224 research outputs found
Online Control of Modular Active Power Line Conditioner to Improve Performance of Smart Grid
This thesis is explored the detrimental effects of nonlinear loads in distribution systems and investigated the performances of shunt FACTS devices to overcome these problems with the following main contribution: APLC is an advanced shunt active filter which can mitigate the fundamental voltage harmonic of entire network and limit the THDv and individual harmonic distortion of the entire network below 5% and 3%, respectively, as recommended by most standards such as the IEEE-519
A review of computer assisted detection/diagnosis (CAD) in breast thermography for breast cancer detection
Breast cancer is the leading type of cancer diagnosed in women. For years human limitations in interpreting the thermograms possessed a considerable challenge, but with the introduction of computer assisted detection/diagnosis (CAD), this problem has been addressed. This review paper compares different approaches based on neural networks and fuzzy systems which have been implemented in different CAD designs. The greatest improvement in CAD systems was achieved with a combination of fuzzy logic and artificial neural networks in the form of FALCON-AART complementary learning fuzzy neural network (CLFNN). With a CAD design based on FALCON-AART, it was possible to achieve an overall accuracy of near 90%. This confirms that CAD systems are indeed a valuable addition to the efforts for the diagnosis of breast cancer. Lower cost and high performance of new infrared systems combined with accurate CAD designs can promote the use of thermography in many breast cancer centres worldwide
Effects of Iron-Core Topology on Inrush Currents in Three-Phase Multi-Leg Power Transformers
This paper investigates the inrush currents of three-phase (a)symmetric multi-leg transformer cores considering magnetic core structure (e.g., three-leg vs. five-leg) and switching effects (e.g., recloser operating). The electromagnetic steady-state and transient behavior of three-phase transformers significantly differs from single-phase transformer operation mainly because of the unique flux coupling interactions in multi-leg and asymmetric core structures. A recently developed three-leg nonlinear transformer core model is applied to this study which considers the influence of magnetic hysteresis, flux couplings in the core-structure and nonsinusoidal operation in three-phase transformers. Simulations results for multi-leg (e.g., three-leg and five-leg) transformer cores demonstrating inrush current behavior based on the model are presented and discussed
Improving the Learning Experience of Power System Protection Students using Computer-based Simulations and Practical Experiments
This paper presents a survey on the activities carried out to improve the learning experience of electrical engineering undergraduate students in power system protection unit in Curtin University, Australia. The unit was conducted initially based on lectures and tutorials where only two sessions on computer simulation and one session of laboratory demonstration were conducted. In academic year of 2013, to improve the learningexperience of students, several computer-based simulations and laboratory experiments were prepared. The students are introduced with two power system analysis software, namely ETAP and PSCAD/EMTDC which are used to demonstrate the overcurrent relays performance and their coordination as well as the time transient analysis of different faults in an electric network where some protection relays are applied. A practical setupcomposed of LabVolt electrical modules and SEL relays is used to simulate an electric network. Several tests are built up to simulate fault and protection layout for transformer and induction motor. Finally, a secondary injection test set is used to introduce the concepts of relay testing and commissioning
Motivating Power System Protection Course Students by Practical and Computer-Based Activities
This paper presents several methods for motivating students taking a power system protection (PSP) course. The paper reviews the laboratory activities developed for the PSP course at Curtin University, Australia; these methods are applicable and can be used for PSP course instruction at any institution. These activities were developed to improve the learning experience of the electrical engineering undergraduate and postgraduate students enrolled in this course. Initially, the PSP course at Curtin University consisted of lectures and tutorials accompanied by two sessions of software-based simulations and one session of laboratory demonstration. To motivate the students, several computer-based simulations and practical laboratory experiments were developed. PSCAD and ETAP power system analysis software tools are introduced and used to demonstrate the performance and coordination of different protection relays from steady-state and dynamic points of view. Also, a practical setup composed of a LabVolt power system simulator and industrial relays is used to carry out several practical experiments. The experiments help students observe the performance of protection systems for transformers and induction motors during faults and abnormal operating conditions. Finally, the concept of relay testing and commissioning is introduced by relay standalone experiments using a secondary injection relay test set. The results of these activities were evaluated according to the students’ satisfaction, comments, total scores, and interest in PSP
The alkaloid composition of Nicotiana gossei and Duboisia hopwoodii used in the production of pituri by Australian Aboriginal people
Investigations into the pituri plant: nicotine content, nicotine conversion to nornicotine, nicotine release and cytotoxicity of Australian native Nicotiana spp.
In vitro cytotoxicity of Aboriginal Australian smokeless tobacco product 'pituri' compared to nicotine in human lung epithelial cells
New Model for VDT Associated Visual Comfort in Office Spaces
In office rooms a significant aspect of visual discomfort is related to visual quality of computer screens and it\u27s necessary to consider this visual quality as an important subject in quality of design. In this study a new method was developed to predict the visual quality of computer screen which is based on contrast reduction due to reflection. The new developed contrast model which is the basis of the new developed evaluation method is named the model of minimum required contrast
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