By Topic

Electrical Insulation, IEEE Transactions on

Issue 4 • Date Aug. 1979

Filter Results

Displaying Results 1 - 13 of 13
  • Table of contents

    Page(s): c1
    Save to Project icon | Request Permissions | PDF file iconPDF (714 KB)  
    Freely Available from IEEE
  • IEEE Electrical Insulation Society

    Page(s): c2
    Save to Project icon | Request Permissions | PDF file iconPDF (178 KB)  
    Freely Available from IEEE
  • Effect of Avalanche Space Charge Field on the Calculation of Corona Onset Voltage

    Page(s): 181 - 192
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1366 KB)  

    Many researchers have suggested that the space charge field of the primary electron avalanche should not be neglected in calculating the corona onset voltage based on the streamer criterion. Some researchers consider only the space charge field of the positive ions created during the avalanche growth, while others consider only the space charge field of the electrons at the head of the avalanche. The authors suggest that both space charge fields should be considered in calculating the corona onset voltage. Computer programs are written to calculate the breakdown voltage (for uniform field: parallel-plane geometry) and corona onset voltage (for non-uniform field: point-to-plane geometry). The space charge fields of both the positive ions and the electrons are considered in the calculations. Results are obtained for air and SF6 for a wide range of geometrical parameters and gas pressures. The results indicate that the effect of space charge fields is to reduce the corona onset voltage (or breakdown voltage in uniform field geometry) by less than 5%. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Deformation and Fracture Behavior of Stator Windings Subjected to Cyclic Bending Loading

    Page(s): 193 - 199
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2987 KB)  

    This paper presents the deformation and fracture behavior of stator windings under cyclic bending loading. In this study, two different kinds of stator windings, which are impregnated with epoxy and polyester resins, are examined. The flexural stiffness and tan¿ characteristics of the stator windings are measured, applying cyclic loading to the stator nd-windings of up to 107 load cycles. Their variations are revealed under various strain amplitudes, and the failure mechanism of the stator windings under cyclic loading is discussed. The breakdown voltage is also measured in the last stage of each test, and the correlation between the reduction rates in the breakdown own voltage and the flexural stiffness is clarified. The failure criterion on the mechanical strength of the stator windings under cyclic loading is proposed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On Tree-Inhibition in Polyethylene

    Page(s): 200 - 206
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1618 KB)  

    During a series of experiments aimed at developing a better understanding of the basic mechanisms of electrical treeing in polymer insulations, the dependence nce of the dc conductivity of polyethyle ( with and without additives) on temperature and field strength was examined. It was discovered that all additives, and especially acetophenone, which is well known to resist electrical treeing, substantially increase the conductivity. Due to the low conductivity of insulators, in the case of ac voltage excitation capacitive voltage division ion generally occurs. This leads to enormous stress concentrations at the sites of impurities, which finally may lead to the start of trees. Computations using the results of the dc conductivity measurements showed that these local stress concentrations ions can be diminished by the field-depen conconductivity of the polymer even for 50 or 60 Hz ac voltage, thus leading to an improved resistance to treeing. The experimental proof of the relevance of this field-grading mechanism is given by the results of treeing experiments with polyethylene containing specific additives. Furthermore, tree-inception voltages of cross linked polyethylene containing various amounts of etoacetophenone show a dependence on temperature and frequency as expected from the mutual capacitive-conductive lvoltage division by the additive. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Representation of Three-Core Cables Using Line-Charge Simulation

    Page(s): 207 - 210
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    A charge simulation technique has been used to represent sheathed three-core belted cables. The cable can be represented by six line charges. A digital computer was used to determine the best position of these line charges which would result in equipotentials conforming with the conductor surfaces. The results indicate that this position depends on the cable geometrical factor as determined by the ratio of insulation thickness conductor diameter. By taking the potential as the criterion, the results give a more satisfactory representation than that reported previously by the authors, in which electrical stresses were used as the criterion. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Short-Term Electrical Insulating Characteristics of Some Polymeric Materials Immersed in Liquid Nitrogen

    Page(s): 211 - 221
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2083 KB)  

    This paper reports the short-term partial-discharge and electrical breakdown characteristics of some film-type and fibrous materials and laminates of fibrous and film-type materials immersed in liquid nitrogen (LN2) Partial discharge inception and extinction voltages, and also the distribution of their magnitude and repetition rate are studied in the various specimens with and without artificial cavities at pressures up to 0.4 MPa. The results emphasize the relative roles played by the gas bubbles inside the cavity and the structure of the material. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Life Expectancy of Liquid - Nitrogen Taped Cable Insulation

    Page(s): 222 - 228
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1041 KB)  

    Tests are described on lapped taped cable models impregnated with liquid nitrogen to investigate discharge activity and insulation life. A number of polymeric materials are discussed with an emphasis on high density polyethylene. For all the polymers a life expectancy-stress relationship of the form tEn = constant is obtained. The exponent n is seen to be strohgly dependent on the pressure of the impregnant. The effect of tape thickness is also discussed. Variation in the rate of rise of the applied voltage for polyethylene tape does not affect the life expectancy, provided the initial high discharges are withstood. The application of the experimental results to cable design is discussed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Full text access may be available. Click article title to sign in or learn about subscription options.
  • Editorial

    Page(s): 231
    Save to Project icon | Request Permissions | PDF file iconPDF (154 KB)  
    Freely Available from IEEE
  • Guidelines for Referees

    Page(s): 232
    Save to Project icon | Request Permissions | PDF file iconPDF (151 KB)  
    Freely Available from IEEE
  • Editorial policies and criteria

    Page(s): 232-a
    Save to Project icon | Request Permissions | PDF file iconPDF (195 KB)  
    Freely Available from IEEE
  • Information for authors

    Page(s): 232b
    Save to Project icon | Request Permissions | PDF file iconPDF (923 KB)  
    Freely Available from IEEE

Aims & Scope

This Transactions ceased production in 1993. The current retitled publication is  IEEE Transactions on Dielectrics and Electrical Insulation.

Full Aims & Scope