Abstract: This article presents a new vibration diagnostic
method designed to (PM) machines with permanent magnets. Those
devices are commonly used in small wind and water systems or
vehicles drives. The author’s method is very innovative and unique.
Specific structural properties of PM machines are used in this method
- electromotive force (EMF) generated due to vibrations. There was
analysed number of publications which describe vibration diagnostic
methods and tests of electrical PM machines and there was no
method found to determine the technical condition of such machine
basing on their own signals. In this article will be discussed: the
method genesis, the similarity of machines with permanent magnet to
vibration sensor and simulation and laboratory tests results. The
method of determination the technical condition of electrical machine
with permanent magnets basing on its own signals is the subject of
patent application and it is the main thesis of author’s doctoral
dissertation.
Abstract: OEE has been used in many industries as measure of
performance. However due to limitations of original OEE, it has been
modified by various researchers. OEE for mining application is
special version of classic equation, carries these limitation over. In
this paper it has been aimed to modify the OEE for mining
application by introducing the weights to the elements of it and
termed as Mine Production index (MPi). As a special application of
new index MPishovel has been developed by authors. This can be used
for evaluating the shovel effectiveness. Based on analysis, utilization
followed by performance and availability were ranked in this order.
To check the applicability of this index, a case study was done on
four electrical and one hydraulic shovel in a Swedish mine. The
results shows that MPishovel can evaluate production effectiveness of
shovels and can determine effectiveness values in optimistic view
compared to OEE. MPi with calculation not only give the
effectiveness but also can predict which elements should be focused
for improving the productivity.
Abstract: WiMAX is a telecommunications technology and it is
specified by the Institute of Electrical and Electronics Engineers Inc.,
as the IEEE 802.16 standard. The goal of this technology is to
provide a wireless data over long distances in a variety of ways. IEEE
802.16 is a recent standard for mobile communication. In this paper,
we provide an overview of various key management algorithms to
provide security for WiMAX.
Abstract: Load Forecasting plays a key role in making today's
and future's Smart Energy Grids sustainable and reliable. Accurate
power consumption prediction allows utilities to organize in advance
their resources or to execute Demand Response strategies more
effectively, which enables several features such as higher
sustainability, better quality of service, and affordable electricity
tariffs. It is easy yet effective to apply Load Forecasting at larger
geographic scale, i.e. Smart Micro Grids, wherein the lower available
grid flexibility makes accurate prediction more critical in Demand
Response applications. This paper analyses the application of
short-term load forecasting in a concrete scenario, proposed within the
EU-funded GreenCom project, which collect load data from single
loads and households belonging to a Smart Micro Grid. Three
short-term load forecasting techniques, i.e. linear regression, artificial
neural networks, and radial basis function network, are considered,
compared, and evaluated through absolute forecast errors and training
time. The influence of weather conditions in Load Forecasting is also
evaluated. A new definition of Gain is introduced in this paper, which
innovatively serves as an indicator of short-term prediction
capabilities of time spam consistency. Two models, 24- and
1-hour-ahead forecasting, are built to comprehensively compare these
three techniques.
Abstract: Economic Dispatch (ED) is one of the most
challenging problems of power system since it is difficult to determine
the optimum generation scheduling to meet the particular load demand
with the minimum fuel costs while all constraints are satisfied. The
objective of the Economic Dispatch Problems (EDPs) of electric
power generation is to schedule the committed generating units
outputs so as to meet the required load demand at minimum operating
cost while satisfying all units and system equality and inequality
constraints. In this paper, an efficient and practical steady-state genetic
algorithm (SSGAs) has been proposed for solving the economic
dispatch problem. The objective is to minimize the total generation
fuel cost and keep the power flows within the security limits. To
achieve that, the present work is developed to determine the optimal
location and size of capacitors in transmission power system where,
the Participation Factor Algorithm and the Steady State Genetic
Algorithm are proposed to select the best locations for the capacitors
and determine the optimal size for them.
Abstract: This paper deals with the issue of biomass and sorted
municipal waste gasification and cogeneration using hot-air turbo-set.
It brings description of designed pilot plant with electrical output 80
kWe. The generated gas is burned in secondary combustion chamber
located beyond the gas generator. Flue gas flows through the heat
exchanger where the compressed air is heated and consequently
brought to a micro turbine. Except description, this paper brings our
basic experiences from operating of pilot plant (operating parameters,
contributions, problems during operating, etc.). The principal
advantage of the given cycle is the fact that there is no contact
between the generated gas and the turbine. So there is no need for
costly and complicated gas cleaning which is the main source of
operating problems in direct use in combustion engines because the
content of impurities in the gas causes operation problems to the units
due to clogging and tarring of working surfaces of engines and
turbines, which may lead as far as serious damage to the equipment
under operation. Another merit is the compact container package
making installation of the facility easier or making it relatively more
mobile. We imagine, this solution of cogeneration from biomass or
waste can be suitable for small industrial or communal applications,
for low output cogeneration.
Abstract: The aim of this work is to present a theoretical analysis of a 2D ultrasound transducer comprised of crossed arrays of metal strips placed on both sides of thin piezoelectric layer (a). Such a structure is capable of electronic beam-steering of generated wavebeam both in elevation and azimuth. In this paper a semi-analytical model of the considered transducer is developed. It is based on generalization of the well-known BIS-expansion method. Specifically, applying the electrostatic approximation, the electric field components on the surface of the layer are expanded into fast converging series of double periodic spatial harmonics with corresponding amplitudes represented by the properly chosen Legendre polynomials. The problem is reduced to numerical solving of certain system of linear equations for unknown expansion coefficients.
Abstract: Voltage sags are the most common power quality
disturbance in the distribution system. It occurs due to the fault in the
electrical network or by the starting of a large induction motor and
this can be solved by using the custom power devices such as
Dynamic Voltage Restorer (DVR). In this paper DVR is proposed to
compensate voltage sags on critical loads dynamically. The DVR
consists of VSC, injection transformers, passive filters and energy
storage (lead acid battery). By injecting an appropriate voltage, the
DVR restores a voltage waveform and ensures constant load voltage.
The simulation and experimental results of a DVR using MATLAB
software shows clearly the performance of the DVR in mitigating
voltage sags.
Abstract: This paper aims at finding a suitable neural network
for monitoring congestion level in electrical power systems. In this
paper, the input data has been framed properly to meet the target
objective through supervised learning mechanism by defining normal
and abnormal operating conditions for the system under study. The
congestion level, expressed as line congestion index (LCI), is
evaluated for each operating condition and is presented to the NN
along with the bus voltages to represent the input and target data.
Once, the training goes successful, the NN learns how to deal with a
set of newly presented data through validation and testing
mechanism. The crux of the results presented in this paper rests on
performance comparison of a multi-layered feed forward neural
network with eleven types of back propagation techniques so as to
evolve the best training criteria. The proposed methodology has been
tested on the standard IEEE-14 bus test system with the support of
MATLAB based NN toolbox. The results presented in this paper
signify that the Levenberg-Marquardt backpropagation algorithm
gives best training performance of all the eleven cases considered in
this paper, thus validating the proposed methodology.
Abstract: Researches and concerns in power quality gained
significant momentum in the field of power electronics systems over
the last two decades globally. This sudden increase in the number of
concerns over power quality problems is a result of the huge increase
in the use of non-linear loads. In this paper, power quality evaluation
of some distribution networks at Misurata - Libya has been done
using a power quality and energy analyzer (Fluke 437 Series II). The
results of this evaluation are used to minimize the problems of power
quality. The analysis shows the main power quality problems that
exist and the level of awareness of power quality issues with the aim
of generating a start point which can be used as guidelines for
researchers and end users in the field of power systems.
Abstract: This paper presents the voltage problem location
classification using performance of Least Squares Support Vector
Machine (LS-SVM) and Learning Vector Quantization (LVQ) in
electrical power system for proper voltage problem location
implemented by IEEE 39 bus New- England. The data was collected
from the time domain simulation by using Power System Analysis
Toolbox (PSAT). Outputs from simulation data such as voltage, phase
angle, real power and reactive power were taken as input to estimate
voltage stability at particular buses based on Power Transfer Stability
Index (PTSI).The simulation data was carried out on the IEEE 39 bus
test system by considering load bus increased on the system. To verify
of the proposed LS-SVM its performance was compared to Learning
Vector Quantization (LVQ). The results showed that LS-SVM is faster
and better as compared to LVQ. The results also demonstrated that the
LS-SVM was estimated by 0% misclassification whereas LVQ had
7.69% misclassification.
Abstract: This study models the use of transcutaneous electrical
nerve stimulation on skin with a disk electrode in order to simulate
tissue damage. The current density distribution above a disk electrode
is known to be a dynamic and non-uniform quantity that is intensified
at the edges of the disk. The non-uniformity is subject to change
through using various electrode geometries or stimulation methods.
One of these methods known as edge-retarded stimulation has shown
to reduce this edge enhancement. Though progress has been made in
modeling the behavior of a disk electrode, little has been done to test
the validity of these models in simulating the actual heat transfer
from the electrode. This simulation uses finite element software to
couple the injection of current from a disk electrode to heat transfer
described by the Pennesbioheat transfer equation. An example
application of this model is studying an experimental form of
stimulation, known as edge-retarded stimulation. The edge-retarded
stimulation method will reduce the current density at the edges of the
electrode. It is hypothesized that reducing the current density edge
enhancement effect will, in turn, reduce temperature change and
tissue damage at the edges of these electrodes. This study tests this
hypothesis as a demonstration of the capabilities of this model. The
edge-retarded stimulation proved to be safer after this simulation. It is
shown that temperature change and the fraction of tissue necrosis is
much greater in the square wave stimulation. These results bring
implications for changes of procedures in transcutaneous electrical
nerve stimulation and transcutaneous spinal cord stimulation as well.
Abstract: Attractive and creative advertisement displays are
often in high demand as they are known to have profound impact on
the commercial market. In the fast advancement of technology,
advertising trend has taken a great leap in attracting more and more
demanding consumers. A low-cost and low-power consumption
flipping advertisement board has been developed in this paper. The
design of the electrical circuit and the controller of the advertisement
board are presented. A microcontroller, a Darlington Pair driver and a
unipolar stepper motor were used to operate the electrical flipping
advertisement board. The proposed system has been implemented
and the hardware has been tested to demonstrate the capability of
displaying multiple advertisements in a panel.
Abstract: This paper presents the electrical effect of two neighboring distribution substation during the construction phase. The size of auxiliary grounding grid have an effect on entire grounding system. The bigger the size of auxiliary grounding grid, the lower the GPR and maximum touch voltage, with the exception that when the two grids are unconnected, i.e. the bigger the size of auxiliary grounding grid, the higher the maximum step voltage. The results in this paper could be served as design guideline of grounding system, and perhaps remedy of some troublesome grounding grids in power distribution’s system. Modeling and simulation is carried out on the Current Distribution Electromagnetic interference Grounding and Soil structure (CDEGS) program. The simulation results exhibit the design and analysis of power system grounding and perhaps could be set as a standard in grounding system design and modification in distribution substations.
Abstract: The purpose of this work is to optimize a Switched Reluctance Motor (SRM) for an automotive application, specifically for a fully electric car. A new optimization approach is proposed. This unique approach transforms automotive customer requirements into an optimization problem, based on sound knowledge of a SRM theory. The approach combines an analytical and a finite element analysis of the motor to quantify static nonlinear and dynamic performance parameters, as phase currents and motor torque maps, an output power and power losses in order to find the optimal motor as close to the reality as possible, within reasonable time. The new approach yields the optimal motor which is competitive with other types of already proposed motors for automotive applications. This distinctive approach can also be used to optimize other types of electrical motors, when parts specifically related to the SRM are adjusted accordingly.
Abstract: Current transformers (CTs) are used to transform large primary currents to a small secondary current. Since most standard equipment’s are not designed to handle large primary currents the CTs have an important part in any electrical system for the purpose of Metering and Protection both of which are integral in Power system. Now a days due to advancement in solid state technology, the operation times of the protective relays have come to a few cycles from few seconds. Thus, in such a scenario it becomes important to study the transient response of the current transformers as it will play a vital role in the operating of the protective devices.
This paper shows the steady state and transient behavior of current transformers and how it changes with change in connected burden. The transient and steady state response will be captured using the data acquisition software LabVIEW. Analysis is done on the real time data gathered using LabVIEW. Variation of current transformer characteristics with changes in burden will be discussed.
Abstract: The Indian subcontinent is facing a massive challenge with regards to energy security in its member countries; to provide reliable electricity to facilitate development across various sectors of the economy and consequently achieve the developmental targets. The instability of the current precarious situation is observable in the frequent system failures and blackouts.
The deployment of interconnected electricity ‘Supergrid’ designed to carry huge quanta of power across the Indian sub-continent is proposed in this paper. Not only enabling energy security in the subcontinent it will also provide a platform for Renewable Energy Sources (RES) integration. This paper assesses the need and conditions for a Supergrid deployment and consequently proposes a meshed topology based on Voltage Source High Voltage Direct Current (VSC- HVDC) converters for the Supergrid modeling. Various control schemes for the control of voltage and power are utilized for the regulation of the network parameters. A 3 terminal Multi Terminal Direct Current (MTDC) network is used for the simulations.
Abstract: For Common R or R-L load to apply arbitrary voltage,
the bridge traditional inverters don’t have any difficulties by PWM
method. However for driving some piezoelectric actuator, arbitrary
voltage not a pulse but a steady voltage should be applied.
Piezoelectric load is considered as R-C load and its voltage does not
decrease even though the applied voltage decreases. Therefore it needs
some special inverter with circuit that can discharge the capacitive
energy. Especially for unidirectional arbitrary voltage driving like as
sine wave, it becomes more difficult problem. In this paper, a charge
and discharge circuit for unidirectional arbitrary voltage driving for
piezoelectric actuator is proposed. The circuit has charging and
discharging switches for increasing and decreasing output voltage.
With the proposed simple circuit, the load voltage can have any
unidirectional level with tens of bandwidth because the load voltage
can be adjusted by switching the charging and discharging switch
appropriately. The appropriateness is proved from the simulation of
the proposed circuit.
Abstract: Microwave dielectric ceramic materials of
(Mg1-xNix)2(Ti0.95Sn0.05)O4 for x = 0.01, 0.03, 0.05, 0.07 and 0.09 were
prepared and sintered at 1250–1400 ºC. The microstructure and
microwave dielectric properties of the ceramic materials were
examined and measured. The observations shows that the content of
Ni2+ ions has little effect on the crystal structure, dielectric constant,
temperature coefficient of resonant frequency (τf) and sintering
temperatures of the ceramics. However, the quality values (Q×f) are
greatly improved due to the addition of Ni2+ ions. The present study
showed that the ceramic material prepared for x = 0.05 and sintered at
1325ºC had the best Q×f value of 392,000 GHz, about 23%
improvement compared with that of Mg2(Ti0.95Sn0.05)O4.
Abstract: Surplus electricity can be converted into potential energy via pumped hydroelectric storage for future usage. Similarly, thermo-electric energy storage (TEES) uses heat pumps equipped with thermal storage to convert electrical energy into thermal energy; the stored energy is then converted back into electrical energy when necessary using a heat engine. The greatest advantage of this method is that, unlike pumped hydroelectric storage and compressed air energy storage, TEES is not restricted by geographical constraints. In this study, performance variation of the TEES according to the changes in cold-side storage temperature was investigated by simulation method.