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Piezoelectric Energy Harvesting (PEH) has been increasingly adopted due to its substantial potential to harness unutilized vibrations for multiple small- and large-scale real-life applications. Various publications have discussed the PEH rationale and operating principles. Nonetheless, there is a considerable knowledge gap, reflected in a limited number of peer-reviewed articles, involving the selection of optimal PEH location during real-time operational excitations, like wind turbines. Subsequently, this paper considers the Vertical-Axis Wind Turbines (VAWTs) to accumulate vibrations realized mainly at the turbine's tower. Experimental Modal Analysis (EMA) and Operational Deflection Shape (ODS) analysis were employed to predict the natural frequency behavior, vibrational intensity, and electrical power output at various locations along the VAWT's tower. The tower was divided into eight zones to determine which region could yield the maximum power output from the VAWT-PEH system. Many publications have suggested that the region closer to the fixed base of the VAWT would experience the maximum deflection. Yet, this research has shown that the zone nearer the top of the VAWT tower exhibited the highest deflection rates and greater turbulence, resulting in better electrical power production. Consequently, region No. 1 gave the highest deflection, corresponding to a maximum electrical power from excitations with a peak-to-peak voltage of 2.834 V compared with 2.754 V for point No. 8. These lower charges could be practical for powering small-power consumption devices, such as sensors and LEDs, especially when they need a permanent power supply. [ABSTRACT FROM AUTHOR]

Solar PV system in Jordan holds a significant potential, and studies show that solar radiation levels ranging from 2 to 7 kWh/m2 and approximately 330 sunny days per year. One of the modified designs on photovoltaic systems is the off-grid mobile PV generator system, capable of producing an electric power output up to 2 kWh/day and incorporating a storage battery system as a backup. The proposed system is compact, small and can be transferred to any location easily. The PV arrays mounted on the main body can be hydraulically opened and closed to save space, ensuring high mobility, easy of construction and operation within short time. This innovative system represents an intelligent solution for numerous locations requiring electrical power such as disaster areas like flood and earthquake zones, sparsely populated regions and camping places. Moreover, this project serves as an educational, practical, and training exercise on Mechanical Engineering principles for undergraduate students. It also constitutes a high-performance engineering project, enabling engineering students to acquire knowledge in solar PV systems, engineering skills, and the freedom to express their creativity and imaginations. Ultimately, this initiative aims to foster the development of experience, skills and professionalism, cultivating "hands on engineers", and potentially contributing to the enhancement of the automotive industry in Jordan. The research work in this paper encompasses the design, construction, and test of a 1 kW mobile PV generator with results demonstrating alignment with the design system. [ABSTRACT FROM AUTHOR]

The Organic Rankine Cycle (ORC) is a promising method for converting thermal energy into electrical power. The National Research and Innovation Agency (BRIN) developed an ORC pilot plant with a power output of 100 kilowatts using heat from waste powerplant exhaust heat at Soreang, Jawa Barat, Indonesia. The working fluid utilized in this pilot plant is n-pentane, a highly flammable fluid; thus, the turbine used must be hermetically sealed. This plant uses a threestage radial outflow and axial inflow turbine that is designed using the analytical/empirical method and validated by numerical simulation analysis. A numerical simulation was conducted by varying the turbine rotation and outlet pressure in order to obtain the turbine performance curve. Through a comparison between analytical calculation and numerical simulation, the turbine's general performance at 8000 rpm is characterized by a pressure ratio of approximately 5.42, a mass flow rate of 3.28 kg/s, and a power output of 41.21 kW. The turbine stage performance typically fails to meet the desired design specifications when initiated at stator 1 and then extended to the remaining stages. In order to achieve a power output of 100 kW, the turbine must undergo a process of redesign or optimization. [ABSTRACT FROM AUTHOR]

In this research, a mathematical model was built to analyze the energy recovery potential of a annular thermoelectric generator. For the study, the conditions of mass flow and exhaust gas temperature of an internal combustion engine, which was operated at five load percentages (20%, 40%, 60%, 80% and 100%), were used. The study involves an analysis of the power output, loss power and net power of the annular TEG. Additionally, the effect of geometrical changes such as the height of the thermoelectric modules, and variations in the length and width of the heat exchanger are evaluated. The analysis of the results shows that the change in the engine load causes an increase of 8.40% and 15.41% in the mass flow and exhaust gas temperature. These types of changes lead to a 31.90% and 19.11% increase in electrical power and efficiency of the annular TEG. Additionally, the increase in the length of the P-type and N-type semiconductors leads to a 5.41% and 2.42% increase in power output and efficiency. The variation in the geometrical parameters of the heat exchanger demonstrates the existence of an optimal geometry that maximizes the electric power of the annular TEG. Therefore, a complete parametric analysis is required to balance the heat transfer capacity and loss power due to the hydraulic resistance of the TEG in the engine exhaust system. [ABSTRACT FROM AUTHOR]

An optimal energy harvesting system is required at the remote seismic node due to the constraints of photovoltaic cells and high cost of seismic installations. The conventional approach concentrates on upgrading the hardware and charging to sustain the power at the node. However, the DC-DC converter as electrical conditioning unit and the lead-acid battery as an energy storage medium lose electrical energy, usually characterized by energy leakage and a shorter lifecycle. In the first contribution, a developed algorithm is modelled around the curve-fitting equations and embedded in a common 8-bit microcontroller-based MPPT system. The MPPT algorithm controls the curve equations using polynomial regression and approximates the order of the equation to track optimal electrical power. This enables the prediction of instantaneous duty cycle levels across synchronous buck DC-DC converters for optimal energy conversion. The second contribution is the implementation of a system that involves a dedicated supercapacitor energy storage as a buffer and charge controller for the stability of the current flow through the remote seismic node. Most conventional MPPT predicting procedures initiated will result to expensive computational costs, especially for a relatively high-consuming power system. The contributions of this work allow relatively less computational yet Maximum Power Point Tracking (MPPT) for low-power remote seismic nodes. Therefore, a longer continuous runtime and sustainable electrical energy are achieved. In addition, the proposed approach was validated using Computer Controlled Photovoltaic System (CCPS). The curve fitting equation models linearized the non-linear characteristic relationship between the irradiance, temperature, and voltage levels with the selected photovoltaic module parameters. These models are implemented in C programming code as an algorithm, embedded in an 8-bit microcontroller, and deliver optimal duty cycle levels across the converter. Implying any low-cost microcontroller can be deployed due to simple computational processes. The performance of the proposed approach is evaluated with the CCPS with a deviation between 2.5 % and 5 % based on tabulated results and graphs. [ABSTRACT FROM AUTHOR]

This paper investigates improving the quality of the energy used in the railway field. Due to structural aspects, the railway substations of the high-speed lines generate a voltage imbalance, polluting the electric power. To solve this unbalance problem, a new structure of unbalance compensation based on the concept of impedance controller by Ac-chopper was introduced. This new strategy's dimensioning and control were based on real data provided by the Moroccan national railway operator ONCF. To prove that this solution has a significant impact on the treatment of the unbalance phenomenon and that the CCI compensator behaves like an Eco-design due to its constitution and the reduction of power losses, a comparison was established with the topologies using a Voltage Source Inverter (VSI) and Current Source Inverter (CSI) in terms of energy loss in the semi-conductors; the modelling of the three structures was performed under the MATLAB Simulink environment. The results showed that the CCI compensator is more efficient in limiting the unbalance problem than the other compensators (VSI and CSI). [ABSTRACT FROM AUTHOR]

There has been a lot of research on garbage collection vessels, but not many have utilized renewable energy. This research aims to utilize piezoelectricity as a power source for the conveyor of the garbage collection ship. When it rains, piezoelectricity will convert rainwater vibrations into electricity. This research uses an inner flat catamaran garbage collection vessel with a conveyor and a wing conveyor. The power source from piezoelectricity is planned to fulfil the power of the electric motor driving the conveyor. Piezoelectric experiments have been conducted with artificial raindrops with raindrop diameter variations of 8.5 mm, 10 mm, and 12 mm. The results have showed that the piezoelectricity required to support the electrical power of the conveyor is 520 pieces, with the average power generated is 55.69 watts per beat. In addition, the research has also produced a conceptual design of a garbage collection vessel with piezoelectricity on the ship's deck. [ABSTRACT FROM AUTHOR]

Renewable energy sources play a pivotal role in global energy reserves, with solar energy standing out as a prominent option due to its cleanliness, abundance, and minimal emissions. The conversion of solar energy into electrical power is facilitated by Photovoltaic (PV) technology. However, the efficiency of PV systems could be improved by elevated temperatures, adversely affecting both efficiency and operational lifespan. In order to address this challenge, this study explores the integration of passive cooling systems by using Phase Change Materials (PCM), specifically focusing on the enhanced capabilities provided by nanoparticles, referred to as Nanoparticles Enhanced Phase Change Materials (NePCM). This investigation establishes a 50-watt peak (Wp) PV system as a passive cooling system, comparing its performance with and without PCM and NePCM. The study evaluates three materials: traditional paraffin PCM, NePCM-Al2O3, and NePCM-ZnO. Experimental results, obtained at an intensity of 1000 W/m2, are validated by using a PV-PCM panel temperature modeling approach. The findings indicate that NePCM-ZnO performs better in reducing the PV system's operating temperature, lowering it from 59.4 °C to 52.62 °C at 1000 W/m2 intensity. Compared to PV systems without passive cooling, the study reveals that implementing NePCM-ZnO as a passive coolant enhances maximum PV output power by 10.85 W and maximum PV efficiency by 3.08%. This improvement is attributed to the significant reduction in the maximum PV temperature by 6.78 °C, displaying the efficacy of NePCM-ZnO in optimizing the operational performance of PV systems. [ABSTRACT FROM AUTHOR]

Wind power offers a clean and viable solution for generating electricity, but its effective utilization demands a thorough analysis of wind characteristics and precise wind energy forecasting at the study location. In this study, wind speed distributions are examined to calculate two Weibull parameters (shape and scale) using the Matlab software, which is frequently employed for modeling and offers accurate estimates of wind resources. These parameters are derived from a year of measured wind speed data collected in El Fnidek, Dakhla, and Essouira, Morocco. Six methods are presented for estimating the Weibull parameters: the Empirical Method of Justus (EMJ), the Empirical Method of Lysen (EML), Wind Energy Pattern Factor Method (WEPFM), the Graphical method (GRAPH), Alternative Maximum Likelihood Method (AMLM), and Method of Four Moments Mixture (MFMM). The comparison of these methods is based on four scoring criteria to assess goodness-of-fit, including Root Mean Square Error (RMSE), Mean Absolute Error (MAE), Chi-square (X2), and Correlation Coefficient (R2). The results indicate that the AMLM, GRAPH, and EMJ methods are the most successful in computing Weibull parameters. Additionally, the Annual Energy Production (AEP) and the economic analysis were calculated by using RETScreen software. The wind turbine models used in this study are the Sinovel 1500/77 and the Guodian Power UP77/1500, which have been considered for the production of 60 MW of electric power from the wind energy farm installed in three cities in Morocco: Dakhla, El Fnidek, and Essouira. According to the study results, the Guodian Power UP77/1500 has higher annual production with lower installation costs, making it a more favorable option. The resource analysis highlights Dakhla as a location with good potential for wind farm deployment compared to other sites. The comprehensive assessment of wind data, Weibull parameters, and economic aspects contributes valuable insights to the field of wind energy forecasting and decision-making for renewable energy projects. [ABSTRACT FROM AUTHOR]

Wind is an environmentally friendly form of energy and currently many researchers focus on the development of this energy, because this energy can be used as a promising future Renewable Energy Source (RES). The development of equipment for the use of this energy is an expected and necessary contribution, one of which is as a tool to analyse its energy potential against the probability density function (Pdf). These two models (Weibull and Rayleigh distributions) are proposed for the analysis and the evaluation of wind speed potential in Medan, Indonesia. Data for analysis and evaluation have been taken for three years (2017-2019) obtained from the Meteorology, Climatology, and Geophysics Agency (MCGA), owned by the Government of Indonesia. The purpose of this study is to get the best model proposed to be applied. Statistical analysis and evaluation with three coefficients, namely the correlation model (R2), Chi-Square (χ2) and Root Mean Square Error (RMSE) has been chosen as a model that can be applied. In addition to analysis and evaluation, the form factor (k) and the scale (c) are also determined under different conditions and situations. These two parameters are very important to determine the potential of wind energy in Medan, Indonesia. It has been found out that the magnitude of R2 for Weibull distribution is between 0.934-0.978 in May and June, while for Rayleigh distribution it is between 0.195-0.788. The wind speed for three years (2017-2019) had minimum, maximum, and average speeds between 2.33-2.71 m/s, 7.35-7.71 m/s, and 4.91-5.06 m/s, respectively. On the other hand, the annual electrical power is about 72.21-79.46 W/m2, while the energy is about 623.88-686.55 J. The annual k and c values vary, with k ranging from 4,560-5,266 and c ranging from 5,347-5,496, respectively, with an average k of 4,914 and c of 5,405. [ABSTRACT FROM AUTHOR]

Until now, Physical sensors have been used for estimating the speed of the DC motor for precise speed control. These Physical sensors not only increase the cost but also contribute to the failure of the overall control system. This paper proposes a novel observer for estimating the rotor speed of the DC motor based on the assumption that the speed will not vary during a short sampling period. Speed estimation is carried out by using the armature current and the supply voltage. Initially, a half order observer has been proposed where the speed is the only estimation variable. It has been found out that the half order observer has maintained an accurate speed estimation until a load disturbance has been introduced. In order to overcome this problem, a robust full order observer is proposed where both the speed and current are estimated. The proposed full order observer shows an accurate estimation during both speed step change and load variation. The closed loop operation of the speed sensor-less DC motor is verified through extensive simulation. [ABSTRACT FROM AUTHOR]

This paper discusses a technique of reducing harmonics in electric power grids using Shunt Hybrid Active Power Filter. The filter is controlled by a Model-Predictive Control technique. It can predict the output current magnitude based on its predictive model by noticing the constructed grid topology. Then, this current prediction has been compared to reference currents in order to get an optimal switching pattern concerning a cost function while the optimization has been conducted in order to figure out the maximum condition for the switching pattern. In addition, the Shunt Hybrid Active Power Filter has been compared by combining passive and active filters, which has been expected to be able to reduce harmonics optimally. The use of an LC filter in a single tuned has been also targetted in order to reduce the harmonics in the fifth-order, while the active filter would reduce harmonics due to their resonances. The constructed model has been tested in the simulation in order to evaluate how much harmonic reduction could be performed by the model, and how this model has coped with an unbalanced load, and later affecting the electric power quality. The simulation shows that Shunt Hybrid Active Power Filter along with the Model-Predictive Control method tested by non-linear loads, in terms of balanced and unbalanced loads, can reduce Total Harmonic Distortion of current loads to under 1%. As for unbalanced loads, the phase angle on source voltage does not encounter displacement. Therefore, the Model-Predictive Control on Shunt Hybrid Active Power Filter can effectively be used to reduce harmonics in the grid, during both balanced and unbalanced loading condition. [ABSTRACT FROM AUTHOR]

Due to stochastic and intermittent nature of distributed generation (DG) sources, different types of nonlinear loads, different transmission lines and heterogeneous energy storage devices (ESDs) the direct current (DC) microgrid (MG) system becomes complex and diverse in nature. The battery module of different capacities, different types, different age and of different state of charge (SoC) makes the system heterogeneous. With the traditional droop control method, characteristics of the system parameters are homogeneous in nature which neglect the dynamics of different distributed energy resources (DERs) and ESDs. If multiple DERs are present, the dynamics and characteristics of different DERs would be different since the environment is dynamically varying in nature. In this article, modified SoC reference based droop control technique to examine the complex and heterogeneous autonomous DC MG system operation considering multiple DGs is presented. The controller implemented in this paper regulates the DC bus voltage on the basis of interconnected battery bank SoC and it also ensures equal load/power sharing between heterogeneous battery banks and neighbour nodes. The effectiveness of the proposed DC MG system with modified droop controller has been validated by MATLAB/Simulink environment. The simulation result validates the approach presented for hetrogeneous MG system with regulation of DC bus voltage with effective power sharing. [ABSTRACT FROM AUTHOR]

Power transformers are one of the most important and vital apparatus in power plants, transmission lines and distribution networks which any failures into these elements directly reduce network reliability and increase maintenance costs. Consequently, condition monitoring, fault diagnosis and maintenance of power transformers are increasingly developed. Having a systematic manner and specified framework is the most important requirement to reach a successful fault diagnosis. This paper is focused on how to deal with the problem and how to make decisions facing with a suspected transformer. In this regard, available requirements and assessment methods for monitoring and maintenance of transformers are described and classified briefly. Afterwards, field experiences on a 230/63kV, 125 MVA power transformer are represented. Applied manners and corresponding decisions can be valuable and helpful for the engineers who work on power transformers. [ABSTRACT FROM AUTHOR]

A Multi-Coiled Full-Bridge (MCFB) resonant inverter has been proposed for a dynamic wireless charging application, with the design concept and the theoretical analysis discussed. The newly designed dynamic wireless charging system uses Switch-Branched Sharing (SBS), so that the number of power semiconductor devices is reduced. The closed-loop control strategy for MCFB resonant inverter is presented without any communication between the transmitting and receiving side. The study of the optimal conditions to achieve maximum efficiency transfer with respect to resistive load has been investigated. Then, applying the optimal resistive value improves the total efficiency. A 100 W scaled-down prototype MCFB resonant inverter consisting of four transmitting coupler modules and two receiving coupler modules have been implemented. Moreover, the dynamic power transferring has been measured at various speeds. Finally, various experimental tests have been undertaken to confirm the proposed system's feasibility. [ABSTRACT FROM AUTHOR]

A mathematical model is proposed in this paper of the flax linkage of a Switched Reluctance Generator (SRG) which depends on the magnetization curves at aligned and unaligned positions, and on the angular function. This model is applied to the voltage equation to determine the phase current model. The SRG model based on the phase current is used to find the output power profile versus the excitation angles and rotor speed. The optimal excitation angles with different rotor speeds of the SRG for maximum output power can be determined from the output power profile which can be expressed as a polynomial equation P23. The output power control system which can determine the optima! excitation angles based on the polynomial equation P23 is presented. The SRG based on the flywheel energy storage system was set up to verify the proposed output power control system. The experimental results indicated that the system generating the maximum output power as the SRG is controlled by the optimal excitation angles. [ABSTRACT FROM AUTHOR]

In this paper, the conception, design and initial experimental development of an innovative solar-thermal application with the capacity to harness the heat of domestic Solar Water Heaters (SWHs) and transform it into low-cost and clean electric power, is presented. In the heart of the application, lies a novel -high efficiency- compressing device able to transform thermal energy into potential energy from a working fluid and enabling solar thermal collectors to generate twice as must electricity as solar photovoltaic panels at nearly half the cost. The proposed compressor tackles the inherent disadvantages of conventional compressors, by reducing the number of moving parts and being capable of handling fluids in multiple phases. Moreover, the compressor is compatible with typical installations that would otherwise include a standard compressor, as well with installations where an abundance of thermal energy and a need for compressing a working fluid coexist. This paper presents the core concept of the research venture, provides the technical details and operation of the proposed innovative compressor and finally discusses the potential market innovation and impact of the invention. The ultimate objective of the research presented in this paper is to introduce to the market the first solar application with the capacity to harness the heat absorbed by domestic SWHs. [ABSTRACT FROM AUTHOR]

Various fault locating techniques have been thoroughly discussed throughout the decades. Many of the techniques prior to this require many monitors and also relay operation information to accurately locate the fault. The latest fault locating approach utilizes power quality (PQ) monitors, which are faster and able to detect any short duration events. Majority of the fault locating techniques however focuses on locating downstream faults only. This paper proposes a novel technique to locate faults in several neighboring substations utilizing only one PQ monitor, thus breaking the boundaries of conventional downstream fault locating techniques. Besides locating faults in neighboring substations, this technique also allows the type of fault to be identified. The algorithm uses Three-Dimension (3D) Voltage Vector Database Matching method to accomplish this task. The algorithm proposed in this paper can accurately point to the fault location. Successful identification of fault location using this proposed technique will allow engineers to identify incipient faults in the substation. This will certainly revolutionize the way engineers plan and execute their substation maintenance strategy. [ABSTRACT FROM AUTHOR]

The wind power has the most rapid growth in comparison with other renewable energies. The main issue of wind turbines that equipped with Doubly Fed Induction Generators (DFIGs) is the grid faults or low voltage ride through capability. In this paper, a new solution for uninterrupted operation of wind turbine driving a DFIG has been proposed during fault condition in the grid. A Fault Current Limiter (FCL) is placed in series with the rotor circuit. During fault condition FCL enters a huge solenoid in the rotor circuit to inhabit increasing of current in the rotor circuit. When the fault is cleared the FCL bypasses the solenoid. A Static Synchronous Compensator (STATCOM) has been applied for supplying required reactive power in faults and steady states. Capability and modeling accuracy of the proposed method confirmed with simulating a sample power system in PSCAD/EMTDC software. [ABSTRACT FROM AUTHOR]

In this paper the modelling of a motion control system with Variable Structure System (VSS) theory using Matlab/Simulink and Caspoc is elaborated The keystep of most sliding mode designs is the chattering free implementation. The usual sources of chattering are the limited switching frequency and the non-modeled dynamics. The main contribution of this paper is the introduction of a powerful integrated simulation tool, which enables a detailed analyze of chattering. The control is modeled in Simulink, while the power converter is modeled in Caspoc. This has advantages on both sides. Powerful toolboxes existing for Simulink can be used and the power electronics can be modeled in detail in the dedicated power electronics and drives simulation program Caspoc. This approach and advantages of it are demonstrated by analysing the chattering phenomena of a motion control system. Experimental results of a DSP-controlled single-degree-of-freedom motion-control system are presented and compared with the simulation. [ABSTRACT FROM AUTHOR]

This paper presents the thermal modelling and analysis of a hybrid excitation synchronous generator with alternated current linkages (HESG-ACL) for stand-alone power supply. The HESG-ACL belongs to a class of hybrid excitation synchronous machines (HESMs), which combine the merits of electrically excited synchronous machines (EESMs) and permanent magnet synchronous machines (PMSMs). To confirm the performance and thermal behaviour of the HESG-ACL, an experimental prototype (69 kVA apparent power) equipped with thermal sensors was built and tested. A description of the HESG-ACL is given. The thermal analysis of the HESG-ACL is carried out based on the thermal resistance network model. The results obtained from the thermal model are verified by the experimental results. [ABSTRACT FROM AUTHOR]

This work provides the analytical derivation of the characteristic function of noisy digital measurements of fundamental and harmonic active power in electrical systems. Knowledge of the characteristic function, in fact, allows a complete statistical description of the measured active power since both the probability density function and the distribution function can be readily derived. Moreover, from the characteristic function all the statistical moments can be evaluated, whereas in the existing literature only the first- and second-order moments of the fundamental component were provided. More specifically, it is well known that voltage and current waveforms in electrical systems under non-sinusoidal conditions are digitized through analog-to-digital conversion and transformed into the frequency domain. Each waveform spectral line is processed to evaluate active power at the corresponding frequency. Since spectral lines are affected by additive noise the measured active power can be properly treated as a random variable. In particular, harmonic active power is more sensitive to additive noise since it is given by low-magnitude spectral lines .In the paper, the probability density function corresponding to the derived characteristic function is validated through numerical simulation of the whole measurement process and the impact of waveform and sampling parameters is investigated. [ABSTRACT FROM AUTHOR]

The application interval type-2 fuzzy inference systems (1T2FIS) has been attention for a short-term load forecasting problems solution. This paper present optimization membership function of antecedent (X,Y) and consequent (Z) interval type-2 Fuzzy Logic System using Big Bang - Big Crunch Algorithm for application short term load forecasting on national holiday. This method has implemented on the historical peak load data during 14 national holiday case study in South and Central Kalimantan - Indonesia electrical power system on year 2008. The Big Bang-Big Crunch (BB-BC) algorithm will applied to optimization interval footprint of uncertainty (FOU) membership functions of interval type-2 fuzzy logic system. BB-BC Algorithm is a global optimization algorithm and has a low computational cost and a high convergence speed, so very efficient in this research. The test result showed main absolute percentage error (MAPE) less than interval type-2 fuzzy inference system (FIS) and type-1 fuzzy inference system (FIS). Finally, this paper defined main absolute percentage error (MAPE) 0.58045% for type-1 FIS, 0.53906% for interval type-2 FIS, and 0.52421% for optimization interval type-2 FIS-Big Bang Big Crunch Algorithm. [ABSTRACT FROM AUTHOR]

This paper proposes a novel method of reactive power management and pricing in the background of re-structured electricity market. Financial compensation for reactive power support provided by the generators is considered in this paper along with the consideration of voltage stability margin. Those generators which have re-scheduled its real power generation to provide more reactive power are eligible for payment. The system operator has to find the optimum re-scheduling and minimum payment using RGA and PSO. This procedure is illustrated using 6 bus system and IEEE 30 bus system. The results show that cost of reactive power is optimum for PSO when compared with RGA for the given conditions. [ABSTRACT FROM AUTHOR]

This paper presents a new methodology for optimal placement, size and electricity price of different types of Distributed Generation (DG) considering electricity market price fluctuation. DG is introduced to participate in electricity market comparing with voltage regulator devices and interruptible load, to solve the lacking electric power supply problem with a reasonable price. The problem of optimal placement and size is formulated in two stages; minimization the total cost to find optimal sizing and siting of the different types of DG vs. different investment payback time, and maximization the Global System Benefit (GSB) function to find optimum DG electricity price. In this methodology, cost function is investment costs, which evaluated as Equivalent Annual Cost (EAC), plus to total running cost and GSB function is defined as the difference between global system costs before and after DG installation. Different system conditions are assumed to indicate the effect of the system conditions on planning decision. In this paper , five types of DG are studied. The proposed two-stage model aims to find optimal DG placement and DG electricity price, especially in a deregulated electricity market environment. The proposed methodology is tested in IEEE 30-bus test system by using a developed user-friendly software package. [ABSTRACT FROM AUTHOR]

This paper describes the operation and control of a variable-speed wind generator using the permanent magnet synchronous generator (PMSG). This generator is connected to the grid by means of fully controlled converters, which consists of a pulse width-modulation (PWM) rectifier, an intermediate DC circuit, and a PWM inverter. Two main objectives are analyzed, extracting maximum power from wind, and feeding the grid by high-power quality of electrical energy; for that we applied the strategies of maximum power point tracking (MPPT) with speed controller which allows the PMSG to operate at an optimal speed. For delivering power to the grid, DC-link voltage is controlled by inverter using pulse wave modulation (PWM) in a way to deliver only the active power into the grid, thus we have unit power factor. This paper shows the dynamic performance of the complete system by its simulation using Matlab Simulink. [ABSTRACT FROM AUTHOR]

The paper presents a nine-level selective harmonic elimination pulse width modulation (SHE-PWM) cascaded voltage source converter based STATCOM system. The structure allows direct connection to the grid without the need of any step-up transformers. The converter is controlled with the SHE-PWM technique which provides an elimination to lower order harmonics to improve output waveforms and furthermore, allowing the use of smaller filters. The control methods used for voltage, stress balance and dc voltage regulation are also described in the paper. The operations and the performance of the STATCOM for reactive power (VAR) compensation are validated by simulation studies using SIMULINK/MATLAB software which confirm the theoretical predictions. [ABSTRACT FROM AUTHOR]

In this paper a novel synchronization method is proposed to obtain a reference signal for active power filters (APF), which is used to determine the fundamental component of the load current in-phase with the mains voltage, without any signal measurement for synchronization. The principle idea of this paper is based on the proposition that "the required minimum value of the mains current is the value at which the reactive power becomes zero". Therefore, the proposed reference signal extraction algorithm uses only the mains current. It is based on artificial neural networks (ANN) and when compared to the alternative methods, the proposed method comes forward with its simplicity in terms of hardware and software. In harmonic component extraction stage, an adaptive filter structure is used. Instead of common least mean squares (LMS) method, averaged least mean squares (A-LMS) method, which is generated by adding a moving average filter (MAF) block to the LMS algorithm, is preferred because it allows faster and more accurate determination of the fundamental harmonic component. A prototype APF with 3-KVA rated power is built to verify the proposed method. It uses only mains current and dc link voltage measurements. The results verified the successful performance of the proposed method in APF operation. [ABSTRACT FROM AUTHOR]

Small or zero impedance lines are frequent cause of power flow calculation divergence or invalid convergence. Impedances of bus couplers are almost equal to zero while impedances of lines which connect generators high voltage busbars to neighboring substations are usually very small. This paper presents an approach by which buses connected by small or zero impedance lines are merged into single bus and nonlinear system of power flow equations is solved without these lines. After solution of nonlinear systems of power flow equations is found, power flows through small or zero impedance lines are solved as system of linear equations. The main advantage of solving system of linear equations comparing to solving system of nonlinear equations is that linear system is solved in one step without iterative procedure. The approach of solving the system of linear equations representing active and reactive power flows through lines with the same voltages and angles at their terminals is presented in the paper. [ABSTRACT FROM AUTHOR]

Power system restoration decision-making is one of the most important and indispensable issues for ensuring fast power supply restoration to end users. In recent years, the power industry around the globe has been undertaking an in-depth restructuring, and this has led to some new challenges to the problem of service restoration. Service restoration is a complicated combinatorial and multi objective, multi constraint optimization problem that often has a great number of candidate solutions to be evaluated by the operators. This paper presents a comprehensive review of the various Computational Intelligence Techniques applied to solve Distribution Service Restoration problem reported in the specialized literature. As part of this review, a classification of the approaches is included, and a main feature of each proposal has been identified. In the last part of the paper, some of the topics within this field that are considered as promising areas of future research are listed. [ABSTRACT FROM AUTHOR]

This paper deals with reactive-power compensation and harmonics elimination using a hybrid active-power filter. It proposes a state-feedback-controlled hybrid filter as a combination of a three-phase, two-level, voltage-source converter connected in parallel with an inductor of a shunt, single-tuned, passive filter. This topological structure greatly decreases the voltage and current stress over the elements of the active filter. Since the topology is composed of a single-tuned branch, the control structure also has to ensure sufficient filtering at other harmonic frequencies. In this paper an integral, state-feedback, multi-loop controller is proposed. To design the controller a mathematical model of the proposed filter in state-space is developed first. The effectiveness of the hybrid active filter is demonstrated on a realistic industrial-network model by means of computer simulations. [ABSTRACT FROM AUTHOR]

The present paper presents a methodology to perform the optimal sizing of grid connected micro-grid that consists of wind turbines, photovoltaic panels, fuel cell and the capacities of battery bank, interruptible and uninterruptible loads. Also Micro-grid can exchange power with grid. When total of produced power in micro-grid plus purchased power from grid can not satisfy demand, first interruptible and then uninterruptible loads are shed. In this paper, the problem is formulated as a nonlinear integer minimization problem which minimizes the sum of the total capital, operational and maintenance and replacement cost of DERs, penalty for interrupted loads, subject to constraints such as energy limits of each DER, limits of exchanged power, interruptible and uninterruptible loads. This paper proposes Particle Swarm Optimization (PSO) for solving this minimization problem. The proposed methodology was used to design micro-grid for northwest of Iran. The simulation studies have shown that the proposed methodology provides excellent convergence and feasible optimum solution for sizing of islanded micro-grids using particle swarm optimization. In this paper Forced Outage Ratio (FOR) of each component and some notions of reliability are considered for micro-grid, and the effect of reliability and FOR on total cost of micro-grid is evaluated. [ABSTRACT FROM AUTHOR]

Wind energy is a prominent area of application of variable-speed generators operating on the constant grid frequency. This paper describes the operation and control of one of these variable-speed wind generators. In this paper maximum power control of wind turbine and Permanent Magnet Synchronous generator are studied. Machine currents are controlled by indirect vector control method. In this method, generator side converter controls the maximum excitation (air gap flux) by machine's d-axis current and controls generator torque by machine's q-axis current. Induction generator speed is controlled by tip speed ratio (TSR) upon the wind speed variations in order to generate the maximum output power. Grid side converter regulates the DC link voltage and injective active power by d-axis current and regulates the injective reactive power by q-axis current using simple control method P-Q. Simulation results show that the proposed method operates correctly. [ABSTRACT FROM AUTHOR]

This paper presents a new model for steady-state and dynamic-study of a grid-connected SCIG. The system consisting of Squirrel Cage Induction Generators (SCIG); the generator is driven by wind turbine through a gearbox. The studied wind turbine is connected to distribution system through Power Electronics Converters (PECs), filters and step-up transformers. The mathematical models of the studied SCIG generation system including wind speed, filter, turbine system, gearbox, SCIG, PECs, DC-link, step-up transformer, etc. are established and implemented using MATLAB/SIMULINK software. The paper presents the vector control strategy of SCIG that allows the independent control of flux and electromagnetic torque on the PWM converter, and extracting maximum power (MPPT). On the PWM inverter, the vector control strategy is implemented to regulate the DC-voltage and the reactive power from the grid, to have a Power Factor Control (PFC). The simulation results verify the effectiveness of the controls strategies, so it can be concluded that the proposed control of the studied SCIG system can be effectively utilized to study wind farm based on SCIG under any selected operating conditions. [ABSTRACT FROM AUTHOR]

This paper presents a Global Maximum Power Point Tracking (GMPPT) for a series connected Solar Photovoltaic Array (SPVA) under mismatched irradiance conditions/partially shaded conditions using Particle Swarm Optimization (PSO) technique. Partial shaded SPV modules produce several local maximum power points, which makes the tracking of the global maximum power point a difficult task. Most of conventional tracking methods fail to work properly under these non uniform insolation conditions. Some methods proposed in the literature track the global peak (GP) with some limitations. This paper proposes PSO based GP tracking with the objective of maximizing the power. This method tracks GP by finding the optimum value of SPVA current which maximizes the total power extracted from SPVA. The proposed method is checked for different shading patterns through simulation and verified through experimentation using TMS320LF2407 DSP. The results show the effectiveness and robustness of the proposed optimization approach. [ABSTRACT FROM AUTHOR]

Insulation system of high voltage equipment has a vital role in apparatus lifetime and continuity of power supply. In power transformers one major source which can cause insulation failure is partial discharge (PD). PD localization has significant importance in the maintenance and repair of a transformer. In this paper two methods by use of neural networks for identifying partial discharge locations in transformer winding are proposed. Detailed model (DM) of transformer is developed for simulation and detection of PD. With modeling of partial discharge impulse source in EMTP software, this phenomenon is implemented in different points of transformer winding. Then produced currents in the both ends of winding are used for training and test of neural networks. In actual, obtained current signals contain noisy components. Thus in this paper the performance of the Fuzzy ARTmap neural network and Bayesian network for correct determination of partial discharge location in power transformer with considering different noises on simulated current signals for simulation of actual conditions is surveyed. [ABSTRACT FROM AUTHOR]

This paper presents a hybrid power quality solution in a test system consisting of distributed passive filters, an Universal Power Quality Conditioner (UPQC) and Distributed Generation (DG) units. In the system, single passive filters are designed and connected to eliminate main harmonics and compensate reactive power for each nonlinear load. The UPQC is utilized for voltage unbalance compensation and cancellation of the remaining current harmonics at the point of common coupling of the power distribution system. Configuration of the test system, nonlinear loads, DGs, active filters and UPQC and their modeling in Matlab software are presented in this paper. Matlab implementation of the control system based on dq reference frame theory is also described. Frequency response of the given system is performed and presented to study the issue of resonance under harmonic conditions. Simulation results are demonstrated and confirmed the effectiveness of the proposed configuration in simulated test system. It is shown that the UPQC rating can be reduced in the proposed configuration due to the reactive power compensation using passive filters. [ABSTRACT FROM AUTHOR]

Series FACTS devices such as TCSC, with its ability to directly control the power flow can be very effective to improve the operation of transmission network. In this paper, corrective solution for congestion management by using TCSC has been reviewed. A novel genetic algorithm for finding the optimal location and size of this device was proposed for congestion management with the aim of increasing social welfare while cost of TCSC was incorporated. The simulation results were successfully tested on IEEE 14-bus system. Analyzing the results with and without FACTS devices confirms that these devices are appropriate for long time congestion management. [ABSTRACT FROM AUTHOR]

This paper presents a method for power quality measurement and analysis in electrical power systems. Sag, swell, sag with harmonic, swell with harmonic and flicker are studied in this paper as Power quality problems. The detection and localization of the disturbances and their duration, starting time and ending time are attained by discrete wavelet transform (DWT). The standard deviation curve of wavelet of the given signal is evaluated. This paper shows that each power quality wavelet disturbance has unique deviations from the pure sinusoidal wavelet and this is adopted to provide a reliable classification of power quality type. Finally, a new technique is proposed to determine amplitude of sag and swell. [ABSTRACT FROM AUTHOR]

As one of the most important ancillary services, reactive power production plays a crucial rule in power system operation, reliability and security. Because of the opportunity costs in providing reactive power, producers are under great pressure to provide VAr support. This paper presents a new challenge on the reactive capability curves (RCC) of the synchronous generator taking in account the normal limits of operation without exceeding thermal limitations. The importance of re-evaluation of RCC in the real world is because of the RCC is changed over time and aging of the generators. In this paper it is discusses about some reasons, which lead to the variations, and the importance of re-evaluation of RCC. [ABSTRACT FROM AUTHOR]

In the next future, hybrid electric vehicles and electric vehicles will be more and more hybridized using different electrical storage devices. Traditionally in a vehicle having many energy storage systems, several independent power electronic converters were utilized. Due to their reduced part count, control simplicity and better efficiency, multi-input dc-dc converters seem to be a promising choice in hybridizing energy systems, therefore in literature many solutions have been proposed. In the paper, a new bidirectional soft-switching multi-input dc-dc converter for automotive applications is proposed. Such configuration is obtained as combination of two individual half-bridge dc-dc converters feeding a common dc bus. The soft-switch capability is achieved adding a simple auxiliary active clamping circuit for each leg. Such auxiliary circuit is operational regardless of boost or buck mode operation. The configuration guarantees fixed switching frequency, active clamped zero voltage switching operations of the main switches and bidirectional power flow. ZVS operations are guaranteed with wide load range. Reverse recovery effects are minimized and the drop voltage occurred over the switches is significantly reduced. In the paper the operating principle, soft-switching conditions and steady state analysis are presented. A 500 W prototype has been built and experimental results to verify the theoretical analysis are provided. [ABSTRACT FROM AUTHOR]

Stability of a system is one of its most crucial yet largely hidden characteristic. Power systems, both ac and dc, face instability; with dc systems facing voltage instability only while ac systems have to confront frequency and rotor angle instability in addition to the voltage irritability. Apparently, this makes dc systems easier to design since there is only one form of instability i.e. voltage instability which needs to be tackled. Yet this has proved a huge challenge and even now, a decade and a half after the beginning of active research for stabilizing a dc distributed power system, research efforts are still in progress. This paper attempts to present and compare some of the latest research techniques for dc distributed power system stability as well as briefly reviews the history of research efforts in this area. A short description of the dc distributed system paradigm along with its applications is also included in this paper. [ABSTRACT FROM AUTHOR]

An electricity distribution system is a vital part of a total electric power supply system, since it is a link between a bulk transmission system and customers. It has been estimated that 80% of supply interruptions faced by customers are due to failures that occur in the distribution network To secure more costumers with increasing competition, the energy supply companies are now increasingly under pressure to maintain a high degree of uninterrupted power supply quality and reliability. Therefore a practice of disconnecting all distributed generation units once a fault occurs is not a practical solution in a deregulated electricity market environment since it relies on power outage. Operation of safe intentional islanding would be viable solution. The aim of this paper is to present a genetic-based coordinated methodology for islanding operation and management of active and reactive powers in a distribution network after occurrence of a fault with regard to cost related to active and reactive powers generation of distributed generations, price of energy purchasing from a retail market, and loads interruption cost. Since optimal operation and islands configuration of a distribution network is a complicated and discrete problem, the genetic algorithm has been used for implementation and solving of the proposed algorithm. Simulations have been applied on 33-bus IEEE test system in three scenarios according to faulty branches and DGs penetration rate. [ABSTRACT FROM AUTHOR]

In this paper, an innovative method is proposed to improve the performance of linear optimal control for mitigation of sub-synchronous resonance in power systems. This method is based on shifting eigenvalues of the stale matrix of system to the left hand-side of s plane. It is found that this proposed controller is an extended state of linear optimal controller with determined degree of stability. A proposed design, which is presented in this paper, has been developed in order to control of severe sub-synchronous oscillations in a nearby turbine-generator. The proposed strategy is tested on second benchmark model and compared with the optimal full-slate feedback method by means of simulation. It is shown that this method creates more suitable damping for these oscillations. The proposed method is applied to the IEEE Second Benchmark system for sub-synchronous resonance studies and the results are verified based on comparison with those obtained from digital computer simulation by MATLAB. [ABSTRACT FROM AUTHOR]

This paper shows the latest development and directions in Power Electronic simulations. One of them is visualization of the simulation results and "freeze and go back" feature is here introduced. As typical power electronics system analyses consist of many aspects and it is multidisciplinary an open interface and integrated approach is often applied. Requirements on the interface for an integrated simulator are given and communication between various tools and its structure is described in the paper and illustrated by many examples. [ABSTRACT FROM AUTHOR]

In the last years, the on-board electric power requirement in vehicles is continuously increasing. The increase in power demand is even due to emerging automotive technologies such as variable engine valve, active suspension, x-by-wire (e.g. steering-by-wire, brake-by-wire, etc.) and heated catalytic converter. Since the adaptability of the conventional electrical system to the needs of next future and present electrical loads is very little, alternative architectures of powernet are required, but it isn't still clear how to detect the best architecture for a fixed automotive application. The goal of this paper is to introduce a new computer aided technique for the choice of new architectures oriented for advanced automotive applications. The paper presents the software suite EVALUATOR to compare different electrical power systems and to identify which of them has superior performances and is economically competitive. [ABSTRACT FROM AUTHOR]

Maintaining the power balance between electricity consumption and generation might become more challenging in the near future due to intermittent electricity generation. The decrease in flexibility on the generation side may at least to some extent be compensated by managing demand. Therefore, this paper concentrates on modeling the flexibility electric vehicles (EVs) are able to offer to the maintaining of power balance over a typical weekday. The modeling rests on real mobility behavior data utilized in the dynamic simulations of an EV fleet. Of particular interest are the hourly powers and energies available when a portion of the EV battery capacity is reserved for the maintaining of the balance. Employing the estimated flexibility, EV contribution to the power system frequency control and hourly regulation is analyzed in the Finnish power system. The results indicate that EVs are able to contribute to the maintaining of power balance, but this depends greatly on the reserved energy content of the batteries. [ABSTRACT FROM AUTHOR]

An attempt has been made to analyze the methods to improve the electromagnetic properties of a solid-rotor induction motor. The slip of the solid rotor is reduced notably if the solid rotor is axially slitted. The slitting patterns of the solid rotor are examined. It is shown how the slitting parameters affect the produced torque. Finite element analysis is used to numerically analyze the effect of axial slitted rotor on the electromagnetic performance characteristics of a 180 kW, 170 Hz 3-phase induction motor. The paper considered the effect of variation of slit depth, variation of no of rotor slits and the variation of air gap length on the performance of 3-phase induction motor using Flux-2D Maxwell software package from ANSYS. It is found that larger and deeper slit of the rotor with minimum valve of air gap gives the better and higher operating torque. It is also found that deeper slit gives the higher efficiency of the slitted rotor, high speed induction motor. [ABSTRACT FROM AUTHOR]

This paper presents a Newton-Raphson method with an approximated second-order term of the Taylor series for solving the power flow problem where the power flow equations are in polar form. The proposed method is to include the second-order derivative term of the Taylor series in the Newton-Raphson method and subsequently approximate it using the first-order differentiation of the central finite difference. To compare the proposed method's capability of finding a solution, it is compared with the Newton-Raphson method both in the polar form and rectangular form of power flow equations. The proposed method and the comparative methods are applied to the ill-conditioned 13 bus, IEEE 14 bus and IEEE 30 bus systems. The results demonstrate that the proposed method is the only method that can satisfy in all systems and the ill-conditioned 13 bus systems with a high and highly reactive load at bus 11. While the Newton-Raphson method both in polar form and rectangular form can identify the solution in all systems, it cannot identify the solution in the ill-conditioned 13 bus with a highly reactive load at bus 11. [ABSTRACT FROM AUTHOR]

The need for more efficient generation and provision of electric power has led the setting of electric power industry to change quickly from its regulated conventional setup to a deregulated one, in several countries, traditionally under the control of federal and state governments. One of the important aspects of the policies liberalized by the Indian government in 1990s is the opening of power generation to private sector that has resulted in the entry of Independent Power Producers (IPPs) into power generation field. IPPs make use of third-party owned transmission network to "wheel" the electrical energy to its customers. The wheeling party is paid 'Wheeling cost' annually for its service as well as for meeting the losses. This paper introduces the concept of wheeling, summarizes different types of embedded wheeling cost methodologies and gives a detailed presentation of an 'embedded' wheeling cost methodology namely 'MVA-km' method to determine the annual wheeling cost. The wheeling cost is calculated by the MVA-km method and compared by changing the location of seller, to an application example illustrated. [ABSTRACT FROM AUTHOR]