SUST Journal Systems (Sudan Univ. of Science and Technology)
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Harmonics Analysis Due to Connecting an Electrical Traction to A 3-phase Power Supply System Through V/V Transformer
Get PDFThe wide application and usage of electrical traction system presents utilities with planning and
operation challenges. Electric railways impose several power quality problems to the utility grid. Such as generated
large negative sequence components (NSCs), undesirable harmonics, cause system voltage and current unbalance.
Harmonics and unbalanced voltage also may cause negative effects on the components of the power system such as:
overheating the transformers and the transmission lines, vibration and cause torque reduction of rotating machines,
additional losses of lines and transformers, interference with communication systems, malfunctions of protection
relays, measuring instrument error. All these problems have become more and more significant. This paper is an
attempt to quantify and assess the impact of electrical traction on the grid side through a V/V transformer. Firstly in
this paper, the typical utility power grid and traction power supply system model are designed. Then, the traction
system is integrated with the power supply system through a V/V transformer. Two cases of the connection are
considered. The first case, when the traction system is connected to one side of transformer. The second case, when
there is a balance traction load on the both transformer side. Finally, PSCAD simulation is used to analyze the power
system quality and to estimate the harmonics that are generated in the traction and power supply system sides due to
this integration. The simulation results show that, in the both cases, high levels of voltage and current harmonics are
generated in the traction side. These harmonics are generated only on the phases that the traction is connected to
them, while the other phase will not be affected. Also, it is observed that, the generated harmonics at the traction
load side have also been transferred to the power supply system side though the transformer
Battery Storage System for Frequency Stabilization of AC Networks with High Penetration of Renewable Power
Get PDFThis paper investigates the uses of battery energy storage system (BESS) in ac networks highly populated
with wind power generation. The investigation includes power system load levelling, frequency stabilization, and
provision of reactive power support to the wind farm network. The BESS is connected to the wind farm main hub
via voltage source converter, while the wind farm is connected to ac network modelled with detailed synchronous
generator, including excitation and turbine-governor control. In general the paper attempted to study the role of
BESS in modern power system regarding improving system stability. Time-domain simulations conducted in
Matlab/Simulink are used to validate the importance of the BESS
Speed Sensorless Vector Control of Induction Motors Using Rotor Flux based Model Reference Adaptive System
Get PDFVector Control (VC) schemes are increasingly used in Induction Motor (IM) drive systems
to obtain high performance. However, in order to implement the vector control technique, the induction
motor speed information is required. Different speed sensors are used to detect the speed. But in most
applications, speed sensors have several problems. These problems are eliminated by speed estimation by
using different speed estimation algorithms. Out of which, Model Reference Adaptive System (MRAS)
techniques are one of the popular methods to estimate the rotor speed due to its good performance and
simplicity. In this paper, the induction motor with Rotor Flux based Model Reference Adaptive System
(RF-MRAS) rotor speed estimator is designed and validated through MATLAB/SIMULINK software
package. The results of simulations show that the performance of the speed estimation is very good under
different operation condition
The Accuracy of Temperature Monitoring of the Incubator for Newborns
Get PDFThe objective of this paper is to investigate the performance of the Incubator for Newborns at the departments of intensive care in Jafer Ibn Aouf Reference Children Hospital, is governmental Children specialized hospital. Using the INCUTM Incubator Analyzer to analyzing various aspects of performance of neonatal incubator and its compliance with the set requirements and regulations according to the technical standard IEC (International Electro technical Commission) 60601-2-19. The data used in this study were obtained by interpreting of the performance test results of neonatal incubator. Numerically, According to the results presented in Tables (1 & 3), the neonatal incubator have achieved acceptable performance and sustaining the requirements of the standard IEC 60601-2-19. In other words, the temperature at points T1, T2, T3, and T4 does not differ from the neonatal incubator average temperature by more than 0.8°C, and this temperature does not differ more than 1.5 °C from the incubator control temperature. Compared to the established technique, the estimation error is negligible
Speed Control of Vector Controlled Induction Motors Using Integral-Proportional Controller
Get PDFControl of Induction Motor (IM) is well known to be difficult owing to the fact the
mathematical models of IM are highly nonlinear and time variant. The advent of vector control techniques
has solved induction motor control problems. The most commonly used controller for the speed control of
induction motor is traditional Proportional plus Integral (PI) controller. However, the conventional PI
controller has some demerits such as: the high starting overshoot in speed, sensitivity to controller gains
and sluggish response due to sudden change in load torque. To overcome these problems, replacement of
PI controller by Integral plus Proportional (IP) controller is proposed in this paper. The goal is to
determine which control strategy delivers better performance with respect to induction motor’s speed.
Performance of these controllers has been verified through simulation using MATLAB/SIMULINK
software package for different operating conditions. According to the simulation results, IP controller
creates better performance in terms of overshoot, settling time, and steady state error compared to
conventional PI controller. This shows the superiority of IP controller over conventional PI controlle
The Effect of Loom Speeds and Shed Heights on Beating Force
Get PDFA series of experiments was carried out on Picanol (president) loom in order to study the effect
of loom speed and shed height on the beating – up force. The mathematical model of warp threads mechanics
established by the researcher was used to predict the warp threads tension.The results obtained clearly show
that as the loom speed increased the beating – up force also increased. However, with speeds up to 180
revs/min the rate of increase of the beating – up force is not pronounced, but at higher speeds there is a
substantial increase in the values of the beating – up force. Furthermore, the results obtained also showed
that the beating-up force increased as the shed height increase
Implementation of Direction Control Algorithms for Fixed Wings UAV
Get PDFThe demand for unmanned aircraft vehicles, UAV, has grown quite significantly in recent
years. It is therefore important to implement efficient and accurate computer controlled navigation
algorithms on such vehicles to guarantee the successful and reliable delivery of the vehicle to its final
destination. This paper describes algorithms that use the Global Positioning system data to navigate from the
current position to the destination point. The algorithm continuously adjusts the direction of flight thus
ensuring the shortest path to the target. The algorithm has been successfully tested within Khartoum
Province
Flood Modeling Water Appraisal and Land Reclamation: A Case Study of Gash River
Get PDFWith the objective to solve Kassala Town flooding on one hand and appraise and utilize the surface and ground water potential on the other, a Correlation Model applied at El Gira, station with Kassala indicated that Kassala is continuously subjected to high floods risks. Gumbel Distribution Model and digitized map of the Gash River catchment area gave the same degree of risk. A four to five years flood return period was found to be about 600 m3/sec at Kassala Station with a discharge at El Gira about 750 m3/sec. Only 5 % of the surface water passing Kassala Town is consumed for irrigating an area of 20 000 feddans per year. It was found that the agricultural area can be reclaimed through a by pass upstream Kassala Town, making Kassala safe on one hand and using the excess water in cultivation on the other. Using HEC-HMS Model at the confluence of Khor Abu Alaga with the Gash River a hydrograph was obtained which indicated that the base flow has a maximum of 400 m3/sec. with a maximum observed surface flow of 900m3/sec. Hence the HEC-HMS Model besides indicating ground water base verified the results of the surface flow upstream Kassala gauging station obtained by both Empirical and Gumbel Distribution Models. The observed surface flow being 900 m3/sec is logical and consistent with the corresponding result obtained at Kassala which was found to be a maximum of only 750 m3/sec. Using G.I.S. available facilities contour maps were plotted, and ground water potential being both quantitatively and qualitatively excellent were found to be 3897.6 Mm3. The study recommended cooperation between Sudan, and Gash River Basin countries, as well as establishing an early warning system to reduce the risk hazards
Performance Analysis of Isolated Self-Excited Reluctance Generators Connected to Diode Bridge Rectifier
Get PDFThis paper presents the performance of a three-phase self-excited reluctance generator connected to a diode bridge rectifier. The steady-state mathematical model is used to perform the self-excited reluctance generator performance. The performance is presented under load and no load cases for different operation conditions. The experiments are performed using a prototype reluctance generator. MATLAB/SIMULINK softwar
Space Vector Pulse Width Modulation Technique Applied to Two Level Voltage Source Inverter
Get PDFSpace vector pulse width modulation SVPWM provides a better technique compared to
the other pulse width modulation techniques. This paper presents simulation and implementation of
SVPWM signal generation for driving three phase two level voltage source inverter VSI, also
proposes and analyzes a new switching sequence for generating an SVPWM. Simulation results are
obtained using the simulation package PSIM. and the inverter performance is evaluated in terms of
total harmonic distortion (THD). The model is experimentally implemented and verified on Arduino
Mega Atmega2560 microcontroller