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Takada T.,Measurement and Electrical Machine Control Labs | Mori T.,Measurement and Electrical Machine Control Labs | Kato T.,Measurement and Electrical Machine Control Labs | Miyake H.,Measurement and Electrical Machine Control Labs | Tanaka Y.,Measurement and Electrical Machine Control Labs
IEEJ Transactions on Fundamentals and Materials | Year: 2014

The LDPE impregnated with acetophenone (AP), one of cross linking byproducts, under a high electrical stress of E=150kV/mm caused a breakdown by the consumption electric power density of κE2=2.5W/cm2, which was measured by using the advanced technique combined with the space charge measurement (PEA system) and the terminal current measurement. The consumption electric power (κE2) leads to a thermal breakdown of LDPE specimen, where κ is an electric conductivity. The conductivity of LDPE with AP is much increased because the injection barrier of electron carrier from cathode decrease 4.25 eV to 2.60eV and the injection barrier of hole carrier from anode also decrease 3.37eV to 2.54eV. These injection barrier height were calculated by Gaussian 09 software of Quantum Chemical Calculation. It is proposed the thermal breakdown mechanism that the conductivity (κ) of LDPE with AP increases, the consumption electric power (κE2) also increases, the temperature of filamentary conductivity path increases to a melting temperature, and then the breakdown is occurred. © 2014 The Institute of Electrical Engineers of Japan. Source


Takada T.,Measurement and Electrical Machine Control Labs | Mori T.,Measurement and Electrical Machine Control Labs | Kato T.,Measurement and Electrical Machine Control Labs | Miyake H.,Measurement and Electrical Machine Control Labs | Tanaka Y.,Measurement and Electrical Machine Control Labs
IEEJ Transactions on Fundamentals and Materials | Year: 2014

The LDPE impregnated with acetophenone, one of cross-linking by-products in XLPE, under a high electrical stress of 150kV/mm caused a breakdown with the consumption electric power of κE2=2.3W/cm2 which was measured by using the advanced technique combined with the space charge measurement (PEA system) and the external current measurement. This paper discusses on the thermal breakdown model which is occurred when an intrinsic energy, mdCv (Tm-To) =220J/cm3, required to impulse breakdown of LDPE equals to the supplying electric power, kE2δt, where md is a density of material, Cv a specific heat, Tm a melting point of LDPE and To a room temperature, κ a conductivity, E an electric field, δt a formation time of breakdown. It is found that when the thermal breakdown was occurred, the measured electric power, κE2=2.3W/cm2, was consumed in a filamentary higher conductivity path (size; a thickness of specimen of a=100μm, and a cross section of filament of δS=100μm×100μm). © 2014 The Institute of Electrical Engineers of Japan. Source


Kato T.,Measurement and Electrical Machine Control Labs | Onozawa R.,Measurement and Electrical Machine Control Labs | Miyake H.,Measurement and Electrical Machine Control Labs | Tanaka Y.,Measurement and Electrical Machine Control Labs | Takada T.,Measurement and Electrical Machine Control Labs
IEEJ Transactions on Fundamentals and Materials | Year: 2015

Space charge behavior and conduction current in polyethylene under DC stress were investigated. One of the reasons for the different breakdown property in XLPE from that in LDPE may be based on the existence of cross-linking by-products in XLPE. Furthermore, a thermal history in cross-linking process for XLPE may also cause of the difference. It is generally accepted that the existence of the cross-linking by-products increase the conduction current in XLPE under DC stress. It is also said that an anneal treatment in air atmosphere may affect to the electrical properties under DC stress. Therefore, we investigated the effect of the cross-linking by-products and the anneal treatment on space charge behavior and conduction current in polyethylene under DC stress. In our research, it is thought that the increasing dissipation power in XLPE is the cause of the breakdown in it under DC stress. Therefore, to calculate the dissipation power in the bulk of test sample, we measured the space charge distribution and the external circuit current simultaneously. Based on the results, we discussed the reason of the difference of the space charge properties in XLPE and LDPE focusing on the cross-linking by-products and the oxidation of the test samples. © 2015 The Institute of Electrical Engineers of Japan. Source

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