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Articles 61 - 90 of 104
Full-Text Articles in Electrical and Electronics
Wind Power Integration And Its Impact On Power Quality-A Didactic Approach, Santos Kihwele Dr
Wind Power Integration And Its Impact On Power Quality-A Didactic Approach, Santos Kihwele Dr
Tanzania Journal of Engineering and Technology (TJET)
This paper presents a model of a wind power system integrated with realistic power system, with intention of using it in addressing power quality issues in relations to grid codes during steady-state operation transient-state operation i.e., presence of grid fault events. For that case, a didactic approach of the normal performance of power systems due to the connection of fixed-speed wind turbine with induction generators is used. A study of integrating wind farms will be presented, including the incidence of high inrush current due to switching capacitor banks, out-rush current and voltage sags due to nearby three phase faults. As …
Performance Analysis Of Renewable Energy Resources In Rural Areas: A Case Study Of Solar Energy, Jackson Justo
Performance Analysis Of Renewable Energy Resources In Rural Areas: A Case Study Of Solar Energy, Jackson Justo
Tanzania Journal of Engineering and Technology (TJET)
This paper presents an overview of the recent development trends of solar photovoltaic (PV) systems and the performance in the Tanzanian context. The two types of solar power generation that are considered in this paper are: i) solar PV systems and ii) concentrated solar power (CSP). The two are compared in terms of cost of energy and energy storage mechanism. Moreover, the effect of ambient temperature on the solar PV module is analyzed. In addition, a detailed analysis on using solar axis tracking to increase the power generation is also presented. The extent to which the cell surface temperature and …
Modeling And Control Of Solar Pv With Battery Energy Storage For Rural Electrification, Irene Masenge
Modeling And Control Of Solar Pv With Battery Energy Storage For Rural Electrification, Irene Masenge
Tanzania Journal of Engineering and Technology (TJET)
In rural areas where electric power grid network is rarely available, power generation from renewable energy resource such as solar photovoltaic (PV) is mostly accomplished in standalone mode. The standalone solar PV system requires energy storage device to achieve reliable power supply to the end users. This paper presents modelling and coordination control of solar PV with battery energy storage system (BESS) for rural-electrification applications. The proposed control is accomplished via a bidirectional buck-boost converter with the objective of maintaining voltage at the DC bus constant. Simulation results based-on MATLAB/Simulink platform confirms good performance of the proposed system
Multipath Exploitation-Based Indoor Target Localization Model Using Single Marginal Antenna, Joseph Sisala
Multipath Exploitation-Based Indoor Target Localization Model Using Single Marginal Antenna, Joseph Sisala
Tanzania Journal of Engineering and Technology (TJET)
Recently, indoor target localization became an area of interest due to its diverse applications. In indoor target localization, surrounding environment creates multipath components, which can be exploited to aid in localization process. A number of studies have been proposed to employ multipath exploitation in localizing indoor targets. However, their localization errors can still be improved. This study proposed a new localization model based on multipath exploitation techniques by using triangulation method. Ultra-wide band signals were resolved and associated using marginal antenna-based scheme. The estimate of the target location was then obtained using measured round-trip time delays. The location was determined …
The Potentials Of Faecal Sludge Treatment Using Local Conditioners In Tanzania: A Review, Doglas Benjamin1
The Potentials Of Faecal Sludge Treatment Using Local Conditioners In Tanzania: A Review, Doglas Benjamin1
Tanzania Journal of Engineering and Technology (TJET)
Worldwide, every day human beings generate millions of tons of Faecal Sludge (FS), which is rich in water, nutrients, energy, and organic compounds. Yet FS is not being managed in a way that permits us to derive value from its reuse, while at the same time, millions of farmers struggle with depleted soils and lack of water. In most of the developing countries, energy for cooking is mainly derived from cutting of trees, either as wood or charcoal. Resource recovery and reuse from FS can create livelihoods, enhance food security, support green economies, reduce waste and contribute to cost recovery …
Blind Algorithm Development For Peak To Average Power Ratio Reduction In Ofdm Systems Under Frequency Selective Channels, Kwame S. Ibwe
Blind Algorithm Development For Peak To Average Power Ratio Reduction In Ofdm Systems Under Frequency Selective Channels, Kwame S. Ibwe
Tanzania Journal of Engineering and Technology (TJET)
One major drawback of orthogonal frequency division multiplexing (OFDM) system is peak to average power ratio (PAPR). This effect causes high power amplifier (HPA) to introduce intermodulation and out of band radiation as the signal goes through, thus degrades the performance of OFDM systems. This paper proposes blind algorithms which takes advantage of signal transformation technique and signal distortion technique. Simulation results show that at complementary cumulative distribution function (CCDF) level of 10-3, the proposed algorithm achieved 3.2 dB PAPR improvement compared to discrete Fourier transform with interleaved frequency division multiple access (DFT-IFDMA) based algorithm. The bit error rate (BER) …
The Comparative Analysis Of The Performances Of Four And Six Pole Pairs Permanent Magnet Synchronous Generator, Ra Msuya
Tanzania Journal of Engineering and Technology (TJET)
Wind power applications using multi-poles permanent magnet generators have become very attractive especially in small ratings. Low-speed multi-pole PM generators are maintenance-free and may be used in different climate conditions. Most of the low speed wind turbine generators presented is permanent magnet machines, which have advantages of high efficiency and reliability since there is no need of external excitation and conductor losses are removed from the rotor. From the study two types of PM AC generator are designed with 6 pole pairs and the other one with 4 pole pairs. These generators were designed and analysed using Maxwell software. The …
Nonlinear Direct Torque Control Of Interior Permanent Magnet Synchronous Motor Drive, Jackson Justo
Nonlinear Direct Torque Control Of Interior Permanent Magnet Synchronous Motor Drive, Jackson Justo
Tanzania Journal of Engineering and Technology (TJET)
This paper presents a nonlinear direct torque control (NDTC) strategy of interior permanent magnet synchronous motors (IPMSMs) for electric vehicle (EV) propulsion. The proposed NDTC scheme applies a nonlinear model of IPMSM to dynamically determine the optimal switching states that optimize the EV drivers’ decision to reduce the workload. Moreover, the proposed NDTC method has a simple control structure and can explicitly handle system constraints and nonlinearities. The performance evaluation is conducted via a prototype IPMSM test-bed with a TMS320F28335 DSP. Comparative experimental results provide the evidence of improvements of the proposed NDTC strategy over the conventional DTC strategy by …
Low Voltage Ride Through Enhancement For Wind Turbines Equipped With Dfig Under Symmetrical Grid Faults, Francis Mwasilu
Low Voltage Ride Through Enhancement For Wind Turbines Equipped With Dfig Under Symmetrical Grid Faults, Francis Mwasilu
Tanzania Journal of Engineering and Technology (TJET)
In modern power systems with significant penetration of wind-turbines (WTs), improvement of low voltage ride through (LVRT) capability of WTs equipped with doubly-fed induction generators (DFIGs) is an important issue. Thus, this paper proposes a low voltage ride through (LVRT) strategy, which comprise of a capacitor connected in series with an inductor both connected in parallel to a resistor. The configuration is then connected to a small series resistor via a pair of antiparallel-Thyristors. The circuit and its switching control scheme of the proposed LVRT circuit are designed to: minimize the transition times, maintain the RSC connection to the rotor-windings, …
Loss Modeling Of A Permanent Magnet Dc Motor Drive Water Pumping System, Nelson Lujara
Loss Modeling Of A Permanent Magnet Dc Motor Drive Water Pumping System, Nelson Lujara
Tanzania Journal of Engineering and Technology (TJET)
The paper presents an analytical approach to the determination of losses in each of the sub-systems of the Photovoltaic (PV) Permanent Magnet DC Motor (PMDC) drive water pumping system with and without maximum power tracking. The losses of the system at varying heads are firstly, determined using parameters from the data sheets and then validated by experimental results. The results are used to establish the head and the flow rate optimal operating point of the system.
Analysis Of Power Efficiency Of A Direct-Driven Locally Fabricated Permanent Magnet Ac Generator For Small-Scale Wind Power Applications In Tanzania, Mussa Iddi Mgwatu Dr.
Analysis Of Power Efficiency Of A Direct-Driven Locally Fabricated Permanent Magnet Ac Generator For Small-Scale Wind Power Applications In Tanzania, Mussa Iddi Mgwatu Dr.
Tanzania Journal of Engineering and Technology (TJET)
The use of direct-driven permanent magnet alternating current (AC) generators offers the opportunity to reduced costs and increased system efficiency. This type of generator could be the best alternative for rural population whom are not connected to the national grid. To improve the design and efficiency of locally fabricated generators, it is imperative to characterize both their mechanical and electrical parameters. This paper presents the analysis of power efficiency of the synchronous permanent AC generator locally fabricated in Tanzania. In this case, load resistance and rotational speed are characterized using designed experiment. The output current and voltage of the generator …
Gas Leakage Detection System (Glds), Daudi Simbeye
Gas Leakage Detection System (Glds), Daudi Simbeye
Tanzania Journal of Engineering and Technology (TJET)
This paper mainly focuses on the detection of gas leakage and providing security when the user is around or away from home. The system is Short Message Service (SMS) based and uses wireless technology for providing security against gas leakage to users hence cost effective and more adaptable. The system comprises of sensors for detecting gas leak interfaced to microcontroller that will give an alert to user whenever there is a gas leakage, display warning information by using Liquid Crystal Display (LCD), sending SMS to the user for notification wherever he/she might be and turning off electric power with the …
Adaptive Iir Filters For Single Interference Suppression In A Bpsk Ds Cdma System In Rayleigh Fading Channel, Aloys Mvuma
Adaptive Iir Filters For Single Interference Suppression In A Bpsk Ds Cdma System In Rayleigh Fading Channel, Aloys Mvuma
Tanzania Journal of Engineering and Technology (TJET)
In this paper, effect of a single narrow-band interference (NBI) on bit error rate (BER) performance for a binary phase shift keying (BPSK) synchronous direct-sequence code-division multiple access (DS CDMA) communication system operating in a frequency nonselective Rayleigh fading channel is analyzed. Second-order adaptive infinite impulse response (IIR) notch filters with plain gradient algorithm (GA) for suppression of NBI in the DS CDMA system are proposed. A general closed-form BER expression for the DS CDMA system with NBI suppression second order adaptive IIR notch filters is derived based on the standard Gaussian approximation (SGA) method. BER expressions are then derived …
Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor
Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor
Tanzania Journal of Engineering and Technology (TJET)
This paper reports on a research project conducted with an objective of identifying and assessing various approaches used by different computer users (Management, System Administrators and end users) in Tanzania to combat computer viruses (CVs), and to assess users' awareness level on CVs. Specifically, the study aimed at assessing the awareness level on CVs to the Tanzanian business community; analyze the socio -economic impact caused by CVs in Tanzania and; assess existing methods, capacity and limitations on controlling CVs in Tanzania. Data was collected using both questionnaires and interview from financial institutions such as NBC and BOT, and telecommunications sector …
Short-Term Scheduling Of A Hydro-Thermal System Using Linear Programming Technique, A Kyaruzi
Short-Term Scheduling Of A Hydro-Thermal System Using Linear Programming Technique, A Kyaruzi
Tanzania Journal of Engineering and Technology (TJET)
The paper discusses the short term scheduling of Hydrothermal for Tanzania Electricity Supply Company (TANESCO) Power System. The problem is to determine on hourly interval the Hydro and Thermal generation. The scheduling keeps balance between production and consumption in a reliable and economical way during the study period. Linear programming (LP) mathematical model using MATL4B has been developed. The constraints are hydrological balance, thermal power plants limitations and load requirements. The result from LP solution gave low operation cost. Generation was mainly from hydro and all reservoirs elevation was high at the end ofplanning period.
Energy Meter Reading And Tampering Protection Through Powerline Communication Channel, S Naiman
Energy Meter Reading And Tampering Protection Through Powerline Communication Channel, S Naiman
Tanzania Journal of Engineering and Technology (TJET)
POwer utility companies have suffered revenue losses due to uncollected bills and energy tampering for many years. The use of powerline communication to overcome the problems has been proposed. This needs tampering detection and transceivers capable of communicating data through poww•line channel. This paper identifies different methods Of tampering, presents simulated results for tampering detection scheme and proposes a Direct Sequence Spread Spectrum (DSSS) wilh Binary Phase Shift Keying (BPSK) transceiver design for energy metering as a solution to the problem. The choice of DSSS-BPSK modulation scheme is based on its robustness and its ability to spread signal inro wide …
Review Of The Product Development Process And Information Flow In The Manufacturing Industry: Problems And A Possible Wav Forward, E Opiyo
Tanzania Journal of Engineering and Technology (TJET)
No abstract provided.
Derivation And Analysis Of Maximum And Conditional Work Of An Electromagnet In Relays With Small Gaps And Constant Armature Load, Dominic Chambega
Derivation And Analysis Of Maximum And Conditional Work Of An Electromagnet In Relays With Small Gaps And Constant Armature Load, Dominic Chambega
Tanzania Journal of Engineering and Technology (TJET)
No abstract provided.
Probabilistic Load Flow For Mv Radial Distribution Networks Supplying Statistical Loads, B Kundy
Probabilistic Load Flow For Mv Radial Distribution Networks Supplying Statistical Loads, B Kundy
Tanzania Journal of Engineering and Technology (TJET)
Aecurate load models are required Jör 'he computation OJ' load on Medium Voltage (MV) distribution net•.vovk.s_ Modern microprocessors in recent times have enabled researchers stunple and log domestic loads. The findings show that domestic loads are stochastic in nonwe and are best described bv u beta probability distribution [Herman et al. 1999]. The statistical evaluafion lhe consumer voltages requires description load currents al rhe lime e/ lhe system maximum demand. In this paper. an analytical 1001 computing voltage vegulation on MV distribution net-norks fi•eding statistical louds is presenled. To deal beta- distributed currents on MV distribution networks, new scaling factors …
Service And Network Modeling For Implementation Of Powerline Remote Monitoring Of Electrical Power Metering In Tanzania, J Anatory
Tanzania Journal of Engineering and Technology (TJET)
The conventional metering. pyepa.vmen,' and estimates have been used in power utilities industries. The svslen,'s hare experienced many problems such as power tampering, bill tampering, ./åiluve ro receive invoices by poner unlity customers and so on. Different technologies have been investigated To overcome the problems and recently it has been realized that remote 'nonitoring sysle•ns through powerline channel is a solution offhese problems in Tanami". However. 'he powerline network has been used for electrical power IO use i,' for implementation of remote monitoring: network must be setup and has to be modeled to accommodate communications. The contribution has analyzed 'he …
Load Flow Solution For Three-Phase Mv Radial Distribution Connected Network Supplying Different Line Topologies, B. J. Kundy
Load Flow Solution For Three-Phase Mv Radial Distribution Connected Network Supplying Different Line Topologies, B. J. Kundy
Tanzania Journal of Engineering and Technology (TJET)
In this paper, a load flow solution for the Medium Voltage (MV) three-phase radial distribution in delta-delta (Δ–Δ) connected network supplying different line topologies such as three phase, phase to phase and single-wire earth return (SWER) networks is presented. The general voltage related network equations are developed using Kirchhoff’s voltage and current laws. Development of a solution to the load flow analysis applying the developed general voltage related network equations is proposed in order to evaluate the network voltage profile. Various numbers of arrays are developed for the identification of the network under study. The proposed method is a new …
Analysis On Possible Solution To Decreasing The Effect Of Non-Uniform Air-Gaps Due To Rotor Eccentricity In Asynchronous Machines, Dominic Chambega
Analysis On Possible Solution To Decreasing The Effect Of Non-Uniform Air-Gaps Due To Rotor Eccentricity In Asynchronous Machines, Dominic Chambega
Tanzania Journal of Engineering and Technology (TJET)
Rotor eccentricity introduces non-uniformity of the airgap which in turn causes additional frictional torques and losses in addition to establishing a uni-directional pulling magnetic force which is disastrous to the machine. This paper analyses the extent of the damage to the machine due to non-uniformity of the air-gap and proposes increasing the number of poles as a possible solution to arrest the effect. It is found through the analysis that as the number of poles increases the effect of eccentricity decreases.
A Comparative Application Of Telecommunication Traffic Forecasting Methods To A Backbone Link In Tanzania, M. L. Luhanga
A Comparative Application Of Telecommunication Traffic Forecasting Methods To A Backbone Link In Tanzania, M. L. Luhanga
Tanzania Journal of Engineering and Technology (TJET)
In this paper various mathematical models to characterize and forecast telecommunication traffic time series traffic have been applied, and the ranges of validity of the models are determined by comparing them with measured traffic data using the measurement errors criteria method which resulted into the superior model. Based on this model the ARIMA (0,2,1) model for smoothed data, the traffic forecast findings show that by the year 2006, the traffic demand will exceed the current installed capacity of 140 Mbps in the Tanzania Telecommunications Company Limited (TTCL) network along the major link between the Dar es Salaam and Dodoma backbone …
Application Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Arton Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Art, Silas Kajuna
Tanzania Journal of Engineering and Technology (TJET)
Vibration is one of the techniques employed in the determination of dynamic properties of fruits and vegetables. It entails generation of a mechanical or acoustic vibrational signal which is propagated through the flesh of the agricultural material. A transducer is either attached or held close to the specimen to monitor the propagation of the signal through the specimen. The manner in which the signal is transmitted through the material is analyzed, and the dynamic properties of the specimen which relate to its firmness or its internal being are derived. The technique has been around for the past 30 years or …
Evaluation Of The Influence Of The Magnetic System In Relays, D Chambega
Evaluation Of The Influence Of The Magnetic System In Relays, D Chambega
Tanzania Journal of Engineering and Technology (TJET)
The paper evaluates the influence of different cores on the performance of relays. In particular two types ofc-cores, all made from IOW quality mag- netic steel, are considered. The two cores, one butt-constructed and the other interleaved, are mathematically modelled and the tesults are analyzed and obtained experimentally. Then the two sets of results are compared with those ofa c-shaped core of excellent magnetic material with the aim of qualifying the influence of the core material. It is observed that the method of constructing the core also influences the performance.
Power Shedding Experiences And Lessons In A Township, Alexander Kyaruzi
Power Shedding Experiences And Lessons In A Township, Alexander Kyaruzi
Tanzania Journal of Engineering and Technology (TJET)
This paper presents how power shedding by taking out one of the trans- former high voltage fuses causes phase imbalance. And for the same elec- nicc,l energy output generator fuel consuntption with unbalanced phases is 12.5% of The fuel consunwtion with balanced phases. Furthermore it is shown thal energy efficient lighting by use of energy efficient bulbs can reduce load shedding.
Application Of Improved Pressure Transducers For Pressure Measurements, P Mtui
Application Of Improved Pressure Transducers For Pressure Measurements, P Mtui
Tanzania Journal of Engineering and Technology (TJET)
Substantial improvement of low sensitivity pressure transducers aiming at obtaining a more realistic output signal is discussed. The output signal direct from these transducers has deficiencies of amplitude attenuation and phase lag, thus the measured values are not necessarily the true in- stantaneous values. In order to correct for such shortcomings the unit step response of these transducers is also studied experimentally. A math- ematical model is established based on the experimental results to build up a compensation circuit which is then included in the instrumentation setup to eliminate these deficiencies. The effectiveness of the compensated transducer is demonstrated by …
An Alternative Method Of Interfacing A Dc Motor To A Microprocessor For Mo- Tion Control, M Selekwa
An Alternative Method Of Interfacing A Dc Motor To A Microprocessor For Mo- Tion Control, M Selekwa
Tanzania Journal of Engineering and Technology (TJET)
A Simple and cheap alternative method Of interfacing a permanent mag- net dc motor to a motion control using switch- ing transistor motor drivers is presented. This method involves the use Of very few transistor-transistor logic (TTL) devices and a 555 timer to pro- duce a pulse width modulated (P WM) signal which is required by the mo- ror driver. The motor driver in this case should be of an H-bridge type. Like other methods currently in use, it relieves the MPU of all timing func- tions which are necessary in the generation of P WM signals. The present method, …
Dual Versus Single Spark Plug: A Critique, I Mshoro
Dual Versus Single Spark Plug: A Critique, I Mshoro
Tanzania Journal of Engineering and Technology (TJET)
Dual spark plugs are occasionally employed on certain modern Spark lg- nited (S') engines, viz lean burn engines. Their benefit has generally been noticed in the operating conditions whenfuel-air mixture is very lean, or when a larger proportion of EGR has been employed, or during the part load conditions and so on. An extensive literature survey has indi- cared an interesting spectrum of reasons for gains due to the dual spark plug. A consistent explanation is found to be missing which can describe the behaviour of the engines with single versus dual spark plugs There are quite "few researchers who …
A Check Parameter Method For Use In Designing Relays, H Kadete
A Check Parameter Method For Use In Designing Relays, H Kadete
Tanzania Journal of Engineering and Technology (TJET)
Low quality magnetic steel available locally has been successfully used as core material for a relay. New design principles as well as construction procedure used in development of a prototype are presented. Then the new approach is assessed and found to deliver acceptable accuracy.