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Space charges analysis on insulator with uniform layer contamination effect Mohd Haris Asyraf Shee Kandar; Nor Akmal Mohd Jamail; Qamarul Ezani Kamarudin; Nordiana Azlin Othman; Nor Asiah Muhamad
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 4: August 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i4.12765

High voltage direct current (HVDC) transmission provides an attractive alternative for bulk power transfer. However, HVDC transmission may have loss about half per unit length of high voltage alternating current (HVAC) at the same amount of power carried. This is due to the space charge formation around the conductor in HVDC cables. It is known that the presence of space charge inside an insulator may distort the local electric field and surface energy. This paper investigates the effect of electrostatics for space charge, electric field and surface energy in the HVDC cable in clean and contaminated conditions. The effect of uniform layer contamination from oil, sandstone and fresh water was conducted on 11 kV XLPE cable using finite element software under electrostatics study. The contamination layer was created around the XLPE cable by multifarious the radius of layer contamination from the conductor. The simulation results show that enlargement of contamination layer radius by 1.0 mm (light), 1.5 mm (medium) and 2.0 mm (heavy) resulted in the reduction of surface energy by 20% and electric field by 22% but increase the space charge amplitude by 76%. The study also found that fresh water can be considered as the worst contamination compared to oil and sandstone.

Virgin coconut oil dielectrical properties as electrical insulation material Siti Syafiqah Mat Sauki; Nor Asiah Muhamad; Zawani Amirah Rasid
Bulletin of Electrical Engineering and Informatics Vol 8, No 3: September 2019
Publisher : Institute of Advanced Engineering and Science

Mineral oil played an important role as insulating liquid such as to reduce failure, ageing effect, increase the life span and heat transfer agent. Mineral oil had a good dielectric strength and cooling performance but it had serious negative environmental impact like non-biodegradable, non-renewable resource and difficult to dispose when it deteriorates completely. Hence, virgin coconut oil (VCO) was chosen as alternative to replace mineral oil since it biodegrades completely without toxic and easy to get in the tropical country. Three dielectric tests were conducted to investigate the dielectric properties of VCO. Those were breakdown voltage, water content and kinematic viscosity. A study about the effect of the moisture level of VCO on the breakdown voltage and kinematic viscosity was also presented. VCO and mineral oil also undergone heating process to reduce moisture in sample. The study showed that VCO has good potential breakdown voltage with the ability to absorb a lot of moisture keeping the KRAFT paper dry. However, VCO had very high kinematic viscosity compared to mineral oil. Further, the rate of breakdown voltage decreases with increasing of moisture of VCO was lower than mineral oil.

Virgin coconut oil dielectrical properties as electrical insulation material Siti Syafiqah Mat Sauki; Nor Asiah Muhamad; Zawani Amirah Rasid
Bulletin of Electrical Engineering and Informatics Vol 8, No 3: September 2019
Publisher : Institute of Advanced Engineering and Science

Mineral oil played an important role as insulating liquid such as to reduce failure, ageing effect, increase the life span and heat transfer agent. Mineral oil had a good dielectric strength and cooling performance but it had serious negative environmental impact like non-biodegradable, non-renewable resource and difficult to dispose when it deteriorates completely. Hence, virgin coconut oil (VCO) was chosen as alternative to replace mineral oil since it biodegrades completely without toxic and easy to get in the tropical country. Three dielectric tests were conducted to investigate the dielectric properties of VCO. Those were breakdown voltage, water content and kinematic viscosity. A study about the effect of the moisture level of VCO on the breakdown voltage and kinematic viscosity was also presented. VCO and mineral oil also undergone heating process to reduce moisture in sample. The study showed that VCO has good potential breakdown voltage with the ability to absorb a lot of moisture keeping the KRAFT paper dry. However, VCO had very high kinematic viscosity compared to mineral oil. Further, the rate of breakdown voltage decreases with increasing of moisture of VCO was lower than mineral oil.

Virgin coconut oil dielectrical properties as electrical insulation material Siti Syafiqah Mat Sauki; Nor Asiah Muhamad; Zawani Amirah Rasid
Bulletin of Electrical Engineering and Informatics Vol 8, No 3: September 2019
Publisher : Institute of Advanced Engineering and Science

Mineral oil played an important role as insulating liquid such as to reduce failure, ageing effect, increase the life span and heat transfer agent. Mineral oil had a good dielectric strength and cooling performance but it had serious negative environmental impact like non-biodegradable, non-renewable resource and difficult to dispose when it deteriorates completely. Hence, virgin coconut oil (VCO) was chosen as alternative to replace mineral oil since it biodegrades completely without toxic and easy to get in the tropical country. Three dielectric tests were conducted to investigate the dielectric properties of VCO. Those were breakdown voltage, water content and kinematic viscosity. A study about the effect of the moisture level of VCO on the breakdown voltage and kinematic viscosity was also presented. VCO and mineral oil also undergone heating process to reduce moisture in sample. The study showed that VCO has good potential breakdown voltage with the ability to absorb a lot of moisture keeping the KRAFT paper dry. However, VCO had very high kinematic viscosity compared to mineral oil. Further, the rate of breakdown voltage decreases with increasing of moisture of VCO was lower than mineral oil.

Status Review on Gas Insulated Switchgear Partial Discharge Diagnostic Technique for Preventive Maintenance Visa Musa Ibrahim; Zulkurnain Abdul-Malek; Nor Asiah Muhamad
Indonesian Journal of Electrical Engineering and Computer Science Vol 7, No 1: July 2017
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v7.i1.pp9-17

Gas insulated switchgear (GIS) plays a vital role in high voltage transmission of electrical energy due to its advantages of high reliability and performance, compact in dimensions and outstanding compatibility with the environment. It uses sulphur hexafluoride gas as its insulant and coolant because of its high dielectric strength and excellent arc quenching ability. Gas insulated switchgear in operation suffers the challenge of its insulation decomposition and eventually failure due to the activities of partial discharge that arouses from defects. This failure is catastrophic and it will lead to entire power out stage that will affect all categories of human activities, so there is a need for Gas insulated switchgear condition monitoring and diagnoses in order to carry out preventive maintenance. This paper reviews diagnostic techniques and methods for Gas insulated switchgear insulation degradation caused by partial discharge for the purpose of carrying out preventive maintenance to avert its failure.

A Preliminary Study on Optimizing the In-Lab Reclamation Process Parameters of Used Transformer Oils Using the Taguchi Method Sharin Ab Ghani; Zulkarnain Ahmad Noorden; Nor Asiah Muhamad; Imran Sutan Chairul; Muhammad Asyraf Mohd Khalid
Indonesian Journal of Electrical Engineering and Computer Science Vol 10, No 3: June 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v10.i3.pp1090-1097

In this study, the Taguchi method is used to optimize the in-lab reclamation process parameters of used transformer oils. The main benefit of this method is that one can determine the optimum parameters of the reclamation process in a simple, efficient, and cost-effective manner. The L4 (23) Taguchi design is used to optimize the following process parameters: (1) weight of the Fuller’s Earth adsorbent, (2) stirring speed, and (3) oil temperature. These parameters are optimized in order to minimize the AC breakdown voltage, total acid number, and dynamic viscosity of the reclaimed transformer oil samples. The signal-to-noise ratios are determined for each process parameter in order to identify the significance of each factor on the three output responses. Based on the results, the oil temperature has the most significant effect on the AC breakdown voltage whereas the weight of the Fuller’s Earth adsorbent has the most significant effect on the total acid number and dynamic viscosity of the reclaimed transformer oils. Tests are carried out to verify the results using the optimum reclamation process parameters and indeed, it is found that there is significant improvement in the mean AC breakdown voltage, total acid number, and dynamic viscosity for the reclaimed transformer oil compared with those for the used transformer oil. It is believed that this method can be an indispendable tool to determine the optimum parameters for the reclamation process without going through the hassle of trial and error associated with conventional experimentation.

Chemical by-Product Diagnostic Technique for Gas Insulated Switchgear Condition Monitoring Visa Musa Ibrahim; Zulkurnain Abdul-Malek; Nor Asiah Muhamad
Indonesian Journal of Electrical Engineering and Computer Science Vol 7, No 1: July 2017
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v7.i1.pp18-28

Chemical by product diagnostic technique is an efficient, cost-effective and reliable diagnostic technique for gas insulate switchgear condition monitoring in view of its high sensitivity and anti- internal and external electromagnetic interference and noise. In this research paper, coaxial simulated gas insulated switchgear chamber and four different types of artificial defect were designed to cause partial discharge that will simulate the decomposition of sulphur hexafluoride gas in the chamber when energize. Fourier transform infrared spectrometer was used as the method of chemical by-product technique to detect the SF6 decomposition product and its concentration. Different numerous by-products were detected (SO2, SOF2, SO2F2, SO2F10, SiF4, CO, C3F8, C2F6 ) under this experiment using four different types of defect and the by-products differs with the type of defect and the generation rate. Gas insulated switchgear health condition can be feasibly diagnosed by analyzing the decomposition products of SF6 to identify its fault.

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