Design And Simulation Of Static Var Compensator For Voltage Sags Mitigation

Modem power networks are loaded more heavily than ever before to fully utilize the existing transmission facilities while power quality has become an important issue in power system, this is due to the fact that the usage of power electronic equipment and electronic-based loads, which are sensitive to power quality has increased, and thus normal operations in industrial and commercial environments are becoming more vulnerable to power quality problems. One of the problems associated with power quality is voltage sag. Voltage sag is a major power quality problem. It occurs because most voltage sags are due to short circuit on transmission and distribution lines. High technology industries are highly sensitive to voltage sags. A small voltage sag for several cycle, (short duration) is sufficient to interrupt the operation of the facility resulting in costly downtime.Traditional voltage regulating devices such as electromechanical transformer taps and shunt capacitor have been used extensively at the transmission and distribution. However, they are too slow to response to correct voltage sags. This problem can be overcome by replacing them with power-electronics based devices known as Flexible Alternating Currents Transmission System (FACTS). FACTS devices can provide a real-time control of transmission line impedance, voltage magnitude and phase angle. With advancement of high power electronics, fast response of FACTS device is now available. Through proper coordination, they can be utilized to control system power flow, increase power transfer capabilities, improve system transient stability, and damp power system oscillations. Static Var Compensator, SVC is a shunt connected FACTS device having capability of supplying reactive power and thus could protect the system from the potential threats of voltage sags. The objective of this research is to investigate and design SVC for voltage sags mitigation on a small test power system. This work has indicated SVC has the potential to mitigate voltage sag if properly designed and located

PROMOTING SCIENTIFIC AND TECHNOLOGICAL LITERACY AMONG POSTGRADUATE STUDENTS AT THE FACULTY OF EDUCATION UTM

One important issue in the Science Education debate over the last century was how to preparea more relevant science education of the 21st Century that emphasizes on promoting scientificliteracy through a more meaningful science education program. In response to this call, ageneral science education elective course code named MPS1163 Epistemological, Social andEthical Issues in Science and Technology was designed and implemented starting in Semester2 Session 2009/2010. By the end of Semester 2 Session 2012/2013 the course has been runningfor 7 semesters and had invited 128 postgraduate students from 7 different programs, includinga PhD program. A questionnaire was distributed to 26 course participants at the end ofsemester 2 Session 2012/2013. The objective of the questionnaire was to seek their personalassessment on their knowledge and understanding on the eleven course contents taken duringthe whole semester. The results indicated that there was a mean increment of between 40- 50%on their knowledge and understanding on the topics covered compared to their knowledge andunderstanding before taking the course. The second part of the questionnaire consisted of sixitems, using five point Likert Scale, seeking their suggestions for improving a more relevantscience education through the elective course. The response was commendable. Implicationsof the study related to course contents and students opinions on the course contents andsuggestions for the improvement of the course are discussed in this paper.Keywords: scientific literacy, technological literacy, general education elective course, a morerelevant science education

Comparison of lightning return stroke channel-base current models with measured lightning current

Electromagnetic pulse radiation produced around the lightning stroke channel has caused the disturbance to the microelectronic industry, especially to disturbance of high frequency to electronic systems. Lightning channel-base current function (CBC) characteristics and parameters determine lightning electromagnetic field (LEMF) results obtained on the basis of the used models. This paper evaluated and compared the measured lightning current and six lightning current-based channels models namely Bruce and Golde, Heidler, Diendorfer and Uman, Nucci, Pierce and Cianos and new current-based current (NCBC) models. In terms of the waveshape, among all the six lightning channel-based current models discussed, the models developed by Javor, Nucci and Diendorfer and Uman have showed a good agreement compared to the measured lightning current. In terms of 10-90% risetime and full width half maximum time (FWHM) comparison, NCBC and Nucci models have showed compatible comparison. However, Nucci model is not easily adjustable to different desired pulse-current waveshapes. On the other hand, NCBC model can be simplified, the values of lightning peak current and risetime can be chosen arbitrarily and independently from other parameters, and there is no need for the peak-correction factor, so that reduces the number of parameters. Therefore, the NCBC model was suggested to be used in the future in order to simulate much accurate return stroke model. This knowledge will contribute to the development of a new accurate and efficient return stroke model

Comparison of purification methods to purify recombinant bromelain from Escherichia coli BL21-A1 = Perbandingan kaedah penulenan rekombinan bromelain daripada Escherichia coli BL21-A1

Recombinant bromelain is a cysteine protease that can be exploited for its protease activity in food and pharmaceutical applications. The aim of this study was to compare different purification methods aqueous two-phase system (ATPS), ammonium sulphate precipitation, ion exchange, affinity, and gel filtration chromatography) for the recombinant bromelain purification from Escherichia coli BL21-A1. From the SDS-PAGE analysis, all methods produced band with molecular weight between 50 to 55 kDa. Among the methods used, the ATPS purification consisting of 13% (w/w) of PEG6000 and 11% (w/w) potassium phosphate at pH 7.0 was chosen as the best purification method. The method produced 16.39 ± 0.03 % of yield, purification fold of 5.35 ± 0.11, and specific activity of 3.47 ± 0.11 unit/mg of recombinant bromelain. This proposed study can be used as a platform for large-scale downstream processing of recombinant bromelain in industry. Rekombinan bromelain adalah sisteina protease yang boleh dieksploitasi dalam aplikasi makanan dan farmaseutikal. Tujuan kajian ini adalah untuk membandingkan kaedah penulenan yang berbeza dengan menggunakan sistem akueus dua fasa (ATPS), pemendakan amonium sulfat, pertukaran ion, afiniti dan gel penapisan kromatografi untuk penulenan rekombinan bromelain daripada Escherichia coli BL21-A1. Daripada analisis SDS-PAGE, semua kaedah menghasilkan jalur dengan berat molekul antara 50 hingga 55 kDa. Antara kaedah yang digunakan, sistem akueus dua fasa (ATPS) yang terdiri daripada 13% (w/w) PEG6000 dan 11% (w/w) kalium fosfat pada pH 7.0 telah dipilih sebagai kaedah penulenan yang terbaik. Kaedah ini mendapat 16.39 ± 0.03% hasil, kadar penulenan 5.35 ± 0.11, dan aktiviti rekombinan bromelain sebanyak 3.47 ± 0.11 unit/mg. Kajian ini dicadangkan boleh digunakan sebagai platform untuk pemprosesan hiliran rekombinan bromelain secara besar-besaran dalam industri

Initial study of invasive approach of electrical capacitance tomography for identifying non-conducting medium in steel pipe application

The paper aims to investigate the possibility of an invasive method for electrical capacitance tomography system for steel pipe application. This work presents the development process for modeling an ECT (Electrical Capacitance Tomography) sensor using COMSOL Multiphysics. COMSOL Multiphysics software is implemented as the main tool to model the ECT system. The 12 electrodes are modeled in 2-dimensional and it is based on the invasive approach. The ECT system is developed to obtain the electrical potential distribution between electrodes when an electric field is applied. Besides, it also obtains the permittivity distribution inside the closed pipe. This invasive approach is applied for the steel pipe that cannot be used with common ECT. Several positions of bubble air as the obstacle in the oil medium are tested. As a result, the sensor readings performance inside the region of interest is analyzed. Simultaneously, the tomograms are also obtained and analyzed using MATLAB software. A linear back-projection algorithm is implemented to reconstruct the image of the region of interest. Thus, the possibility of the ECT system applied for steel pipe can be observed and compared when there is a change of readings between the full oil and the existing obstacle inside the steel pipe. Besides, the tomograms for each condition tested can be observed. In short, the invasive approach for ECT is seen to be possible to apply for oil-gas application in steel pipe. The LBP algorithm with the average MSSIM value around 0.3 was able to detect the oil-gas regime inside the steel pipe

Initial study of invasive approach of electrical capacitance tomography for identifying non-conducting medium in steel pipe application

The paper aims to investigate the possibility of an invasive method for electrical capacitance tomography system for steel pipe application. This work presents the development process for modeling an ECT (Electrical Capacitance Tomography) sensor using COMSOL Multiphysics. COMSOL Multiphysics software is implemented as the main tool to model the ECT system. The 12 electrodes are modeled in 2-dimensional and it is based on the invasive approach. The ECT system is developed to obtain the electrical potential distribution between electrodes when an electric field is applied. Besides, it also obtains the permittivity distribution inside the closed pipe. This invasive approach is applied for the steel pipe that cannot be used with common ECT. Several positions of bubble air as the obstacle in the oil medium are tested. As a result, the sensor readings performance inside the region of interest is analyzed. Simultaneously, the tomograms are also obtained and analyzed using MATLAB software. A linear back-projection algorithm is implemented to reconstruct the image of the region of interest. Thus, the possibility of the ECT system applied for steel pipe can be observed and compared when there is a change of readings between the full oil and the existing obstacle inside the steel pipe. Besides, the tomograms for each condition tested can be observed. In short, the invasive approach for ECT is seen to be possible to apply for oil-gas application in steel pipe. The LBP algorithm with the average MSSIM value around 0.3 was able to detect the oil-gas regime inside the steel pipe

ID-Map (Interactive Digital Map)

The invention of Interactive Digital Map (iD-MAP) is to establish, display and relay information of rural village and its dwellers to the visitors; serving as a one-stop center that delivers all the information related to the uniqueness and tourism products of the village. The establishment of a digital tourism system based on digital and interactive multimedia technology will develop and enhance the competitiveness and rapid development of rural and cultural tourism industry. At the same time, the system also is an artistic approach created for a more reliable storage, accessible record and to ease the retrieval of information for future development. Additionally, iD-MAP is a response to the unorganized and unpresentable condition of the existing visitor information board located at the entrance of Pa’ Lungan in Bario. This invention is an interactive and informative digital mapping using a technology that superimposes a digitally-generated image on the user’s view with the intention to provide and share required visuals and hence, providing a composite view of the displayed materials. This highly informative digital map using digital mapping and Augmented Reality (AR) to illustrate the location of local tourist attraction, available public facilities, prominent landmarks as well as the mean in locating the locality of each house in the village. The retrieval of the desired information is made possible with the usage of the smart phone equipped with the selected AR Apps. The establishment of iD-MAP based on digital and interactive multimedia technology will develop and enhance the competitiveness and rapid development of rural tourism industry. This acts also as a response towards supporting the key economic sectors within the Digital Economy initiatives by the Government of Sarawak

Does parallel projection is suitable in electrical capacitance tomography

Electrical Capacitance Tomography (ECT) is one of the soft field tomography that widely used for the purpose of measurement and monitoring of multiphase flow. Common problem of the soft field tomography is low quality and unstable images in the pipe especially at the center section of the pipe. In this paper, an ECT system with a comparison between common approach and a parallel approach is presented. Simulation in 2 dimensions with 16-electrode is carried out to observe a potential projection. The COMSOL Multiphysics software is used to investigate the state and response of the electric field with this approach by exporting data with 128x128 pixels. Air bubbles as a phantom in the oil medium have been tested and analyzed. Linear Back-Projection Algorithm (LBP) is implemented using MATLAB software to obtain a tomogram. A Multi Scale Structural Similarity, MSSIM was applied to compare both approaches. Consequently, the resolution and quality of the pictures in the pipes can be distinguished. However, a further investigation is needed to improve the parallel approach for ECT system

Does parallel projection is suitable in electrical capacitance tomography? -A comparison with common approach

Electrical Capacitance Tomography (ECT) is one of the soft field tomography that widely used for the purpose of measurement and monitoring of multiphase flow. Common problem of the soft field tomography is low quality and unstable images in the pipe especially at the center section of the pipe. In this paper, an ECT system with a comparison between common approach and a parallel approach is presented. Simulation in 2 dimensions with 16-electrode is carried out to observe a potential projection. The COMSOL Multiphysics software is used to investigate the state and response of the electric field with this approach by exporting data with 128x128 pixels. Air bubbles as a phantom in the oil medium have been tested and analyzed. Linear Back-Projection Algorithm (LBP) is implemented using MATLAB software to obtain a tomogram. A Multi Scale Structural Similarity, MSSIM was applied to compare both approaches. Consequently, the resolution and quality of the pictures in the pipes can be distinguished. However, a further investigation is needed to improve the parallel approach for ECT system