R. Rieke, was told to head west by northwest, to Mt. Pleasant, Michigan, embarking on one of the strangest Schlumberger journeys you've heard of." "You see, they ended up in Canada, not looking for oil, but for gold. The preliminary work had been conducted by Andre A1legret and, as a result of surface exploration, a contract had been let. "When we arrived, Rieke said, ‘trouble was afoot. They had found gold alright, but not where the survey had said. When they drilled there nothing. We left rather quickly’." Two years, later, "electric logs" were introduced to the Canadian oil patch in 1939 by the forerunner of today's Halliburton Services Ltd. The first Halliburton unit was operated out of Black Diamond, Alberta, by Jack Pettinger, who remained active until 1979. Jack and another pioneer, Stan Nelner, currently with Halliburton in London, England, recalls that trips of hundreds of miles to such far-flung wildcat sites as Kamsack, Saskatchewan, Pouce Coupe, B.C., and Lloydminster were not uncommon. During the war years, equipment was also stationed at Norman Wells on the Canol Project and at Vermilion, Alberta. The logger of those days had to be versatile because he was often called upon to operate cementing and acidizing equipment, or to run drill-stem tests, in addition to the standard electrical survey (ES). With increased demands after Leduc, more modern survey equipment was added. Also, the "FM" (frequency modulated) system of transmitting subsurface data via a single conductor cable was adopted by Halliburton. This technique has remained a unique feature of the Halliburton-Welex wireline equipment. The approximate dates of first availability of modern logging methods, as recalled by Gerry Obermeyer, current manager of operations for Halliburton, were Focused Resistivity 1952, Radioactive 1954, Induction 1954 and Acoustic 1958. A shift in the development of Canadian operations also occurred in 1957 when the parent company purchased WELEX Incorporated. A combined WELEX-Halliburton Electrical Well Section operated in Canada as a separate company for some time. The perforating service, which had also been introduced to Canada by Halliburton in 1940, was expanded. Later, that group was absorbed as an operating division of Halliburton Services Ltd. Schlumberger arrived permanently in Canada in 1946 by opening a location at Lloydminster, manned by such notables as Ed Burge, Hugh Gough and Arne Thorson. Truck numbers were in the 200 series. One of the older units in Canada about that time required that the crew jack up the rear end and install a chain from the rear axle to the winch drive.

Deep borehole testing techniques developed for Canada's nuclear fuel waste management program

Atomic Energy of Canada Limited's nuclear fuel waste management program is presently centred around the concept of deep burial of immobilized fuel waste within igneous plutons of the Archaean Canadian Shield. Contaminant transport within this host medium would be by movement through rock fractures. Consequently, as part of the overall concept assessment phase, hydrogeological research has been initiated to assess potential pathways for contaminant leaks to the biosphere. Determination of accurate rock mass and fracture hydraulic conductivities and travel times are essential to the deep burial concept. Five continuously cored, inclined boreholes have been drilled to equivalent vertical depths up to 1100 m into the Eye-Dashwa Lakes pluton of Northern Ontario. This granitic body is a massive, medium to coarse grained hornblende — biotite granite which is intrusive into a series of tonalitic gneisses. Detailed core logging and surface fracture mapping have provided fracture geometry data as vital input to the on-going hydrogeological research. Slim-hole, single - and double-packer assemblies including down-hole transducers and thermistors have been developed to measure transient and steady state pressures and temperatures. Down-hole measurements are multiplexed to surface recording equipment via a single conductor cable. Pressure and temperature responses can be observed as frequently as every four seconds. Essential test data are recorded on magnetic tape. The on-site, surface data acquisition system has the capability of plotting the pressure-temperature data as it is recorded, thus allowing immediate inspection and evaluation of test data. Preliminary analysis of hydraulic data indicate that at least three discrete flow regimes may exist within the pluton. Hydraulic conductivity values show a general decrease with depth, although zones of relatively high hydraulic conductivity do occur: values range from 10 −6 m/s near the surface to about 10 −13 m/s at 1000 m vertical depth, when porous medium analysis is used.

An in situ attenuance meter for very turbid waters

For investigations in very turbid waters an attenuance meter has been built with a range of attenuation coefficientsc between 4 m−1 and 400 m−1. The instrument is of conventional mechanical design with opposite windows 10 mm apart. Unmodulated light is used. Basic features of the meter are a rugged and compact housing, solid state electronics and electro-optical components, a monochromatic light source, and an efficient lens system. The underwater unit can operate on a single conductor cable. The data output is compatible with larger data acquisition systems. The low power requirements admit measurements from small boats. The effect of forward scattering is estimated, which may cause an error of less than 5% in the attenuation coefficient. It is shown that a short path length is a reasonable low cost solution to the problem of measuring attenuation in very turbid waters.

Models of horizontal electric cables and cable trays exposed to a fire plume

Models are developed to describe horizontal insulated cables and cable trays exposed to a fire plume. The models also apply to cables protected by fire-retardant coatings. A cable or coated cable can ignite when its surface is hot enough to generate flammable gas, unless the level of O 2 available is insufficient for ignition. Then the gas can often accumulate elsewhere and burn later. A first set of models predicts the delay time to the onset of gasification. Other models estimate the attainable mass flux of flammable gas generated by a tray of cables when the cables do not ignite directly. Longitudinal heat flow is identified as a factor tending to prevent direct ignition of single-conductor cables in the cool plumes encountered over cable-tray fires.

Fault tests on embedded copper wire and copper tape shielded single conductor cables

A major challenge in the design and application of single conductor shielded power cable is to minimize losses in the insulation shield and at the same time provide adequate fault current capability for the shield. This paper discusses a test program and the results obtained in the investigation of fault current in the shield and fault current capability of the shield of a new cable design (embedded copper wire shield) as compared to an existing cable design (copper tape shield). The methods used should be of interest to cable producers and users in the investigation of other cable shield designs.

Exact equation for calculation of sheath proximity loss of single-conductor cables

The sheath proximity loss of single-conductor cables is calculated by Miller's equation [1]. However, this equation involves a correction term which causes considerable error in calculated values for large-size, aluminum-sheathed cables. Taking the self-inductance of eddy current into account, the author has derived the exact equation. Miller's equation is no longer valid, especially for large-size, aluminum-sheathed cables.

Calculation of Propagation, Reflection and Refraction at Cross Bond on the Single Conductor Cable Circuit

Calculation of Propagation, Reflection and Refraction at Cross Bond on the Single Conductor Cable Circuit

EHY Cables: Present Situation in France

The authors first give a short description of the existing 225-kV underground system of the Paris area, where oil-pressure pipe-type cables have been mainly used since 1954. The new plans of development of this system call for new 225-kV cables, which will supply 225/20-kV distribution substations right in the heart of the city. Self-contained single-conductor cables would probably present some advantages for laying along such difficult urban routes. This is the reason why oil-filled aluminum-sheathed cables are being studied for possible future use. However, all the corresponding problems do not seem to be solved yet.

Insulations and Jackets ror Cross-Linked Polyethylene Cables

Numerous advances in the formulation and processing of electrical insulating compounds based on chemically cross-linked polyethylenes have taken place since they were first introduced commercially in 1958. The result has been a new family of polyethylene based insulations covering a wide range of properties. A review of the available types of cross-linked polyethylene insulations reveals that their properties appear adequate for some applications as an integral insulation-jacket covering for wire and cable. In some cases, however, cable performance can be improved by the addition of a compatible jacket. This is true for unshielded single-conductor cables rated above 600 volts as well as for shielded cables and multiconductor cables.

The stress of tension on the single conductor cable during measurements by the bathysonde in the deep sea : Siedler, G. 1962. Kieler Meeresf. 18(1): 34–35.

The stress of tension on the single conductor cable during measurements by the bathysonde in the deep sea : Siedler, G. 1962. Kieler Meeresf. 18(1): 34–35.