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Sample records for ac underground cable

  1. Online Location of Faults on AC Cables in Underground Transmission Systems

    Jensen, Christian Flytkjær

    2013-01-01

    A transmission grid is normally laid out as an almost pure overhead line (OHL) network. The introduction of transmission voltage level XLPE cables and the increasing interest in the environmental impact of OHL has resulted in an increasing interest in the use of underground cables on transmission level. In Denmark for instance, the entire 150 kV, 132 kV and 220 kV and parts of the 400 kV transmission network will be placed underground before 2030.To reduce the operating losses of a cable-base...

  2. Superconducting ac cable

    The components of a superconducting 110 kV ac cable for power ratings >= 2000 MVA have been developed. The cable design especially considered was of the semiflexible type, with a rigid cryogenic envelope and flexible hollow coaxial cable cores pulled into the former. The cable core consists of spirally wound Nb-Al composite wires and a HDPE-tape wrapped electrical insulation. A 35 m long single phase test cable with full load terminations for 110 kV and 10 kA was constructed and successfully tested. The results obtained prove the technical feasibility and capability of our cable design. (orig.)

  3. Online Fault Location on AC Cables in Underground Transmission Systems using Sheath Currents

    Jensen, Christian Flytkjær; Nanayakkarab, Kasun; Rajapakse, Athula;

    2014-01-01

    This paper studies online travelling wave methods for fault location on a crossbonded cable system using sheath currents. During the construction of the electrical connection to the 400 MW off shore wind farm Anholt, it was possible to perform measurements on a 38.4 km crossbonded cable system. At...

  4. Online Location of Faults on AC Cables in Underground Transmission Systems

    Jensen, Christian Flytkjær

    deviations in the parameters of the OHL will result in large errors for fault location in the cable section. Field measurements showing the effect of short circuits on crossbonded systems conducted on parts of the electrical connection to the Anholt offshore wind farm are performed. The purpose is to examine...... whether neural networks can be trained using data from state-of-theart cable models to predict and estimate the fault location on crossbonded cables. Numerous measurements of different short circuits are carried out and it is concluded that the state-ofthe-art models predict general behaviour of the...... crossbonded system under fault conditions well, but the accuracy of the calculated impedance is low for fault location purposes. The neural networks can therefore not be trained and no impedance-based fault location method can be used for crossbonded cables or hybrid lines. The use of travelling wave...

  5. Online fault location on crossbonded AC cables in underground transmission systems

    F. Jensen, Christian; Bak, Claus Leth; Gudmundsdottir, Unnur Stella

    2014-01-01

    In this paper, a fault locator system specifically designed for crossbonded cables is described. Electromagnetic wave propagation theory for crossbonded cables with focus on fault location purposes is discussed. Based on this, the most optimal modal component and input signal to the fault locator system are identified. The fault locator system uses the Wavelet Transform both to create reliable triggers in the units and to estimate the fault location based on time domain signals obtained in th...

  6. High Temperature Superconducting Underground Cable

    Farrell, Roger, A.

    2010-02-28

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the world’s first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  7. High Temperature Superconducting Underground Cable

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the worlds first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  8. Online fault location on crossbonded AC cables in underground transmission systems

    F. Jensen, Christian; Bak, Claus Leth; Gudmundsdottir, Unnur Stella

    2014-01-01

    of a 245 kV crossbonded cable system, connecting the newly installed 400 MW Danish offshore wind farm Anholt to the main grid, are obtained and used to verify the proposed system. Furthermore, extensive simulation data created in PSCAD/EMTDC is used in order to examine the robustness of the system to......In this paper, a fault locator system specifically designed for crossbonded cables is described. Electromagnetic wave propagation theory for crossbonded cables with focus on fault location purposes is discussed. Based on this, the most optimal modal component and input signal to the fault locator...... system are identified. The fault locator system uses the Wavelet Transform both to create reliable triggers in the units and to estimate the fault location based on time domain signals obtained in the substations by two fault locator units. Field measurements of faults artificially created on a section...

  9. Online fault location on AC cables in underground transmission systems using screen currents

    Jensen, Christian Flytkjær; Nanayakkara, O.M.K.K; Rajapakse, Athula;

    This paper studies online travelling wave methods for fault location on a crossbonded cable system using screen currents. During the construction of the electrical connection to the 400 MW off shore wind farm Anholt, it was possible to perform measurements on a 38.4 km crossbonded cable system. At...... coils if the screen currents contain the necessary information for accurate fault location. In this paper, this is examined by analysis of field measurements and through a study of simulations. The wavelet transform and visual inspection methods are used and the accuracy is compared. Field measurements...

  10. 47 CFR 32.2422 - Underground cable.

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Underground cable. 32.2422 Section 32.2422... FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2422 Underground cable. (a) This account shall include the original cost of underground cable installed in conduit and...

  11. EHV AC undergrounding electrical power performance and planning

    Benato, Roberto

    2010-01-01

    EHV AC Undergrounding Electrical Power discusses methods of analysis for cable performance and for the behaviour of cable, mixed and overhead lines. The authors discuss the undergrounding of electrical power and develop procedures based on the standard equations of transmission lines. They also provide technical and economical comparisons of a variety of cables and analysis methods, in order to examine the performance of AC power transmission systems. A range of topics are covered, including: energization and de-energization phenomena of transmission lines; power quality; and cable safety cons

  12. Modeling of long High Voltage AC Underground

    Gudmundsdottir, Unnur Stella; Bak, Claus Leth; Wiechowski, W. T.

    2010-01-01

    This paper presents the work and findings of a PhD project focused on accurate high frequency modelling of long High Voltage AC Underground cables. The project is cooperation between Aalborg University and Energinet.dk. The objective of the project is to investigate the accuracy of most up to date...... cable models, perform highly accurate field measurements for validating the model and identifying possible disadvantages of the cable model. Furthermore the project suggests and implements improvements and validates them against several field measurements. It is shown in this paper how a new method for...... calculating the frequency dependent cables impedance greatly improves the modeling procedure and gives a highly accurate result for high frequency simulations....

  13. 30 CFR 75.804 - Underground high-voltage cables.

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground high-voltage cables. 75.804 Section... AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in...

  14. 30 CFR 57.4057 - Underground trailing cables.

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground trailing cables. 57.4057 Section 57... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control § 57.4057 Underground trailing cables. Underground trailing cables shall be accepted...

  15. 47 CFR 32.6422 - Underground cable expense.

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Underground cable expense. 32.6422 Section 32.6422 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM... Underground cable expense. (a) This account shall include expenses associated with underground cable....

  16. AC loss in superconducting tapes and cables

    Oomen, Marijn Pieter

    2000-01-01

    The present study discusses the AC loss in high-temperature superconductors. Superconducting materials with a relatively high critical temperature were discovered in 1986. They are presently developed for use in large-scale power-engineering devices such as power-transmission cables, transformers an

  17. Comparison of advanced high power underground cable designs

    In this paper, advanced high power underground cable designs are compared in the light of available literature, of reports and information supplied by participating industries (AEG, BICC, CGE, Pirelli, Siemens), spontaneous contributions by EdF, France, BBC and Felten and Guilleaume Kabelwerke A.G., Germany, and Hitachi, Furukawa, Fujikura and Sumitomo, Japan, and earlier studies carried out at German public research centres. The study covers cables with forced cooling by oil or water, SF6-cables, polyethylene cables, cryoresistive and superconducting cables. (orig.)

  18. AC loss in superconducting tapes and cables

    Oomen, Marijn Pieter

    High-temperature superconductors are developed for use in power-transmission cables, transformers and motors. The alternating magnetic field in these devices causes AC loss, which is a critical factor in the design. The study focuses on multi-filament Bi-2223/Ag tapes exposed to a 50-Hz magnetic field at 77 K. The AC loss is measured with magnetic, electric and calorimetric methods. The results are compared to theoretical predictions based mainly on the Critical-State Model. The loss in high- temperature superconductors is affected by their characteristic properties: increased flux creep, high aspect ratio and inhomogeneties. Filament intergrowths and a low matrix resistivity cause a high coupling-current loss especially when the filaments are fully coupled. When the wide side of the tape is parallel to the external magnetic field, the filaments are decoupled by twisting. In a perpendicular field the filaments can be decoupled only by combining a short twist pitch with a transverse resistivity much higher than that of silver. The arrangement of the inner filaments determines the transverse resistivity. Ceramic barriers around the filaments cause partial decoupling in perpendicular magnetic fields at power frequencies. The resultant decrease in AC loss is greater than the accompanying decrease in critical current. With direct transport current in alternating magnetic field, the transport-current loss is well described with a new model for the dynamic resistance. The Critical- State Model describes well the magnetisation and total AC loss in parallel magnetic fields, at transport currents up to 0.7 times the critical current. When tapes are stacked face-to-face in a winding, the AC-loss density in perpendicular fields is greatly decreased due to the mutual shielding of the tapes. Coupling currents between the tapes in a cable cause an extra AC loss, which is reduced by a careful cable design. The total AC loss in complex devices with many tapes is generally well

  19. Development of YBCO HTS cable with low AC loss

    High temperature superconducting (HTS) cables using YBCO tapes are expected to be more economical because AC losses will be much smaller than conventional cables. To reduce AC loss, 10 mm wide YBCO tapes were divided into five strips using a YAG laser. Using narrower strips and optimizing the space between the strips were effective in reducing AC loss. A 1 m conductor was fabricated, and AC loss was 0.048 W/m at 1 kA and 50 Hz. Based on the successful AC loss reduction in the 1 m conductor, we will fabricate a 10 m HTS cable with a three-layer HTS conductor, electrical insulation, and a one-layer HTS shield and cupper protection layer for overcurrent. In addition, we have developed a prototype of the HTS cable joint that can withstand an overcurrent condition of 31.5 kA for 2 s

  20. 30 CFR 75.822 - Underground high-voltage longwall cables.

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground high-voltage longwall cables. 75... MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.822 Underground high-voltage longwall cables. In addition to the...

  1. Energy dispatching analysis of lightning surges on underground cables in a cable connection station

    The paper aimed to simulate the transient over-voltage phenomena which occur at 345 kV and 161 kV underground cables, when lighting strikes on or near the cable connection station, by using the Electro-Magnetic Transients Program (EMTP). A feasibility study on changing related parameters, as well as cable connections and grounding methods to reduce the impact caused by lightning strikes, will be thoroughly conducted. The various components required for a detailed simulation including; lightning surges, transmission line and tower, arrester, and underground cables are all considered. Then, the transient voltage of the cables will be analyzed under different situations including; connection methods, grounding locations, length of the grounding wire of arrester, and the grounding resistance for different locations. The simulation results show that the length of the grounding wire is more sensitive to the transient over-voltage which occurred when a common grounding topology was adopted. In contrast, the use of an independent grounding topology resulted in a reduction of the grounding resistance, which effectively decreased the over-voltage, thereby avoiding surpassing the shielding voltage level of the cable, caused by the rise of ground voltage.

  2. Assessment of 69 kV Underground Cable Thermal Ratings using Distributed Temperature Sensing

    Stowers, Travis

    Underground transmission cables in power systems are less likely to experience electrical faults, however, resulting outage times are much greater in the event that a failure does occur. Unlike overhead lines, underground cables are not self-healing from flashover events. The faulted section must be located and repaired before the line can be put back into service. Since this will often require excavation of the underground duct bank, the procedure to repair the faulted section is both costly and time consuming. These added complications are the prime motivators for developing accurate and reliable ratings for underground cable circuits. This work will review the methods by which power ratings, or ampacity, for underground cables are determined and then evaluate those ratings by making comparison with measured data taken from an underground 69 kV cable, which is part of the Salt River Project (SRP) power subtransmission system. The process of acquiring, installing, and commissioning the temperature monitoring system is covered in detail as well. The collected data are also used to evaluate typical assumptions made when determining underground cable ratings such as cable hot-spot location and ambient temperatures. Analysis results show that the commonly made assumption that the deepest portion of an underground power cable installation will be the hot-spot location does not always hold true. It is shown that distributed cable temperature measurements can be used to locate the proper line segment to be used for cable ampacity calculations.

  3. Comparative Analysis of Thermography Studies and Electrical Measurement of Partial Discharges in Underground Power Cables

    Gonzalez-Parada, A.; Guzman-Cabrera, R.; Torres-Cisneros, M.; Guzman-Sepulveda, J. R.

    2015-09-01

    The principal cause of damage in underground power cable installations is partial discharge (PD) activity. PD is a localized non-linear phenomenon of electrical breakdown that occurs in the insulating medium sitting between two conducting materials, which are at different potentials. The damage to the insulating material is induced by the AC voltage to which the insulator is subjected during the discharge process, and it can be directly or indirectly measured by the charge displacement across the insulation and the cavity defect. Non-invasive detection techniques that help in identifying the onset of the discharge process are required as PD is a major issue in terms of maintenance and performance of underground power installations. The main locations of failure are the accessories at points of connection such as terminals or splices. In this article, a study of electrical detection of PD and image processing of thermal pictures is presented. The study was carried out by controllably inducing specific failures in the accessories of the installation. The temporal evolution of the PD signals was supported with thermal images taken during the test in order to compare the PD activity and thermal increase due to failure. The analysis of thermographic images allows location of the failure by means of intensity-based texture segmentation algorithms. This novel technique was found to be suitable for non-invasive detection of the PD activity in underground power cable accessories.

  4. Narrow strand YBCO Roebel cable for lowered AC loss

    We have constructed test lengths of Roebel cable from wide strips of second generation YBCO wire. The strand width is 2mm to allow for lowered AC losses in comparison with standard HTS wires. Up to 10 strands can be cut from the 40mm wide strip and assembled into a 10 strand cable with a transposition length of 90mm. Electrical measurements show good retention of critical current through the cutting and cabling processes. Initial AC loss measurements confirm the reduction expected from full width wire. Results from mechanical modeling are presented which have been used to optimise strand geometry to reduce stress concentrations. Manufacturing capability to produce up to 100m lengths has been demonstrated

  5. Experimental investigation of a.c. losses in cabled superconductors

    A.c. losses in multifilamentary composite superconducting strands and cables have been measured in adiabatic conditions for transverse field sweep rates up to 50 T s-1. Measurements were performed on NbTi and Nb3Sn conductors of several configurations and surface preparations: single strands, soldered strands and cables of varying degrees of compaction composed of bare strands, with CuNi barriers and strands with chrome plating. The experimental data agree well with existing loss models. The data suggests that the total cable loss grows as approx.= 1/(void)3 below void fractions of 40%. This observed cable loss dependence on void fraction does not agree well with a previously proposed model. (author)

  6. Non-invasive monitoring of underground power cables using Gaussian-enveloped chirp reflectometry

    In this paper, we introduce non-invasive Gaussian-enveloped linear chirp (GELC) reflectometry for the diagnosis of live underground power cables. The GELC reflectometry system transmits the incident signal to live underground power cables via an inductive coupler. To improve the spatial resolution of the GELC reflectometry, we used the multiple signal classification method, which is a super-resolution method. An equalizer, which is based on Wiener filtering, is used to compensate for the signal distortion due to the propagation characteristics of underground power cables and inductive couplers. The proposed method makes it possible to detect impedance discontinuities in live underground power cables with high spatial resolution. Experiments to find the impedance discontinuity in a live underground power cable were conducted to verify the performance of the proposed method. (paper)

  7. Research on communication system of underground safety management based on leaky feeder cable

    CHEN Jian-hong; ZHANG Tao; CHENG Yun-cai; ZHANG Han

    2007-01-01

    According to the current working status of underground safety management and production scheduling, the importance and existed problem of underground mine radio communication were summarized, and the basic principle and classification of leaky feeder cable were introduced and the characteristics of cable were analyzed specifically in depth, and the application model of radio communication system for underground mine safety management was put forward. Meanwhile, the research explanation of the system component, function and evaluation was provided. The discussion result indicates that communication system of underground mine safety management which is integrated two-way relay amplifier and other equipment has many communication functions, and underground mine mobile communication can be achieved well.

  8. Low AC Loss in a 3 kA HTS Cable of the Dutch Project

    Chevtchenko, Oleg; Zuijderduin, Roy; Smit, Johan; Willén, Dag; Lentge, Heidi; Thidemann, Carsten; Traeholt, Chresten; Melnik, Irina; Geschiere, Alex

    2012-01-01

    Requirements for a 6km long high temperature superconducting (HTS) AC power cable of the Amsterdam project are: a cable has to fit in an annulus of 160mm, with two cooling stations at the cable ends only. Existing solutions for HTS cables would lead to excessively high coolant pressure drop in th...

  9. Models for electromagnetic coupling of lightning onto multiconductor cables in underground cavities

    Higgins, Matthew Benjamin

    This dissertation documents the measurements, analytical modeling, and numerical modeling of electromagnetic transfer functions to quantify the ability of cloud-to-ground lightning strokes (including horizontal arc-channel components) to couple electromagnetic energy onto multiconductor cables in an underground cavity. Measurements were performed at the Sago coal mine located near Buckhannon, WV. These transfer functions, coupled with mathematical representations of lightning strokes, are then used to predict electric fields within the mine and induced voltages on a cable that was left abandoned in the sealed area of the Sago mine. If voltages reached high enough levels, electrical arcing could have occurred from the abandoned cable. Electrical arcing is known to be an effective ignition source for explosive gas mixtures. Two coupling mechanisms were measured: direct and indirect drive. Direct coupling results from the injection or induction of lightning current onto metallic conductors such as the conveyors, rails, trolley communications cable, and AC power shields that connect from the outside of the mine to locations deep within the mine. Indirect coupling results from electromagnetic field propagation through the earth as a result of a cloud-to-ground lightning stroke or a long, low-altitude horizontal current channel from a cloud-to-ground stroke. Unlike direct coupling, indirect coupling does not require metallic conductors in a continuous path from the surface to areas internal to the mine. Results from the indirect coupling measurements and analysis are of great concern. The field measurements, modeling, and analysis indicate that significant energy can be coupled directly into the sealed area of the mine. Due to the relatively low frequency content of lightning (< 100 kHz), electromagnetic energy can readily propagate through hundreds of feet of earth. Indirect transfer function measurements compare extremely well with analytical and computational models

  10. Installation of underground power transmission cables. Proceedings of a Department of Energy workshop

    None

    1979-06-01

    The proceedings of a Department of Energy-sponsored workshop in the installation of underground power transmission cables are reported. The workshop was held in Pittsburgh, Pennsylvania, October 2--5, 1978. Sixty-two participants, representing equipment manufacturers, utilities, contractors, universities, and government agencies, were divided into topic groups covering specific installation activities. Discussion was directed toward a review of the state of the art in underground cable installation, future equipment and technique development requirements, and the formulation of conclusions and recommendations. The principal technological problem for underground installation is the lack of ability to locate underground obstacles, principally in urban and suburban areas. Development of a sensing system to locate obstacles was given a high priority by nearly all topic groups. The lack of market definition was seen as the principal impediment to competition and development of specialized equipment. Most participants felt that the federal government must assume a role in research and development of new equipment and techniques. However, the participants did not favor increased federal regulation of underground cable installation systems.

  11. A Study on the Thermal Effect of the Current-Carrying Capacity of Embedded Underground Cable

    LI Dewen

    2012-10-01

    Full Text Available The current paper aims to study embedded underground cable and the effect of temperature that surrounds it. Determining the carrying capacity of the cable is important to predict the temperature changesin the embedded pipe. Simulating the temperature field and the laying environment according to the IEC standard enables the calculation of the carrying capacity of the buried region. According to the theoryof heat transfer, the embedded pipe tube model temperature field should be coupled with a numerical model. The domain and boundary conditions of the temperature field should also be determined using the 8.7/15kV YJV 400 cable. In conducting numerical calculation and analysis using the temperature field model, the two-dimensional temperature distribution of the emission control area should be determined. The experimental results show that the simulation isconsistent with the IEC standard. Furthermore, in identifying the cable ampacity, the different seasons and different cable rows should be taken into account using the finite element method. Finally, theappropriate choice of root and circuit numbers of the cable will improve the cable’s the carrying capacity.

  12. The scaling of transport AC losses in Roebel cables with varying strand parameters

    A Roebel cable is a good candidate for low-voltage windings in a high-temperature superconductor (HTS) transformer because of its high current-carrying capability and low AC loss. Transport AC loss measurements were carried out in 1.8 m long 15/5 (fifteen 5 mm wide strands) and 15/4 Roebel cables. The results were compared with those in many Roebel cables composed of 2 mm wide Roebel strands. Comparison of the AC losses hinted that the intrinsic difference in normalized transport AC losses is due to differences in the g/w (ratio of the horizontal gap between the Roebel strands over the Roebel strand width) values. The intrinsic difference was confirmed by measuring transport AC loss in a series of horizontally arranged parallel conductor pairs with various g values. A method to scale transport AC losses in Roebel cables with varying strand parameters was developed. The scaling method will be useful for a rough assessment of AC loss in one-layer solenoid winding coils, such as in a HTS transformer. (papers)

  13. Detection and Location of Underground Power Cable using Magnetic Field Technologies

    Wang, P.; Goddard, K.F.; Lewin, P L; Swingler, S.G

    2011-01-01

    The location of buried underground electricity cables is becoming a major engineering and social issue worldwide. Records of utility locations are relatively scant, and even when records are available, they almost always refer to positions relative to ground-level physical features that may no longer exist or that may have been moved or altered. The lack of accurate positioning records of existing services can cause engineering and construction delays and safety hazards when new construction,...

  14. Development and Improvement of an Intelligent Cable Monitoring System for Underground Distribution Networks Using Distributed Temperature Sensing

    Jintae Cho

    2014-02-01

    Full Text Available With power systems switching to smart grids, real-time and on-line monitoring technologies for underground distribution power cables have become a priority. Most distribution components have been developed with self-diagnostic sensors to realize self-healing, one of the smart grid functions in a distribution network. Nonetheless, implementing a real-time and on-line monitoring system for underground distribution cables has been difficult because of high cost and low sensitivity. Nowadays, optical fiber composite power cables (OFCPCs are being considered for communication and power delivery to cope with the increasing communication load in a distribution network. Therefore, the application of distributed temperature sensing (DTS technology on OFCPCs used as underground distribution lines is studied for the real-time and on-line monitoring of the underground distribution power cables. Faults can be reduced and operating ampacity of the underground distribution system can be increased. This paper presents the development and improvement of an intelligent cable monitoring system for the underground distribution power system, using DTS technology and OFCPCs as the underground distribution lines in the field.

  15. Full Scale Test on a 100km, 150kV AC Cable

    Faria da Silva, Filipe Farria; Wiechowski, W.; Bak, Claus Leth; Gudmundsdottir, Unnur Stella

    2010-01-01

    This paper presents some of the results obtained from the electrical measurements on a 99.7 km, 150 kV three-phase AC cable, connecting 215 MW offshore wind farm Horns Rev 2, located in Denmark west coast, to Denmark's 400 kV transmission network. The measurements were performed at nominal voltag...

  16. On the Degradation Mechanism of Low-Voltage Underground Cable with Poly(Vinyl Chloride) Insulation

    Tawancy, H. M.; Hassan, M.

    2016-06-01

    A study has been undertaken to determine the degradation mechanism leading to localized short-circuit failures of an underground low-voltage cable with PVC insulation. It is shown that that the insulation of outer sheath and conductor cores has been cracked by thermal degradation involving dehydrochlorination, oxidation, and loss of plasticizers leading to current leakage between the cores. Most evidence points out that overheating due to poor connection of copper wires as well as a chemically active soil has caused the observed degradation.

  17. Theory of AC Loss in Cables with 2G HTS Wire

    Clem, J.R.; Malozemoff, A.P.

    2009-09-13

    While considerable work has been done to understand AC losses in power cables made of first generation (1G) high temperature superconductor (HTS) wires, use of second generation (2G) HTS wires brings in some new considerations. The high critical current density of the HTS layer 2G wire reduces the surface superconductor hysteretic losses. Instead, gap and polygonal losses, flux transfer losses in imbalanced two layer cables and ferromagnetic losses for wires with NiW substrates constitute the principal contributions. Current imbalance and losses associated with the magnetic substrate can be minimized by orienting the substrates of the inner winding inward and the outer winding outward.

  18. AC loss performance of cable-in-conduit conductor. Influence of cable mechanical property on coupling loss reduction

    The ITER Central Solenoid (CS) model coil, CS Insert and Nb3Al Insert were developed and tested from 2000 to 2002. The AC loss performances of these coils were investigated in various experiments. In addition, the AC losses of the CS and Nb3Al Insert conductors were measured using short CS and Nb3Al Insert conductors before the coil tests. The coupling time constants of these conductors were estimated to be 30 and 120 ms, respectively. On the other hand, the test results of the CS and Nb3Al Inserts show that the coupling currents induced in these conductors had multiple decay time constants. In fact, the existence of the coupling currents with long decay time constants, the order of which was in the thousands of seconds, was directly observed with hall sensors and voltage taps. Moreover, the AC loss test results show that electromagnetic force decreases coupling losses with exponential decay constants. This is because the weak sinter among the strands, which originated during heat treatment, was broken due to the electromagnetic force, and then the contact resistance among strands increased. It was found that this exponential decay constant was the function of a gap (i.e., a mechanical property of the cable) created between the cable and conduit due to electromagnetic force. The gap can be estimated by pressure drop, measured under the electromagnetic force. The pressure drop can easily be measured at an initial trial charge, and then it is possible to estimate the exponential decay constant before normal coil operation. Accordingly, it is possible to predict promptly how many times the trial operations are necessary to decrease the coupling losses to the designed value by measuring the coupling losses and the pressure drop during the initial coil operation trial. (author)

  19. Magnetic fields and childhood cancer: an epidemiological investigation of the effects of high-voltage underground cables.

    Bunch, K J; Swanson, J; Vincent, T J; Murphy, M F G

    2015-09-01

    Epidemiological evidence of increased risks for childhood leukaemia from magnetic fields has implicated, as one source of such fields, high-voltage overhead lines. Magnetic fields are not the only factor that varies in their vicinity, complicating interpretation of any associations. Underground cables (UGCs), however, produce magnetic fields but have no other discernible effects in their vicinity. We report here the largest ever epidemiological study of high voltage UGCs, based on 52,525 cases occurring from 1962-2008, with matched birth controls. We calculated the distance of the mother's address at child's birth to the closest 275 or 400 kV ac or high-voltage dc UGC in England and Wales and the resulting magnetic fields. Few people are exposed to magnetic fields from UGCs limiting the statistical power. We found no indications of an association of risk with distance or of trend in risk with increasing magnetic field for leukaemia, and no convincing pattern of risks for any other cancer. Trend estimates for leukaemia as shown by the odds ratio (and 95% confidence interval) per unit increase in exposure were: reciprocal of distance 0.99 (0.95-1.03), magnetic field 1.01 (0.76-1.33). The absence of risk detected in relation to UGCs tends to add to the argument that any risks from overhead lines may not be caused by magnetic fields. PMID:26344172

  20. New piercing for insulated cables in underground networks; Novos conectores compactos perfurantes ('piercings') para cabos isoldados em redes subterraneas

    Moreno, Fernando; Corral, Horacio [Tradis, SP (Brazil). E-mail: tradis@mandic.com.br

    1999-07-01

    This work presents a tap and transition connection in low voltage protected underground cables. This connection allows tapping for clients or branchings from a main energized cables. The compact connectors range various types of insulated cables protected and under grounded in a simple way. The work analysed the advantages of using two components polyurethane resins for the tapping protection and insulation restoring.

  1. Experimental study of thermal field deriving from an underground electrical power cable buried in non-homogeneous soils

    The electrical cables ampacity mainly depends on the cable system operation temperature. To achieve a better cable utilization and reduce the conservativeness typically employed in buried cable design, an accurate evaluation of the heat dissipation through the cables and the surrounding soil is important. In the traditional method adopted by the International Electrotechnical Commission (IEC) and the Institute of Electrical and Electronics Engineers (IEEE) for the computation of the thermal resistance between an existing underground cable system and the external environment, it is still assumed that the soil is homogeneous and has uniform thermal conductivity. Numerical studies have been conducted to predict the temperature distribution around the cable for various configurations and thermal properties of the soil. The paper presents an experimental study conducted on a scale model to investigate the heat transfer of a buried cable, with different geometrical configurations and thermal properties of the soil, and to validate a simplified model proposed by the authors in 2012 for the calculation of the thermal resistance between the underground pipe or electrical cable and the ground surface, in cases where the filling of the trench is filled with layers of materials with different thermal properties. Results show that experimental data are in good agreement with the numerical ones. -- Highlights: • Heat transfer of a buried cable has been experimentally studied on a scale model. • Different configurations and thermal properties of the soil have been tested. • Authors previously proposed a simplified model and obtained numerical results. • Experimental results and numerical ones previously obtained were in accordance

  2. Numerical simulation of coupled heat, liquid water and water vapor in soils for heat dissipation of underground electrical power cables

    The trend towards renewable energy comes along with a more and more decentralized production of electric energy. As a consequence many countries will have to build hundreds or even thousands of miles of underground transmission lines during the next years. The lifetime of a transmission line system strongly depends on its temperature. Therefore an accurate calculation of the cable temperature is essential for estimating and optimizing the system's lifetime. The International Electrotechnical Commission and the Institute of Electronics and Electrical Engineers are still employing classic approaches, dating back from the 1950s, that are missing fundamental phenomena involved in heat transport in soils. In recent years several authors [4,37] pointed out that for a proper computation of heat transport in soils, physical processes describing heat, liquid water and vapor transport must be coupled and the respective environmental weather conditions need to be considered. In this study we present a numerical model of coupled liquid water, vapor and heat flow, to describe heat dissipation from underground cables. At first the model is tested and validated on a downscaled experiment [32], secondly the model is applied on a simplified system to demonstrate the strong relation of the cable temperature on soil water content and finally the model is applied using real weather conditions to demonstrate that small changes in the design of underground transmission line systems can lead to considerable improvements in both average as well as peak-to-peak temperatures. - Highlights: • Wind farms and heat dissipation in underground power cables. • Cable lifetime, cable temperature and properties of surrounding soil. • Coupled model for heat dissipation, liquid water and vapor transport in soils. • Numerical simulation under real weather conditions. • Cable temperature depending on construction of transmission line system

  3. Interstrand and AC-loss measurements on Rutherford-type cables for accelerator magnet applications

    Otmani, R; Tixador, P

    2001-01-01

    One of the main issues for particle accelerator magnets is the control of interstrand resistances. Too low resistances result in large coupling currents during ramping, which distort field quality, while too large resistances may prevent current redistribution among cable strands, resulting in degraded quench performance. In this paper, we review a series of interstrand resistance and AC-loss measurements performed on four Rutherford-type cables. The four cables have the same number of strands and similar outer dimensions, corresponding to LHC quadrupole cable specifications. The first cable is made from NbTi strands, coated with silver-tin alloy, the second one is made from bare Nb/sub 3/Sn strands, the third one is made also from bare Nb/sub 3/Sn strands but includes a 25- mu m-thick stainless steel core between the strand layers, and the last one is made from Nb/sub 3/Sn strands plated with chromium. To cross-check the two measurement types and assess their consistency, we compare the coupling-current time...

  4. Earth return path impedances of underground cable for three-layer earth

    B. HEMMATIAN; B. VAHIDI; S. H. HOSSEINIAN

    2009-01-01

    One of the factors that affect the parameters of an underground cable is earth return path impedance. Pollaczek developed a formula for the case of one-layer (homogenous) earth. But in practice the earth is composed of several layers. In this study we develop a new formula for earth return path impedance in the case of a three-layer earth. To check the accuracy of the obtained results, a comparison has been made with the finite element method (FEM). A comparison between the results of the Poilaczek formula and results of the obtained formula for a three-layer earth has been made, showing that the use of the Pollaczek formula instead of the actual formula can cause serious errors.

  5. External electromagnetic transient sources: analysis of its effect in underground power cables; Fuentes transitorias electromagneticas externas: analisis de su efecto en los cables de potencia subterraneos

    Escamilla Paz, Antonio

    2009-07-01

    In most of the electrical power systems that operate at present, the subterranean cables are only a complement. The cost of these cables is generally higher than the one of the aerial power lines, thus its use is restricted only to those areas where the construction of the aerial power lines is not feasible. It is estimated that for voltages lower than 110 kV this cost is up to seven times greater than the one of an aerial power line and for voltages higher than 380 kV it can be up to twenty times greater. Nevertheless, important reasons exist to construct a subterranean cable system such as: a) the fast growth of the urban centers and the industrial zones, which brings about restrictions of the rights of way for the construction of aerial power lines, b) the crossing of large water bodies, c) the congestion of aerial power lines near the generating substations or power plants, d) the crossing of air lines and e) the laws and the regulations, to mention some of them. The importance of the underground transmission systems of high and extra high voltage will be increased in the medium and the long term, therefore, it is considered that the effects of the external phenomena in these systems, like the inductions produced by the electromagnetic transient sources, will be more severe. In this research work the atmospheric discharges are defined as the external electromagnetic transient sources. The large dimension cables such as the power cables, behave as large collectors of the interferences produced by the atmospheric discharges, which can bring about damages in the components of a system. In order to avoid the damages and to increase the reliability of the subterranean cable systems it is necessary to use protective devices and appropriate insulation levels, mainly. If the phenomenon and the behavior of the system are properly represented, it is possible to more accurately determine the characteristics that the equipment must have to resist the over voltages and the

  6. Theory of ac loss in power transmission cables with second generation high temperature superconductor wires

    While a considerable amount of work has been done in an effort to understand ac losses in power transmission cables made of first generation high temperature superconductor (HTS) wires, use of second generation (2G) HTS wires brings in some new considerations. The high critical current density of the HTS layer in 2G wires reduces the surface superconductor hysteretic losses, for which a new formula is derived. Instead, gap and polygonal losses, flux transfer losses in imbalanced two-layer cables and ferromagnetic losses for wires with NiW substrates constitute the principal contributions. A formula for the flux transfer losses is also derived with a paramagnetic approximation for the substrate. Current imbalance and losses associated with the magnetic substrate can be minimized by orienting the substrates of the inner winding inward and the outer winding outward.

  7. Measuring ac losses in superconducting cables using a resonant circuit:Resonant current experiment (RESCUE)

    Däumling, Manfred; Olsen, Søren Krüger; Rasmussen, Carsten;

    1998-01-01

    A simple way to obtain true ac losses with a resonant circuit containing a superconductor, using the decay of the circuit current, is described. For the measurement a capacitor is short circuited with a superconducting cable. Energy in the circuit is provided by either charging up the capacitors...... with a certain voltage, or letting a de flow in the superconductor. When the oscillations are started-either by opening a switch in case a de is flowing or by closing a switch to connect the charged capacitors with the superconductor-the current (via a Rogowski coil) or the voltage on the capacitor can...

  8. Quantification of the heat dissipation of underground medium and low-voltage cables; Quantifizierung der Waermeableitung bei erdverlegten Mittel- und Niederspannungskabeln

    Stegner, Johannes; Drefke, Christof; Sass, Ingo [Technische Univ. Darmstadt (Germany). Inst. fuer Angewandte Geowissenschaften; Hentschel, Klaus [E.ON Bayern AG, Regensburg (Germany)

    2013-06-01

    The performance of underground power cables depends on its operational warming. In a research project, the influence of soil and bedding materials on this performance is investigated in consideration of climate, weather and water balance of the site.

  9. Double Layered Sheath in Accurate HV XLPE Cable Modeling

    Gudmundsdottir, Unnur Stella; Silva, J. De; Bak, Claus Leth;

    2010-01-01

    This paper discusses modelling of high voltage AC underground cables. For long cables, when crossbonding points are present, not only the coaxial mode of propagation is excited during transient phenomena, but also the intersheath mode. This causes inaccurate simulation results for high frequency...

  10. Identification of problems when using long high voltage AC cable in transmission system I: Switching transient problems

    Rahimi, Saeed; Wiechowski, W.; Randrup, M;

    2008-01-01

    the proper substitution and solution which make the transmission expansion possible with minimized visual impacts on the communities. Within European countries, Denmark was been at the forefront of replacing the transmission lines with cables. The project was supplying the power to the greater......Due to political and environmental pressures from the public and government side, upgrading and building new transmission facilities are becoming more and more difficult and in some cases the expansion of overhead transmission lines are impossible. This means that underground cable technology is...

  11. Power applications for superconducting cables in Denmark

    Tønnesen, Ole; Østergaard, Jacob; Olsen, S. Krüger

    1999-01-01

    In Denmark a growing concern for environmental protection has lead to wishes that the open country is kept free of overhead lines as far as possible. New lines under 100 kV and existing 60/50 kV lines should be established as underground cables. Superconducting cables represent an interesting...... alternative to conventional cables, as they are able to transmit two or more times the energy than a conventional cable. HTS cables with a room temperature dielectric design are especially interesting as a target for replacing overhead lines. Superconducting cables in the overall network are of interest in...... cases such as transmission of energy into cities and through areas of special interest. The planned large groups of windmills in Denmark generating up to 2000 MVA or more both on dry land and off-shore will be an obvious case for the application of superconducting AC or DC cables. These opportunities...

  12. Techniques and equipment for detecting and locating incipient faults in underground power transmission cable systems. First technical progress report, 21 August 1978-31 March 1979

    Phillips, A.C.; Nanevicz, J.E.; Adamo, R.C.; Cole, C.A.; Honey, S.K.; Petro, J.P.

    1979-05-01

    This work is to provide practical methods for detecting and locating incipient faults in energized and deenergized underground power transmission cable systems. Radio-frequency probing techniques are emphasized. Supporting tasks include measurements of cable characteristics at manufacturing plants and utility installations, field evaluation, development of signal couplers to access transmission lines, and a study of methods leading to technically effective and economical use of incipient-fault locators.

  13. Numerical simulation of heat dissipation processes in underground power cable system situated in thermal backfill and buried in a multilayered soil

    Highlights: • A practical thermal analysis of underground power cable system. • The geological measurements were performed for cable line placement location. • Dry zone formation effect included in soil and FTB thermal conductivity formula. • A simplified FEM model of underground power cable system. • The computational numerical code validation with ANSYS. - Abstract: This paper presents the thermal analysis of the underground transmission line, planned to be installed in one of the Polish power plants. The computations are performed by using the Finite Element Method (FEM) code, developed by the authors. The paper considers a system of three power cables arranged in flat (in-line) formation. The cable line is buried in the multilayered soil. The soil layers characteristic and thermal properties are determined from geological measurements. Different conditions of cable bedding are analyzed including power cables placement in the FTB or direct burial in a mother ground. The cable line burial depth, measured from the ground level, varies from 1 m to 2.5 m. Additionally, to include the effect of dry zones formation on the temperature distribution in cable line and surroundings, soil and FTB thermal conductivities are considered as a temperature-dependent. The proposed approach for determining the temperature-dependent thermal conductivity of soil layers is discussed in detail. The FEM simulation results are also compared with the results of the simulation that consider soil layers as homogeneous materials. Therefore, thermal conductivity is assumed to be constant for each layer. The results obtained by using the FEM code, developed by the authors, are compared with the results of ANSYS simulations, and a good agreement was found

  14. Failure evaluation of underground high voltage cables (115 kV) in Mazatlan, Sinaloa: Microscopic method

    Valero-Huerta, M.A.; Ramirez-Delgado, R. [Lab. de Pruebas de Equipos y Materiales, Irapuato (Mexico)

    1995-11-01

    The present paper is a complete analysis of the failure which occurred to the 115 kV power cable installed between the Mazatlan Centro and Mazatlan Norte Substations. Laboratory analysis that established the causes of the failure are included. It was concluded that the failure of the cable was provoked by the entrance of sewage water to the screen, and due to the presence of anaerobic organisms, resulted in the formation of sulfidic acid, which caused the severe corrosion that can be observed in the screen. The resulting loss of conductivity provoked heating capable of melting the isolator until its rupture.

  15. Ac loss modelling and measurement of superconducting transformers with coated-conductor Roebel-cable in low-voltage winding

    Pardo, Enric; Staines, Mike; Jiang, Zhenan; Glasson, Neil

    2015-11-01

    Power transformers using a high temperature superconductor (HTS) ReBCO coated conductor and liquid nitrogen dielectric have many potential advantages over conventional transformers. The ac loss in the windings complicates the cryogenics and reduces the efficiency, and hence it needs to be predicted in its design, usually by numerical calculations. This article presents detailed modelling of superconducting transformers with Roebel cable in the low-voltage (LV) winding and a high-voltage (HV) winding with more than 1000 turns. First, we model a 1 MVA 11 kV/415 V 3-phase transformer. The Roebel cable solenoid forming the LV winding is also analyzed as a stand-alone coil. Agreement between calculations and experiments of the 1 MVA transformer supports the model validity for a larger tentative 40 MVA 110 kV/11 kV 3-phase transformer design. We found that the ac loss in each winding is much lower when it is inserted in the transformer than as a stand-alone coil. The ac loss in the 1 and 40 MVA transformers is dominated by the LV and HV windings, respectively. Finally, the ratio of total loss over rated power of the 40 MVA transformer is reduced below 40% of that of the 1 MVA transformer. In conclusion, the modelling tool in this work can reliably predict the ac loss in real power applications.

  16. Modelling of long High Voltage AC Cables in the Transmission System

    Gudmundsdottir, Unnur Stella

    for comparison at the measuring site. Measurements are performed on a 400 kV 7.6 km long cable, which is a part of a hybrid OHL/cable transmission line. The cables are laid in flat formation and have been in operation for several years. For performing the measurements, the cables are disconnected from...... time. From analysing the modal currents, the source of deviation is identified. The same phenomena and source for deviation between field measurements and simulation results is identified for a 400 kV flat formation crossbonded 7.6 km cable line, a 150 kV tight trefoil crossbonded 2.5 km cable line and...... a way, that the impedance matrix is no longer calculated from the analytical equations but from a finite element method including the proximity effect. A MATLAB program is constructed in order to calculate the impedance matrix based on the finite element method. Furthermore, this MATLAB program also...

  17. Condition assessment of power cables using partial discharge diagnosis at damped AC voltages

    Wester, F.J.

    2004-01-01

    The thesis focuses on the condition assessment of the distribution power cables, which have a very critical part in the distribution of electrical power over regional distances. The majority of the outages in the power system is related to the distribution cables, of which for more than 60% to internal defects. The material degradation in the power cables can be categorised into four local degradation processes, which are related to partial discharges. Partial discharge characteristics theref...

  18. Line Differential Protection Scheme Modelling for Underground 420 kV Cable Systems

    Sztykiel, Michal; Bak, Claus Leth; Wiechowski, Wojciech;

    2010-01-01

    Based on the analysis of a specific relay model and an HVAC (High Voltage Alternating Current) cable system, a new approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows to create complex and accurate relay models derived from the original algorithms. Relay mode......-simulated and real world generated current signals connected to the relay.......Based on the analysis of a specific relay model and an HVAC (High Voltage Alternating Current) cable system, a new approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows to create complex and accurate relay models derived from the original algorithms. Relay models...... can be applied with various systems, allowing to obtain the most optimal configuration of the protective relaying. The present paper describes modelling methodology on the basis of Siemens SIPROTEC 4 7SD522/610. Relay model was verified experimentally with its real equivalent by both EMTP...

  19. Line Differential Protection Scheme Modelling for Underground 420 kV Cable Systems

    Sztykiel, Michal; Bak, Claus Leth; Dollerup, Sebastian

    2011-01-01

    Based on the analysis of a specific relay model and an HVAC (High Voltage Alternating Current) cable system, a detailed approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows to create complex and accurate relay models derived from the original algorithms. Relay......-simulated and real world generated current signals connected to the relay.......Based on the analysis of a specific relay model and an HVAC (High Voltage Alternating Current) cable system, a detailed approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows to create complex and accurate relay models derived from the original algorithms. Relay...... models can be applied with various systems, allowing to obtain the most optimal configuration of the protective relaying. The present paper describes modelling methodology on the basis of Siemens SIPROTEC 4 7SD522/610. Relay model was verified experimentally with its real equivalent by both EMTP...

  20. Line Differential Protection Scheme Modelling for Underground 420 kV Cable Systems

    Sztykiel, Michal; Bak, Claus Leth; Dollerup, Sebastian

    2011-01-01

    Based on the analysis of a specific relay model and an HVAC (High Voltage Alternating Current) cable system, a detailed approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows to create complex and accurate relay models derived from the original algorithms. Relay models can be applied with various systems, allowing to obtain the most optimal configuration of the protective relaying. The present paper describes modelling methodology on the basis of Siemens SIP...

  1. A nontrivial factor in determining current distribution in an ac HTS cable-proximity effect

    2010-01-01

    A superconductor has zero resistance at the superconducting state. This unique property creates many exceptional phenomena, of which some are known and the others are not. Our experiments with multilayer high temperature superconductor (HTS) cable samples revealed a new phenomenon that alternating current had a tendency to flow in the inner and outer layers of the cables. We attribute the cause of this phenomenon to the electromagnetic interaction in an infinite electrical conductivity medium and term it "super-proximity-effect". This effect will greatly affect the performance of a multilayer superconducting cable and other superconducting devices which are involved with alternating current transportation.

  2. An EMC Evaluation of the Use of Unshielded Motor Cables in AC Adjustable Speed Drive Applications

    Hanigovszki, Norbert; Poulsen, J.; Spiazzi, G.;

    2004-01-01

    -phase applications the occurrence of common-mode voltage is inherent due to asymmetrical output pulses. As a result, for electromagnetic compatibility (EMC) reasons, in most applications shielded cables are used between the inverter and the motor, implying high installation costs. The present paper discusses the use...... of cheaper, unshielded cables. A new method for measuring electromagnetic interference (EMI) from unshielded cables is proposed and measurement results are presented. The level of EMI is evaluated in different situations: without an output filter, with a classical LC output filter and with an...

  3. Development of buried cable location survey system by underground rader for power distribution cables under pavements. Haiden chichuka no tame no chika radar ni yoru maisetsukan tansa system no kaihatsu

    Suzuki, K.; Kitano, K.

    1990-06-01

    To execute construction work for power distribution cables under pavements reasonably, it is important to develop a technology capable of non-destructive detection of the location of existing buried cables from the ground surface. This study is to clarify the principle, measurement method, effectiveness, and limitation of the underground radar system which is at present considered as the most effective survey method for buried cables. In this system, accuracy in measuring the depth of underground cable location by a separated type antenna has been improved, software to improve resolution by a migration process has been developed, and a compact survey system which can analyze the data on the site has been realized. As aresult of the survey at city areas, all pipes buried less than 1m in depth with the resistivity value of more than 100 {Omega} m were detected as well as those less than 2m in depth with more than some 100 {Omega} m. However, non-metal pipes buried deeper than 1m in the ground of less than 100 {Omega} m were not detected. Consequently, improvement of the system is necessary in future. 7 refs., 23 figs., 6 tabs.

  4. Optimal Selection of AC Cables for Large Scale Offshore Wind Farms

    Hou, Peng; Hu, Weihao; Chen, Zhe

    2014-01-01

    platform in Matlab. A real offshore wind farm is chosen as the study case to demonstrate the proposed method. Furthermore, the optimization is also applied to an offshore wind farm under development. It can be observed from the results that the proposed optimal cable selection framework is an efficient and...

  5. UNDERGROUND

    Full text: Cossetted deep underground, sheltered from cosmic ray noise, has always been a favourite haunt of neutrino physicists. Already in the 1930s, significant limits were obtained by taking a geiger counter down in Holborn 'tube' station, one of the deepest in London's underground system. Since then, neutrino physicists have popped up in many unlikely places - gold mines, salt mines, and road tunnels deep under mountain chains. Two such locations - the 1MB (Irvine/ Michigan/Brookhaven) detector 600 metres below ground in an Ohio salt mine, and the Kamiokande apparatus 1000m underground 300 km west of Tokyo - picked up neutrinos on 23 February 1987 from the famous 1987A supernova. Purpose-built underground laboratories have made life easier, notably the Italian Gran Sasso Laboratory near Rome, 1.4 kilometres below the surface, and the Russian Baksan Neutrino Observatory under Mount Andyrchi in the Caucasus range. Gran Sasso houses ICARUS (April, page 15), Gallex, Borexino, Macro and the LVD Large Volume Detector, while Baksan is the home of the SAGE gallium-based solar neutrino experiment. Elsewhere, important ongoing underground neutrino experiments include Soudan II in the US (April, page 16), the Canadian Sudbury Neutrino Observatory with its heavy water target (January 1990, page 23), and Superkamiokande in Japan (May 1991, page 8)

  6. Tunnel Boring Machine Cutter Maintenance for Constructing Underground Cable Lines from Nuclear Power Plants

    The tunnel boring machine (TBM) can construct an underground tunnel efficiently and without construction noise vibration related problems. Many civil projects, such as NPP construction, set importance on the economics of construction. Thus, advance rate, which is the speed at which the TBM is able to progress along its intended route, is one of the key factors affecting construction period and construction expenses. As the saying goes, time is money. Right Double Quotation Mark In addition, it is important to manage construction permits and civil complaints, even when construction expenses and construction periods are excluded. So, accurate prediction for advance rate is important when designing tunnel project. Several designers and project owners have tried to improve construction efficiency and tunneling advance rate.. There have been several studies on managing the rate of wear, designing an optimum tunnel face, and finding the optimum cutter spacing. Cutter replacements due to cutter wear and tear are very important because the wear and tear of cutters attached to the cutter head profoundly affect the advance rate. To manage cutter wear and tear is to control parameters related to cutter shape and cutter wear rate. There have been studies on the relationship between rock properties or TBM characteristics, and cutter wear or replacement. However, many of these studies relied on computer simulations or other small scale experiments. Therefore, this paper attempts to present a correlation between cutter replacement or cutter wear, against various parameters using practical data such as rock quality and TBM shield specifications, from an actual construction site. This study was conducted to suggest directions in the improvement of TBM cutters by analyzing relationships between rock conditions and cutter maintenance as well as TBM advance rates. Actual field data was collected and compared to actual design values in evaluating the effectiveness of traditional

  7. Tunnel Boring Machine Cutter Maintenance for Constructing Underground Cable Lines from Nuclear Power Plants

    Lee, Jae Wang; Yee, Eric [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2014-10-15

    The tunnel boring machine (TBM) can construct an underground tunnel efficiently and without construction noise vibration related problems. Many civil projects, such as NPP construction, set importance on the economics of construction. Thus, advance rate, which is the speed at which the TBM is able to progress along its intended route, is one of the key factors affecting construction period and construction expenses. As the saying goes, time is money. Right Double Quotation Mark In addition, it is important to manage construction permits and civil complaints, even when construction expenses and construction periods are excluded. So, accurate prediction for advance rate is important when designing tunnel project. Several designers and project owners have tried to improve construction efficiency and tunneling advance rate.. There have been several studies on managing the rate of wear, designing an optimum tunnel face, and finding the optimum cutter spacing. Cutter replacements due to cutter wear and tear are very important because the wear and tear of cutters attached to the cutter head profoundly affect the advance rate. To manage cutter wear and tear is to control parameters related to cutter shape and cutter wear rate. There have been studies on the relationship between rock properties or TBM characteristics, and cutter wear or replacement. However, many of these studies relied on computer simulations or other small scale experiments. Therefore, this paper attempts to present a correlation between cutter replacement or cutter wear, against various parameters using practical data such as rock quality and TBM shield specifications, from an actual construction site. This study was conducted to suggest directions in the improvement of TBM cutters by analyzing relationships between rock conditions and cutter maintenance as well as TBM advance rates. Actual field data was collected and compared to actual design values in evaluating the effectiveness of traditional

  8. AC loss in high-temperature superconducting conductors, cables and windings for power devices

    High-temperature superconducting (HTS) transformers and reactor coils promise decreased weight and volume and higher efficiency. A critical design parameter for such devices is the AC loss in the conductor. The state of the art for AC-loss reduction in HTS power devices is described, starting from the loss in the single HTS tape. Improved tape manufacturing techniques have led to a significant decrease in the magnetization loss. Transport-current loss is decreased by choosing the right operating current and temperature. The role of tape dimensions, filament twist and resistive matrix is discussed and a comparison is made between state-of-the-art BSCCO and YBCO tapes. In transformer and reactor coils the AC loss in the tape is influenced by adjacent tapes in the coil, fields from other coils, overcurrents and higher harmonics. These factors are accounted for by a new AC-loss prediction model. Field components perpendicular to the tape are minimized by optimizing the coil design and by flux guidance pieces. High-current windings are made of Roebel conductors with transposed tapes. The model iteratively finds the temperature distribution in the winding and predicts the onset of thermal instability. We have fabricated and tested several AC windings and used them to validate the model. Now we can confidently use the model as an engineering tool for designing HTS windings and for determining the necessary tape properties

  9. Water treeing in underground power cables: modelling of the trees and calculation of the electric field perturbation

    Acedo García, Miguel; Radu, I.; Frutos Rayego, Fabián; Filippini, Jean César; Notingher, P.

    2001-01-01

    In order to explain the development of different types of water trees and the related dielectric breakdowns in extruded power cables, it is necessary to analyse the dielectric properties of the corresponding treed regions and their influence on the distribution of electric field. The study presented in this paper is both experimental and theoretical. Experimentally, we performed the laboratory ageing of a power cable for accelerated conditions of applied voltage and frequency: ...

  10. Power System Technical Performance Issues Related to the Application of Long HVAC Cables

    Bak, Claus Leth

    The aim of this TB is to serve as a practical guide for preparing models and performing studies necessary during the assessment of the technical performance of HV/EHV systems with a large share of (long) AC cables. The brochure follows all phases of planning and analysis of a typical underground...

  11. Line Differential Protection Scheme Modelling for Underground 420 kV Cable Systems, EMTDC/PSCAD Relays Modelling

    Bak, Claus Leth; Sztykiel, Michal; Dollerup, Sebastian

    2011-01-01

    Based on the analysis of a specific relay model and an HVAC (High Voltage Alternating Current) cable system, a new approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows creating complex and accurate relay models derived from the original algorithms. Relay model......-simulated and real world generated current signals connected to the relay.......Based on the analysis of a specific relay model and an HVAC (High Voltage Alternating Current) cable system, a new approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows creating complex and accurate relay models derived from the original algorithms. Relay models...... can be applied with various systems, allowing obtaining the most optimal configuration of the protective relaying. The present paper describes modelling methodology on the basis of Siemens SIPROTEC 4 7SD522/610. Relay model was verified experimentally with its real equivalent by both EMTP...

  12. Line Differential Protection Scheme Modelling for Underground 420 kV Cable Systems:EMTDC/PSCAD Relays Modelling

    Sztykiel, Michal; Bak, Claus Leth; Wiechowski, Wojciech; Dollerup, Sebastian

    2010-01-01

    Based on the analysis of a specific relay model and an HVAC (High Voltage Alternating Current) cable system, a new approach to EMTDC/PSCAD modelling of protective relays is presented. Such approach allows to create complex and accurate relay models derived from the original algorithms. Relay models can be applied with various systems, allowing to obtain the most optimal configuration of the protective relaying. The present paper describes modelling methodology on the basis of Siemens SIPROTEC...

  13. A flexible super conducting ac cable: radial thermal contraction and the x-ray examination of a sample length of cold core

    The temperature reduction which a superconducting cable core will have to undergo following its manufacture and installation is nearly 300 K before it can be used. The satisfactory accommodation of the corresponding significant amount of thermal contraction of its component parts is therefore of major importance. This paper is concerned with such thermal contraction upon cooling of a flexible superconducting ac cable core comprising helically laid strip conductors of niobium clad copper and a polyethylene tape dielectric with electrostatic screens and bedding layers. A method is described of designing, for a controlled amount of radial contraction, a core held at near constant length. A report is also given of the x-ray examination of a sample core used for voltage tests. The relevance of the results to some other designs of core is discussed. (author)

  14. Design procedure and operation experience of data acquisition and control system for 22.9 kV underground HTS power cable

    Ryoo, H. S.; Sohn, S. H.; Hwang, S. D.; Lim, J. H.; Choi, H. S.; Yatsuka, K.; Masuda, T.; Isojima, S.; Watanabe, M.; Suzawa, C.; Koo, J. Y.

    2007-10-01

    A new 100 m underground HTS cable system was planned for an experimental study in a real scale. The main targets of the project were the verification of the system application. Various types and multipoint analogue data including digital control sequence data were required to be measured. Because of the long operating period of the system cooling and warming sequence, very high operating stability was required. Additionally the economically designed main cooling facility was requested over-night manual operation. The basic function of the data acquisition and control system was the gathering of various type data and the control of test facilities include the cooling facility. Most effort of the design procedure was focused on making the automatic operation including under an emergency situation and the alerting of the emergency state to the operators staying even remote place. The main focus of this function was reducing of the operating man power, specially requested for over-night. So various emergency situations and scenarios were considered and analyzed for the automation operation.

  15. A two-dimensional finite element method to calculate the AC loss in superconducting cables, wires and coated conductors

    In order to utilize HTS conductors in AC electrical devices, it is very important to be able to understand the characteristics of HTS materials in the AC electromagnetic conditions and give an accurate estimate of the AC loss. A numerical method is proposed in this paper to estimate the AC loss in superconducting conductors including MgB2 wires and YBCO coated conductors. This method is based on solving a set of partial differential equations in which the magnetic field is used as the state variable to get the current and electric field distributions in the cross sections of the conductors and hence the AC loss can be calculated. This method is used to model a single-element and a multi-element MgB2 wires. The results demonstrate that the multi-element MgB2 wire has a lower AC loss than a single-element one when carrying the same current. The model is also used to simulate YBCO coated conductors by simplifying the superconducting thin tape into a one-dimensional region where the thickness of the coated conductor can be ignored. The results show a good agreement with the measurement

  16. A two-dimensional finite element method to calculate the AC loss in superconducting cables, wires and coated conductors

    Hong, Z; Jiang, Y; Pei, R; Coombs, T A [Electronic, Power and Energy Conversion Group, Engineering Department, University of Cambridge, CB2 1PZ (United Kingdom); Ye, L [Department of Electrical Power Engineering, CAU, P. O. Box 210, Beijing 100083 (China); Campbell, A M [Interdisciplinary Research Centre in Superconductivity, University of Cambridge, CB3 0HE (United Kingdom)], E-mail: Zh223@cam.ac.uk

    2008-02-15

    In order to utilize HTS conductors in AC electrical devices, it is very important to be able to understand the characteristics of HTS materials in the AC electromagnetic conditions and give an accurate estimate of the AC loss. A numerical method is proposed in this paper to estimate the AC loss in superconducting conductors including MgB{sub 2} wires and YBCO coated conductors. This method is based on solving a set of partial differential equations in which the magnetic field is used as the state variable to get the current and electric field distributions in the cross sections of the conductors and hence the AC loss can be calculated. This method is used to model a single-element and a multi-element MgB{sub 2} wires. The results demonstrate that the multi-element MgB{sub 2} wire has a lower AC loss than a single-element one when carrying the same current. The model is also used to simulate YBCO coated conductors by simplifying the superconducting thin tape into a one-dimensional region where the thickness of the coated conductor can be ignored. The results show a good agreement with the measurement.

  17. Cable Diagnostic Focused Initiative

    Hartlein, R.A.; Hampton, R.N.

    2010-12-30

    This report summarizes an extensive effort made to understand how to effectively use the various diagnostic technologies to establish the condition of medium voltage underground cable circuits. These circuits make up an extensive portion of the electric delivery infrastructure in the United States. Much of this infrastructure is old and experiencing unacceptable failure rates. By deploying efficient diagnostic testing programs, electric utilities can replace or repair circuits that are about to fail, providing an optimal approach to improving electric system reliability. This is an intrinsically complex topic. Underground cable systems are not homogeneous. Cable circuits often contain multiple branches with different cable designs and a range of insulation materials. In addition, each insulation material ages differently as a function of time, temperature and operating environment. To complicate matters further, there are a wide variety of diagnostic technologies available for assessing the condition of cable circuits with a diversity of claims about the effectiveness of each approach. As a result, the benefits of deploying cable diagnostic testing programs have been difficult to establish, leading many utilities to avoid the their use altogether. This project was designed to help address these issues. The information provided is the result of a collaborative effort between Georgia Tech NEETRAC staff, Georgia Tech academic faculty, electric utility industry participants, as well as cable system diagnostic testing service providers and test equipment providers. Report topics include: •How cable systems age and fail, •The various technologies available for detecting potential failure sites, •The advantages and disadvantages of different diagnostic technologies, •Different approaches for utilities to employ cable system diagnostics. The primary deliverables of this project are this report, a Cable Diagnostic Handbook (a subset of this report) and an online

  18. Low Friction Cryostat for HTS Power Cable of Dutch Project

    Chevtchenko, O.; Zuijderduin, R.; Smit, J.; Willen, D.; Lentge, H.; Thidemann, C.; Traeholt, C.

    2012-01-01

    Particulars of 6 km long HTS AC power cable for Amsterdam project are: a cable has to fit in an annulus of 160 mm, with only two cooling stations at the cable ends [1]. Application of existing solutions for HTS cables would result in excessively high coolant pressure drop in the cable, possibly affe

  19. Effects of Formvar coating and copper-nickel outer sheath on the ac losses of multi-strand subsize cables

    Ac losses of two subcables, one with Formvar coating on the strands of the BNL 12-ml NbTi/Cu/CuNi conductor and another without the coating, were measured using the ANL Subcable Test Facility. The results indicate that couplings among the strands with and without the Formvar coating were quite weak. Weak coupling of the bare strands is due to the high resistance of the copper-nickel outer sheath. In the regime of B(dot) = 0 approx. 1.2 T/s and B = 0 approx. 4 T, the magnetic diffusion time constant was (3.8 - 5.7) x 10-3 s

  20. Switching Overvoltages in 60 kV reactor compensated cable grid due to resonance after disconnection

    Bak, Claus Leth; Baldursson, Haukur; Oumarou, Abdoul M.

    2008-01-01

    Some electrical distribution companies are nowadays replacing overhead lines with underground cables. These changes from overhead to underground cable provoke an increased reactive power production in the grid. To save circuit breakers the reactors needed for compensating this excessive reactive ...

  1. Techniques and equipment for detecting and locating incipient faults in underground power transmission cable systems. Technical progress report 3, 1 July 1979-30 September 1979

    Phillips, A.C.; Nanevicz, J.E.; Adamo, R.C.; Cole, C.A.; Honey, S.K.; Petro, J.P.

    1980-04-01

    The study is divided into seven tasks: (1) developing RF sounding techniques including experimental detector/locator units such as the HV crossmodulation sounder; (2) constructing a prototype swept-frequency cable sounder; (3) measuring cable characteristics; (4) developing power-transmission-line signal couplers; (5) constructing an HV source to augment experimental and prototype detector/locator units; (6) evaluating the prototype swept-frequency cable sounder; and (7) studying technically effective and economical use of incipient-fault detector/locator units.

  2. Underground pipeline corrosion

    Orazem, Mark

    2014-01-01

    Underground pipelines transporting liquid petroleum products and natural gas are critical components of civil infrastructure, making corrosion prevention an essential part of asset-protection strategy. Underground Pipeline Corrosion provides a basic understanding of the problems associated with corrosion detection and mitigation, and of the state of the art in corrosion prevention. The topics covered in part one include: basic principles for corrosion in underground pipelines, AC-induced corrosion of underground pipelines, significance of corrosion in onshore oil and gas pipelines, n

  3. Electromagnetic transients in power cables

    da Silva, Filipe Faria

    2013-01-01

    From the more basic concepts to the most advanced ones where long and laborious simulation models are required, Electromagnetic Transients in Power Cables provides a thorough insight into the study of electromagnetic transients and underground power cables. Explanations and demonstrations of different electromagnetic transient phenomena are provided, from simple lumped-parameter circuits to complex cable-based high voltage networks, as well as instructions on how to model the cables.Supported throughout by illustrations, circuit diagrams and simulation results, each chapter contains exercises,

  4. Gjoea power cable; a green solution

    Dretvik, Svein-Egil

    2010-07-01

    An alternative to today's power generation offshore using either gas or diesel, is alternating current (AC) electric power cable from shore. The power from shore through the AC cable gives high savings for the environment. The cable replaces 4 gas turbines with a total CO2 disposal of 240 00 tonnes each year which represents the disposal of 100 000 cars. ABB was awarded the contract which includes engineering, fabrication and installation of the power cable from Mongstad to the Gjoea platform which will be the longest AC cable in the world with a total length of 100 km. The presentation will include system design, qualification of dynamic power cable, cable fabrication experiences, testing at fabrication yard and installation aspects. (Author)

  5. Strengthening future electricity grid of the Netherlands by integration of HTS transmission cables

    The electricity grid of the Netherlands is changing. There is a call of society to use more underground cables, less overhead lines (OHL) and to reduce magnetic emissions. At the same time, parts of the future transmission grid need strengthening depending on the electricity demand in the coming decades [1]. Novel high temperature superconductor (HTS) AC transmission cables can play a role in strengthening the grid. The advantages as compared to alternatives, are: economic, underground, higher power capacity, lower losses, reduced magnetic field emissions in (existing) OHL, compact: less occupation of land and less permits needed, a possibility to keep 380 kV voltage level in the grid for as long as needed. The main obstacles are: the relatively high price of HTS tapes and insufficient maturity of the HTS cable technology. In the paper we focus on a 34 km long connection in the transmission grid (to be strengthened in three of the four of TenneT scenarios [1]), present the network study results, derive the requirements for corresponding HTS transmission cable system and compare HTS system to the alternatives (OHLs and XLPE cables).

  6. Power applications for superconducting cables

    Tønnesen, Ole; Hansen, Steen; Jørgensen, Preben; Lomholt, Karin; Mikkelsen, Søren D.; Okholm, Jan; Salvin, Sven; Østergaard, Jacob

    2000-01-01

    High temperature superconducting (HTS) cables for use in electric ac power systems are under development around the world today. There are two main constructions under development: the room temperature dielectric design and the cryogenic dielectric design. However, theoretical studies have shown...... that the insertion of these cables in the network is not without problems. The network stability requirements may impose severe constraints on the actual obtainable length of superconducting cables. Load flow considerations show that it may be difficult to use these high current cables to their full...

  7. Techniques and equipment for detecting and locating incipient faults in underground power transmission cable systems. Technical progress report 2, 1 April 1979-30 June 1979

    Phillips, A.C.; Naneviez, J.E.; Adamo, R.C.; Cole, C.A.; Honey, S.K.; Petro, J.P.

    1980-01-01

    The study has been divided into seven tasks: (1) development of RF probing techniques including experimental detector/locator units; (2) construction of a prototype detector/locator unit; (3) measurement of cable characteristics; (4) development of power-transmission-line signal couplers; (5) construction of a high-voltage (HV) source to augment experimental or prototype detector/locator units; (6) evaluation of the prototype detector/locator unit; and (7) study of technically effective and economical use of incipient-fault detector/locator units.

  8. Cable manufacture

    Gamble, P.

    1972-01-01

    A survey is presented of flat electrical cable manufacturing, with particular reference to patented processes. The economics of manufacture based on an analysis of material and operating costs is considered for the various methods. Attention is given to the competitive advantages of the several processes and their resulting products. The historical area of flat cable manufacture is presented to give a frame of reference for the survey.

  9. Switching Restrikes in HVAC Cable Lines and Hybrid HVAC Cable/OHL Lines

    da Silva, Filipe Miguel Faria; Bak, Claus Leth; Balle Holst, Per

    2011-01-01

    The disconnection of HV underground cables may, if unsuccessful, originate a restrike in the circuit breaker, leading to high overvoltages, and potentially damaging the cable and near equipment. Due to the cable high capacitance and low resistance the voltage damping is slow, resulting, half a...... cycle after the disconnection, in a voltage of approximately 2 pu at the circuit breaker terminals. In case of restrike in that instant, it is theoretical possible to attain an overvoltage of 3 pu. The overvoltage can be even larger in hybrid cable-Overhead Lines (OHL), due to voltage magnifications in...

  10. Low Friction Cryostat for HTS Power Cable of Dutch Project

    Chevtchenko, Oleg; Zuijderduin, Roy; Smit, Johan;

    2012-01-01

    affecting public acceptance of the project. In order to solve this problem, a model cryostat was developed consisting of alternating rigid and flexible sections and hydraulic tests were conducted using sub-cooled liquid nitrogen. In the 47 m-long cryostat, containing a full-size HTS cable model, measured......Particulars of 6km long HTS AC power cable for Amsterdam project are: a cable has to fit in an annulus of 160mm, with only two cooling stations at the cable ends [1]. Application of existing solutions for HTS cables would result in excessively high coolant pressure drop in the cable, possibly...

  11. Superconducting power cables in Denmark - a case study

    Østergaard, Jacob

    1997-01-01

    HTS cables will be less expensive for high power ratings, have lower losses for lines with a high load, and have a reduced reactive power production. The use of superconducting cables in Denmark accommodate plans by the Danish utility to make a substantial conversion of overhead lines to underground......A case study of a 450 MVA, 132 kV high temperature superconducting (HTS) power transmission cable has been carried out. In the study, a superconducting cable system is compared to a conventional cable system which is under construction for an actual transmission line in the Danish grid. The study...

  12. Electrohydrodynamic pumping in cable pipes. Final report

    Crowley, J.M.; Chato, J.C.

    1983-02-01

    Many oil-insulated electric power cables are limited by heat buildup caused in part by the low thermal conductivity of the oil. Circulation of the oil is known to reduce the cable temperature, but can lead to excessive pressure buildup on long cables when using conventional pumping methods. An alternate pumping method using distributed electric fields to avoid this pressure buildup is described. Electrohydrodynamic (EHD) pumping was studied both theoretically and experimentally for possible application in underground cable cooling. Theoretical studies included both analytical and finite-element analysis of the flow patterns driven by travelling electric fields. Experimentally, flow rates in a cable-pipe model were measured under a wide variety of operating conditions. Theory and experiment are in agreement for velocities below 10 cm/s, but higher velocities could not be reached in the experiment, due to increased electroconvection and, possibly, turbulence.

  13. Cable Stability

    Bottura, L

    2014-01-01

    Superconductor stability is at the core of the design of any successful cable and magnet application. This chapter reviews the initial understanding of the stability mechanism, and reviews matters of importance for stability such as the nature and magnitude of the perturbation spectrum and the cooling mechanisms. Various stability strategies are studied, providing criteria that depend on the desired design and operating conditions.

  14. On stiffening cables of a long reach manipulator

    A long reach manipulator will be used for waste remediation in large underground storage tanks. The manipulator's slenderness makes it flexible and difficult to control. A low-cost and effective method to enhance the manipulator's stiffness is proposed in this research by using suspension cables. These cables can also be used to accurately measure the position of the manipulator's wrist

  15. Undergrounding issues

    As part of a general review of British Columbia Hydro's rights-of-way policies, a task group was formed to explore and assess the technical, social, environmental, and economic issues related to the provision of suitable underground rights-of-way for distribution and transmission lines. Issues considered were: evaluations of undergrounding; designation of service areas as underground areas; the BC Hydro fund to assist municipalities in beautifying selected areas by placing existing overhead lines underground; community funding of undergrounding; underground options to transmission and distribution requirements; and long-range underground row planning. Key findings are as follows. Undergrounding is technically feasible and available for all BC Hydro operating voltages, but initial construction costs of undergrounding continue to exceed equivalent overhead by a significant margin. Undergrounding can contribute to the optimization of existing rights-of-way. Public safety is improved with undergrounding and long-term benefits to BC Hydro and society are provided by undergrounding, compared to overhead options. Customers have shown some willingness to contribute to the cost of undergrounding, and it is generally agreed that those communities that want undergrounding should pay for it. Policy recommendations are made under each of the issue areas, and justifications for the recommendations are given along with implementation costs and alternative options

  16. Applying Diagnostics to Enhance Cable System Reliability (Cable Diagnostic Focused Initiative, Phase II)

    Hartlein, Rick [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Hampton, Nigel [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Perkel, Josh [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Hernandez, JC [Univ. de Los Andes, Merida (Venezuela); Elledge, Stacy [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); del Valle, Yamille [Georgia Tech Research Corporation (GTRC), Atlanta, GA (United States). National Electric Energy Testing, Research and Applications Center (NEETRAC); Grimaldo, Jose [Georgia Inst. of Technology, Atlanta, GA (United States). School of Electrical and Computer Engineering; Deku, Kodzo [Georgia Inst. of Technology, Atlanta, GA (United States). George W. Woodruff School of Mechanical Engineering

    2016-02-01

    The Cable Diagnostic Focused Initiative (CDFI) played a significant and powerful role in clarifying the concerns and understanding the benefits of performing diagnostic tests on underground power cable systems. This project focused on the medium and high voltage cable systems used in utility transmission and distribution (T&D) systems. While many of the analysis techniques and interpretations are applicable to diagnostics and cable systems outside of T&D, areas such as generating stations (nuclear, coal, wind, etc.) and other industrial environments were not the focus. Many large utilities in North America now deploy diagnostics or have changed their diagnostic testing approach as a result of this project. Previous to the CDFI, different diagnostic technology providers individually promoted their approach as the “the best” or “the only” means of detecting cable system defects.

  17. 300 Area signal cable study

    This report was prepared to discuss the alternatives available for removing the 300 Area overhead signal cable system. This system, installed in 1969, has been used for various monitoring and communication signaling needs throughout the 300 Area. Over the years this cabling system has deteriorated, has been continually reconfigured, and has been poorly documented to the point of nonreliability. The first step was to look at the systems utilizing the overhead signal cable that are still required for operation. Of the ten systems that once operated via the signal cable, only five are still required; the civil defense evacuation alarms, the public address (PA) system, the criticality alarms, the Pacific Northwest Laboratory Facilities Management Control System (FMCS), and the 384 annunciator panel. Of these five, the criticality alarms and the FMCS have been dealt with under other proposals. Therefore, this study focused on the alternatives available for the remaining three systems (evacuation alarms, PA system, and 384 panel) plus the accountability aid phones. Once the systems to be discussed were determined, then three alternatives for providing the signaling pathway were examined for each system: (1) re-wire using underground communication ducts, (2) use the Integrated Voice/Data Telecommunications System (IVDTS) already installed and operated by US West, and (3) use radio control. Each alternative was developed with an estimated cost, advantages, and disadvantages. Finally, a recommendation was provided for the best alternative for each system

  18. Design and Evaluation of Ybco Cable for the Albany Hts Cable Project

    Ohya, M.; Yumura, H.; Ashibe, Y.; Ito, H.; Masuda, T.; Sato, K.

    2008-03-01

    The Albany Cable Project's aim is to develop a 350 meter long HTS cable system with a capacity of 800 A at 34.5 kV, located between two substations in the National Grid Power Company's grid. In-grid use of BSCCO HTS cable began on July 20, 2006, and successful long-term operation proceeded as planned. The cable system consists of two cables, one 320 meters long and the other 30 meters, a cable-to-cable splice in a vault, two terminations, and a cooling system. In Phase-II of the Albany project, this autumn, the 30-meter section will be replaced with YBCO cable. The test manufacturing and evaluation of YBCO cable has been carried out using SuperPower's YBCO wires in order to confirm the credibility of the cable design. No degradation of the critical current was found at any stage of manufacture. The fault-current test, involving a 1-meter sample carrying 23 kA at 38 cycles, was conducted under open-bath conditions. The temperature increases at the conductor and shield were comparable to those of the BSCCO core, and no Ic degradation was found after the fault-current test. After the design suitability was confirmed, a 30-meter YBCO cable was manufactured. The critical current of the conductor and the shield were approximately 2.6 kA and 2.4 kA, respectively, almost the same as the design values, considering the wire's Ic and the effect of the magnetic field. The AC loss of the sample cable was 0.34 W/m/phase at 800 Arms and 60 Hz. Following favorable shipping test results, the YBCO cable was shipped to the United States, and arrived at the site in June 2007.

  19. Research and Promotion on the Automatic Roll Line Device of Recycling Communication Cable on the Underground Coal Mine Working Face%煤矿井下工作面回收通讯电缆自动卷线装置的研发和推广

    贾鸿飞

    2015-01-01

    随着科学技术的发展,煤矿的建设也发生了日新月异的变化,当代的现代化煤矿逐步开始进入到数字化矿井的阶段。数字化矿井综采工作面的无线通讯、视频的显示、各个综采设备的运行状态的数据,与地面中心站的网络相连接起来,能实时监视综采工作面的状态,达到了煤矿的安全生产。伴随而来的问题就是综采工作面在回采过程中将回收大量的通讯电缆,其中包括通讯光缆。本实用新型提供的煤矿井下工作面回收通讯电缆自动卷线装置,属于煤矿井下综采工作面设备技术领域,主要解决现有技术人工盘电缆存在着电缆凌乱、摆放不整齐、费时费力、效率低、降低采购成本等诸多问题。本文着重从煤矿井下工作面回收各类通讯电缆自动卷线装置的研发和推广方面进行了相关的阐述与分析。%With the development of science and technology, the construction of coal mine has also changed a lot, the contemporary modernization coal mine gradually begins to enter the stage of digital mine. The connection of wireless communications, video display, running status data of each fully mechanized equipment in the digital coal mine fully mechanized working face with network of the ground central station can achieve real-time monitoring of the state of fully mechanized working face and achieve the coal mine safety production. At the same time, the problems are associated that the fully mechanized working face will recycle a lot of communication cable including communication optical cable in the extraction process. This automatic volume line device of recycling communication cable in the underground coal mine working face provided by this utility model belongs to the equipment technology of underground coal mine fully mechanized working face. It mainly solves the messy cable and auf-stellen, time-consuming, low efficiency, reduce procurement costs and other

  20. Universal Cable Brackets

    Vanvalkenburgh, C.

    1985-01-01

    Concept allows routing easily changed. No custom hardware required in concept. Instead, standard brackets cut to length and installed at selected locations along cable route. If cable route is changed, brackets simply moved to new locations. Concept for "universal" cable brackets make it easy to route electrical cable around and through virtually any structure.

  1. Switching Overvoltages in 60 kV reactor compensated cable grid due to resonance after disconnection

    Bak, Claus Leth; Baldursson, Haukur; Oumarou, Abdoul M.

    2008-01-01

    Some electrical distribution companies are nowadays replacing overhead lines with underground cables. These changes from overhead to underground cable provoke an increased reactive power production in the grid. To save circuit breakers the reactors needed for compensating this excessive reactive...... power could be directly connected to long cables. Switching both cable and reactor together will cause resonance to occur between the cable capacitance and the inductance of the cable during last end disconnection. Similar type of resonance condition is known to have caused switching overvoltages on the...... 400kV grid in Denmark. Therefore it is considered necessary to analyze further whether connecting a reactor directly to 60kV cable can cause switching overvoltages. A model in PSCAD was used to analyze which parameters can cause overvoltage. The switching resonance overvoltage was found to be caused...

  2. Conventional cable testing methods: strengths, weaknesses and possibilities

    The paper reviews the major conventional methods that can be used to test power plant cables. It assesses their usefulness in diagnosing the condition of the insulation of the cable and then proposes some possible directions for innovation. The methods examined are dc insulation resistance measurement, ac signal injection for continuous monitoring and fault location, and the ac measurement of capacitance and loss angle. Specific subjects considered are the effects of temperature, cable construction and installation, and the validity of insulation resistance or loss angle measurement. The innovative proposals refer to the use of automation in the measurement and of computer-based Expert Systems for the evaluation of the results

  3. Parametric study on coupling loss in subsize ITER Nb3Sn cabled specimen

    Nijhuis, Arend; Kate, ten, F.J.W.; Bruzzone, Pierluigi; Bottura, Luca

    1996-01-01

    The cable in conduit conductors for the various ITER coils are required to function under pulse conditions and fields up to 13 T. A parametric study, restricted to a limited variation of the reference cable lay out, is carried out to clarify the quantitative impact of various cable parameters on the coupling loss and to find realistic values for the coupling loss time constants to be used in ac loss computations. The investigations cover ac coupling loss measurements on jacketed sub- and full...

  4. Experimental Investigation of the Corona Discharge in Electrical Transmission due to AC/DC Electric Fields

    Fuangpian Phanupong

    2016-01-01

    Full Text Available Nowadays, using of High Voltage Direct Current (HVDC transmission to maximize the transmission efficiency, bulk power transmission, connection of renewable power source from wind farm to the grid is of prime concern for the utility. However, due to the high electric field stress from Direct Current (DC line, the corona discharge can easily be occurred at the conductor surface leading to transmission loss. Therefore, the polarity effect of DC lines on corona inception and breakdown voltage should be investigated. In this work, the effect of DC polarity and Alternating Current (AC field stress on corona inception voltage and corona discharge is investigated on various test objects, such as High Voltage (HV needle, needle at ground plane, internal defect, surface discharge, underground cable without cable termination, cable termination with simulated defect and bare overhead conductor. The corona discharge is measured by partial discharge measurement device with high-frequency current transformer. Finally, the relationship between supply voltage and discharge intensity on each DC polarity and AC field stress can be successfully determined.

  5. Temperature Dependence of PMD of the Optical Cables

    Ahn, S.J. [Korea Electric Power Research Institute, Taejon (Korea)

    2000-03-01

    This report is relevant to the project {sup K}EPCO All-Optical Network Project{sup w}hich is being carried out by Computer and Communication Group in Power System Laboratory. This report is planned to be used as a reference guide for the PMD strategy of the KEPCO optical networks. The PMD of the optical cable installed in the air as OPGW is greatly affected by the environmental temperature change, unlike that of the optical cable installed underground. The variance was turned out to be 70% larger compared with that of underground optical cable and the time scale of the PMD was less than 5 min, in the worst case. Hence, the compensation technology should be chosen taking into account the properties of the aerial optical cables. (author). 6 refs., 3 figs., 1 tab.

  6. The Mathematical Modelling of Heat Transfer in Electrical Cables

    Bugajev Andrej; Jankevičiūtė Gerda; Tumanova Natalija

    2014-01-01

    This paper describes a mathematical modelling approach for heat transfer calculations in underground high voltage and middle voltage electrical power cables. First of the all typical layout of the cable in the sand or soil is described. Then numerical algorithms are targeted to the two-dimensional mathematical models of transient heat transfer. Finite Volume Method is suggested for calculations. Different strategies of nonorthogonality error elimination are considered. Acute triangles meshes ...

  7. Loss and Inductance Investigation in Superconducting Cable Conductors

    Olsen, Søren Krüger; Tønnesen, Ole; Træholt, Chresten;

    1999-01-01

    the layers are therefore studied theoretically. The current distribution between the superconducting layers is monitored as a function of transport current, and the results are compared with the expected current distribution given by our electrical circuit model.The AC-losses are measured as a...... Hz) the AC-loss was measured on cable #2 to 0.6W/mxphase. This is, to our knowledge, the lowest AC-loss (at 2kA and 77K) of a high temperature superconducting cable conductor reported so far....

  8. UtilityTelecom_CABLE2005

    Vermont Center for Geographic Information — The VT Cable System dataset (CABLE2005) includes lines depicting the extent of Vermont's cable system as of 12/31/2005. Numerous cable companies provide service in...

  9. UtilityTelecom_CABLE2007

    Vermont Center for Geographic Information — The VT Cable System dataset (CABLE2007) includes lines depicting the extent of Vermont's cable system as of 12/31/2007. Numerous cable companies provide service in...

  10. Cable-fault locator

    Cason, R. L.; Mcstay, J. J.; Heymann, A. P., Sr.

    1979-01-01

    Inexpensive system automatically indicates location of short-circuited section of power cable. Monitor does not require that cable be disconnected from its power source or that test signals be applied. Instead, ground-current sensors are installed in manholes or at other selected locations along cable run. When fault occurs, sensors transmit information about fault location to control center. Repair crew can be sent to location and cable can be returned to service with minimum of downtime.

  11. Cable Supported Bridges

    Gimsing, Niels Jørgen

    Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...

  12. Cable Television: Franchising Considerations.

    Baer, Walter S.; And Others

    This volume is a comprehensive reference guide to cable television technology and issues of planning, franchising, and regulating a cable system. It is intended for local government officials and citizens concerned with the development of cable television systems in their communities, as well as for college and university classes in…

  13. Fault Location on Mixed Overhead Line and Cable Network

    Han, Junyu

    2015-01-01

    Society is increasingly concerned about the environmental impact of energy systems, and prefers to locate power lines underground. In future, certain socially/environmentally sensitive overhead transmission feeders will need to include underground cable sections. Fault location, especially when using travelling waves, become complicated when the combined transmission line includes a number of discontinuities, such as junction points, teed points and fault points. Consequently, a diverse range...

  14. Modeling vibration response and damping of cables and cabled structures

    Spak, Kaitlin S.; Agnes, Gregory S.; Inman, Daniel J.

    2015-02-01

    In an effort to model the vibration response of cabled structures, the distributed transfer function method is developed to model cables and a simple cabled structure. The model includes shear effects, tension, and hysteretic damping for modeling of helical stranded cables, and includes a method for modeling cable attachment points using both linear and rotational damping and stiffness. The damped cable model shows agreement with experimental data for four types of stranded cables, and the damped cabled beam model shows agreement with experimental data for the cables attached to a beam structure, as well as improvement over the distributed mass method for cabled structure modeling.

  15. Resistive cryogenic cable, phase III. Final report, April 18, 1974--March 31, 1977

    None

    1977-01-01

    Work performed during 3 years of research on development of a foam-insulated underground cryogenic power transmission cable is reported. Information is included on the cryogenic envelope investigation; evaluation and aging study of electrical insulation; test system specifications; and cable system design and cost studies. (LCL)

  16. Control of a long reach manipulator with suspension cables for waste storage tank remediation. Final report

    A long reach manipulator will be used for waste remediation in large underground storage tanks. The manipulator's slenderness makes it flexible and difficult to control. A low-cost and effective method to enhance the manipulator's stiffness is proposed in this research by using suspension cables. These cables can also be used to accurately measure the position of the manipulator's wrist

  17. Commercialization of Medium Voltage HTS Triax TM Cable Systems

    Knoll, David

    2012-12-31

    The original project scope that was established in 2007 aimed to install a 1,700 meter (1.1 mile) medium voltage HTS Triax{TM} cable system into the utility grid in New Orleans, LA. In 2010, however, the utility partner withdrew from the project, so the 1,700 meter cable installation was cancelled and the scope of work was reduced. The work then concentrated on the specific barriers to commercialization of HTS cable technology. The modified scope included long-length HTS cable design and testing, high voltage factory test development, optimized cooling system development, and HTS cable life-cycle analysis. In 2012, Southwire again analyzed the market for HTS cables and deemed the near term market acceptance to be low. The scope of work was further reduced to the completion of tasks already started and to testing of the existing HTS cable system in Columbus, OH. The work completed under the project included: • Long-length cable modeling and analysis • HTS wire evaluation and testing • Cable testing for AC losses • Optimized cooling system design • Life cycle testing of the HTS cable in Columbus, OH • Project management. The 200 meter long HTS Triax{TM} cable in Columbus, OH was incorporated into the project under the initial scope changes as a test bed for life cycle testing as well as the site for an optimized HTS cable cooling system. The Columbus cable utilizes the HTS TriaxTM design, so it provided an economical tool for these of the project tasks.

  18. SC Power leads and cables - Nominal Current Test Performance of 2 kA-Class High-Tc Superconducting Cable Conductors and Its Implications for Cooling Systems for Utility Cables

    Willen, D. W. A; Daumling, M.; Rasmussen, C. N.; Træholt, Chresten; Olsen, Søren Krüger; Rasmussen, Carsten; Jensen, Kim Høj; Østergaard, Jacob; Kyhle, Anders; Tønnesen, Ole

    The current carrying performance of 3-10 m long superconducting cable conductor models has been evaluated. A reduced energy loss compared to conventional cables can be obtained using high-Tc superconducting materials due to the limited resistive and ac hysteresis losses in some conductor configur...

  19. Interstrand contact resistances of Bi-2212 Rutherford cables for SMES

    Kawagoe, A. [Kagoshima University, Kohrimoto 1-21-40, Kagoshima-shi, Kagoshima 890-0065 (Japan)]. E-mail: kawagoe@eee.kagoshima-u.ac.jp; Kawabata, Y. [Kagoshima University, Kohrimoto 1-21-40, Kagoshima-shi, Kagoshima 890-0065 (Japan); Sumiyoshi, F. [Kagoshima University, Kohrimoto 1-21-40, Kagoshima-shi, Kagoshima 890-0065 (Japan); Nagaya, S. [Chubu Electric Power Co. Inc., Kitazekiyama 20-1, Ohtakacho-aza, Midori-ku, Nagoya 249-8522 (Japan); Hirano, N. [Chubu Electric Power Co. Inc., Kitazekiyama 20-1, Ohtakacho-aza, Midori-ku, Nagoya 249-8522 (Japan)

    2006-10-01

    Interstrand contact resistances of Bi-2212 Rutherford cables for SMES coils were evaluated from a comparison between measured data and 2D-FEM analyses on interstrand coupling losses in these cables. The cables were composed of 30 non-twisted Bi-2212 strands with a diameter of 0.81 mm and a cable twist pitch of 90 mm. Three samples were measured; one of them had NiCr cores and the others had no cores. One of the latter two samples repeatedly experienced bending. The interstrand coupling losses were measured in liquid helium for the straight samples under transverse ac ripple magnetic fields superposed on dc bias magnetic fields. The transverse magnetic field was applied to the samples in directions both perpendicular and parallel to the flat face of the cable. The effect of the bending on the interstrand coupling losses could be neglected for the non-cored samples. The interstrand coupling losses of NiCr cored sample decreased by about 30% compared with the non-cored samples, in case the direction of the transverse magnetic fields applied to the cable is perpendicular to the flat face of the cable. Using these results and 2D-FEM analyses, taking into account that interstrand contact conditions vary from the center to the edge in the cross-section of cables, gave us the conclusion that the between side-by-side strands contact with metallurgical bond only in both edges of the cables.

  20. Dynamic Response Analysis of Towed Cable During Deployment/Retrieval

    WANG Fei; HUANG Guo-liang; DENG De-heng

    2008-01-01

    A numerical approach was developed to analyze the transient behavior of towed cable during ac- tively controlled deployment/retrieval (DR). The cable motion is described by the lumped parameter method, its corresponding boundary conditions are presented. In view of its varying length during DR, two auxiliary arguments are introduced to describe its continuous varying length and discrete number of nodes(equations), the length is determined by the pay out(or reel-in) rate, which is then used to determine the node number by a logic relation. For the discrete mathematical model of towed cable, an algorithm was developed to deal with the discrete governing equations. The simulation results indicate that the cable experiences more com- plex motions due to its varying length, and tension fluctuates seriously in the startup and ending stage of deployment/retrieval. The effect of towing ship's motion in waves on cable during deployment/retrieval is also considered via numerical simulation.

  1. Inductance and current distribution analysis of a prototype HTS cable

    This project is partly supported by NSFC Grant 51207146, RAEng Research Exchange scheme of UK and EPSRC EP/K01496X/1. Superconducting cable is an emerging technology for electricity power transmission. Since the high power capacity HTS transmission cables are manufactured using a multi-layer conductor structure, the current distribution among the multilayer structure would be nonuniform without proper optimization and hence lead to large transmission losses. Therefore a novel optimization method has been developed to achieve evenly distributed current among different layers considering the HTS cable structure parameters: radius, pitch angle and winding direction which determine the self and mutual inductance. A prototype HTS cable has been built using BSCCO tape and tested to validate the design the optimal design method. A superconductor characterization system has been developed using the Labview and NI data acquisition system. It can be used to measure the AC loss and current distribution of short HTS cables.

  2. 地下管线对通信电缆的屏蔽效应计算方法%Calculation method of electromagnetic shielding effects of underground pipelines to communication cables

    周宇坤; 马信山

    2001-01-01

    An electromagnetic shielding calculation model of undergroundconductors is presented, which takes the inductive coupling and the resistive coupling into account simultaneously. The traditional electromagnetic shielding calculation method is improved by changing interpolating function with pipeline node currents in place of pipeline element currents. Based on the model, the electromagnetic shielding effectiveness of the buried pipeline to communication cables is calculated and the regularity of electromagnetic shielding effectiveness is discussed. The calculation results show that the dimension of pipeline and grounding resistances will affect shielding effectiveness.%提出了一种同时考虑感性耦合和阻性耦合时的地下管线对通信电缆的电磁屏蔽模型,以管线节点电流代替管线单元电流进行插值,改进了传统电磁屏蔽效应计算方法。在此基础上,进行了地下管线对地下通信电缆的电磁屏蔽系数计算,探讨了屏蔽保护的规律。计算结果表明,管线粗细和端接阻抗将明显影响屏蔽保护效果。

  3. Electrical Aging Phenomena of Power Cables Aged by Switching Impulses

    L.Cao; A.Zanwar; S.Grzybowski

    2013-01-01

    Due to the insufficient information regarding the aging phenomenon of cables caused by switching impulses,we aged 15 kV XLPE and EPR cable samples by 10000 switching impulses in experiments and tested them.Plus in order to compare the aging phenomenon under multi-stress conditions,additional EPR cable samples were aged by rated AC voltage and current with switching impulses superimposed.We used measurements of partial discharge parameters to monitor the cables' conditions during their aging process,and the AC breakdown voltages measurement to evaluate the cables after aging.Moreover,the Fourier transform infrared (FTIR) spectroscopy measurements revealed the changes of insulation materials after aging.The measurement results confirm that the accelerated aging of cable samples had taken place.The impacts of each individual aging factor are shown through the selected measurements and comparison.The study also helps to assess the reliability of the XLPE and EPR cables under similar condition while serving in power systems.

  4. Southwire's High Temperature Superconducting Cable Development - Summary Report

    ORNL for the DC Ic, voltage withstand, ac loss, and other properties using both the Vacuum and Pressure Terminations. The design concept was proven with the 5-m cables and the same design was used for the 30-m cables. Three 30-m cables were constructed during the first two quarters of 1999. The cables were made on flexible formers but they were introduced into three separate rigid vacuum jacketed pipes (VJP). The cables passed the DC Ic tests that were carried out at the manufacturing site. A site was developed at Southwire with a switch yard, liquid nitrogen tank, a cryogenic cooling and delivery system, and a control room with PLC control for the system. The HTS cables were installed by the third quarter of 1999. The HTS cables were energized Jan. 6, 2000. The official opening was carried out on Feb. 18, 2000. As of April 30, 2005 the HTS site has been operating at 100% load for >29,000 hours. Since June 1, 2001 the system has logged over 21,000 hours at full load without an operator on duty at the site. The cryogenic system has been under operation for more than two years and has proven very reliable. Southwire has developed World's First Industrial HTS cable and is continuing to prove its reliability. This report contains several sections outlined below that are related to Southwire's HTS cable development: (1) High Temperature Superconducting (HTS) Tapes; (2) Hand Wound 1-m Cables; (3) Development of Facilities for Construction and testing of HTS cables; (4) 5-m HTS Cables; (5) 30-m HTS Cables, Installation at Southwire; (6) Continued Developments; and (7) Publications. Each of the above sections provide only a short report. The details are given in separate volumes (Vol. 1 to Vol. 7) with separate appendices for each section. These are available at the Cofer Center Technical Library

  5. Underground Mathematics

    Hadlock, Charles R

    2013-01-01

    The movement of groundwater in underground aquifers is an ideal physical example of many important themes in mathematical modeling, ranging from general principles (like Occam's Razor) to specific techniques (such as geometry, linear equations, and the calculus). This article gives a self-contained introduction to groundwater modeling with…

  6. Electrical power cable engineering

    Thue, William A

    2011-01-01

    Fully updated, Electrical Power Cable Engineering, Third Edition again concentrates on the remarkably complex design, application, and preparation methods required to terminate and splice cables. This latest addition to the CRC Press Power Engineering series covers cutting-edge methods for design, manufacture, installation, operation, and maintenance of reliable power cable systems. It is based largely on feedback from experienced university lecturers who have taught courses on these very concepts.The book emphasizes methods to optimize vital design and installation of power cables used in the

  7. Cable fault locator research

    Cole, C. A.; Honey, S. K.; Petro, J. P.; Phillips, A. C.

    1982-07-01

    Cable fault location and the construction of four field test units are discussed. Swept frequency sounding of mine cables with RF signals was the technique most thoroughly investigated. The swept frequency technique is supplemented with a form of moving target indication to provide a method for locating the position of a technician along a cable and relative to a suspected fault. Separate, more limited investigations involved high voltage time domain reflectometry and acoustical probing of mine cables. Particular areas of research included microprocessor-based control of the swept frequency system, a microprocessor based fast Fourier transform for spectral analysis, and RF synthesizers.

  8. The US market for high-temperature superconducting wire in transmission cable applications

    Forbes, D

    1996-04-01

    Telephone interviews were conducted with 23 utility engineers concerning the future prospects for high-temperature superconducting (HTS) transmission cables. All have direct responsibility for transmission in their utility, most of them in a management capacity. The engineers represented their utilities as members of the Electric Power Research Institute`s Underground Transmission Task Force (which has since been disbanded). In that capacity, they followed the superconducting transmission cable program and are aware of the cryogenic implications. Nineteen of the 23 engineers stated the market for underground transmission would grow during the next decade. Twelve of those specified an annual growth rate; the average of these responses was 5.6%. Adjusting that figure downward to incorporate the remaining responses, this study assumes an average growth rate of 3.4%. Factors driving the growth rate include the difficulty in securing rights-of-way for overhead lines, new construction techniques that reduce the costs of underground transmission, deregulation, and the possibility that public utility commissions will allow utilities to include overhead costs in their rate base. Utilities have few plans to replace existing cable as preventive maintenance, even though much of the existing cable has exceeded its 40-year lifetime. Ten of the respondents said the availability of a superconducting cable with the same life-cycle costs as a conventional cable and twice the ampacity would induce them to consider retrofits. The respondents said a cable with those characteristics would capture 73% of their cable retrofits.

  9. UtilityTelecom_CABLE2013

    Vermont Center for Geographic Information — The VT Cable dataset (CABLE2013) includes lines depicting the extent of Vermont's cable modem broadband system as of 6/30/2013 in addition to those companies who do...

  10. Cable tracking system proposal

    The Experimental Facilities Division requires a labeling system to identify and catalog the instrumentation, control, and computer cables that will run throughout the building. Tom Sheridan from the MIS Group has already made some general suggestions about the information that could be included in an Oracle-based Cable Tracking System (E-mail text distributed by Gary Gunderson on the 27th of August). Glenn Decker's LS Note No. 191 is also relevant to the subject since it addresses name assignment rules for the storage ring devices. The intent of this note is to recommend a mechanism for tracking wires/cables, with enough specifics, to which all groups in the Division would adhere when pulling cables. Because most cables will run between various beamline devices, hutch safety components, and equipment racks, any method of tracking cables is related to the Equipment Tracking System. That system has been developed by the APS Project personnel and is described in the APS Project Equipment Tracking System Guidelines (DRAFT). It can be adopted to XFD's needs. Two essential features of the Cable Tracking System are: 1) Each cable shell have a unique Identifier, and 2) Cable label must contain information that is helpful during troubleshooting in the field. The Identifier is an alphanumeric string of characters that will originate in the Oraclebased Cable Tracking System. It is not necessary for the identifier to carry a lot of intelligence its primary purpose is simply to provide a link to the database. Bar-coding the Identifier would make it easy to combine cable information with the Equipment Tracking System

  11. COPPER CABLE RECYCLING TECHNOLOGY

    The United States Department of Energy (DOE) continually seeks safer and more cost-effective technologies for use in deactivation and decommissioning (D and D) of nuclear facilities. The Deactivation and Decommissioning Focus Area (DDFA) of the DOE's Office of Science and Technology (OST) sponsors large-scale demonstration and deployment projects (LSDDPs). At these LSDDPs, developers and vendors of improved or innovative technologies showcase products that are potentially beneficial to the DOE's projects and to others in the D and D community. Benefits sought include decreased health and safety risks to personnel and the environment, increased productivity, and decreased costs of operation. The Idaho National Engineering and Environmental Laboratory (INEEL) generated a list of statements defining specific needs and problems where improved technology could be incorporated into ongoing D and D tasks. One such need is to reduce the volume of waste copper wire and cable generated by D and D. Deactivation and decommissioning activities of nuclear facilities generates hundreds of tons of contaminated copper cable, which are sent to radioactive waste disposal sites. The Copper Cable Recycling Technology separates the clean copper from contaminated insulation and dust materials in these cables. The recovered copper can then be reclaimed and, more importantly, landfill disposal volumes can be reduced. The existing baseline technology for disposing radioactively contaminated cables is to package the cables in wooden storage boxes and dispose of the cables in radioactive waste disposal sites. The Copper Cable Recycling Technology is applicable to facility decommissioning projects at many Department of Energy (DOE) nuclear facilities and commercial nuclear power plants undergoing decommissioning activities. The INEEL Copper Cable Recycling Technology Demonstration investigated the effectiveness and efficiency to recycle 13.5 tons of copper cable. To determine the effectiveness

  12. Rokibaar Underground = Rock bar Underground

    2008-01-01

    Rokibaari Underground (Küütri 7, Tartu) sisekujundus, mis pälvis Eesti Sisearhitektide Liidu 2007. a. eripreemia. Sisearhitekt: Margus Mänd (Tammat OÜ). Margus Männist, tema tähtsamad tööd. Plaan, 5 värv. vaadet, foto M. Männist

  13. Magnetization losses in superconducting YBCO conductor-on-round-core (CORC) cables

    Majoros, M.; Sumption, M. D.; Collings, E. W.; van der Laan, D. C.

    2014-12-01

    Described are the results of magnetization loss measurements made at 77 K on several YBCO conductor-on-round-core (CORC) cables in ac magnetic fields of up to 80 mT in amplitude and frequencies of 50 to 200 Hz, applied perpendicular to the cable axis. The cables contained up to 40 tapes that were wound in as many as 13 layers. Measurements on the cables with different configurations were made as functions of applied ac field amplitude and frequency to determine the effects of their layout on ac loss. In large scale devices such as e.g. Superconducting Magnetic Energy Storage (SMES) magnets, the observed ac losses represent less than 0.1% of their stored energy.

  14. Flux-transfer losses in helically wound superconducting power cables

    Clem, John R; Malozemoff, A P

    2013-06-25

    Minimization of ac losses is essential for economic operation of high-temperature superconductor (HTS) ac power cables. A favorable configuration for the phase conductor of such cables has two counter-wound layers of HTS tape-shaped wires lying next to each other and helically wound around a flexible cylindrical former. However, if magnetic materials such as magnetic substrates of the tapes lie between the two layers, or if the winding pitch angles are not opposite and essentially equal in magnitude to each other, current distributes unequally between the two layers. Then, if at some point in the ac cycle the current of either of the two layers exceeds its critical current, a large ac loss arises from the transfer of flux between the two layers. A detailed review of the formalism, and its application to the case of paramagnetic substrates including the calculation of this flux-transfer loss, is presented.

  15. Test results of a 30-m HTS cable pre-demonstration system in Yokohama project

    High temperature superconducting cable demonstration project supported by Ministry of Economy, Trade and Industry and New Energy and Industrial Technology Development Organization has started since FY 2007 in Japan. Target of this project is to operate a 66 kV, 200 MVA HTS cable in a live grid in order to demonstrate its reliability and stable operation. A demonstration site has been decided to Asahi substation which is located in Yokohama. The cable length will be decided to between 200 and 300 m depending on a site configuration. Various preliminary tests such as critical current, ac losses, fault current loading, mechanical tests, have been conducted by using short core samples in order to confirm a HTS cable design and a cable-to-cable joint structure. From these test results, a HTS cable, a joint and a termination have been designed to meet the required specifications. To verify their performances before the installation of the HTS cable system in Yokohama, a 30-m HTS cable was manufactured and various sample tests were conducted as shipping test. The critical current of the HTS conductor and shield were 6.1 kA and 7.1 kA, respectively. The AC loss was 0.83 W/m/ph at 2 kArms, 60 Hz. As withstand voltage tests, AC 90 kV for 3 h and lightning impulse at ±385 kV were applied to cable core, successfully. These test results has confirmed that the 30-m cable had good properties as designed and satisfied the required specifications. After the success of the shipping tests, the 30-m HTS cable pre-demonstration system has been installed at SEI factory. The cable system will be operated and checked the various performances in this summer.

  16. Test results of a 30-m HTS cable pre-demonstration system in Yokohama project

    Yumura, H.; Ashibe, Y.; Ohya, M.; Itoh, H.; Watanabe, M.; Yatsuka, K.; Masuda, T.; Honjo, S.; Mimura, T.; Kitoh, Y.; Noguchi, Y.

    2010-11-01

    High temperature superconducting cable demonstration project supported by Ministry of Economy, Trade and Industry and New Energy and Industrial Technology Development Organization has started since FY 2007 in Japan. Target of this project is to operate a 66 kV, 200 MVA HTS cable in a live grid in order to demonstrate its reliability and stable operation. A demonstration site has been decided to Asahi substation which is located in Yokohama. The cable length will be decided to between 200 and 300 m depending on a site configuration. Various preliminary tests such as critical current, ac losses, fault current loading, mechanical tests, have been conducted by using short core samples in order to confirm a HTS cable design and a cable-to-cable joint structure. From these test results, a HTS cable, a joint and a termination have been designed to meet the required specifications. To verify their performances before the installation of the HTS cable system in Yokohama, a 30-m HTS cable was manufactured and various sample tests were conducted as shipping test. The critical current of the HTS conductor and shield were 6.1 kA and 7.1 kA, respectively. The AC loss was 0.83 W/m/ph at 2 kA rms, 60 Hz. As withstand voltage tests, AC 90 kV for 3 h and lightning impulse at ±385 kV were applied to cable core, successfully. These test results has confirmed that the 30-m cable had good properties as designed and satisfied the required specifications. After the success of the shipping tests, the 30-m HTS cable pre-demonstration system has been installed at SEI factory. The cable system will be operated and checked the various performances in this summer.

  17. Modeling of a distributed constant electric circuit considering contact resistance and coupling loss analyses for cable twisted at multiple stages

    AC losses in multi-strand superconducting cables, utilized in large-scale applications such as fusion machines, are governed by the contact resistance between strands. Especially, in cable twisted at multiple-stages, a variety of magnetic field diffusion time constants exist and these correspond to the quantity of inter-strand coupling loss in each cabling stage. The rate of magnetic field change is less than several T/s in an average fusion machine. Under this condition, the magnetic field penetrates the cable well and the coupling current circuit with the larger time constant causes larger AC loss. Here, the time constant is equal to the leakage inductance divided by the resistance along the coupling current loop. Therefore, by evaluating the coupling current in the larger loop, which consists of a higher twisting stage (e.g., usually the final cabling stage), the loss in the entire cable can be determined. The leakage inductance between sub-cables can be estimated by considering the electrical centers. On the other hand, inter-sub-cable contact resistance was not previously evaluated due to its complexity. In this study, we established an inter-sub-cable contact resistance model that allows the AC loss in cable with multiple twisting stages to be evaluated numerically. The modeling of contact resistance between sub-cables is discussed in detail. (author)

  18. High current, low loss high temperature superconductor cables, concepts, properties and applications

    High Temperature Superconductors of the second generation (HTS-2G) became an industrial product during the recent years and are applied in several concepts of high current cables for a variety of applications. Low Losses, a thermal stabilization and mechanical strength are the requested features of the cables. We present an overview on the different cable concepts, their performance and the prospected DC and AC applications. Roebel cables and the CORC cable design are in particular suitable for AC operated high current devices as big generators, motors and large magnets. The performance of such cables was investigated under different conditions, as in pancake coils and layered windings. The behavior of the cables could meanwhile quite well be understood and described by FEM modeling. We also report on advanced cable versions which are equipped with a filamentary structure by means of laser assisted grooving of the superconducting layer. For some applications as large fusion magnets and accelerator magnets, even higher currents are requested. For such purpose Rutherford cables and more sophisticated concepts and cable designs are under investigation. We present the first results on such concepts and discuss the further research to be done. A final general outlook will indicate the prospects for the different applications. (author)

  19. Grounding Effect on Common Mode Interference of Underground Inverter

    Cheng, Qiang; Cheng, Ning; LI Zhen-shuang

    2013-01-01

    For the neutral point not grounded characteristics of underground power supply system in coal mine, this paper studied common mode equivalent circuit of underground PWM inverter, and extracted parasitic parameters of interference propagation path. The author established a common mode and differential mode model of underground inverter. Taking into account the rise time of PWM, the simulation results of conducted interference by Matlab software is compared with measurement spectrum on the AC s...

  20. Albany Hts Cable Project Long Term In-Grid Operation Status Update

    Yumura, H.; Masuda, T.; Watanabe, M.; Takigawa, H.; Ashibe, Y.; Ito, H.; Hirose, M.; Sato, K.

    2008-03-01

    High-temperature superconducting (HTS) cable systems are expected to be a solution for improvement of the power grid and three demonstration projects in the real grid are under way in the United States. One of them is the Albany, NY Cable Project, involving the installation and operation of a 350 meter HTS cable system with a capacity of 34.5kV, 800A, connecting between two substations in National Grid's electric utility system. A 320 meter and a 30 meter cable are installed in underground conduit and connected together in a vault. The cables were fabricated with 70km of DI-BSCCO wire in a 3 core-in-one cryostat structure. The cable installation of a 320 meter and a 30 meter section was completed successfully using the same pulling method as a conventional underground cable. After the cable installation, the joint and two terminations were assembled at the Albany site. After the initial cooling of the system, the commissioning tests such as the critical current, heat loss measurement and DC withstand voltage test were conducted successfully. The in-grid operation began on July 20th, 2006 and operated successfully in unattended condition through May 1st, 2007. In the 2nd phase of the Albany project, the 30 meter section is to be replaced by a YBCO cable. The YBCO cable had been developed and a new 30 meter cable was manufactured by using SuperPower's YBCO coated conductors. This paper describes the latest status of the Albany cable project.

  1. Infiniband Based Cable Comparison

    Minich, Makia [ORNL

    2007-07-01

    As Infiniband continues to be more broadly adopted in High Performance Computing (HPC) and datacenter applications, one major challenge still plagues implementation: cabling. With the transition to DDR (double data rate) from SDR (single datarate), currently available Infiniband implementations such as standard CX4/IB4x style copper cables severely constrain system design (10m maximum length for DDR copper cables, thermal management due to poor airflow, etc.). This paper will examine some of the options available and compare performance with the newly released Intel Connects Cables. In addition, we will take a glance at Intel's dual-core and quad-core systems to see if core counts have noticeable effect on expected IO patterns.

  2. Magnet cable manufacturing

    The superconducting magnets used in the construction of particle accelerators are mostly built from flat, multistrand cables with rectangular or keystoned cross sections. The superconducting strands are mostly circular but a design of a cable made of preflattened wires was proposed a few years ago under the name of Berkeley flat; such cable shows some interesting characteristics. Another design consists of a few smaller precabled wires (e.g. 6 around 1). This configuration allows smaller filaments and a better transposition of the current elements. The Superconducting Super Collider project involves the largest amount of superconducting cable ever envisaged for a single machine. Furthermore, the design calls for exceptional accuracy and improved characteristics of the cable. A part of the SSC research and development program is focused on these important questions. In this paper we emphasize the difference between the conventional cabling and wires with superconducting. A new concept for the tooling will be introduced as well as the necessary characteristics of a specialized cabler. 5 figs

  3. Underground logistics

    Foraz, K; CERN. Geneva. TS Department

    2005-01-01

    More than 80’000 tons of materials have to be transported and installed down into the LHC tunnel. The magnet assemblies which represent about 50’000 tons, will be transported according to the master schedule between March 2005 and November 2006. Considering that these about 1’800 cryo-magnets will be transported at a maximum speed of 3 km/h in a narrow tube (where installation works and hardware commissioning activities are ongoing) this duration of 21 months is a real challenge. This paper aims at describing: - the information flows between the different people involved in the logistics attached to the cryo-magnets, - the organization chosen within the Installation Coordination group, - the problems encountered so far and the solutions adopted. The coordination process with other underground transport and activities, mainly for the QRL will also be presented.

  4. A Cool-down and Fault Study of a Long Length HTS Power Transmission Cable

    Yuan, J.; Maguire, J.; Allais, A.; Schmidt, F.

    2006-04-01

    High temperature superconductor (HTS) power transmission cables offer significant advantages in power density over conventional copper-based cables. Currently the US Department of Energy is funding the design, development, and demonstration of the first long length, transmission level voltage, cold dielectric, underground high temperature superconductor power cable. The cable is 620 meters long and is designed for permanent installation in the Long Island Power Authority (LIPA) grid. The cable is specified to carry 574 MVA at a voltage of 138 kV and is designed to withstand a 69 kA fault current for a duration of 200ms. The superconducting state of the cable conductors is maintained by circulating sub-cooled liquid nitrogen, which flows through one phase conductor of the cable and returns through the other two. As HTS cables develop and lengths increase to what may be considered commercial, it is critical to study the cable thermal behavior during cool-down process and fault condition to avoid any possible damage to the cable core due to the thermal stress, over heating or bubble formation. This paper reviews the efforts that have been made to study the cool-down process and fault condition. Descriptions of the transient thermal and fluid model are provided. A discussion of the simulation results is also included.

  5. Report on full-scale horizontal cable tray fire tests, FY 1988

    In recent years, there has been much discussion throughout industry and various governmental and fire protection agencies relative to the flammability and fire propagation characteristics of electrical cables in open cable trays. It has been acknowledged that under actual fire conditions, in the presence of other combustibles, electrical cable insulation can contribute to combustible fire loading and toxicity of smoke generation. Considerable research has been conducted on vertical cable tray fire propagation, mostly under small scale laboratory conditions. In July 1987, the Fermi National Accelerator Laboratory initiated a program of full scale, horizontal cable tray fire tests, in the absence of other building combustible loading, to determine the flammability and rate of horizontal fire propagation in cable tray configurations and cable mixes typical of those existing in underground tunnel enclosures and support buildings at the Laboratory. The series of tests addressed the effects of ventilation rates and cable tray fill, fire fighting techniques, and effectiveness and value of automatic sprinklers, smoke detection and cable coating fire barriers in detecting, controlling or extinguishing a cable tray fire. This report includes a description of the series of fire tests completed in June 1988, as well as conclusions reached from the test results

  6. Free and forced convective cooling of pipe-type electric cables. Volume 1: forced cooling of cables. Final report

    Chato, J.C.; Crowley, J.M.

    1981-05-01

    A multi-faceted research program has been performed to investigate in detail several aspects of free and forced convective cooling of underground electric cable systems. There were two main areas of investigation. The first one reported in this volume dealt with the fluid dynamic and thermal aspects of various components of the cable system. In particular, friction factors for laminar flow in the cable pipes with various configurations were determined using a finite element technique; the temperature distributions and heat transfer in splices were examined using a combined analytical numerical technique; the pressure drop and heat transfer characteristics of cable pipes in the transitional and turbulent flow regime were determined experimentally in a model study; and full-scale model experimental work was carried out to determine the fluid dynamic and thermal characteristics of entrance and exit chambers for the cooling oil. The second major area of activity, reported in volume 2, involved a feasibility study of an electrohydrodynamic pump concept utilizing a traveling electric field generated by a pumping cable. Experimental studies in two different configurations as well as theoretical calculations showed that an electrohydrodynamic pump for the moving of dielectric oil in a cable system is feasible.

  7. Space Charge Accumulation under Effects of Temperature Gradient and Applied Voltage Reversal on Solid Dielectric DC Cable

    Choo, Wilson; Chen, George; Swingler, Steve

    2009-01-01

    A well-known fact of the existence and accumulation of space charge within the insulating material poses threat to the reliability in the operation of dc power cables. When power cables are loaded under high voltage direct current (HVDC), temperature gradient is developed across the insulation. Results of space charge evolution in commercial ac XLPE power cables under an application of 80 kV dc supply at different temperature gradients and during external voltage reversal are discussed in thi...

  8. Water underground

    de Graaf, Inge

    2015-04-01

    The world's largest assessable source of freshwater is hidden underground, but we do not know what is happening to it yet. In many places of the world groundwater is abstracted at unsustainable rates: more water is used than being recharged, leading to decreasing river discharges and declining groundwater levels. It is predicted that for many regions of the world unsustainable water use will increase, due to increasing human water use under changing climate. It would not be long before shortage causes widespread droughts and the first water war begins. Improving our knowledge about our hidden water is the first step to stop this. The world largest aquifers are mapped, but these maps do not mention how much water they contain or how fast water levels decline. If we can add a third dimension to the aquifer maps, so a thickness, and add geohydrological information we can estimate how much water is stored. Also data on groundwater age and how fast it is refilled is needed to predict the impact of human water use and climate change on the groundwater resource.

  9. Analysis of AC loss in superconducting power devices calculated from short sample data

    Rabbers, J.J.; Haken, ten, Bennie; Kate, ten, F.J.W.

    2003-01-01

    A method to calculate the AC loss of superconducting power devices from the measured AC loss of a short sample is developed. In coils and cables the magnetic field varies spatially. The position dependent field vector is calculated assuming a homogeneous current distribution. From this field profile and the transport current, the local AC loss is calculated. Integration over the conductor length yields the AC loss of the device. The total AC loss of the device is split up in different compone...

  10. Pyrotechnic-actuated cable release

    Hanson, R. W.

    1968-01-01

    Remote, unattended means has been designed and reduced to practice that retains and then releases an attached load by means of a restrained cable. The cable is released by an electrical impulse on signal.

  11. The Electrical Aspects of the choice of Former in a High T-c Superconducting Power Cable

    Däumling, Manfred; Kühle (fratrådt), Anders Van Der Aa; Olsen, Søren Krüger; Træholt, Chresten; Tønnesen, Ole

    1999-01-01

    design of a cable. The diameter of the former determines the overall diameter of the total cable, influences the heat loss to the ambient and enters into the total AC-losses. Depending on whether the former is made of a good or poor electrical conductor eddy currents in the former itself may also...

  12. Improved GPS travelling wave fault locator for power cables by using wavelet analysis

    Zhao, W.; Song, Y.H.; Chen, W.R. [Brunel Univ., Dept. of Electronics and Computer Engineering, Uxbridge (United Kingdom)

    2001-06-01

    The paper propose an improved approach to cable-fault location, which is essentially based on synchronised sampling technique, wavelet analysis and travelling wave principle. After an outline of the new scheme and brief introduction to the three major techniques, wavelet analysis of faulty transient waveforms is conducted in details to determine the best wavelet levels for this particular application. Then a 400 kV underground cable system simulated by the Alternative Transient Program (ATP) under various system and fault conditions is used to fully evaluate the approach. Numerical results show that this scheme is reliable and accurate with errors of less than 2% of the length of the cable line. (Author)

  13. Study on interstrand coupling losses in Rutherford-type superconducting cables

    Two sets of experimental apparatus for measuring the AC losses in superconducting strands and Rutherford-type cable conductors have been constructed. A few strand samples and a number of compacted cable samples with and without a CuMn matrix have been measured. The hysteresis loss, loss from coupling within strands and loss from coupling between strands in cables have been distinguished from each other. The results show that, even for Rutherford cables without any soldering and coating, their AC losses may be quite different from each other due to the variation of the interstrand coupling loss. For cables without a CuMn matrix, interstrand coupling loss increases nearly according to a geometrical series with an increase of curing temperature simulating coil fabrication. However, cables with the CuMn matrix show a relatively small curing temperature dependence. For most of the samples, losses do not show any evident dependence on the mechanical pressure. Interstrand resistances in one of these cables have also been measured; the results indicate that the tendency for a decrease in the interstrand resistances is consistent with the results of AC loss measurements. (author)

  14. EHV/HV Underground Cable Systems for Power Transmission

    Bak, Claus Leth

    Power transmission is facing its largest challenges ever with regards to handling a transition from today’s fossil‐based power production into renewable sources of generation. We can no longer place power plants close to centres of consumption; they must be located where the natural resources are...... to be found. One very good example of this is offshore wind power plants. The current transmission system is laid out in a traditional manner, which is based on the idea of not transporting power over longer distances as the power plants have been located near centres of consumption. It has merely...... layout of the transmission system must be re‐thought in order to accommodate the transmission needs for the future. New lines have to be constructed. Transmission lines are usually laid out as overhead lines, which are large structures, i.e. a 400 kV power pylon is 50 meters high. According to public...

  15. Field Demonstration of a 24-kV Superconducting Cable at Detroit Edison

    Customer acceptance of high temperature superconducting (HTS) cable technology requires a substantial field demonstration illustrating both the system's technical capabilities and its suitability for installation and operation within the utility environment. In this project, the world's first underground installation of an HTS cable using existing ductwork, a 120 meter demonstration cable circuit was designed and installed between the 24 kV bus distribution bus and a 120 kV-24 kV transformer at Detroit Edison's Frisbie substation. The system incorporated cables, accessories, a refrigeration system, and control instrumentation. Although the system was never put in operation because of problems with leaks in the cryostat, the project significantly advanced the state-of-the-art in the design and implementation of Warm Dielectric cable systems in substation applications. Lessons learned in this project are already being incorporated in several ongoing demonstration projects

  16. Field Demonstration of a 24-kV Superconducting Cable at Detroit Edison

    Kelley, Nathan; Corsaro, Pietro

    2004-12-01

    Customer acceptance of high temperature superconducting (HTS) cable technology requires a substantial field demonstration illustrating both the system's technical capabilities and its suitability for installation and operation within the utility environment. In this project, the world's first underground installation of an HTS cable using existing ductwork, a 120 meter demonstration cable circuit was designed and installed between the 24 kV bus distribution bus and a 120 kV-24 kV transformer at Detroit Edison's Frisbie substation. The system incorporated cables, accessories, a refrigeration system, and control instrumentation. Although the system was never put in operation because of problems with leaks in the cryostat, the project significantly advanced the state-of-the-art in the design and implementation of Warm Dielectric cable systems in substation applications. Lessons learned in this project are already being incorporated in several ongoing demonstration projects.

  17. Design and performance of ultra-high-density optical fiber cable with rollable optical fiber ribbons

    Hogari, Kazuo; Yamada, Yusuke; Toge, Kunihiro

    2010-08-01

    This paper proposes a novel ultra-high-density optical fiber cable that employs rollable optical fiber ribbons. The cable has great advantages in terms of cable weight and diameter, and fiber splicing workability. Moreover, it will be easy to install in a small space in underground ducts and on residential and business premises. The structural design of the rollable optical fiber ribbon is evaluated theoretically and experimentally, and an optimum adhesion pitch P in the longitudinal direction is obtained. In addition, we examined the performance of ultra-high-density cables with a small diameter that employ rollable optical fiber ribbons and bending-loss insensitive optical fibers. The transmission, mechanical and mid-span access performance of these cables was confirmed to be excellent.

  18. The Danish Superconducting Cable Project

    Tønnesen, Ole

    1997-01-01

    The design and construction of a superconducting cable is described. The cable has a room temperature dielectric design with the cryostat placed inside the electrical insulation.BSCCO 2223 superconducting tapes wound in helix form around a former are used as the cable conductor. Results from...

  19. Cable Television Information.

    New York State Education Dept. , Albany. Bureau of Mass Communications.

    Cable television for the State of New York is discussed in detail with relation to: (1) the regents of the University of the State of New York, (2) legislation, (3) planning and proposals for franchises, (4) the Federal Communications Commission, (5) access rules, (6) a list of companies and those serving schools, and (7) federal/state/local…

  20. Internal coaxial cable seal system

    Hall, David R.; Sneddon, Cameron; Dahlgren, Scott Steven; Briscoe, Michael A.

    2006-07-25

    The invention is a seal system for a coaxial cable and is placed within the coaxial cable and its constituent components. A series of seal stacks including load ring components and elastomeric rings are placed on load bearing members within the coaxial cable sealing the annular space between the coaxial cable and an electrical contact passing there through. The coaxial cable is disposed within drilling components to transmit electrical signals between drilling components within a drill string. The seal system can be used in a variety of downhole components, such as sections of pipe in a drill string, drill collars, heavy weight drill pipe, and jars.

  1. Long length HTS cable with integrated FCL property

    The past years have shown the growth of bottlenecks in electric power grids, among other reasons caused by the increasing demand of energy in the form of electricity and by the large-scaled integration of renewable sources. As solving of these challenges by means of traditional solutions appears to be more and more problematic, the need for new technology solutions has become apparent. The HTS cable technology demonstrates a great potential in solving of grid congestion issues. In addition to their large power transport capacity and low losses, modern-generation HTS cables also have an integrated fault-current limiting (FCL) property. Applications of such cables in power grids will help to solve fault-current issues when connecting new generators, and dispersed and large-scale renewable sources. As HTS cables, used in current projects, are limited to hundreds of meters in length, they have still not been used for energy transport over long distances. The Dutch DSO Alliander, together with Ultera, is working on the development of a 6 km FCL HTS cable for installation in the Alliander's HV grid. In order to get the low-loss benefits of the HTS technology, a cooling system with a high efficiency is needed. The FCL HTS cable will be cooled by one cooling station at each end of the cable, using a liquid nitrogen coolant. Alliander and Ultera have established and work to achieve technical performance targets believed to be required to realise a 6 km long, 50 kV retrofit system with a power rating of 250 MVA with cooling stations only at the two ends of the cable system. These targets aim to reduce the superconductor's AC loss at a nominal current, reduce the heat leak of the thermally insulating envelope, increase the voltage rating and reduce the friction coefficient of the coolant flow.

  2. Method for analysis the complex grounding cables system

    A new iterative method for the analysis of the performances of the complex grounding systems (GS) in underground cable power networks with coated and/or uncoated metal sheathed cables is proposed in this paper. The analyzed grounding system consists of the grounding grid of a high voltage (HV) supplying transformer station (TS), middle voltage/low voltage (MV/LV) consumer TSs and arbitrary number of power cables, connecting them. The derived method takes into consideration the drops of voltage in the cable sheets and the mutual influence among all earthing electrodes, due to the resistive coupling through the soil. By means of the presented method it is possible to calculate the main grounding system performances, such as earth electrode potentials under short circuit fault to ground conditions, earth fault current distribution in the whole complex grounding system, step and touch voltages in the nearness of the earthing electrodes dissipating the fault current in the earth, impedances (resistances) to ground of all possible fault locations, apparent shield impedances to ground of all power cables, e.t.c. The proposed method is based on the admittance summation method [1] and is appropriately extended, so that it takes into account resistive coupling between the elements that the GS. (Author)

  3. Design and evaluation of 66 kV-class HTS power cable using REBCO wires

    Ohya, M., E-mail: ohya-masayoshi@sei.co.jp [Sumitomo Electric Industries, Ltd., 1-1-3, Shimaya, Konohana-ku, Osaka 554-0024 (Japan); Yumura, H.; Masuda, T. [Sumitomo Electric Industries, Ltd., 1-1-3, Shimaya, Konohana-ku, Osaka 554-0024 (Japan); Amemiya, N. [Kyoto University, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto 615-8530 (Japan); Ishiyama, A. [Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Ohkuma, T. [International Superconductivity Technology Center, 1-10-13, Shinonome, Koto-ku, Tokyo 135-0062 (Japan)

    2011-11-15

    A 4-layer cable conductor was manufactured using 4-mm wide REBCO wires with low magnetic textured substrates. The AC loss of the cable conductor was 1.5 W/m at 5 kA. Our cables are expected to achieve the AC loss target of less than 2 W/m/ph at 5 kA. Over-current tests (max. 31.5 kA, 2 s) were conducted for a cable sample and its soundness was verified. A 5 kA-class current lead was also developed. Sumitomo Electric (SEI) has been involved in the development of 66 kV-class HTS cables using REBCO wires. One of the technical targets in this project is to reduce the AC loss to less than 2 W/m/phase at 5 kA. SEI has developed a clad-type of textured metal substrate with lower magnetization loss compared with a conventional NiW substrate. In addition, 30 mm-wide REBCO tapes were slit into 4 mm-wide strips, and these strips were wound spirally on a former with small gaps. The AC loss of a manufactured 4-layer cable conductor was 1.5 W/m at 5 kA at 64 K. Given that the AC loss in a shield layer is supposed to be one-fourth of a whole cable core loss, our cables are expected to achieve the AC loss target of less than 2 W/m/phase at 5 kA. Another important target is to manage a fault current. A cable core was designed and fabricated based on the simulation findings, and over-current tests (max. 31.5 kA, 2 s) were conducted to check its performance. The critical current value of the cable cores were measured before and after the over-current tests and verified its soundness. A 5 kA-class current lead for the cable terminations was also developed. The current loading tests were conducted for the developed current leads. The temperature distribution of the current leads reached to the steady-state within less than 12 h, and it was confirmed that the developed current lead has enough capacity of 5 kA loading.

  4. Design and evaluation of 66 kV-class HTS power cable using REBCO wires

    A 4-layer cable conductor was manufactured using 4-mm wide REBCO wires with low magnetic textured substrates. The AC loss of the cable conductor was 1.5 W/m at 5 kA. Our cables are expected to achieve the AC loss target of less than 2 W/m/ph at 5 kA. Over-current tests (max. 31.5 kA, 2 s) were conducted for a cable sample and its soundness was verified. A 5 kA-class current lead was also developed. Sumitomo Electric (SEI) has been involved in the development of 66 kV-class HTS cables using REBCO wires. One of the technical targets in this project is to reduce the AC loss to less than 2 W/m/phase at 5 kA. SEI has developed a clad-type of textured metal substrate with lower magnetization loss compared with a conventional NiW substrate. In addition, 30 mm-wide REBCO tapes were slit into 4 mm-wide strips, and these strips were wound spirally on a former with small gaps. The AC loss of a manufactured 4-layer cable conductor was 1.5 W/m at 5 kA at 64 K. Given that the AC loss in a shield layer is supposed to be one-fourth of a whole cable core loss, our cables are expected to achieve the AC loss target of less than 2 W/m/phase at 5 kA. Another important target is to manage a fault current. A cable core was designed and fabricated based on the simulation findings, and over-current tests (max. 31.5 kA, 2 s) were conducted to check its performance. The critical current value of the cable cores were measured before and after the over-current tests and verified its soundness. A 5 kA-class current lead for the cable terminations was also developed. The current loading tests were conducted for the developed current leads. The temperature distribution of the current leads reached to the steady-state within less than 12 h, and it was confirmed that the developed current lead has enough capacity of 5 kA loading.

  5. Long term investigation of thermal behaviour of 110 kV underground transmission lines in the Belgrade area

    Sredojevic, M.R.; Naumov, R.M.; Popovic, D.P. [Nikola Tesla Electrical Engineering Inst., Belgrade (Yugoslavia); Simic, M.D. [Electrical Utility Co., Belgrade (Yugoslavia)

    1997-12-31

    The paper describes the procedure for applying a special cable backfill material, developed and manufactured at the Institute ``Nikola Tesla`` for the thermal stabilisation and reduction of hot spot cable operating temperature, on specific hot spots of 110 kV underground transmission lines in the Belgrade area. The results presented in this paper are an important contribution to the proof of the justification and necessity of defining and introducing in practice new procedures for the thermal stabilisation and reduction of operating temperature of existing, as well as of new, underground transmission cable lines to be built. (author)

  6. Full-scale horizontal cable-tray tests: Fire-propagation characteristics

    At the Fermi National Accelerator Center (Fermilab), as at any high-energy physics laboratory, the experimental program depends on complex arrays of equipment that require years to assemble and place in service. These equipment arrays are typically located in enclosed tunnels or experimental halls and could be destroyed by rapidly propagating, uncontrolled fire. Cable trays, both vertical and horizontal, are an integral and ubiquitous component of these installations. Concurrently, throughout industry and within the professional fire-fighting community, there has been concern over the flammability and fire propagation characteristics of electrical cables in open cable trays. While some information was available concerning fire propagation in vertical cable trays, little was known about fires in horizontal cable trays. In view of the potential for loss of equipment and facilities, not to mention the programmatic impact of a fire, Fermilab initiated a program of full-scale, horizontal cable-tray fire tests to determine the flammability and rate of horizontal fire propagation in cable-tray configurations and cable mixed typical of those existing in underground tunnel enclosures and support buildings as Fermilab. This series of tests addressed the effects of ventilation rates and cable-tray fill, fire-fighting techniques, and the effectiveness and value of automatic sprinklers, smoke detection, and cable-coating fire barriers in detecting, controlling, or extinguishing a cable-tray fire. Detailed descriptions of each fire test, including sketches of cable-tray configuration and contents, instrumentation, ventilation rates, Fermilab Fire Department personnel observations, photographs, and graphs of thermocouple readings are available in a report of these tests prepared by the Fermilab Safety Section

  7. New Passive Methodology for Power Cable Monitoring and Fault Location

    Kim, Youngdeug

    The utilization of power cables is increasing with the development of renewable energy and the maintenance replacement of old overhead power lines. Therefore, effective monitoring and accurate fault location for power cables are very important for the sake of a stable power supply. The recent technologies for power cable diagnosis and temperature monitoring system are described including their intrinsic limitations for cable health assessment. Power cable fault location methods are reviewed with two main categories: off-line and on-line data based methods. As a diagnostic and fault location approach, a new passive methodology is introduced. This methodology is based on analyzing the resonant frequencies of the transfer function between the input and output of the power cable system. The equivalent pi model is applied to the resonant frequency calculation for the selected underground power cable transmission system. The characteristics of the resonant frequencies are studied by analytical derivations and PSCAD simulations. It is found that the variation of load magnitudes and change of positive power factors (i.e., inductive loads) do not affect resonant frequencies significantly, but there is considerable movement of resonant frequencies under change of negative power factors (i.e., capacitive loads). Power cable fault conditions introduce new resonant frequencies in accordance with fault positions. Similar behaviors of the resonant frequencies are shown in a transformer (TR) connected power cable system with frequency shifts caused by the TR impedance. The resonant frequencies can be extracted by frequency analysis of power signals and the inherent noise in these signals plays a key role to measure the resonant frequencies. Window functions provide an effective tool for improving resonant frequency discernment. The frequency analysis is implemented on noise laden PSCAD simulation signals and it reveals identical resonant frequency characteristics with theoretical

  8. EIGENFREQUENCY ANALYSIS OF CABLE STRUCTURES WITH INCLINED CABLES

    William Paulsen; Greg Slayton

    2006-01-01

    The approximate eigenfrequencies for the in-plane vibrations of a cable structure consisting of inclined cables, together with point masses at various points were computed. It was discovered that the classical transfer matrix method was inadequate for this task, and hence the larger exterior matrices were used to determine the eigenfrequency equation. Then predictions of the dynamics of the general cable structure based on the asymptotic estimates of the exterior matrices were made.

  9. Applied use of combustion turbine generators as a station blackout alternate AC power source

    In response to the 10 CFR 50.63 Station Blackout Rule and NRC Regulatory Guide (RG) 1.155, Arizona Public Service Company (APS) opted to install dual 13.8kV, 3400kW black start combustion turbine generators (CTG's) as an alternate AC (AAC) power source at the Palo Verde Nuclear Generating Station (PVNGS). These CTG's provide AC power to critical plant loads in the event of a Station Blackout (SBO) in any one of the three PVNGS units. The AAC power source entered service in the fall of 1993 for the first PVNGS unit. Connection of the AAC source for the other two nuclear units will be complete by mid-1995. Two redundant CTGs were used to provide assurance that the AAC system availability requirements of RG 1.155 of 95% were met. A CTG site was chosen near an existing source of diesel fuel oil that was reasonably distant from the plant switchyard. The CTG's were installed along with a prefabricated turbine control room (TCR) which houses the CTG control equipment and associated power distribution equipment and battery systems. Cables were routed from the CTG site to each of the PVNGS units utilizing both new and existing underground duct banks. The cables were sized for the combined output of both CTG's at maximum power output for site worst case conditions. At each of the PVNGS units, additional switchgear cubicles were added to provide an interface with the existing plant power distribution system at a point upstream of the safety related power system. A test program was developed by engineering that tested all aspects of the installation and proved its capability to fulfill its purpose. Testing ranged from verifying emergency lighting adequacy to emissions testing and a complete simulation of a SBO. CTG performance was evaluated and verified to meet all expectations

  10. Stray current induced corrosion in lightning rod cables of 525 kV power lines towers: a case study

    Wojcicki, F. R.

    2003-12-01

    Full Text Available With the growth of several areas in modem society, the necessity to generate and carry electrical energy to big cities has greatly increased. Cables supported by power towers with galvanized steel foundation usually carry energy. As the foundations are underground they may cause high rates of corrosion. These are usually detected by a conventional potential measurement using a Cu/CuSO4 reference electrode. It is believed that corrosion results from stray currents that flow through the ground to close the loop between neighboring towers. Stray currents originate in the lightning rod cables of the power line towers, induced by the strong electromagnetic and electric fields of the energized power lines. The intensity and direction of those currents were measured, indicating substantial values of both their AC and DC components. The potential of the tower ground system, measured in the perpendicular direction of the main axis of the power line, was plotted as a function of the distance to the tower base. The results clearly indicated the tendency to corrosive attack in the anodic towers as reflected by the slope of the plot, whereas no signs of corrosion could be found in the reverse slope, confirming the visual inspection of the foundation. The profile of the potential plots could be changed providing the electric insulation of the lightning rod cable.

    Con el crecimiento de varias áreas en la sociedad moderna, la necesidad de generar y conducir la energía eléctrica a las grandes ciudades ha aumentado enormemente. La energía, normalmente, se transporta por cables sostenidos por torres de energía con base de acero galvanizado. Cuando las bases son subterráneas, pueden ocasionar altas tasas de corrosión. Estas, normalmente, se detectan por la medida convencional del potencial empleando un electrodo de referencia de Cu/CuSO4. Se cree que la corrosión es el resultado de corrientes perdidas que fluyen a través de la

  11. Cable networks, services, and management

    2015-01-01

    Cable Networks, Services, and Management is the first book to cover cable networks, services, and their management, in-depth, for network operators, engineers, researchers, and students. Thirteen experts in various fields have contributed their knowledge of network architectures and services, Operations, Administration, Maintenance, Provisioning, Troubleshooting (OAMPT) for residential and business services, cloud, Software Defined Networks (SDN), as well as virtualization concepts and their applications as part of the future directions of cable networks. The book begins by introducing architecture and services for Data Over Cable Service Interface Specification (DOCSIS) 3.0/ 3.1, Converged Cable Access Platform (CCAP), Content Distribution Networks (CDN, IP TV, and Packet Cable and Wi-Fi for Residential Services. Topics that are discussed in proceeding chapters include: operational systems and management architectures, service orders, provisioning, fault manageme t, performance management, billing systems a...

  12. 14 CFR 23.689 - Cable systems.

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Cable systems. 23.689 Section 23.689... Systems § 23.689 Cable systems. (a) Each cable, cable fitting, turnbuckle, splice, and pulley used must... primary control systems; (2) Each cable system must be designed so that there will be no hazardous...

  13. Current distribution among layers of single phase HTS cable conductor

    Highlights: • A 1.5 m long HTS model cable with 4 layers designed by the uniform current principle has been built. • It is testified that the current distribution is influenced by the proximity effect. • The magnetic flux density and current density have been analyzed. • AC losses of tested current are larger than those of uniform current. - Abstract: High temperature superconducting (HTS) power cable shows high application prospect in modern power transmission, as it is superior over conventional transmission lines in high engineering current density and environmental friendliness. Its configuration is generally composed of several HTS layers designed with the principle of uniform current distribution, but there are few experimental results to verify the distribution. In this paper, a HTS cable model was designed based on the principle of uniform current, and the current distributions among layers in an HTS cable model were measured by Rogowski coils. The results provide an important basis for design of multi-layer HTS cable

  14. Cable Bacteria in Freshwater Sediments

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B.; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the fre...

  15. High-temperature superconducting conductors and cables

    This is the final report of a 3-year LDRD project at LANL. High-temperature superconductivity (HTS) promises more efficient and powerful electrical devices such as motors, generators, and power transmission cables; however this depends on developing HTS conductors that sustain high current densities Jc in high magnetic fields at temperatures near liq. N2's bp. Our early work concentrated on Cu oxides but at present, long wire and tape conductors can be best made from BSCCO compounds with high Jc at low temperatures, but which are degraded severely at temperatures of interest. This problem is associated with thermally activated motion of magnetic flux lines in BSCCO. Reducing these dc losses at higher temperatures will require a high density of microscopic defects that will pin flux lines and inhibit their motion. Recently it was shown that optimum defects can be produced by small tracks formed by passage of energetic heavy ions. Such defects result when Bi is bombarded with high energy protons. The longer range of protons in matter suggests the possibility of application to tape conductors. AC losses are a major limitation in many applications of superconductivity such as power transmission. The improved pinning of flux lines reduces ac losses, but optimization also involves other factors. Measuring and characterizing these losses with respect to material parameters and conductor design is essential to successful development of ac devices

  16. Simplified formulae for the estimation of the positive-sequence resistance and reactance of three-phase cables for different frequencies

    Silva, Filipe Miguel Faria da

    2015-01-01

    The installation of HVAC underground cables became more common in recent years, a trend expected to continue in the future. Underground cables are more complex than overhead lines and the calculation of their resistance and reactance can be challenging and time consuming for frequencies that are...... not power frequency. Software packages capable of performing exact calculations of these two parameters exist, but simple equations able to estimate the reactance and resistance of an underground cable for the frequencies associated to a transient or a resonance phenomenon would be helpful. This paper...... proposes new simplified formulae capable of calculating the positive-sequence resistance and reactance of a cable for frequencies associated to temporary overvoltages, slow-front overvoltages and resonance phenomena. The calculation of a cable’s resistance and reactance is made using a simplified series...

  17. Assessment of rock bolt systems for underground waste storage

    A review of existing rock bolting systems was undertaken to assess their suitability in underground design for storage of nuclear waste. Unique engineering considerations are required due to the thermal pulse generated by the waste causing additional stress to the support system and possibly affecting anchorage stability. Field visits were made to four underground projects to assess the performance of a wide variety of rock bolt systems. Cable bolts, point anchor bolts, locally debonded full column cement grout bolts, and yieldable bolt systems show promise. Full scale testing of bolt systems is recommended, together with assessing temperature effects on grout strength and grout longterm stability

  18. LOCA testing of damaged cables

    Experiments were conducted to assess the effects of dielectric withstand voltage testing of cables and to assess the survivability of aged and damaged cables under loss-of-coolant accident (LOCA) conditions. High potential testing at 240 Vdc/mil on undamaged cables suggested that no damage was incurred on the selected cables. During aging and LOCA testing, Okonite ethylene propylene rubber cables with a bonded jacket experienced unexpected failures. The failures appear to be primarily related to the level of thermal aging. For Brand Rex crosslinked polyolefin cables, the results suggest that 8 mils of insulation remaining should give the cables a high probability of surviving accident exposure following aging. The voltage levels necessary to detect when 8 mils of insulation remain are expected to be roughly 40 kVdc. This voltage level would almost certainly be unacceptable to a utility for use as a damage assessment tool. Although two Rockbestos silicone rubber cables failed during the accident test, the induced wall thickness did not seem to be the major cause of the failures. It appears likely that under less stressful thermal aging conditions, the cables would survive accident testing with as little as 4 mils or less of insulation remaining

  19. Superconducting flat tape cable magnet

    Takayasu, Makoto

    2015-08-11

    A method for winding a coil magnet with the stacked tape cables, and a coil so wound. The winding process is controlled and various shape coils can be wound by twisting about the longitudinal axis of the cable and bending following the easy bend direction during winding, so that sharp local bending can be obtained by adjusting the twist pitch. Stack-tape cable is twisted while being wound, instead of being twisted in a straight configuration and then wound. In certain embodiments, the straight length should be half of the cable twist-pitch or a multiple of it.

  20. Soil scientific supervision of 220/38 kV cable circuits of the power station 'Eemscentrale' in the Dutch province Groningen: Part 2

    Recently, five underground cable circuits were completed at the site of the EPON (an energy utility for the north-eastern part of the Netherlands) title power station, consisting of two 220 kV and two 380 kV connections with a total length of 24 km. In a previous article, attention is paid to theoretical aspects of heat transfer of cables for underground electricity transport, the research method of the soil scientific survey, and the results of the survey for the design of the cable connection, to be made by NKF (cable manufacturer) and for the final execution of the cable design. In this article attention will be paid to soil scientific marginal conditions and soil scientific supervision during the realization. 1 fig., 2 tabs., 2 refs

  1. Cable tray fire tests

    Funds were authorized by the Nuclear Regulatory Commission to provide data needed for confirmation of the suitability of current design standards and regulatory guides for fire protection and control in water reactor power plants. The activities of this program through August 1978 are summarized. A survey of industry to determine current design practices and a screening test to select two cable constructions which were used in small scale and full scale testing are described. Both small and full scale tests to assess the adequacy of fire retardant coatings and full scale tests on fire shields to determine their effectiveness are outlined

  2. Risk assessment of 170 kV GIS connected to combined cable/OHL network

    Bak, Claus Leth; Kessel, Jakob; Atlason, Vidir;

    2009-01-01

    This paper concerns different investigations of lightning simulation of a combined 170 kV overhead line/cable connected GIS. This is interesting due to the increasing amount of underground cables and GIS in the Danish transmission system. This creates a different system with respect to lightning...... BFO. Overvoltages are evaluated for varying front times of the lightning surge, different soil resistivities at the surge arrester grounding in the overhead line/cable transition point and a varying length of the connection cable between the transformer and the GIS busbar with a SA implemented...... inadmissible voltages to appear at the transformer. However, BFO caused by a lightning stroke of extremely high magnitude can cause inadmissible voltages to appear at the transformer. With the GIS bus CB in open position results indicate that both SF and BFO can cause inadmissible voltages to appear at the...

  3. Lightning simulation of a combined overhead line/cable connected GIS

    Kessel, Jakob; Atlason, Vioir; Bak, Claus Leth;

    2008-01-01

    The paper concerns different investigations of lightning simulation of a combined 170 kV overhead line/cable connected GIS. This is interesting due to the increasing amount of underground cables and GIS in the Danish transmission system. This creates a different system with respect to lightning...... implementing a simulation model in PSCAD/EMTDC. Simulations are conducted for both SF and BFO where the overvoltage at the transformer are evaluated as this component has the lowest insulation strength. The overvoltages are evaluated for different front imes of the lightning surge, different soil resistivities...... at the surge arrester grounding in the overhead line/cable transition and different length of the connection cable between the transformer and the GIS busbar with a SA implemented. Those simulations are conducted for different positions of the circuit breaker present at the GIS busbar. The lightning...

  4. Comparison of Bergeron and Frequency-dependent cable models for the simulation of electromagnetic transients

    Silva, Filipe Miguel Faria da

    2016-01-01

    The simulation of electromagnetic transients involving underground cables is very time consuming, when compared with simulations involving overhead lines, and Bergeron models are often used instead of the more accurate frequency-dependent models, in order to reduce the simulation time. This paper...... analyses the simulation errors of different Bergeron models to a reference frequency-dependent model for a 150kV cable. The simulations consider flat and trefoil installation, both-ends bonding and cross-bonding, ideal voltage source and modelling of the area around the cable. The Bergeron model is...... modelling of the area around the cable being energised, the Bergeron model has a small error if tuned for the right frequency....

  5. Design of Underground Current Detection Nodes Based on ZigBee

    Wei Deyu

    2015-01-01

    Full Text Available At present, most current detection devices of underground power equipment in coal mines of China are equipped with the cable monitoring network. Certain problems such as difficult circuit extension and maintenance exist there. With the help of ZigBee technology, it is able to monitor the underground current of monitoring regions in coal mines safely and effectively. Major advantages include extremely low system cost, safe data transmission, flexible networking and ultra-large network capacity.

  6. Test results of full-scale high temperature superconductors cable models destined for a 36 kV, 2 kA(rms) utility demonstration

    Daumling, M.; Rasmussen, C.N.; Hansen, F.;

    2001-01-01

    Power cable systems using high temperature superconductors (HTS) are nearing technical feasibility. This presentation summarises the advancements and status of a project aimed at demonstrating a 36 kV, 2 kA(rms) AC cable system by installing a 30 m long full-scale functional model in a power util...

  7. Length of a Hanging Cable

    Eric Costello

    2011-01-01

    Full Text Available The shape of a cable hanging under its own weight and uniform horizontal tension between two power poles is a catenary. The catenary is a curve which has an equation defined by a hyperbolic cosine function and a scaling factor. The scaling factor for power cables hanging under their own weight is equal to the horizontal tension on the cable divided by the weight of the cable. Both of these values are unknown for this problem. Newton's method was used to approximate the scaling factor and the arc length function to determine the length of the cable. A script was written using the Python programming language in order to quickly perform several iterations of Newton's method to get a good approximation for the scaling factor.

  8. Electromagnetic Transients in Power Cables

    Silva, Filipe Faria Da; Bak, Claus Leth

    For more than a century, overhead lines have been the most commonly used technology for transmitting electrical energy at all voltage levels, especially on the highest levels. However, in recent years, an increase in both the number and length of HVAC cables in the transmission networks...... concerning HVAC cables. An important topic that is not covered in this book is measurements protocols/ methods. The protocols used when performing measurements on a cable depend on what is to be measured, the available equipment and accessibility. Readers interested in the topic are referred to search...... of the method. The chapter continues by analysing the frequency-spectrums of cable-based networks which have lower resonance frequencies than usual because of the larger capacitance of the cables. At the same time, a technique that may help save time when plotting the frequency spectrum of a network is proposed...

  9. Cable Bacteria in Freshwater Sediments

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus;

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  10. The underground storage

    In this work are given summaries of the addresses presented at the conference on the underground storage of June 2008. The topics described are: 1)sites and legislation of the underground storage in France (Carole Mercier) 2)oil and gas underground storage in salt cavities (Patrick Renoux) 3) geothermal storages (Herve Lesueur) 4)CO2 geological storage in aquifers and exploited oil deposits (Etienne Brosse). (O.M.)

  11. Blasting in underground mining

    Doneva, Nikolinka; Despodov, Zoran; Mirakovski, Dejan; Hadzi-Nikolova, Marija; Mijalkovski, Stojance

    2015-01-01

    The long history of underground facilities gives us a lot of cognitions that we use in the choice of appropriate drilling and blasting parameters to obtain satisfactory results in underground facility constructions. In this paper are represent parts of those cognitions. Selection of an appropriate blast hole pattern, hole cut type, total quantity of explosives, initiation sequence and to the amount of explosive detonated per delay are crucial for successfully blasting in underground facilitie...

  12. Numerical Analysis of Heat Transfer and Fluid Characteristics of Flowing Liquid Nitrogen in HTS Cable

    Maruyama, O.; Ohkuma, T.; Izumi, T.; Shiohara, Y.

    High-temperature superconducting (HTS) cable has heat intrusion from the termination including joule heat generation at the terminal joint and from the room temperature cable through the Cu current lead. According to the length of the HTS cable, this heat loss may become a considerable amount which cannot be ignored in the HTS cable system. In this study, referring to a high-voltage cable (HV cable) which was developed in M-PACC project, the effect of heat transfer at the interface between the terminal joint and LN2 in the terminal vessel (ho) on the temperature of the HTS cable were calculated and evaluated. The condition of flow in the terminal vessel was assumed to be natural convection, forced flow or static condition for evaluating this effect with various heat transfer condition. As a result, in the case of the natural convection, most of heats flow into the LN2 in the terminal vessel where the volumetric flow of the LN2 is large since ho becomes high. Accordingly, the temperature rise of the LN2 in the inner pipe of Cu former and the terminal vessel can be restricted. However, in the cases of the forced flow and the static condition, most of heats flow into the LN2 in the inner pipe where the volumetric flow of the LN2 is small since ho becomes small. Accordingly, the temperature rise of the LN2 in the inner pipe becomes high. This temperature rise of the LN2 in the inner pipe makes the temperature of the HTS conductor large resulting in remarkable increase of AC losses. Consequently, on the HV cable design, for restriction of the AC loss increase, it is expected that designing the HTS cable termination such as extending outer surface of the terminal joint for increasing of the heat inflow from the terminal joint to the LN2 in the vessel is effective.

  13. Status and Progress of a Fault Current Limiting Hts Cable to BE Installed in the con EDISON Grid

    Maguire, J.; Folts, D.; Yuan, J.; Henderson, N.; Lindsay, D.; Knoll, D.; Rey, C.; Duckworth, R.; Gouge, M.; Wolff, Z.; Kurtz, S.

    2010-04-01

    In the last decade, significant advances in the performance of second generation (2G) high temperature superconducting wire have made it suitable for commercially viable applications such as electric power cables and fault current limiters. Currently, the U.S. Department of Homeland Security is co-funding the design, development and demonstration of an inherently fault current limiting HTS cable under the Hydra project with American Superconductor and Consolidated Edison. The cable will be approximately 300 m long and is being designed to carry 96 MVA at a distribution level voltage of 13.8 kV. The underground cable will be installed and energized in New York City. The project is led by American Superconductor teamed with Con Edison, Ultera (Southwire and nkt cables joint venture), and Air Liquide. This paper describes the general goals, design criteria, status and progress of the project. Fault current limiting has already been demonstrated in 3 m prototype cables, and test results on a 25 m three-phase cable will be presented. An overview of the concept of a fault current limiting cable and the system advantages of this unique type of cable will be described.

  14. Parametric study on the axial performance of a fully grouted cable bolt with a new pull-out test

    Chen Jianhang⇑; Hagan Paul C.; Saydam Serkan

    2016-01-01

    Modified cable bolts are commonly used in underground mines due to their superior performance in pre-venting bed separation when compared with plain strands. To better test the axial performance of a wide range of cable bolts, a new laboratory short encapsulation pull test (LSEPT) facility was developed. The facility simulates the interaction between cable bolts and surrounding rock mass, using artificial rock cylinders with a diameter of 300 mm in which the cable bolt is grouted. Furthermore, the joint where the load is applied is left unconstrained to allow shear slippage at the cable/grout or grout/rock interface. Based on this apparatus, a series of pull tests were undertaken using the MW9 modified bulb cable bolt. Various parameters including embedment length, test material strength and borehole size were evalu-ated. It was found that within a limited range of 360 mm, there is a linear relationship between the max-imum bearing capacity of the cable bolt and embedment length. Beyond 360 mm, the peak capacity continues to rise but with a much lower slope. When the MW9 cable bolt was grouted in a weak test material, failure always took place along the grout/rock interface. Interestingly, increasing the borehole diameter from 42 to 52 m in weak test material altered the failure mode from grout/rock interface to cable/grout interface and improved the performance in terms of both peak and residual capacity.

  15. Underground laboratories in Asia

    Deep underground laboratories in Asia have been making huge progress recently because underground sites provide unique opportunities to explore the rare-event phenomena for the study of dark matter searches, neutrino physics and nuclear astrophysics as well as the multi-disciplinary researches based on the low radioactive environments. The status and perspectives of Kamioda underground observatories in Japan, the existing Y2L and the planned CUP in Korea, India-based Neutrino Observatory (INO) in India and China JinPing Underground Laboratory (CJPL) in China will be surveyed

  16. Underground laboratories in Asia

    Lin, Shin Ted, E-mail: linst@mails.phys.sinica.edu.tw [College of Physical Science and Technology, Sichuan University, Chengdu 610064 China (China); Yue, Qian, E-mail: yueq@mail.tsinghua.edu.cn [Key Laboratory of Particle and Radiation Imaging (Ministry of Education) and Department of Engineering Physics, Tsinghua University, Beijing 100084 China (China)

    2015-08-17

    Deep underground laboratories in Asia have been making huge progress recently because underground sites provide unique opportunities to explore the rare-event phenomena for the study of dark matter searches, neutrino physics and nuclear astrophysics as well as the multi-disciplinary researches based on the low radioactive environments. The status and perspectives of Kamioda underground observatories in Japan, the existing Y2L and the planned CUP in Korea, India-based Neutrino Observatory (INO) in India and China JinPing Underground Laboratory (CJPL) in China will be surveyed.

  17. 400 MW grid connection to the Anholt offshore wind farm in a single 220 kV cable system

    Kvarts, Thomas [Energinet.dk (Denmark); Bailleul, March; Douima, Youssef; Petitot, Francois [General Cable Group, Silec, Cachan (France); Domingo, Jose M. [General Cable Group (Spain); Jensen, Anders; Salwin, Sven T. [nkt cables (Denmark)

    2011-07-01

    In 2012, the so far largest wind farm in Denmark, Anholt offshore wind farm, will bring 400 MW more electrical power to Denmark. To that effect, Energinet.dk, Denmark's transmission system operator, will install and operate an 85-km-long grid connection from the Anholt platform to the Danish electricity transmission grid. This connection is composed of: (1) a single 24 km 245 kV submarine, 3 core cable, delivered and installed by nkt cables, and (2) a 60 km 245 kV underground cable system, delivered by the General Cable group. (3) an offshore transformer platform. (4) reactive compensation and transformation onshore. This aim of this paper is to present the characteristics of this project, the first at 245 kV in Denmark, and one of the first 245 kV 3 core submarine cables worldwide. We will first discuss the reasons that prevailed in defining the link's design: routes, voltage, cables dimensioning, impact of capitalized losses etc. Then, the submarine and underground cable systems' characteristics and necessary type test are presented. Finally, we present an overview of the actual implementation of each solution. (orig.)

  18. Roebel cables from REBCO coated conductors: a one-century-old concept for the superconductivity of the future

    Goldacker, Wilfried; Grilli, Francesco; Pardo, Enric; Kario, Anna; Schlachter, Sonja I.; Vojenčiak, Michal

    2014-09-01

    Energy applications employing high-temperature superconductors (HTS), such as motors/generators, transformers, transmission lines and fault current limiters, are usually operated in the alternate current (ac) regime. In order to be efficient, the HTS devices need to have a sufficiently low value of ac loss, in addition to the necessary current-carrying capacity. Most applications are operated with currents beyond the current capacity of single conductors and consequently require cabled conductor solutions with much higher current carrying capacity, from a few kA up to 20-30 kA for large hydro-generators. A century ago, in 1914, Ludwig Roebel invented a low-loss cable design for copper cables, which was successively named after him. The main idea behind Roebel cables is to separate the current in different strands and to provide a full transposition of the strands along the cable direction. Nowadays, these cables are commonly used in the stator of large generators. Based on the same design concept of their conventional material counterparts, HTS Roebel cables from REBCO coated conductors were first manufactured at the Karlsruhe Institute of Technology and have been successively developed in a number of varieties that provide all the required technical features such as fully transposed strands, high transport currents and low ac losses, yet retaining enough flexibility for a specific cable design. In the past few years a large number of scientific papers have been published on the concept, manufacturing and characterization of such cables. Therefore it is timely for a review of those results. The goal is to provide an overview and a succinct and easy-to-consult guide for users, developers, and manufacturers of this kind of HTS cable.

  19. Roebel cables from REBCO coated conductors: a one-century-old concept for the superconductivity of the future

    Energy applications employing high-temperature superconductors (HTS), such as motors/generators, transformers, transmission lines and fault current limiters, are usually operated in the alternate current (ac) regime. In order to be efficient, the HTS devices need to have a sufficiently low value of ac loss, in addition to the necessary current-carrying capacity. Most applications are operated with currents beyond the current capacity of single conductors and consequently require cabled conductor solutions with much higher current carrying capacity, from a few kA up to 20–30 kA for large hydro-generators. A century ago, in 1914, Ludwig Roebel invented a low-loss cable design for copper cables, which was successively named after him. The main idea behind Roebel cables is to separate the current in different strands and to provide a full transposition of the strands along the cable direction. Nowadays, these cables are commonly used in the stator of large generators. Based on the same design concept of their conventional material counterparts, HTS Roebel cables from REBCO coated conductors were first manufactured at the Karlsruhe Institute of Technology and have been successively developed in a number of varieties that provide all the required technical features such as fully transposed strands, high transport currents and low ac losses, yet retaining enough flexibility for a specific cable design. In the past few years a large number of scientific papers have been published on the concept, manufacturing and characterization of such cables. Therefore it is timely for a review of those results. The goal is to provide an overview and a succinct and easy-to-consult guide for users, developers, and manufacturers of this kind of HTS cable. (topical review)

  20. Cable Aerodynamic Control

    Kleissl, Kenneth

    categorization of the different control technics together with an identification of two key mechanisms for reduction of the design drag force. During this project extensive experimental work examining the aerodynamics of the currently used cable surface modifications together with new innovative proposals have...... drag force due to the high intensity of streamwise vorticity, whereas the helical fillets resulted in a more gradual flow transition because of the spanwise variation. During yawed flow conditions, the asymmetrical appearance of the helical solution was found to induce a significant lift force with a...... were tested. While a proper discrete helical arrangement of Cylindrical Vortex Generators resulted in a superior drag performance, only systems applying "mini-strakes" were capable of complete rivulet suppression. When the strakes was positioned in a staggered helical arrangement, the innovative system...

  1. Cable Bacteria in Freshwater Sediments.

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-09-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage. PMID:26116678

  2. Recent development of an HTS power cable using YBCO tapes

    Overcurrent characteristics and reduction of AC loss are essential for high temperature superconducting (HTS) cable in a real grid. AC loss in an HTS conductor using YBCO could be potentially small but protection for overcurrent was needed. A 0.1 mm thick copper tape soldered to the YBCO tape was effective as protection from overcurrent and did not affect the increase in AC loss. The 2 m HTS conductor with Cu strands of 250 mm2 and YBCO tapes with copper was fabricated. This conductor could withstand overcurrent of 31.5 kA for 2 s. To reduce AC loss, 10 mm wide YBCO tapes were divided into five strips using YAG laser. Using narrower strips and decreasing the space between the strips were effective in reducing AC loss. In consideration of this configuration, a three-layer conductor was fabricated, and AC loss of 0.054 W/m at 1 kA rms was achieved even though it had a small outer diameter of 19.6 mm

  3. HAWAII UNDERGROUND STORAGE TANKS

    This is a point coverage of underground storage tanks(UST) for the state of Hawaii. The original database was developed and is maintained by the State of Hawaii, Dept. of Health. The point locations represent facilities where one or more underground storage tanks occur. Each fa...

  4. Investigation of mechanism of breakdown in XLPE cables. Final report

    McKean, A.L.

    1976-07-01

    The basic hypothesis that microporosity plays a significant role in the mechanism of breakdown of XLPE cable is explored. The potential improvement achieved by impregnating the microporous regions of the cable core with a neutral liquid is evaluated, with relation to ac voltage life and impulse strength. The effect at higher frequency is also demonstrated. A similar test program is pursued on model cables, designed to explore the effects of gas pressure and gas type on breakdown and life, since it is reasonable to expect that only the microporous regions of the insulation should be sensitive to the gas-pressure environment. Comparison of gas-pressurized model breakdown stress (and related microvoid size) with basic Paschen curves demonstrates reasonably good agreement, indicating that partial discharge is the basic mechanism of fatigue and breakdown. The form of the voltage life curve above and below the discharge inception level is proposed, and evidence is presented indicating breakdown originates in the bulk insulation as well as at the shield interface. It is also shown that model cable discharge energies are below 0.1 pC, even at very high stress, and cannot be measured with modern detectors. Results with liquid or gas impregnation suggest a possible approach to dielectric improvement.

  5. Magnetization Losses of Roebel Cable Samples with 2G YBCO Coated Conductor Strands

    Yang, Y.; Falorio, I.; Young, E.A.; Kario, A.; Goldacker, W.; Dhallé, M. M. J.; van Nugteren, J.; Kirby, G.; Bottura, L.; Ballarino, A.; 10.1109/TASC.2016.2525926

    2016-01-01

    Roebel cable with 2G YBCO strands is one of the promising HTS solutions of fully transposed high current conductors for high field accelerator magnets. Following the considerable research effort on the manufacturing of Roebel cables in recent years, sample conductors are now available in useful lengths with reproducible performances to allow detailed characterizations beyond the standard critical current measurements. The ac loss and strands coupling are of significant interest for the field quality of the accelerator magnets. We report a set of systematic ac loss measurements on two different Roebel cable samples prepared for the EuCARD2 collaboration. The measurements were performed over a wide range of temperature between 5 K and 90 K and the results were analyzed in the context of strands architecture and coupling. The results show that the transposed bundles are partially decoupled and the strands in transposition sections behave as an isolated single tape if the strands are insulated.

  6. A full 3D time-dependent electromagnetic model for Roebel cables

    Rodriguez Zermeno, Victor Manuel; Grilli, Francesco; Sirois, Frederic

    2013-01-01

    High temperature superconductor Roebel cables are well known for their large current capacity and low AC losses. For this reason they have become attractive candidates for many power applications. The continuous transposition of their strands reduces the coupling losses while ensuring better curr...

  7. Analysis of AC loss in superconducting power devices calculated from short sample data

    Rabbers, J.J.; Haken, ten B.; Kate, ten H.H.J.

    2003-01-01

    A method to calculate the AC loss of superconducting power devices from the measured AC loss of a short sample is developed. In coils and cables the magnetic field varies spatially. The position dependent field vector is calculated assuming a homogeneous current distribution. From this field profile

  8. 一体式电缆井的使用%Use of Integrated Cable Pit

    蒋彦; 韦玮; 谈东波

    2012-01-01

    通过分析现有室外电缆井施工存在的不足,提出预制一体式电缆井的解决方案。分析一体式电缆井的技术优势、施工方法和注意事项,说明一体式电缆井的可实施性和推广价值。%Ac cording to the analysis on the disadvantages of construction of existing outdoor cable pits, a solution for prefabricated integrated cable pits is proposed. The technical advantages, construction methods and precautions of integrated cable pits are analyzed, and the practicality and promotion value of integrated cable pits is explained

  9. An Annotated Bibliography of High-Voltage Direct-Current Transmission and Flexible AC Transmission (FACTS) Devices, 1991-1993.

    Litzenberger, Wayne; Lava, Val

    1994-08-01

    References are contained for HVDC systems, converter stations and components, overhead transmission lines, cable transmission, system design and operations, simulation of high voltage direct current systems, high-voltage direct current installations, and flexible AC transmission system (FACTS).

  10. On the cable expansion formula

    Liu, Qihou

    2008-01-01

    In this paper, a generalized version of Morton's formula is proved. Using this formula, one can write down the colored Jones polynomials of cabling of an knot in terms of the colored Jones polynomials of the original knot.

  11. Static and Dynamic Characteristics of a Long-Span Cable-Stayed Bridge with CFRP Cables

    Xu Xie

    2014-06-01

    Full Text Available In this study, the scope of CFRP cables in cable-stayed bridges is studied by establishing a numerical model of a 1400-m span of the same. The mechanical properties and characteristics of CFRP stay cables and of a cable-stayed bridge with CFRP cables are here subjected to comprehensive analysis. The anomalies in the damping properties of free vibration, nonlinear parametric vibration and wind fluctuating vibration between steel cables and CFRP cables are determined. The structural stiffness, wind resistance and traffic vibration of the cable-stayed bridge with CFRP cables are also analyzed. It was found that the static performances of a cable-stayed bridge with CFRP cables and steel cables are basically the same. The natural frequencies of CFRP cables do not coincide with the major natural frequencies of the cable-stayed bridge, so the likelihood of CFRP cable-bridge coupling vibration is minuscule. For CFRP cables, the response amplitudes of both parametric vibration and wind fluctuating vibration are smaller than those of steel cables. It can be concluded from the research that the use of CFRP cables does not change the dynamic characteristics of the vehicle-bridge coupling vibration. Therefore, they can be used in long-span cable-stayed bridges with an excellent mechanical performance.

  12. Alternating current losses of a 10 metre long low loss superconducting cable conductor determined from phase sensitive measurements

    Olsen, Søren Krüger; Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten;

    1999-01-01

    The ac loss of a superconducting cable conductor carrying an ac current is small. Therefore the ratio between the inductive (out-of-phase) and the resistive (in-phase) voltages over the conductor is correspondingly high. In vectorial representations this results in phase angles between the current...... and the voltage over the cable close to 90 degrees. This has the effect that the loss cannot be derived directly using most commercial lock-in amplifiers due to their limited absolute accuracy. However, by using two lock-in amplifiers and an appropriate correction scheme the high relative accuracy of...... such lock-in amplifiers can be exploited. In this paper we present the results from ac-loss measurements on a low loss 10 metre long high temperature superconducting cable conductor using such a correction scheme. Measurements were carried out with and without a compensation circuit that could reduce...

  13. Parametric Vibration and Vibration Reduction of Cables in Cable-stayed Space Latticed Structure

    BAO Yan; ZHOU Dai; LIU Jie

    2008-01-01

    Mechanical model and vibration equation of a cable in cable-stayed sparse latticed structure (CSLS) under external axial excitation were founded. Determination of the mass lumps and natural frequencies supplied by the space latticed structure (SLS) was analyzed. Multiple scales method (MSM) was introduced to analyze the characteristics of cable's parametric vibration, and the precise time-integration method (PTIM) was used to solve vibration equation. The vibration behavior of a cable is closely relative to the frequency ratio of the cable and SLS. The cable's parametric vibration caused by the external axial excitation easily occurs if the frequency ratio of the cable and SLS is in a certain range, and the cable's vibration amplitude varies greatly even if the initial disturbance supplied by SLS changes a little. Furthermore, the mechanical model and vibration equation of the composite cable system consisting of main cables and assistant cables were studied. The parametric analysis such as the pre-tension level and arrangement of the assistant cables was carried out. Due to the assistant cables, the single-cable vibration mode can be transferred to the global vibration mode, and the stiffness and damping of the cable system are enhanced. The natural frequencies of the composite cable system with the curve line arrangement of assistant cables are higher than those with the straight-line arrangement and the former is more effective than the latter on the cable's vibration suppression.

  14. The underground macroeconomics

    Marin Dinu

    2013-01-01

    Full Text Available Like Physics, which cannot yet explain 96% of the substance in the Universe, so is Economics, unprepared to understand and to offer a rational explicative model to the underground economy.

  15. Orpheus in the Underground

    Puskás Dániel

    2015-12-01

    Full Text Available In my study I deal with descents to the underworld and hell in literature in the 20th century and in contemporary literature. I will focus on modem literary reinterpretations of the myth of Orpheus, starting with Rilke’s Orpheus. Eurydice. Hermes. In Seamus Heaney’s The Underground. in the Hungarian Istvan Baka’s Descending to the Underground of Moscow and in Czesław Miłosz’s Orpheus and Eurydice underworld appears as underground, similarly to the contemporary Hungarian János Térey’s play entitled Jeramiah. where underground will also be a metaphorical underworld which is populated with the ghosts of the famous deceased people of Debrecen, and finally, in Péter Kárpáti’s Everywoman the grave of the final scene of the medieval Everyman will be replaced with a contemporary underground station. I analyse how an underground station could be parallel with the underworld and I deal with the role of musicality and sounds in the literary works based on the myth of Orpheus.

  16. Flat conductor cable design, manufacture, and installation

    Angele, W.; Hankins, J. D.

    1973-01-01

    Pertinent information for hardware selection, design, manufacture, and quality control necessary for flat conductor cable interconnecting harness application is presented. Comparisons are made between round wire cable and flat conductor cable. The flat conductor cable interconnecting harness systems show major cost, weight, and space savings, plus increased system performance and reliability. The design application section includes electrical characteristics, harness design and development, and a full treatise on EMC considerations. Manufacturing and quality control sections pertain primarily to the developed conductor-contact connector system and special flat conductor cable to round wire cable transitions.

  17. Optical Measurement of Cable and String Vibration

    Y. Achkire

    1998-01-01

    Full Text Available This paper describes a non contacting measurement technique for the transverse vibration of small cables and strings using an analog position sensing detector. On the one hand, the sensor is used to monitor the cable vibrations of a small scale mock-up of a cable structure in order to validate the nonlinear cable dynamics model. On the other hand, the optical sensor is used to evaluate the performance of an active tendon control algorithm with guaranteed stability properties. It is demonstrated experimentally, that a force feedback control law based on a collocated force sensor measuring the tension in the cable is feasible and provides active damping in the cable.

  18. Numerical estimation of AC loss in superconductors with ripple current

    Highlights: •The loss energy density with ripple current is numerically calculated. •Irie–Yamafuji model is used for magnetic field dependence of critical current. •Calculated result of cylindrical superconductor agrees with theoretical result. •AC loss of strip superconductor becomes large at small ripple current amplitude. •Strip superconductor should be used as a form of hollow cylinder to reduce AC loss. -- Abstract: The loss energy density (AC loss) with ripple current is numerically calculated by finite element method for cylindrical and strip superconductors based on Irie–Yamafuji model in which the magnetic field dependence of the critical current density is taken into account for design of DC transmission cable system. It is confirmed that calculated result of the AC loss in the cylindrical superconductor with the ripple current agrees well with theoretical estimation which was reported in the previous work. On the contrary, the AC loss in the strip superconductor with the ripple current is obtained only by numerical calculation. It is found that the AC loss in the strip superconductor of the ripple current becomes larger than that without DC current at small ripple current amplitude, since the penetration depth of magnetic field becomes large. Therefore, it is recommended that strip superconductor is better to use as cylindrical hollow superconductor for DC transmission cable system to reduce the AC loss

  19. The data quality monitoring system of non-cable self-positioning seismographs

    Zheng, F.; Lin, J.; Linhang, Z.; Hongyuan, Y.; Zubin, C.; Huaizhu, Z.; Sun, F.

    2013-12-01

    Seismic exploration is the most effective and promising geophysical exploration methods, it inverts underground geological structure by recording crust vibration caused by nature or artificial means. In order to get rid of the long-term dependence on imported seismographs, China pays more and more attention to the independent research and development of seismic exploration equipment. This study is based on the self-invented non-cable self-positioning seismographs of Jilin University. Non-cable seismographs have many advantages such as simple arrangement, light, easy to move, easy to maintain, low price, large storage space and high-quality data, they especially apply to complex terrain and field construction environment inconvenient laying big lines. The built-in integration of GPS realizes precise clock synchronization, fast and accurate self-positioning for non-cable seismographs. The low power design and the combination of built-in rechargeable battery and external power can effectively improve non-cable seismographs` working time, which ensures the stability of exploration and construction. In order to solve the problem that the non-cable seismographs are difficult to on-site data monitor and also to provide non-cable seismographs` ability of real-time data transmission, We integrate the wireless communication technology into non-cable seismographs, combing instrument, electronic, communication, computer and many other subject knowledge, design and develop seismic exploration field work control system and seismic data management system. Achieve two research objectives which are real-time data quality monitoring in the resource exploration field and status monitoring of large trace spacing long-term observations for seismographs. Through several field experiments in different regions, we accumulate a wealth of experience, and the experiments effectively prove the good practical performance of non-cable self-positioning seismographs and data quality monitoring

  20. Online Cable Tester and Rerouter

    Lewis, Mark; Medelius, Pedro

    2012-01-01

    Hardware and algorithms have been developed to transfer electrical power and data connectivity safely, efficiently, and automatically from an identified damaged/defective wire in a cable to an alternate wire path. The combination of online cable testing capabilities, along with intelligent signal rerouting algorithms, allows the user to overcome the inherent difficulty of maintaining system integrity and configuration control, while autonomously rerouting signals and functions without introducing new failure modes. The incorporation of this capability will increase the reliability of systems by ensuring system availability during operations.

  1. Equalization of data transmission cable

    Zobrist, G. W.

    1975-01-01

    The paper describes an equalization approach utilizing a simple RLC network which can obtain a maximum slope of -12dB/octave for reshaping the frequency characteristics of a data transmission cable, so that data may be generated and detected at the receiver. An experimental procedure for determining equalizer design specifications using distortion analysis is presented. It was found that for lengths of 16 PEV-L cable of up to 5 miles and data transmission rates of up to 1 Mbs, the equalization scheme proposed here is sufficient for generation of the data with acceptable error rates.

  2. Development of the communication cable suspending robot. Automation of cable suspending works; Tsushin cable tsurika robot no kaihatsu. Cable tsurika sagyo no jidoka

    Maeda, T. [Kansai Electaric Power Co. Inc., Osaka (Japan)

    2000-04-01

    The automatic communication cable suspending robot was developed. For disuse of dangerous stringers and improvement of suspending workability, adoption of the new mechanical high-speed labor-saving cable laying method was decided regardless of current communication cable laying methods. This robot can deal with automatic removal works of existing cable hangers which has been thought to be extremely difficult, and thus integration works of many cables by a cable hanger in cable additional installation work. For easy handling of the robot, the robot body is composed of 6 separated parts such as driving part, power source part, cable draw-in part, hanger attaching part, hanger removing part and hanger recovering part according to each function. For avoiding troubles with telephone lines and CATV lines in city areas, the size and mass of the robot were considered enough. After this, some verification tests on the robot effectiveness including performance test, workability test on dummy poles, and field test are scheduled. (NEDO)

  3. North American Submarine Cable Association (NASCA) Submarine Cables

    National Oceanic and Atmospheric Administration, Department of Commerce — These data show the locations of in-service and out-of-service submarine cables that are owned by members of NASCA and located in U.S. territorial waters. More...

  4. 47 CFR 76.640 - Support for unidirectional digital cable products on digital cable systems.

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Support for unidirectional digital cable products on digital cable systems. 76.640 Section 76.640 Telecommunication FEDERAL COMMUNICATIONS... Standards § 76.640 Support for unidirectional digital cable products on digital cable systems. (a)...

  5. Improvements in electric cable gland seals

    An electric cable gland seal has a deformable sealing member which is penetrated by cables arranged in annular spaced array, the sealing member being disposed between two spreader plates which when urged together by springs compress and deform the sealing member into sealing contact with the cables, a distributor which holds the cables in the spaced array, and a cylindrical body adapted for sealing about an opening in the wall of a vessel. (UK)

  6. Cable Insulation Breakdowns in the Modulator with a Switch Mode High Voltage Power Supply

    Cours, A

    2004-01-01

    The Advanced Photon Source modulators are PFN-type pulsers with 40 kV switch mode charging power supplies (PSs). The PS and the PFN are connected to each other by 18 feet of high-voltage (HV) cable. Another HV cable connects two separate parts of the PFN. The cables are standard 75 kV x-ray cables. All four cable connectors were designed by the PS manufacturer. Both cables were operating at the same voltage level (about 35 kV). The PS’s output connector has never failed during five years of operation. One of the other three connectors failed approximately five times more often than the others. In order to resolve the failure problem, a transient analysis was performed for all connectors. It was found that transient voltage in the connector that failed most often was subjected to more high-frequency, high-amplitude AC components than the other three connectors. It was thought that these components caused partial discharge in the connector insulation and led to the insulation breakdown. Modification o...

  7. The Application of Novel Polypropylene to the Insulation of Electric Power Cable (2)

    Miyashita, Yoshitsugu; Demura, Tsuyoshi; Ueda, Asakiyo; Someya, Akira; Kawahigashi, Masaki; Murakami, Tsuyoshi; Matsuda, Yoshiji; Kurahashi, Kiyoshi; Yoshino, Katsumi

    The authors had investigated the basic properties of newly developed stereoregular syndiotactic polypropylene (s-PP) which had been synthesized with homogeneous metallocene catalyst, in the previous paper. As the result of this, it was revealed that s-PP had superior thermal and electrical properties to cross-linked polyethylene (XLPE) which was adopted as conventional insulating material for high voltage power cable. In this paper, we estimated the possibility to apply s-PP to the actual power cable from the viewpoint of long-term thermal durability and processability. Consequently, it was found that the thermal stability of s-PP could be significantly improved by adding both hindered phenol and sulfur antioxidants, and wide molecular weight distribution of s-PP contributed to good processability during extrusion. On the basis of these results, 600V and 22kV class cables with insulation of s-PP were manufactured. Successfully manufactured cables proposed that s-PP could be available to electric power cable. Lightning Impulse and AC breakdown strength of both cables at the temperature range of RT to 120°C will be discussed.

  8. EMP coupling to multiconductor shielded cables

    A method is presented for calculating EMP coupling to multiconductor shielded cables by electromagnetic pulse. The induced voltage of inner conductor of the SYV-50-7 cable and SYVZ-9 cable placed on the ground are computed. The computed results agree with those measured

  9. Using Cable Television for Library Data Transmission.

    Whitaker, Douglas A.

    1985-01-01

    Discusses information gained from a test of cable data circuits on a Geac bibliographic control system at the Wayne Oakland Library Federation (WOLF) (Michigan). Highlights include an introduction to cable, hardware profile, the WOLF experience, and key questions that will affect the future use of cable for data transmission. (EJS)

  10. Your Personal Genie in the Cable.

    Schlafly, Hubert J.

    The technology necessary for the use of cable television (TV) has been invented; it simply must be put to use. By the 1970's, cable TV should be commonplace in this country. Its rapid growth was caused in part by its appearance at a time of explosive expansion of related technologies like data theory and computer design. The coaxial cable system…

  11. Underground physics with DUNE

    Kudryavtsev, Vitaly A.; DUNE Collaboration

    2016-05-01

    The Deep Underground Neutrino Experiment (DUNE) is a project to design, construct and operate a next-generation long-baseline neutrino detector with a liquid argon (LAr) target capable also of searching for proton decay and supernova neutrinos. It is a merger of previous efforts of the LBNE and LBNO collaborations, as well as other interested parties to pursue a broad programme with a staged 40-kt LAr detector at the Sanford Underground Research Facility (SURF) 1300 km from Fermilab. This programme includes studies of neutrino oscillations with a powerful neutrino beam from Fermilab, as well as proton decay and supernova neutrino burst searches. In this paper we will focus on the underground physics with DUNE.

  12. Underground Physics with DUNE

    Kudryavtsev, Vitaly A. [Sheffield U.

    2016-01-14

    The Deep Underground Neutrino Experiment (DUNE) is a project to design, construct and operate a next-generation long-baseline neutrino detector with a liquid argon (LAr) target capable also of searching for proton decay and supernova neutrinos. It is a merger of previous efforts of the LBNE and LBNO collaborations, as well as other interested parties to pursue a broad programme with a staged 40 kt LAr detector at the Sanford Underground Research Facility (SURF) 1300 km from Fermilab. This programme includes studies of neutrino oscillations with a powerful neutrino beam from Fermilab, as well as proton decay and supernova neutrino burst searches. In this paper we will focus on the underground physics with DUNE.

  13. Underground physics with DUNE

    Kudryavtsev, Vitaly A

    2016-01-01

    The Deep Underground Neutrino Experiment (DUNE) is a project to design, construct and operate a next-generation long-baseline neutrino detector with a liquid argon (LAr) target capable also of searching for proton decay and supernova neutrinos. It is a merger of previous efforts of the LBNE and LBNO collaborations, as well as other interested parties to pursue a broad programme with a staged 40 kt LAr detector at the Sanford Underground Research Facility (SURF) 1300 km from Fermilab. This programme includes studies of neutrino oscillations with a powerful neutrino beam from Fermilab, as well as proton decay and supernova neutrino burst searches. In this paper we will focus on the underground physics with DUNE.

  14. Underground mineral extraction

    Miller, C. G.; Stephens, J. B.

    1980-01-01

    A method was developed for extracting underground minerals such as coal, which avoids the need for sending personnel underground and which enables the mining of steeply pitched seams of the mineral. The method includes the use of a narrow vehicle which moves underground along the mineral seam and which is connected by pipes or hoses to water pumps at the surface of the Earth. The vehicle hydraulically drills pilot holes during its entrances into the seam, and then directs sideward jets at the seam during its withdrawal from each pilot hole to comminute the mineral surrounding the pilot hole and combine it with water into a slurry, so that the slurried mineral can flow to a location where a pump raises the slurry to the surface.

  15. Evaluation of AC losses for HT-7U CICC on plasma disruption

    AC loss is one of the main issues in the design of the CICC used for PF and TF coils of superconducting tokamak. A preliminary calculation of AC loss for the designed HT-7U CICCs used for TF magnets is given. The authors only consider the hysteresis and coupling losses related to transversal and longitudinal kinds. In addition to the strand resistive barriers (Pb-30Sn-2Sb coating for NbTi strands), a stainless steel strip has been used inside these cables to reduce the AC loss in this kind of conductor. The available theory has enabled to emphasize the role played by the stainless steel strip in the reduction of total AC losses in this kind of conductor. It was shown that AC losses of cable were affected by the structure and change rate of magnetic field

  16. ALOHA Cabled Observatory: Early Results

    Howe, B. M.; Lukas, R.; Duennebier, F. K.

    2011-12-01

    The ALOHA Cabled Observatory (ACO) was installed 6 June 2011, extending power, network communications and timing to a seafloor node and instruments at 4726 m water depth 100 km north of Oahu. The system was installed using ROV Jason operated from the R/V Kilo Moana. Station ALOHA is the field site of the Hawaii Ocean Time-series (HOT) program that has investigated temporal dynamics in biology, physics, and chemistry since 1988. HOT conducts near monthly ship-based sampling and makes continuous observations from moored instruments to document and study climate and ecosystem variability over semi-diurnal to decadal time scales. The cabled observatory system will provide the infrastructure for continuous, interactive ocean sampling enabling new measurements as well as a new mode of ocean observing that integrates ship and cabled observations. The ACO is a prototypical example of a deep observatory system that uses a retired first-generation fiber-optic telecommunications cable. Sensors provide live video, sound from local and distant sources, and measure currents, pressure, temperature, and salinity. Preliminary results will be presented and discussed.

  17. Dynamic Underground Stripping Project

    LLNL is collaborating with the UC Berkeley College of Engineering to develop and demonstrate a system of thermal remediation and underground imaging techniques for use in rapid cleanup of localized underground spills. Called ''Dynamic Stripping'' to reflect the rapid and controllable nature of the process, it will combine steam injection, direct electrical heating, and tomographic geophysical imaging in a cleanup of the LLNL gasoline spill. In the first 8 months of the project, a Clean Site engineering test was conducted to prove the field application of the techniques before moving the contaminated site in FY 92

  18. Raman distributed temperature sensing in underground geoexchange system

    Giuseffi, Marie; Ferdinand, Pierre; Vrain, Alexandre; Philippe, Mikael; Lesueur, Hervé

    2010-09-01

    Underground heat exchangers are instrumented by eight multimode optical fiber cables connected to a distributed temperature sensing (DTS) Raman system which provides real time temperature monitoring, versus operational conditions of the installation. A user-friendly Labview® software has been developed, allowing the configuration of the full installation, the signal processing of raw DTS data and storage, as well as the visualization of any temperature profile, on request. Preliminary temperature profiles are very promising. This platform will allow R&D about geothermal exchanges, will provide a full scale bench to characterize new equipments, and will encourage professionals to develop this renewable energy sector.

  19. Advanced method for cable aging evaluation

    The project of 'Assessment of Cable Aging for Nuclear Power Plants' started in FY2002. Until the end of FY2006, approximately 80% of the planned aging data has been acquired by the cable aging evaluation tests. The LOCA tests for nine kinds of cables were also conducted using the simultaneous aging specimens. Based on these results, the outlines of 'Guidelines for environmental qualification test for cables (Draft)' were developed. And a tentative assessment for seven kinds of cables was made using data acquired until present according to the outlines of guidelines. (author)

  20. Aeolic vibration of aerial electricity transmission cables

    Avila, A.; Rodriguez-Vera, Ramon; Rayas, Juan A.; Barrientos, Bernardino

    2005-02-01

    A feasibility study for amplitude and frequency vibration measurement in aerial electricity transmission cable has been made. This study was carried out incorporating a fringe projection method for the experimental part and horizontal taut string model for theoretical one. However, this kind of model ignores some inherent properties such as cable sag and cable inclination. Then, this work reports advances on aeolic vibration considering real cables. Catenary and sag are considered in our theoretical model in such a way that an optical theodolite for measuring has been used. Preliminary measurements of the catenary as well as numerical simulation of a sagged cable vibration are given.

  1. Underground Storage Tanks in Iowa

    Iowa State University GIS Support and Research Facility — Underground storage tank (UST) sites which store petroleum in Iowa. Includes sites which have been reported to DNR, and have active or removed underground storage...

  2. Inflation and the underground economy

    Ahiabu, Stephen

    2006-01-01

    This paper studies the optimal rate of seigniorage in an economy characterized by decentralized trade and a tax-evading underground sector. The economy has buyers, some of whom visit the formal market, while others visit the underground market. I find that the optimal rate of inflation depends on which of the two sectors, formal or underground, is more crowded/congested with buyers. If the underground sector is more crowded, the optimal inflation rate is as high as 42% per a...

  3. Offshore Cable Installation - Lillgrund. Lillgrund Pilot Project

    Unosson, Oscar (Vattenfall Vindkraft AB, Stockholm (Sweden))

    2009-01-15

    This report describes the installation method and the experiences gained during the installation of the submarine cables for the offshore wind farm at Lillgrund. The wind farm consists of 48 wind turbines and is expected to produce 0.33 TWh annually. Different aspects of the installation, such as techniques, co-operation between the installation teams, weather conditions and regulatory and environmental issues are described in this report. In addition, recommendations and guidelines are provided, which hopefully can be utilised in future offshore wind projects. The trenches, in which the submarine cables were laid, were excavated weeks before the cable laying. This installation technique proved to be successful for the laying of the inter array cables. The export cable, however, was laid into position with difficulty. The main reason why the laying of the export cable proved more challenging was due to practical difficulties connected with the barge entrusted with the cable laying, Nautilus Maxi. The barge ran aground a number of times and it had difficulties with the thrusters, which made it impossible to manoeuvre. When laying the inter array cables, the method specification was closely followed, and the laying of the cables was executed successfully. The knowledge and experience gained from the offshore cable installation in Lillgrund is essential when writing technical specifications for new wind plant projects. It is recommended to avoid offshore cable installation work in winter seasons. That will lower the chances of dealing with bad weather and, in turn, will reduce the risks

  4. Electrical testing of generator station cables

    Tests have been performed at a decommissioned nuclear plant to assess the ability of electrical diagnostic tests to determine the remaining life of cable insulation. Power and control cables with either SBR or PVC insulation were tested. These materials are typical of cables in plants built before 1960. Insulation resistance, capacitance, dissipation factor and partial discharge activity were not correlated to the dc breakdown voltage of the cables, which is taken as a measure of insulation condition. Thus it is uncertain if such tests can be used to predict remaining life, especially if historical data has not been collected. All the cables had very high dc breakdown voltages, which was consistent with the generally good physical condition of the cables. Based on this limited study, it seems that hipot tests may be the only convenient electrical method currently available to assure the condition of cables in a generating station undergoing life extension. However more work is needed to determine suitable hipot test voltages

  5. Self-healing cable apparatus and methods

    Huston, Dryver (Inventor); Esser, Brian (Inventor)

    2007-01-01

    Self-healing cable apparatus and methods are disclosed. The cable has a central core surrounded by an adaptive cover that can extend over the entire length of the cable or just one or more portions of the cable. The adaptive cover includes a protective layer having an initial damage resistance, and a reactive layer. When the cable is subjected to a localized damaging force, the reactive layer responds by creating a corresponding localized self-healed region. The self-healed region provides the cable with enhanced damage resistance as compared to the cable's initial damage resistance. Embodiments of the invention utilize conventional epoxies or foaming materials in the reactive layer that are released to form the self-healed region when the damaging force reaches the reactive layer.

  6. Underground Economy in Croatia

    Marija Švec

    2009-12-01

    Full Text Available The subject of this paper is to estimate the size of underground economy in the period 2001-2007 using labour approach. Two types of data are used: administrative and survey. The main questions are: How did the activity rates move? What is the relationship between activity rates and the size of shadow economy? Is there correlation between official employment, official unemployment and unofficial employment (shadow economy and what is it like? What is the position of Croatia considering the members of the European Union? It is presumed that the increase of activity rates causes decrease of underground economy. However, this assumption is valid only for administrative data. Correlation analysis is based on regression models and given results are quite logical. If Croatian and European underground economy is compared, it can be confirmed that the position of Croatia is extremely poor. Given results are approximative and show the level of Croatian underground economy which is presumably underestimated. These phenomena occur because of available statistics and method limitations

  7. Ripple current loss measurement with DC bias condition for high temperature superconducting power cable using calorimetry method

    Kim, D.W.; Kim, J.G.; Kim, A.R. [Changwon National University, 9 sarim-dong, Changwon 641-773 (Korea, Republic of); Park, M., E-mail: paku@changwon.ac.k [Changwon National University, 9 sarim-dong, Changwon 641-773 (Korea, Republic of); Yu, I.K. [Changwon National University, 9 sarim-dong, Changwon 641-773 (Korea, Republic of); Sim, K.D.; Kim, S.H.; Lee, S.J.; Cho, J.W. [Superconducting Device and Cryogenics Group, Korea Electrotechnology Research Institute, Changwon, 641-120 (Korea, Republic of); Won, Y.J. [Korea Electric Power Corporation, 411, youngdong-dearo, Gangnam-gu, Seoul (Korea, Republic of)

    2010-11-01

    The authors calculated the loss of the High Temperature Superconducting (HTS) model cable using Norris ellipse formula, and measured the loss of the model cable experimentally. Two kinds of measuring method are used. One is the electrical method, and the other is the calorimetric method. The electrical method can be used only in AC condition. But the calorimetric method can be used in both AC and DC bias conditions. In order to propose an effective measuring approach for Ripple Dependent Loss (RDL) under DC bias condition using the calorimetric method, Bismuth Strontium Calcium Copper Oxide (BSCCO) wires were used for the HTS model cable, and the SUS tapes were used as a heating tape to make the same pattern of the temperature profiles as in the electrical method without the transport current. The temperature-loss relations were obtained by the electrical method, and then applied to the calorimetric method by which the RDL under DC bias condition was well estimated.

  8. Ripple current loss measurement with DC bias condition for high temperature superconducting power cable using calorimetry method

    The authors calculated the loss of the High Temperature Superconducting (HTS) model cable using Norris ellipse formula, and measured the loss of the model cable experimentally. Two kinds of measuring method are used. One is the electrical method, and the other is the calorimetric method. The electrical method can be used only in AC condition. But the calorimetric method can be used in both AC and DC bias conditions. In order to propose an effective measuring approach for Ripple Dependent Loss (RDL) under DC bias condition using the calorimetric method, Bismuth Strontium Calcium Copper Oxide (BSCCO) wires were used for the HTS model cable, and the SUS tapes were used as a heating tape to make the same pattern of the temperature profiles as in the electrical method without the transport current. The temperature-loss relations were obtained by the electrical method, and then applied to the calorimetric method by which the RDL under DC bias condition was well estimated.

  9. Grounding Effect on Common Mode Interference of Underground Inverter

    CHENG Qiang

    2013-09-01

    Full Text Available For the neutral point not grounded characteristics of underground power supply system in coal mine, this paper studied common mode equivalent circuit of underground PWM inverter, and extracted parasitic parameters of interference propagation path. The author established a common mode and differential mode model of underground inverter. Taking into account the rise time of PWM, the simulation results of conducted interference by Matlab software is compared with measurement spectrum on the AC side and motor side of converter, the difference is consistent showing that the proposed method has some validity. After Comparison of calculation results by Matlab simulation ,it can be concluded that ungrounded neutral of transformer could redue common mode current in PWM system, but not very effective, the most efficient way is to increase grounding  impedance of  inverter and motor.

  10. An Analytical Benchmark for the Calculation of Current Distribution in Superconducting Cables

    Bottura, L; Fabbri, M G

    2002-01-01

    The validation of numerical codes for the calculation of current distribution and AC loss in superconducting cables versus experimental results is essential, but could be affected by approximations in the electromagnetic model or incertitude in the evaluation of the model parameters. A preliminary validation of the codes by means of a comparison with analytical results can therefore be very useful, in order to distinguish among different error sources. We provide here a benchmark analytical solution for current distribution that applies to the case of a cable described using a distributed parameters electrical circuit model. The analytical solution of current distribution is valid for cables made of a generic number of strands, subjected to well defined symmetry and uniformity conditions in the electrical parameters. The closed form solution for the general case is rather complex to implement, and in this paper we give the analytical solutions for different simplified situations. In particular we examine the ...