Proceedings., Second International Conference on Properties and Applications of Dielectric Materials

12-16 Sept. 1988

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  • Proceedings. Second International Conference on Properties and Applications of Dielectric Materials (Cat. No.88CH2587-4)

    Publication Year: 1988
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    Freely Available from IEEE
  • Long time range breakdown in polymeric insulating films subjected to step voltage

    Publication Year: 1988, Page(s):355 - 358 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (343 KB)

    The breakdown time lags for five kinds of polymeric insulating films subjected to a step voltage were measured in the minute range at room temperature. The time-lag distributions were classified into two types, exponential and normal distributions. Low-density polyethylene (LDPE), polystyrene (PS), and polypropylene (PP) belong to the exponential distribution class while polycarbonate (PC) and eth... View full abstract»

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  • Factors affecting partial discharges in SF6 gas impregnated polymer film insulation

    Publication Year: 1988, Page(s):594 - 597 vol.2
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (204 KB)

    The partial discharge characteristics of SF6 gas-impregnated PET (polyethylene terephthalate) and PP (polypropylene) film insulation were studied. Experimental results indicate that it is essential to distinguish partial discharges at the electrode edge from discharges in the gas-filled mid-dielectric void because they have different characteristics. Apart from the common influencing fa... View full abstract»

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  • Effect of temperature and humidity on electrical breakdown characteristics of low-density polyethylene film for the various stressing modes

    Publication Year: 1988, Page(s):590 - 593 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    The effects of temperature and humidity on the electric strength of low-density polyethylene (LDPE) film for various stressing modes were studied experimentally. As the temperature exceeds the glass-transition temperature of the polymer, the temperature dependence of the impulse electric strength follows the free volume breakdown theory. If the breakdown process is greatly controlled by space char... View full abstract»

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  • Study of space charge effects in polyethylene by thermal pulse current technique

    Publication Year: 1988, Page(s):586 - 589 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    The effects of oxidation on space-charge formation, carrier injection, and electrical conduction in polyethylene (PE) were studied by using thermal pulse current and thermally stimulated current (TSC) techniques. Oxidation increases the conduction current by a few orders of magnitude and negative homo space charge is formed near the cathode. The introduction of oxidized PE layer on the surface of ... View full abstract»

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  • Analysis of the depolarized current in polyvinylidene flouride

    Publication Year: 1988, Page(s):416 - 419 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (200 KB)

    There is a significant difference between the depolarized current spectrum of the α-form of polyvinylidene fluoride (PVDF) from room temperature to 160°C and that of the γ-form. For the former, a depolarized current peak (called peak P3) appears around 50°C. but it is not so distinct for the latter. Peak P 3 around 50°C is related to ... View full abstract»

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  • Correlation between charge injection and electroluminescence in polyethylene under prebreakdown AC field

    Publication Year: 1988, Page(s):582 - 585 vol.2
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    The space charge injection (SCI) and electroluminescence (EL) threshold fields in low-density polyethylene were investigated using highly sensitive detection setups. It is shown that space-charge injection set in before electroluminescence, in apparent contradiction with recent results concerning epoxy resin (see T. Beumann et al. 1987). An exact correlation between EEL and View full abstract»

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  • Fractal properties of breakdowns

    Publication Year: 1988, Page(s):519 - 522 vol.2
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    The fractal dimension of real discharge figures for solid dielectrics is calculated and its change is discussed based on a generalized breakdown theory. The fractal dimension increases according to the developments of tree beaches in a solid dielectric. The fractal dimension of tree-type trees is approximately 1.55 to 1.60, and that of aegagropila-type trees is about 1.70 to 1.88. The observed bre... View full abstract»

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  • The effect of oscillatory switching surges on the breakdown of non-uniform gaps

    Publication Year: 1988, Page(s):156 - 159 vol.1
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    Results are presented of the testing of a rod/sphere gap with oscillatory-switching surges produced in the laboratory. These surges are unidirectional or bidirectional, and the frequency and decay rate can be controlled by varying the resistances, capacitances, and inductances of the components in a modified impulse generator circuit. The resultant output wave can be either unidirectional or bidir... View full abstract»

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  • Regularity of breakdown of solid dielectrics after moisture absorption

    Publication Year: 1988, Page(s):412 - 415 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    The authors examine the usually encountered problems of environmental compatibility experiments on the breakdown of solid dielectrics after moisture absorption. These include: (1) the excessive reduction of dielectric strength and (2) an abnormal phenomenon in the case of which increases in moisture absorption cause the dielectric strength of the solid dielectric to increase at the start and then ... View full abstract»

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  • The study of interreaction of insulating oils with PP film-the effect of impregnant on crystal structure of PP film

    Publication Year: 1988, Page(s):579 - 581 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    The thermal stimulated current (TSC) technique and differential thermal analysis (DTA) were used to investigate the effect of impregnant on the crystal structure of polypropylene (PP) film. PP film samples used in DTA were impregnated in PXE (phenylxylyl ethane) for one day, ten days, and 20 days at 60°C, 80°C, and 100°C, respectively. It is shown that the unstable β-crystal form ... View full abstract»

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  • Chemical, physical and microstructural properties of thermally aged XLPE cable models

    Publication Year: 1988, Page(s):764 - 768 vol.2
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (624 KB)

    The thermal aging of cross-linked polyethylene (XLPE) cable models has been investigated to obtain information on aging effects and mechanisms. After thermal life tests, XLPE cable models were subjected to chemical, physical, electrical and microstructural characterizations. The results of density, melting point and enthalpy, electrical conductivity and electric strength measurements, scanning ele... View full abstract»

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  • Investigation of soil as a lossy dielectric

    Publication Year: 1988, Page(s):515 - 518 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (212 KB)

    The authors present results of measurements and laboratory tests performed with several soil samples to investigate their dielectric and conduction characteristics in the predominant range of frequencies for transient phenomena in electric power systems. The effects of such factors as humidity and frequency variation on these characteristics are considered, and an analysis of the obtained data is ... View full abstract»

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  • Impact of imperfections in GIS on their electric withstand

    Publication Year: 1988, Page(s):152 - 155 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    Results from experiments have been analyzed, in which the influence of particulate pollution on the withstand of gas-insulated systems (GIS) were studied. Special attention was paid to the prebreakdown phenomena in the presence of free or fixed metallic particles and to the impact which these particles have on the dielectric withstand of GIS under AC, DC, and impulse voltages. The main parameters ... View full abstract»

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  • Investigation of breakdown values and charge storage properties of PVDF

    Publication Year: 1988, Page(s):408 - 411 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    The breakdown values and charge storage properties of thin-film PVDF (polyvinylidene fluoride) were investigated with a view to the possible manufacture of small volume, high-energy-density capacitors for use in medical implant devices. The dielectric breakdown fields of 3.5-μm- and 6-μm-thick films of PVDF have been measured using a field which increases linearly with time. The rate of rise... View full abstract»

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  • Studies on influencing factors to the ageing of porcelain insulators under DC stresses

    Publication Year: 1988, Page(s):16 - 19 vol.1
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    Results are presented of the aging performance of HVDC line porcelain insulators and related influential factors such as body current and electric-field intensity. The residual dielectric strengths of porcelain materials with different aging times have been measured, and the energy spectrum of aged insulators has been examined. The influence of space charge on field distribution is analyzed View full abstract»

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  • The electromagnetic radiation and scanning characteristics of a circular dielectric resonator loaded with metallic discs

    Publication Year: 1988, Page(s):554 - 557 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    A theoretical analysis is suggested for a wide angle scanning disc antenna. The radiation performance of the ferrite disc antenna loaded with the two metallic discs is presented. The analysis approach is based on a surface-wave concept which explains the scanning mechanism. The equivalence principle (Huygen's principle) is used to compute the radiation patterns. It is shown that the steering of th... View full abstract»

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  • Thermal performance evaluation of an insulation system for cast resin power transformers

    Publication Year: 1988, Page(s):576 - 578 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    The thermal performance evaluation study is based on a proper thermal characterization of the PET (polyethylene terephthalate) film to be used as part of the insulation system. The film is tested in conditions similar to the ones present in the intended application and a meaningful set of data is obtained, which makes it possible to draw the relevant thermal life curves and to complete the analysi... View full abstract»

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  • Elevated temperature operation of XLPE distribution cable system

    Publication Year: 1988, Page(s):758 - 763 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (476 KB)

    The authors report on a continuing investigation to determine the maximum emergency and continuous ratings which cross-linked-polyethylene (XLPE)-insulated concentric neutral cables may sustain without impairing operating life. Detailed investigations include the measurement of temperatures at different parts of a cable during heavy current cycling and the resulting mechanical stresses and strains... View full abstract»

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  • Evaluation of internal electric field by separation method

    Publication Year: 1988, Page(s):511 - 514 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    The author describes the separation method for evaluating the internal field of insulating composites under any conditions. This method is shown to be useful for analyzing a composite if it contains a dipole. Using this method, experiments were performed on PE (polyethylene) and EVA (ethylene-vinyl acetate copolymer) composite. At 253 K the ratio of internal field of PE to EVA in the EVA-PE compos... View full abstract»

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  • Study of flame resistant ethylene-propylene rubber insulation formulary

    Publication Year: 1988, Page(s):667 - 670 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    The effects of different kinds of EPDM (ethylene-propylene diene monomer), fillers, silane, lead compounds, flame retardants and antioxidants on the physical-mechanical properties and electrical properties of EPDM insulation were studied and the main results are presented. The temperature index of the flame resistant EPDM insulation was evaluated as 115°C according to IEC Publication 216 and t... View full abstract»

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  • Estimation and analysis of XLPE cable life in China

    Publication Year: 1988, Page(s):654 - 657 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    The service life of XLPE (cross-linked polyethylene) cable which is manufactured in China is calculated. XLPE cables have been tested for about four years to estimate the cable life exponent N. Tests of water tree, dielectric loss, cross-linking degree of the cables, and cable insulation restoration after aging were performed. The voltage breakdown and aging phenomena of the cables are an... View full abstract»

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  • Calculation of flashover voltage of polluted insulators under DC and AC voltages

    Publication Year: 1988, Page(s):229 - 232 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    The flashover processes of polluted insulators under both DC and AC voltages were observed with a high-speed camera. Physical and mathematical models to describe the DC and AC flashover are proposed. A formula expressing the resistance of the remainder pollution layer of a polluted insulator is derived. As a result the flashover criteria of a polluted insulator can be calculated directly, and it i... View full abstract»

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  • New concepts in polymer concrete insulation

    Publication Year: 1988, Page(s):292 - 295 vol.1
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (360 KB)

    The author deals with polymer-concrete insulation, a technically viable, low-cost alternative to energy-intensive porcelain for high-voltage electrical applications both indoors and outdoors. He briefly describes the advances in polymer-concrete insulation made to date and presents new concepts for further utilizing this versatile material advantageously in present and future electric power system... View full abstract»

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  • Prediction of internal faults of GIS by frequency spectrum of typical vibration on the enclosure

    Publication Year: 1988, Page(s):148 - 151 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    The authors report several typical frequency characteristics of vibrations of the metallic enclosure of a GIS (gas-insulated substation), especially the characteristics of vibration caused by free conducting particles and partial discharge under alternating voltage. An examination is made of contaminants under different SF6 gas pressures, the shapes of the electrodes, and their electric... View full abstract»

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