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VOLUME 5
NUMBER 2
SUMMER-FALL 2006

Table of Contents


Editorial Note


 

SPECIAL SECTION ON POWER ENGINEERING:
 


Implementation of an Intelligent Method to Forecast Long-Term Electric Demand

M. Al Mamun and B. Kermanshahi

75-82 

Mid-Term Forecasting of Water Elevation and Discharge for Micro-Hydro Power Plant Generation Schedule

N. N. Estoperez and B. Kermanshahi

PP. 83-89 

Installation of Unified Power Flow Controller for Voltage Stability Margin Enhancement Under Line Outage Contingencies

A. S. Venkataramu and T. Ananthapadmanabha

PP. 90-96 

Performance Analysis of a Cost Effective 4-Switch 3-Phase Inverter Fed IM Drive

M. Nasir Uddin, T. S. Radwan, and M. A. Rahman

PP. 97-102 

Modeling the Effects of Trace and Parameters of Transmission Lines on the Lightning Stroke

B. Vahidi, A. M. Jafari, and S. M. Ahadi

PP. 103-108 

 

REGULAR PAPERS:
 

Abstracts:

 


Implementation of an Intelligent Method to Forecast Long-Term Electric Demand

M. Al Mamun* and B. Kermanshahi*

* Electrical and Electronics Department, Tokyo University of Agriculture and Technology,  Japan


Abstract: The electric power demand in Japan has steadily increased and the load factor of total power system has decreased. It is therefore very important to the utilities to have advance knowledge of their electrical load, so that they may ensure that this load is met and to minimize any interruptions to their service. One of the important points for forecasting the long-term load in Japan is to take into account the past and present economic situations and power demand. Here, the proposed Artificial Neural Network (ANN) that is Radial Basis Function Network (RBFN) has also showed that the changes in loads are a reflection of economy. The data used are: actual yearly, incremental growth rate from previous year, and blend (actual and incremental growth rate from previous years). In this research, we also predict the input factors (GDP, GNP, Population, Household, Summer days, Cool days, IIP, Oil price, Electricity price) for forecasting the maximum electric power. As a result, prediction of peak loads in Japan up to year 2015 is discussed using the RBFN and the maximum demands for 2001 through 2015 are predicted to be elevated from 179.42GW to 209.18GW. Based on the obtained results, it will help the power utilities to maintain power quality and reliability over the long term. .



Mid-Term Forecasting of Water Elevation and Discharge for Micro-Hydro Power Plant Generation Schedule

N. Estoperez* and B. Kermanshahi*

* Electrical and Electronics Department, Tokyo University of Agriculture and Technology,  Japan


Abstract: The unprecedented restructuring and deregulation of power industry pave the way to competition in wholesale generation of electricity. Clean energy producers, which supply energy to a community, can have opportunity to sell their energy to the grid in times of over-generation. Hence, an advance generation profile will be very important for the energy producers. In this paper, an intelligent method of scheduling the generation of a micro-hydro power plant (MHPP) for a period of one month is presented. As an intelligent method, artificial neural network is used to forecast the water elevation and discharge for a month, and these are then used to determine the power output of MHPP. Simulation results show that multi-layer perceptron (MLP) employing back-error propagation (BP) is efficient in forecasting the water elevation and discharge. .



Installation of Unified Power Flow Controller for Voltage Stability Margin Enhancement Under Line Outage Contingencies

P. S. Venkataramu* and T. Ananthapadmanabha**

* Department of Electrical and Electronics Engineering, Vellore Institute of Technology, Deemed University, India

** Electrical Engineering Department, National Institute of Engineering, India


Abstract: Voltage stability margin (VSM) enhancement of a system under line outage contingencies is an important task for secured operation of large interconnected power system. This paper proposes a novel placement strategy for a unified power flow controller (UPFC), which enhances the VSM of the system. The location for the installation of UPFC is identified using voltage stability index (VSI) and the voltage change index (VCI). The proposed method has been tested under simulated conditions on a few power systems and the results of a 22-node real-life equivalent power network are presented for illustration.



Performance Analysis of a Cost Effective 4-Switch 3-Phase Inverter Fed IM Drive

M. Nasir Uddin*, T. S. Radwan**, and M. A. Rahman***

* Department of Electrical Engineering, Lakehead University, Canada

** Menoufiya University, Egypt

*** Faculty of Engineering & Applied Science, Memorial University of Newfoundland, Canada


Abstract: This paper investigates the performance of a cost effective 4-switch, 3-phase inverter (4S3P) fed induction motor (IM) drive system for high performance industrial drive systems. In the proposed approach, instead of a conventional 6-switch, 3-phase inverter (6S3P) a 4-switch, 3-phase inverter is utilized. This reduces the cost of the inverter, the switching losses, and the complexity of the control algorithms and interface circuits to generate 6 PWM logic signals. Furthermore, the proposed control approach reduces the computation for real-time implementation. The complete vector control scheme for the IM drive fed from the proposed 4S3P inverter is implemented in real-time using digital signal processor (DSP) TI TMS320C31 for a prototype 1 hp motor. Theoretical and experimental results of the proposed drive verify the robustness of the drive. A performance comparison of the proposed 4S3P inverter fed drive with a conventional 6S3P inverter fed drive is also made in terms of speed response and total harmonic distortion (THD) of the stator current. The proposed inverter fed IM drive is found acceptable considering its cost reduction and other advantageous features.



Modeling the Effects of Trace and Parameters of Transmission Lines on the Lightning Stroke

B. Vahidi*, A. M. Jafari*, and S. M. Ahadi*

* Department of Electrical Engineering, Amirkabir University of Technology, I. R. Iran


Abstract: The electrogeometric model (EGM) is a technique used for analyzing the termination of lightning flashes on transmission lines, masts, etc. When using the EGM for modeling the lightning stroke to transmission lines, the power line is normally represented by a set of horizontal wires where the sag of the wire, the existence of the towers and the effect of uneven way have been ignored. This approach has serious shortcomings including inability to determine the percentage of the strokes terminating on the towers, failure to correctly predict the effect of height and giving an approximate value for the number of collected strokes. This paper eliminates the above-mentioned problems by taking into consideration the existence of the towers, the sag of the wires, uneven way and the inequality of the striking distances to towers and to wires. Results of simulation for finding effects of these parameters on lightning strokes are shown in graphs.



Modification of Mammograms for Detection and Early Diagnosis of Breast Cancer Using Wavelet Techniques and Neural Networks

A. R. Zolghadr-e-asli* and Z. Maghsoodzadeh*

* Department of Electrical Engineering, Shiraz University, I. R. Iran


Abstract: In this paper, some modifications of mammography slides for the detection of microcalcifications are explained. This can be achieved in two steps. First, to detect the abnormal pixels, wavelet transformation and two statistical properties are used. Second, a set of ten characteristics are applied to images to cancel some erroneous pixels and resulting in a very low error percentage. Therefore, in both steps, a neural network with a hidden layer, which is trained by some vectors, is used. The results are shown in free response operating characteristics (FROC) curves. For more understanding, a typical process will be explained in the paper. It should be mentioned that the main difference of this research with previous ones, in addition to improved algorithms, is in the databases, which in our case are the images of the local patients at Dr. Faghihi hospital in Shiraz that made this research an applicable work.



General Response of Transmission Lines to Electromagnetic Plane Waves

M. Khalaj-Amirhosseni*

* Department of Electrical Engineering, Iran University od Science and Technology, I. R. Iran


Abstract: A simple method is introduced to find general response of transmission lines to electromagnetic plane waves. The differential equations of illuminated transmission lines are solved analytically and some general formulas are obtained. Finally, these formulas are verified using an experimental example.



Performance Evaluation of Several Well-Known Channel Coding in OFDM System

A. R. Zolghadr-e-asli* and S. Izadpanah**

* Department of Electrical Engineering, Shiraz University, I. R. Iran

** Electrical Engineering Department of Islamic Azad University, Dehdasht Branch, I. R. Iran


Abstract: Orthogonal frequency division multiplexing (OFDM) is an effective technique for high bit rate applications in multipath channels. Many researches have been carried out to develop and enhance OFDM efficiency. Because of the special structure of OFDM, the channel coding is very important. In this paper, channel coding in OFDM, the efficiency of various codes such as convolutional code, turbo code and their concatenated components with Reed-Solomon code are studied. The techniques of improving the effectiveness of channel coding with soft decoding and the use of channel state information are presented with simulation results. It can be seen that in a high signal to noise ratio, the coding gain of concatenated codes is more than the pure codes. The coding scheme can be chosen according to the complexity, suitable delay, and desired coding gain for the system.


ISSN: 1682-0053
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