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Comparison of Mechanical and Low-Frequency Dielectric Properties of Thermally and Thermo-Mechanically Aged Low Voltage CSPE/XLPE Nuclear Power Plant Cables. ELECTRONICS 2021. [DOI: 10.3390/electronics10222728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
During the service period of low-voltage nuclear cables, multiple stresses influence the aging of polymeric materials of cables. Thermal and radiation stresses are considered service aging factors in qualification tests, while the standards usually do not prescribe mechanical stress. CSPE/XLPE insulated nuclear cable samples were exposed to thermal and combined thermo-mechanical aging for more than 1200 h at 120 °C. The real and imaginary parts of permittivity were measured in the 200 μHz to 50 mHz range as dielectric properties. The Shore D hardness of the samples was measured to analyze the mechanical characteristics of the cable. To characterize the dielectric spectrum, derived quantities, namely central real and imaginary permittivities and real and imaginary permittivities’ central frequencies were calculated. The change of dielectric spectra did not show a clear trend with aging, but the imaginary permittivity’s central frequency was higher by 0.5 mHz in the case of thermo-mechanically aged samples. The Shore D hardness was also higher on the thermo-mechanically aged samples. These findings show the combined aging has a higher impact on the insulation properties. Hence, involving the mechanical stress in the aging procedure of cable qualification enables the design of more robust cables in a harsh environment.
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Lapa HE, Kökce A, Özdemir AF, Altındal Ş. Investigation of Dielectric Properties, Electric Modulus and Conductivity of the Au/Zn-Doped PVA/n-4H-SiC (MPS) Structure Using Impedance Spectroscopy Method. Z PHYS CHEM 2019. [DOI: 10.1515/zpch-2017-1091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The 50 nm thickness Zn-doped polyvinyl alcohol (PVA) was deposited on n-4H-SiC semiconductor as interlayer by electro-spinning method and so Au/Zn-doped PVA/n-4H-SiC metal-polymer-semiconductor (MPS) structure were fabricated. The real and imaginary parts of the complex dielectric constant (ε′, ε′′), loss-tangent (tan δ), the real and imaginary parts of the complex electric modulus (M′, M′′) and ac electrical conductivity (σ
ac
) behavior of this structure were examined using impedance spectroscopy method in a wide range of frequency (1 kHz–400 kHz) and voltage (−1 V)–(+6 V) at room temperature. The values of ε′, ε′′, tan δ, M′, M′′ and σ
ac
are determined sensitive to the frequency and voltage in depletion and accumulation regions. The values of ε′ and ε′′ decrease with increasing frequency while the values of M′ and σ
ac
increase. The peak behavior in the tan δ and M′′ vs. frequency curves was attributed to the dielectric relaxation processes and surface states (Nss
). The plots of ln (σ
ac
) vs. ln (f) at enough high forward bias voltage (+6 V) have three linear regions with different slopes which correspond to low, intermediate and high frequencies, respectively. The dc conductivity is effective at low frequencies whereas the ac conductivity effective at high frequencies. According to experimental results, the surface/dipole polarizations can occur more easily occur at low frequencies and the majority of Nss
between Zn-doped PVA and n-4H-SiC contributes to the deviation of dielectric behavior of this structure.
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Affiliation(s)
- Havva Elif Lapa
- Department of Physics, Faculty of Sciences and Arts , Süleyman Demirel University , Isparta 32260 , Turkey
| | - Ali Kökce
- Department of Physics, Faculty of Sciences and Arts , Süleyman Demirel University , Isparta 32260 , Turkey
| | - Ahmet Faruk Özdemir
- Department of Physics, Faculty of Sciences and Arts , Süleyman Demirel University , Isparta 32260 , Turkey
| | - Şemsettin Altındal
- Department of Physics, Faculty of Sciences , Gazi University , Ankara 06500 , Turkey
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Eroğlu AG, Yıldırım M, Durmuş P, Dökme İ. Distribution of interface traps in Au/2% GC‐doped Ca
3
Co
4
Ga
0.001
O
x
/
n
‐Si structures. J Appl Polym Sci 2019. [DOI: 10.1002/app.48399] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ayşe Gül Eroğlu
- Department of Physics, Faculty of ScienceGazi University 06500 Ankara Turkey
| | - Mert Yıldırım
- Department of Mechatronics Engineering, Faculty of EngineeringDüzce University 81620 Düzce Turkey
| | - Perihan Durmuş
- Department of Physics, Faculty of ScienceGazi University 06500 Ankara Turkey
| | - İlbilge Dökme
- Department of Science Education, Faculty of EducationGazi University 06500 Ankara Turkey
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