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Power Delivery, IEEE Transactions on

Issue 1 • Date Jan. 1987

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Displaying Results 1 - 25 of 40
  • Table of contents

    Publication Year: 1987 , Page(s): c1 - 288b
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    Freely Available from IEEE
  • IEEE Power Engineering Society

    Publication Year: 1987 , Page(s): c2
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    Freely Available from IEEE
  • Development of New Diagnostic Method for Hot-Line XLPE Cables with Water Trees

    Publication Year: 1987 , Page(s): 1 - 7
    Cited by:  Papers (3)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4006 KB)  

    A new insulation diagnostic method for XLPE cables containing water trees is presented. A dc component in the ac charging current of these cables was found to be a significant sign of the existence of water trees. The dc component has good correlations with such insulation characteristics of aged XLPE cables as ac breakdown voltage and dc leakage current. Criteria for insulation diagnosis of 6.6kV XLPE cables have been established. An automatic insulation diagnostic device has been developed. It is now being applied to hot-line XLPF cables in distribution systems of TEPCO (The Tokyo Electric Power Co., Inc.). View full abstract»

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  • Non-Destructive Status Testing of Lead-Sheathed, 5-KV Undergound Cable

    Publication Year: 1987 , Page(s): 8 - 14
    Cited by:  Papers (2)
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    We report the successful conclusion to phase one of a program to solve the problem of determining in unambiguous but non-destructive fashion the on/off status of a lead-sheathed underground distribution cable. An automatic, remote-controlled prototype machine has been developed with self-test and monitoring functions. The machine cuts a small hole through the lead jacket, applies a detector probe to the cable's outer, high-resistivity screen. This screen is capacitively coupled to the inner conductor so the small voltage drop caused by the displacement current to the screen can be used to determine the on-off status of the cable. If the cable tests off, at the operator's direction the machine spikes the cable to provide absolute proof of the off status of the cable. View full abstract»

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  • Generalized Coefficients of External Thermal Resistance for Ampacity Evaluation of Underground Multiple Cable Systems

    Publication Year: 1987 , Page(s): 15 - 20
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1301 KB)  

    The Equivalent External Thermal Resistance (ETR) of power cable installations is the principal quantity which determines cable ampacity. Variations of ETR with respect to various cable designs and surrounding parameters are of major interest to cable engineers, especially when the effect of varying many independent parameters (individually or simultaneously), on the cable ampacity, is to be determined. On the basis of accurate analysis of a variety of cable systems, this paper describes a simple technique to evaluate the effects of cable and ambient parameters variations on the computed cable ampacity. The technique utilizes coefficients of ETR of multiple cable systems and their observed linearized characteristics. The paper describes the technique and illustrates its implementation on several cable system examples. View full abstract»

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  • Computation of Cable Impedances Based on Subdivision of Conductors

    Publication Year: 1987 , Page(s): 21 - 27
    Cited by:  Papers (16)
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    The frequency-dependent resistances and inductances of cables can either be found from analyt ical formulas, or with numerical methods based on finite elements or subdivision of conductors. While analytical formulas are limited to coaxial configurations, numerical methods can be used for non-concentric configurations as well. This paper discusses the method of subdivision into subconductors of circular, square or elemental shape, and compares the results for the case of a coaxial cable, where exact solutions are available from analytical formulas. The inclusion of ground return impedances is discussed next. The method is then applied to the calculation of impedances of pipe-type cables with magnetic pipe material, and of internal impedances of stranded conductors in the power line carrier frequency range. View full abstract»

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  • Signal Propagation on Single Phase Power Distribution Lines at Power Line Carrier Frequencies

    Publication Year: 1987 , Page(s): 28 - 35
    Cited by:  Papers (12)
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    Two sets of propagation measurements were made on a 20,847 foot unenergized power distribution line in the frequency range 0 to 50 kHz. The line was configured with and without distribution transformers. From the first set of measurements a voltage transfer function was calculated for this line. In the second set of measurements the line was energized with a 25 kHz signal and the voltage, current and impedance were measured along the line. Various propagation characteristics such as attenuation, characteristic impedance, velocity of propagation, and standing wave ratios were determined from these measurements. View full abstract»

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  • The Effect of Distribution Transformers on Distribution Line Carrier Signals

    Publication Year: 1987 , Page(s): 36 - 40
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (889 KB)  

    A study is made of the primary impedance of single phase power distribution transformers at frequencies of 2-50 kHz. This band includes the frequencies used for distribution line communications. A range of primary impedance values is found as the secondary impedance varies between 1 and 100% of full load. Then the effect of these transformers on the attenuation, phase constant and characteristic impedance of a power distribution line is computed. Calculations are compared with measurements reported elsewhere. View full abstract»

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  • A Cost Effective PI Network Filter for Elimination of Stiff Transmission Crosstalk in Zero Sequence Propogated Distribution Power Line Carrier Signals

    Publication Year: 1987 , Page(s): 41 - 49
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1419 KB)  

    A cost effective method for elimination of intersubstation crosstalk problem in distribution power line carrier communications systems is presented. A shunt three-phase wye-configured capacitor bank is connected between a substation transformer and any source of zero-sequence power line carrier commu nication signals being transmitted on the substation distribution network to partially alleviate unbalance conditions in the communication signals. When balan ced, these signals are not passed by a three-phase delta-wye grounded substation transformer to the main transmission line. The signal is further attenuated by connecting the common wye-point of the capacitor bank through an inductance to neutral. This forms a shunt element of either an L or pi attentuation circuit with the series inductance of the substation transformer and the transmission line inductance. The transformer series inductance and the transmission line form the serial elements of the L or pi circuit. A further shunt element at another substation distribution network completes the attenuation circuit for the pi configuration. The method was verified in an actual field application. The cost of this method is shown to be only one-fifth that of the conventional approach. View full abstract»

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  • Digital Signal Transmission on Power Line Carrier Channels: An Introduction

    Publication Year: 1987 , Page(s): 50 - 56
    Cited by:  Papers (4)  |  Patents (36)
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    The possibility of transmitting digital signals on power line carrier channels is investigated. An accurate model of the multiconductor transmission line and a rigorous propagation algorithm are used. A computer aided procedure is presented to evaluate channel transient response to any input digital signal code. The discrete convolution method uses the inverse Fourier transform of the channel frequency response in amplitude and phase. The eye diagram approach permits evaluation of channel perfomance. The results obtained in an application on a three-phase long line, confirm the feasibility of the proposed method. View full abstract»

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  • Application of Approximated Modal Analysis Methods for PLC System Design

    Publication Year: 1987 , Page(s): 57 - 63
    Cited by:  Papers (2)
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    In this paper recent developments rela ted to the analysis of electromagnetic waves propagation by means of modal analysis in H. V. transmission lines are presented. The developments showed here are concerned with the computation of the earth-return path impedance, pro posed earlier by Dubanton {1}, as well as the inclusion of the earth-wires in the impedance matrix. Three phase lines in horizontal and delta configuration (i.e. with centre-phase symmetry) are commonly used in H. V. and E. H. V. transmission. These lines are prone to modal cancellation phenomena. Formulae have been developed by Wedepohl for the calculation of their propagation constants and modal quantities. These formulae greatly simplify the computation of EM waves propagation. The graphical method proposed by Senn and Morf {2} and its application to assess coupling alternatives are discussed. This method is also used by the authors to evaluate non-conventional coupling arrangements. View full abstract»

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  • Earth Resistivity Measurements Using Cylindrical Electrodes at Short Spacings

    Publication Year: 1987 , Page(s): 64 - 71
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1933 KB)  

    The accuracy of power system grounding analysis is critically dependent on the resistivity of the local soil surrounding the grounding system. This paper develops and discusses a new closed-form formula based on field theory relating soil resistivity to measured resistance which relaxes the requirement that rod electrodes have a large spacing compared to their buried length. The paper also demonstrates that the interpretation of practical resistivity measurements based on the new equation is significantly more accurate than the one based on the classical equation. View full abstract»

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  • Errors in Digital Measurement of Voltage, Active and Reactive Powers and an on-Line Correction for Frequency Drift

    Publication Year: 1987 , Page(s): 72 - 76
    Cited by:  Papers (4)
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    In this paper, errors in digitally measured power system variables under non-ideal conditions namely, off-nominal frequency, finite word length sampling and harmonics are obtained by simulation. A new and efficient correction term for errors due to frequency drift is derived theoretically and its effectiveness is also illustrated. All the simulations are performed on a personal computer using LOTUS 123 spreadsheet (Copyright Lotus Development Corporation) with 16 bit integer arithmetic and 12 bit integers as input from the analog to digital conversion. View full abstract»

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  • Decontamination of IREQ's High Voltage Laboratory Following a PCB Fire

    Publication Year: 1987 , Page(s): 77 - 86
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    A fire in a capacitor bank in IREQ's High Voltage Laboratory resulted in structural damage and widespread PCB and furan contamination throughout the building. A description is presented of the organization which was set up to handle the decontamination and repair work. Details are also included regarding the medical considerations, acceptance criteria, site facilities, protective measures and decontamination techniques. The decontamination schedule was arranged so that the various parts of the laboratory were returned to normal operation in the shortest possible time without having to wait for the decontamination of the complete building. The office section of the laboratory was reoccupied after 3 months, the large hall after 6 months anid the annex after 11 months. Simultaneously with the decontamination operation, an outdoor area was constructed for the testing of power transformers. This area went into operation approximately 3¿ months after the fire and it continued to function for 7 months until testing was resumed in the annex. View full abstract»

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  • Development of Fiber-Optic Voltage Sensors and Magnetic-Field Sensors

    Publication Year: 1987 , Page(s): 87 - 93
    Cited by:  Papers (19)  |  Patents (8)
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    The principle, temperature characteristics, and frequency characteristics of fiber-optic voltage sensors and magnetic field sensors are reported, along with the results of an aging test on these sensors. The fiber-optic voltage sensor utilizes the "Pockels" effect of Bi12SiO20 single crystal and the fiber-optic magnetic-field sensor utilizes the "Faraday" effect of ZnSe polycrystal and Bi12SiO20 single crystal. The basic performance of these sensors has been investigated from the perspective of their use as parts in electrical apparatuses. In addition, in this paper some practical applications in electrical substations and transmission lines are presented. These include a fault section detecting system for gas insulated transmission line (GIL), an optical voltage transformer and optical current transformer which are embedded in gas insulated switchgear (GIS), and a surge voltage receiving system. View full abstract»

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  • Digital Wattmeters for Loss Measurements of Power Transformers

    Publication Year: 1987 , Page(s): 94 - 100
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1969 KB)  

    This paper gives particular attention to the theoretical and practical difficulties that arise in the measurement of power losses in very large transformers or inductors. The most serious of these problems is the measurement of very low power factor loads, values down to 0.01 or 1% may be encountered. Major difficulties in making these measurements include problems associated with non-ideal power sources, problems introduced by the necessity - in some cases - of making measurements on highly distorted waveforms, and problems associated with making measurements in a restricted amount of time. While a measurement involves a complete system, the emphasis in this paper is upon the power measurement circuitry itself. An attempt is made to point out the theoretical limitations of various approaches and to separate these from the practical limitations of certain types of circuits. The major emphasis is upon digital methods of measuring power. The final section of the paper provides a comparison between some of the available types of digital wattmeters. It is hoped that this paper will provide help in selecting and in understanding the use of instruments to be used in the measurement of transformer losses. View full abstract»

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  • Metallic Particle Motion in 3-Phase SF6 Gas Insulated Bus

    Publication Year: 1987 , Page(s): 101 - 106
    Cited by:  Papers (2)
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    To investigate the behavior of metallic particles in 3-phase gas insulated buses (3-phase GIB), we conducted a test by using a 3-phase 275kV, ac, 60Hz full-scale model. The test results revealed that in a 3-phase electric field, unlike in a single-phase field, metallic particles were trapped on and around the high-voltage conductors and revolved circumferentially. Computer analysis shows that it was closely related to locational and periodic changes in the electric field provided by the 3-phase GIB, and that there were points on the high-voltage conductors in which metallic particles were readily trapped. It also was proved that phenomena peculiar to the 3-phase GIB could be reproduced very well by computer simulation. View full abstract»

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  • Surge Limiters for Vacuum Circuit Breaker Switchgear

    Publication Year: 1987 , Page(s): 107 - 116
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2070 KB)  

    The use of vacuum circult breakers In motor feeder applications (where motor terminal surge protection is not normally used) may require overvoltage surge protection within the switchgear to properly protect the motors. This need can be fulfilled by surge limiters designed for installation within the switchgear connected to the load side of the vacuum circuit breaker. This paper reviews the basic phenomena which cause vacuum switchgear related surges and dtscusses the need for surge limiters. This paper also describes the design of these surge limiters and provides information and performance data for their application. View full abstract»

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  • Performances of M. V. Circuit-Breakers Using Different Quenching Media, with Reference to Industrial Plant Situation

    Publication Year: 1987 , Page(s): 117 - 125
    Cited by:  Papers (2)
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    The behaviour of four medium voltage circuit-breakers using different breaking techniques has been compared under actual service conditions with reference to industrial plants. Test conditions not fully covered by the International Standard were chosen. Description of the laboratory circuits and the test methodology have been reported. View full abstract»

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  • Creepage Flashover Characteristics of Oil/Pressboard Interfaces and Their Scale Effects

    Publication Year: 1987 , Page(s): 126 - 132
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    Creepage flashover characteristics in transformer oil under positive impulse voltage were studied by using models of which the electric field distribution was equivalent to that of actual transformeis. In the experiments, some geometrical parameters concerning creepage flashover and the model scale were varied. It is concluded that the flashover voltage characteristics are determined by electric field strength of the high-voltage electrode surface and stressed oil volume. The scale effect of the creepage flashover was found to be the power of 0.7 of the model scale. View full abstract»

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  • Calculation of Series Capacitance Eor Transient Analysis of Windings

    Publication Year: 1987 , Page(s): 133 - 139
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1113 KB)  

    Knowledge of the series capacitance of a winding (transformer, reactor or magnet) is essential in order to analyze its transient behavior. A method of computing the series capacitance of a winding is proposed which is mathematically rigorous but simple to execute. As a check, the equivalent series capacitance of a four-turn double-disk winding was computed by the proposed method as well as by simple circuit reduction. This method of calculating the series capacitance was applied to determine the natural frequencies of large magnets. View full abstract»

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  • Distribution Transformer Winding Losses Due to Nonsinusoidal Currents

    Publication Year: 1987 , Page(s): 140 - 146
    Cited by:  Papers (19)
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    Increased transformer winding losses are an important consideration in determining the overall impact of harmonic currents in a power system. Frequently, losses due to harmonic currents are assumed to vary with the square of frequency. The purpose of this paper is to compare winding loss calculations from a finite element method with measured losses in single phase distribution transformers and to test the principle of superposition of harmonic losses due to nonsinusoidal currents. The results confirm both the finite element method and the principle of superposition. Furthermore, it is shown that, due primarily to inaccuracy in measuring 60 Hz eddy current losses, application of the commonly accepted frequency squared rule can yield overly pessimistic loss predictions for typical power system harmonic frequencies. View full abstract»

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  • Normal State Optimal Load Allocation in Distribution Systems

    Publication Year: 1987 , Page(s): 147 - 155
    Cited by:  Papers (34)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1226 KB)  

    This paper addresses a subproblem related to distribution automation. It outlines an algorithm and presents computer results for minimizing the losses in a loop distribution system based on the remote operation of sectionalizing switches on feeders interconnecting different substations. The minimization is carried out subject to the voltage-drop, line-capacity and substation-capacity constraints. Computational experience with a system of realistic size indicates that the procedure proposed here is valid and effective in practical operations. View full abstract»

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  • DC System Resonance Analysis

    Publication Year: 1987 , Page(s): 156 - 164
    Cited by:  Papers (4)
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    DC filters and dc smoothing reactors are primarily designed to meet performance requirements with regard to telephone interference levels and commutation failure frequency. Other factors, however, place constraints on the size of the dc filter capacitance and the smoothing reactor inductance. The principal constraint is the avoidance of resonance conditions on the dc side at a low order harmonic of the commutating voltage. This paper discusses the factors which must be considered when analyzing dc side resonance. Specific considerations for the Intermountain Power Project are given. View full abstract»

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  • Optimum Shunt Capacitor for Power Factor Correction at Busses with Lightly Distorted Voltage

    Publication Year: 1987 , Page(s): 165 - 173
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1050 KB)  

    The goal of this paper is to determine the effect of time variation of system impedances and voltage harmonics on the value of optimum capacitor for power factor correction at busses with nonsinusoidal voltage. Two types of 24 hours time-variation of voltage harmonices and Thevenin impedance are assumed. The equivalent load impedance is also considered time variable and assumed to contain a large proportion of induction motors. The daily energy losses are computed and graphed in function of the shunt capacitance used for power factor correction. The results of this study indicate that in order to avoid resonances and to find the optimum capacitor the time variation of harmonics and system impedances must be known as precise as possible. View full abstract»

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Aims & Scope

Installation and operation of apparatus, equipment, structures, materials and systems for the safe, reliable and economic generation, transmission, distribution, conversion, measurement and control of electric energy.

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Meet Our Editors

Editor-in-Chief
Wilsun Xu
Ph.D., P.Eng.
Dept. Electrical and Computer Eng.
University of Alberta
(9107 - 116 Street)
Edmonton, Alberta T6G 2V4 Canada
wxu@ualberta.ca
Phone:780-492-5965
Fax:780-492-1811