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Polarization and depolarization current of linear low density polyethylene-natural rubber nanocomposite subjected to electrical tracking and moisture

Mohd Jamail, Nor Akmal (2015) Polarization and depolarization current of linear low density polyethylene-natural rubber nanocomposite subjected to electrical tracking and moisture. PhD thesis, Universiti Teknologi Malaysia.

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Polymeric nanocomposites are widely used for high voltage outdoor insulating application due to their efficient electrical performance. Recently, SiO2, TiO2 and MMT nanofillers are used as fillers because there are listed as the main nanofiller commonly used in electrical engineering due to the increases of effective activation energy. Natural rubber (NR) is used because the nature of the interphase is found to affect viscoelasticity and it develops several interphases with the Linear Low-Density Polyethylene (LLDPE) matrix. This thesis presents the outcome of an experimental study which has been carried out to determine the conductivity level and dielectric response function of the LLDPE-NR compound, filled with different amount of SiO2, TiO2 and MMT nanofillers using Polarization and Depolarization Current (PDC) measurement technique. LLDPE and NR with the ratio composition of 80:20 were selected as a base polymer. The PDC testing was done on samples at various conditions: without any defect (normal condition), wet condition (moisture absorption) and after electrical tracking effect condition based on BS EN 60587:2007 standards. One of the problems associated with outdoor polymeric insulators is the tracking of the surface which can directly influence the reliability of the insulator. The amount of water content can be used to monitor the dielectric quality of insulation and as an indicator of possible deterioration for outdoor degradation. Besides PDC, surface morphology analysis using FESEM was also conducted to study the changes in physical structure which can explain the conductivity and response function. This research found that an addition of certain weight percentage of nanofiller and NR into the LLDPE improved conductivity level of the insulator. LLDPE-NR/TiO2 at 5 wt% has become the best sample in terms of the lowest conductivity in normal and under electrical tracking effect. Besides, this sample has the fastest time response under electrical tracking and moisture condition. This investigation has successfully identified the PDC pattern, conductivity and dielectric response function of LLDPE-NR nanocomposite. Results show that different compositions as well as the surface physical conditions affect the PDC measurement results.

Item Type: Thesis (PhD)
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK4001-4102 Applications of electric power
Depositing User: En. Sharul Ahmad
Date Deposited: 04 May 2016 02:15
Last Modified: 04 May 2016 02:15
URI: http://eprints.uthm.edu.my/id/eprint/7804
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