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The paper presents issues concerning power system modelling and model validation, with particular emphasis on renewable energy sources and their integration in large electrical networks. These issues were raised at a workshop organized by UVIG and IREQ held earlier this year. From the presentations and discussions, we synthesize a general framework to summarize the model validation process. Presented in the form of tables, this framework can serve as a checklist of considerations to help model designers validate their models. [ABSTRACT FROM AUTHOR]

Renewable generation is mainly connected through converters. It can provide more and more services to the grid such as voltage support or frequency control. However, these services may not be sufficient for extremely high penetrations. As the share of such generating units is growing rapidly, some synchronous areas could in the future occasionally be operated without synchronous machines. In such conditions, system stability will have to be ensured with the same level of reliability as today. Presently, operation of power systems is based on the presence of synchronous machines. Frequency is linked to the balance between load and generation via the rotating masses equation. This will not be inherently valid for grids without synchronous machines. The matter of operating a network with 100 % power electronics is quite well resolved for small isolated systems. The same doesn't apply for large transmission systems where grid topology and power injections are highly variable and are not known at every moment by all system components or even by a centralized entity. This paper describes the research that needs to be achieved to remove barriers for high penetrations of converters. [ABSTRACT FROM AUTHOR]

India is responsible for delivery of 8+1(prototype) RF sources to ITER Organization. Each RF source will provide 2.5MW of RF power at 2 VSWR in the frequency range of 35 to 65MHz. Eight such RF sources will generate total 20MW of RF power. A large number of high power transmission line components are required for connecting various stages of RF source. To test these passive transmission line components at high power, prior to connecting with RF source system, a test facility is required. India is developing a 3MW test facility based on the concept of Traveling Wave Resonator (TWR) for testing of transmission line components. TWR is basically a ring resonator which will build high power under certain operation condition at resonant frequency (~55MHz in this case). In TWR, power is fed to the ring via a directional coupler continuously which leads to development of high circulating power in the ring. The voltage and current magnitude inside the ring increases with the increasing circulating power. Detailed RF simulation and design of the TWR test bed has been done using high frequency simulator Microwave Studio (MWS). Calculations done for the ring gain, transmission loss, resonance frequency etc. and are verified with the simulation results. Concept validated using 3-1/8 inch prototype TWR test bed, where experiments were carried out with a ~10dB (λ/4 coupled) coupler to feed the ring. Ring gain of ~13.24dB (~21times) was achieved with ~0.17 dB of ring loss. Around 9.2 kW ring power is achieved with an input power of 440W. At present, the 3-1/8inch TWR test bed is being upgraded with a ~15dB coupler to achieve ring gain ~ 19-20dB (~80-100 times). This concept will be finally adopted for 12inch TWR test bed to achieve 3MW ring power with ~ 30-40kW of input power. In this paper, detailed design, simulation, test results out of prototype activity and future plan for establishing MW level transmission line test bed is described. [ABSTRACT FROM AUTHOR]

The paper reports on latest developments for the ITER Ion Cyclotron Heating and Current Drive system: imminent acceptance tests of a prototype power supply at full power; successful factory acceptance of candidate RF amplifier tubes which will be tested on dedicated facilities; further design integration and experimental validation of transmission line components under 6MW hour-long pulses. The antenna Faraday shield thermal design has been validated above requirements by cyclic high heat flux tests. R&D on ceramic brazing is under way for the RF vacuum windows. The antenna port plug RF design is stable but major evolution of the mechanical design is in preparation to achieve compliance with the load specification, warrant manufacturability and incorporate late interface change requests. The antenna power coupling capability predictions have been strengthened by showing that, if the plasma scrape-off layer turns out to be steep and the edge density low, the reference burning plasma can realistically be displaced to improve the coupling. [ABSTRACT FROM AUTHOR]

An energy storage technology is valuable if it makes energy systems cheaper. Traditional ways to improve storage technologies are to reduce their costs; however, the cheapest energy storage is not always the most valuable in energy systems. This paper reviews techno-economic storage valuation methods and expands them by the introduced 'market potential method'. The market potential method derives the value of technologies by examining common deployment signals from energy system model outputs in a structured way. We apply and compare this method to cost evaluation approaches in a renewables-based European power system model, covering diverse energy storage technologies. We find that characteristics of high-cost hydrogen storage can be equally or even more valuable than low-cost hydrogen storage. Additionally, we show that modifying the freedom of storage sizing and component interactions can make the energy system 10% cheaper and impact the value of technologies. The results suggest to look beyond the pure cost reduction paradigm and focus on developing technologies with value approaches that can lead to cheaper electricity systems in future. One practical and useful value method guiding energy storage innovation could be the 'market potential method'. [ABSTRACT FROM AUTHOR]

Energy security is one of the most intensely debated topics. Majority of papers treat the issue from the hydrocarbon market perspective, but this research focuses on the coal market broken into two specific market segments: heating and electricity production. Using the case of Poland as an example, we conduct a cointegration analysis between the coal and natural gas markets. The study uses monthly data from 2011 until the beginning of 2019. Our results show that the Polish electricity sector is more connected to the international coal market than it is to the natural gas market, while the heating sector, despite using insignificant quantities of imported coal, is more connected to the natural gas market. Hence, energy security--in its price dimension--in those two market segments differs. This situation has important policy implications. First, energy policy should take this difference into account, and second, such variation implies that different market tools should be used in those market segments. [ABSTRACT FROM AUTHOR]

One of the possible ways of transition to the eco-friendly energy is widening the use of the solar cells. It requires the enhancement of their efficiency and the reduction of the cost of manufacture. One of the most common tools for producing silicon films for the solar cells is the Plasma Enhanced Chemical Vapor Deposition (PECVD). The present paper describes a new Particle-In-Cell code for simulation of the PECVD reactor. The goal of the research is the optimization of real PECVD reactor by means of the simulation performed with the code under study. We simulate the radio frequency (RF) discharge in the mixture of silane and hydrogen. The validity of the research method being used, namely the Particle-In-Cell method with Monte Carlo collisions is confirmed by the long employment of these methods to the subject area. Another confirmation of the validity of simulation methods is comparing with analytical solution of Vlasov equation when they are available. The results of the research are the following: we were able to simulate the ion current at the grounded electrode depending on the applied electric power. Considering novelty of the research: the new feature is a portable Python code for PECVD simulation. While the numerical method being used is quite traditional and well-known, its implementation with Python numerical libraries and GPU-oriented libraries is new as well as the high portability of the resulting code. The code is executed with no changes on GPUs, CPUs like Intel Xeon and IBM Power and computational accelerators like Intel Xeon Phi. [ABSTRACT FROM AUTHOR]

Large-scale integration of Inverter-based Resources (IBRs) such as wind parks brings new challenges in modelling, analysis and simulation of power systems for protection engineers and system operators. IBRs have complex controller and electronic circuit structures but the use of faster solvers in protection studies will save valuable engineering time and alleviate transfer of black box models between different parties including Original Equipment Manufacturers (OEMs) and system operators. This paper aims to evaluate solver relaxation in an objective manner for the first time in the analysis of impact of IBRs on power swing protections. The foundation of this work is a detailed Electromagnetic Transients-type (EMT-type) model of a wind park built in PowerFactory® software. Then, an equivalent of this model compatible with RMS solvers is developed in the same software by mapping circuit and controller components to ensure objective comparisons. The two models are equivalent in terms of power, short circuit ratings and fault behavior within the typical range of simulation resolution of RMS solvers. By using these two equivalent models, the impact of wind generation on power swing protection elements based on a conventional approach are studied in EMT and RMS solvers. The results suggest consistency in the response of the two solvers for the PSRC WG-D6 test case under investigation. [ABSTRACT FROM AUTHOR]

Micro-cogeneration is cogeneration with small performance, with maximal electric power up to 50 kWe. On the present, there are available small micro-cogeneration units with small electric performance, about 1 kWe, which are usable also in single family houses or flats. These micro-cogeneration units operate on principle of conventional combustion engine, Stirling engine, steam engine or fuel cell. Micro-cogeneration units with fuel cells are new progressive developing type of units for single family houses. Fuel cell is electrochemical device which by oxidation-reduction reaction turn directly chemical energy of fuel to electric power, secondary products are pure water and thermal energy. The aim of paper is measuring and evaluation of operation parameters of micro-cogeneration unit with fuel cell which uses natural gas as a fuel. [ABSTRACT FROM AUTHOR]

This paper describes the initial design of an adaptive weather station. The device relays on an ultra-low power micro architecture, adaptive power distribution mechanism, small form factor, and GPS receiver for time synchronization. The device is dynamically reconfigurable for working in high performance, real time transfer mode with direct operator control; and ultra-low power, fully autonomous, self-monitoring, long-term measurement mode. For convenience the collected data of the environment parameters will be initially analyzed and visualized by specialized software. [ABSTRACT FROM AUTHOR]

The paper is an original research article with the aim of encourage works that support innovations, debates and collaborations within the energy community. The existing situation in the former USSR republics, in the former Eastern Socialist Republics and in some nearby countries Electrical Power Energy systems (EPE) especially in the Russian Federation allows confirming: the firm development warranty - really none, the reliable execution function - truly none, the consolidation effort on these problems decision - actually none. Their energy strategy to 2030 is already collapsed. The forecasted growing of the load in 2008-2010 yeas was broken by the incomprehensibly whence financial crisis, fell all general schemes of the EPE system development, all are moldered, the countries ware left approximately on the consumption of 1990. They have no any generalized theories, non post crisis-chaos development conceptual forecast models (however new predictable crisis is coming), but there are some fragments only. Know-how of the work is concluded in that, it suppose to use here the elements of the system realized management, too. [ABSTRACT FROM AUTHOR]

Universitas Indonesia has developed an electric bus (EV-BUS) with an energy source from the main 384 VDC 300 AH battery and a 25.8 VDC 100 AH secondary battery. The energy is continued for a prime mover of 200 kW with a BLDC motor, 15 kW air conditioning, 7.5 kW hydraulic power steering, 4 kW compressor for braking systems, each with an induction motor, and 2.4 kW for other accessories. Analysis of power consumption for this electric bus, power efficiency in intervals of 65% to 80%, torque efficiency in 75% to 82.5% intervals, and relatively constant and small steering power load on the main motor. In this paper, several types of steering, manual steering, hydraulic power steering, and electric power steering will be presented. This model will explain what components are involved in a steering system. Data collection on the steering system on large-scale buses is also carried out, to ensure that electric power steering is not available on this type of bus. The bus that will collect the data from the kind of chassis used includes the type of bus with an internal combustion engine and also the electric bus currently available. In EV-Bus Molina UI uses a type of hydraulic power steering that will be converted to electric power steering. The components are directly involved in electric power steering including wheel drive, steering column, rack and pinion gear, motor booster, drag link, tie rod, knuckle, kingpin, tire, and so on. The real difference between the city car and the large bus is the long distance from the steering column and front axle, which is as far as 2380 mm, which is about twice that of the city car. Then the link drag structure must be made in such a way as to produce a kinematic mechanism. The first, it is necessary to do kinematic analysis and make the equivalent stiffness matrix, and then to be easy to create equations of motion in the steering system as in the electric power steering in city cars. [ABSTRACT FROM AUTHOR]

In this paper, a fault detection algorithm for photovoltaic systems based on artificial neural networks (ANN) is proposed. Numerous literatures can be found on the topic of PV fault detection through the implementation of artificial intelligence. The novel part of this research is the successful development, deployment and validation of a fault detection PV system using radial basis function (RBF), requiring only two parameters as the input to the ANN (solar irradiance and output power). The results obtained through the testing of the developed ANN on a PV installation of 2.2 kW capacity, provided an accuracy of 97.9%. [ABSTRACT FROM AUTHOR]

In this paper the tecno-economic assessment of two novel hydrogen production plants for small refueling stations is analyzed and compared. In the first one renewable ammonia, that is the hydrogen carrier, is cracked in a Solid Oxide Fuel Cell (SOFC) power unit that cogenerates the required hydrogen and the electric power needed for the hydrogen separation and storage. In the second one the hydrogen production is based on the autothermal reforming of the biogas obtained from an anaerobic digester and the electric power consumption for the hydrogen separation and storage is supplied by an SOFC power unit fed with part of the syngas exiting the biogas processing unit. In both the plant configurations the product hydrogen is separated by means of a Pd-Ag membrane separation unit and is compressed up to 820 bars by using an ionic compression system. The economic performance comparison is based on the evaluation of the levelized cost of the hydrogen (LCOH) for a decentralized hydrogen refueling station (HRS). [ABSTRACT FROM AUTHOR]

Recently proposed ambitious targets for Ireland and Northern Ireland will require that the power system of Ireland and Northern Ireland is capable of operating with significantly high levels of non-synchronous variable renewable generation. Ensuring such high levels of RES-E on the Ireland and Northern Ireland power system will require operation of the system with instantaneous penetration of non-synchronous renewables in excess of 90%. Such high levels of non-synchronous generation in an island system are unprecedented and pose considerable technical challenges. Transitioning from a level of instantaneous non-synchronous penetration of renewables of 75% to more than 90% will exacerbate existing technical challenges and may reveal new, as of yet, unaccounted-for-scarcities. The focus of this paper is on a sample of the detailed analysis for the Ireland and Northern Ireland power system from Work Package 2 of the Horizon 2020 funded EU-SysFlex project. [ABSTRACT FROM AUTHOR]

The transition from marginal to dominant renewable energy systems in electricity generation globally has posed new challenges in terms of intermittency, variability, uncertainty and low-reliability. This situation has led to a significant supply-demand gap in terms of temporal mismatch (times of supply and demand) and quantity mismatch (high supply with low demand, and vice versa). These mismatches lead to several issues, including surplus or insufficient electricity generation, erratic grid operation, etc. Hence, the electricity planners have to match "dynamic supply with dynamic demand.". In managing such a transitioning electricity system, the planning from the electricity supply side requires efficient management of existing electric power systems, on rationalizing generation portfolios. Therefore, to address these decisions, we have developed a generic linear programming-based optimisation model that dynamically balances supply and demand at least cost. In addition to achieving this objective of dynamic supply-demand balance, the model is designed to evaluate all the supply-side options and arrive at a least-cost generation portfolio. This would enable an RE dominated electricity taking in to account the inherent challenges associated with renewable energy integration. The model is validated using data from the electricity system of Karnataka, India where actual data was compared to modelled outputs for the calendar year 2019. Precision metrics, which measures standard error, were used to assess the model's accuracy. The results indicated that the standard error ranged from ±10%, which is within acceptable limits. This model can be effectively used for electricity transition planning and can provide critical inputs to policy makers. [ABSTRACT FROM AUTHOR]

Power production systems are made up of assets that support material handling and production of electricity. As these assets deteriorate, it may be difficult to deliver the expected quality of service, and to meet regulatory requirements and sustainable development goals (Lutchman, 2018). Moreover, Covid 19 has accelerated both manufacturing and service industries to go digital (Biard & Nour, 2021), increasing demand for both electrical power and production systems reliability. This challenge imposes an increase in the focus on efficiency of physical asset management and has prompted power production Industries to look for innovative solutions that yield maximum value for physical asset management functions. The arrival of asset management 4.0 concepts enables the exploitation of big data to improve and manage system reliability (Longhitano, et al., 2021). Furthermore, asset performance depends on various factors like quality of maintenance and operating environmental factors, such that even two identical assets will seldom obey their estimated mean time to failure (Longhitano, et al., 2021). Considering this, a data driven approach is necessary as it spot deviations in time and maintenance is done when required, increasing its effectiveness (Jasiulewicz-Kaczmarek, et al., 2020). The present research aims to develop a data driven asset management framework that is enhanced by Industry 4.0 technologies to execute the key functions of asset management in the operation, maintenance, and management phase of the physical asset's life cycle, and effectively integrate the environmental, social, and economic aspects into physical asset management related activities to improve system performance and extend its service life. [ABSTRACT FROM AUTHOR]

In the frame of the European project SOPHIA a concentrator photovoltaic (CPV) module measurement round robin has been initiated. The round robin includes measurements of four CPV modules at seven different test laboratories located in Europe. IV curves of the modules are measured with different measurement equipment under various climatic conditions. The aim of this activity is to perform at each site a rating of the modules at concentrator standard operating conditions CSOC according to IEC 62670-1. The outcome of the round robin is intended for direct feedback to the current draft standard IEC 62670-3 "Concentrator Photovoltaic (CPV) Performance Testing - Performance Measurements and Power Rating". The paper discusses initial results from the first three partners that have already finished the measurements up to now. [ABSTRACT FROM AUTHOR]

Copyright of Proceedings on Maintenance is the property of University of Zenica, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Town of Normal's electric power infrastructure and their community leaders' progressive decisions to incorporate sustainability into the town's strategic plan have prompted conditions favorable to distributed generation (DG). Increased quality assurance through DG from small modular sources, such as solar photovoltaic (PV) technology has been recognized by the recent Illinois Renewable Portfolio Standard (RPS) 1% DG carve-out. To determine the feasibility of DG implementation, preliminary analysis deploying a new geographic information systems approach was required. The unique methodology of this study provides the Town of Normal with an opportunity to invest in their energy future and economic stability by assessing the town's solar potential. This study reports the outcomes of a technical assessment of the Town of Normal's solar irradiance determining rooftop PV potential. The results of this paper will assist in assessing the economic and environmental impacts of integrating varying amounts of solar photovoltaic modules into the existing electrical infrastructure. [ABSTRACT FROM AUTHOR]

Copyright of International Conference: Crisis Management Days is the property of University of Applied Sciences Velika Gorica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper describes the main measures taken to reduce environmental pollution within MINTIA - DEVA power plant, part of Complexul Energetic Hunedoara S.A. By burning fossil fuels (hard coal), the Large Combustion Plants respectively the power units discharge large quantities of pollutants into the atmosphere, such as dust (under the form of suspensions or particulate matter) and flue gas (SO2, NOX, CO/CO2). In order to reduce such pollutants emission, Mintia Thermal Power Plant is in progress of implementing a rehabilitation program for two power units within the Large Combustion Plant, no. 2 (LCP 2), respectively power unit no. 3 and power unit no.4. This rehabilitation program involves: - Accomplishment of the flue gas desulphurization system for power units 3 and 4; - Fulfillment of a NOX reduction installation from flue gas at boilers 3A, 3B and 4A, 4B, pertaining to power units no.3 and no.4; - ESP rehabilitation works at power unit no.3 and no.4 for reduction of dust discharged into the atmosphere through the stack; - Technological rehabilitation of power unit 4. All these measures actually represents the short-term priorities of Complexul Energetic Hunedoara S.A which have as final purpose the environment protection as well as the protection of the operational personnel's health working in the power plant and of the population residing next to the facility. [ABSTRACT FROM AUTHOR]

In this paper, a large-scale implementation of electric vehicles in Romania is studied, considering that half of all road vehicles form the total fleet would be converted by the year 2030. This study is focused on the installed power growth and the increase of vehicles' number in Romania, for a time frame of ten years: 2002-2011. Based on this analysis, it is estimated the power consumption of the electric vehicles that would replace the internal combustion-based existing vehicles. [ABSTRACT FROM AUTHOR]

Fossil fuel energy is essential for our modern lives. Recently, environmental problems caused by the fuel are critical. Space solar power system (SSPS) is expected as one of future sustainable energy sources. SSPS will consist of large-size solar panels and equipment to transmit the electric power to the earth. Collision of debris with SSPS in space is a matter of concern. In our former paper, we reported a prospect to construct a thin and light weight CFRP protector by oblique collision. In the former experiment, two panels were placed parallel and a nylon 66 projectile was collided with the CFRP panels at a speed of 5km/s. The projectile did not penetrate the first CFRP panel and slid along the surface of it when the collision angle was less than 60 degree. In this paper, damage on the second CFRP panel with an oblique angle to the first panel, was precisely investigated. A projectile of nylon-66 was collided with the panels at a speed of 6 km/s. The projectile did not penetrate the second panel even though the first panel was seriously damaged. From these results, we obtained a prospect to construct a thin and lightweight protective panel. Novel shapes of a protector based on oblique collision are proposed. [ABSTRACT FROM AUTHOR]

This paper describes a dynamic price mechanism to coordinate eletric power generation from micro Combined Heat and Power (micro-CHP) systems in a network of households. It is assumed that the households are prosumers, i.e. both producers and consumers of electricity. The control is done on household level in a completely distributed manner. Avoiding a centralized controller both eases computation complexity and preserves communication structure in the network. Local information is used to decide to turn on or off the micro-CHP, but through price signals between the prosumers the network as a whole operates in a cooperative way. [ABSTRACT FROM AUTHOR]

Improvements to T&D efficiency, energy conservation by end-users, and demand response programs offer significant low-carbon, renewable electric power and energy resources for the future grid. They also offer other benefits, such as improved equipment life, system reliability, and reduced congestion. These resources are not always given the same consideration as generation in resource comparisons for a number of reasons, including regulatory restrictions on benefits from investments and difficulties in accurate economic evaluations. This paper will examine these issues, summarize the latest research results, and suggest future directions for researchers, grid planners and operators, and regulators to better take advantage of these resources. [ABSTRACT FROM AUTHOR]

Direct current (dc), high temperature superconducting (HTS) cable systems have been suggested as an effective method of transmitting very large amounts of electric power (up to 10 GW) over very long distances (thousands of kilometers). This is made possible mainly by the high-current-carrying capability of the HTS materials when operated below their critical temperatures and by their near zero resistance to constant current. Most HTS cable concepts rely on liquid nitrogen or gaseous helium as the coolant. As an alternative, liquid air offers certain benefits and is discussed here as a cable system coolant. Air has a lower freezing temperature than nitrogen, it can be produced locally, and a liquid air leak will not displace the oxygen in a closed compartment. The dc cable design concept proposed by the Electric Power Research Institute (EPRI) in which the coolant flows in a cryogenic enclosure that includes the cable and a separate return tube, and refrigeration stations positioned every 10 to 20 km is assumed for this analysis. Both go and return lines are contained in a single vacuum envelope. The thermal management of this superconducting cable concept with liquid air in long-distance HTS power cables is developed in this paper. The results are compared to the use of liquid nitrogen, gaseous helium and gaseous hydrogen. [ABSTRACT FROM AUTHOR]

Current leads are utilized to deliver electrical power from a room temperature junction mounted on the vacuum vessel to a superconducting magnet located within the vacuum space of a cryostat. There are many types of current leads used at laboratories throughout the world; however, conduction-cooled current leads are often chosen for their simplicity and reliability. Conduction-cooled leads have the advantage of using common materials, have no superconducting/normal state transition, and have no boil-off vapor to collect. The XFEL (X-Ray Free Electron Laser) magnets are operated at 2 K, which makes vapor-cooled current leads impractical due to the sub-atmospheric bath pressure. This paper presents a numerical model for conduction-cooled current lead heat loads. This model takes into account varying material and fluid thermal properties, varying thicknesses along the length of the lead, heat transfer in the circumferential and longitudinal directions, electrical power dissipation, and the effect of thermal intercepts. The model is validated by comparing the numerical model results to ideal cases where analytical equations are valid. The models are compared using the geometry and operating conditions for the XFEL prototype current leads. [ABSTRACT FROM AUTHOR]

We propose to perform the sonoporation by use of direct excitation employing the square wave pulser. Addition of the arbitrary waveform generator and programmable high voltage power supply to the pulser should allow for more economical experiment arrangement. Excitation stage has to be capable of transmitting high voltage signal into capacitive load. This paper reports the generator topology and performance evaluation experimental results. Transformer push-pull topology was suggested. Thanks to proposed pulser structure both unipolar and bipolar pulses can be obtained. Energy per pulse was suggested as performance parameter: any combination of achievable bust duration and repetition frequency can be estimated. Comparison of experimental results to Pspice modeling and energy delivered to load is presented. Energy per pulse at 300 V (600 Vpp) 2.7 MHz output into 3000 pF load was 1.1 mJ. Using 5 W power supplies this would allow for 3 kHz pulse repetition frequency single pulse of 100 Hz pulse repetition at 40 pulses burst. Focused 2.7 MHz center frequency transducer was targeted as load. Transducer impedance was measured to estimate the load and power delivery efficiency. It was found that 5 Ω is the optimal generator output impedance at 2.7 MHz. Using 2.7 MHz transducer we were able to achieve 1 MPa peak negative pressure at 250 V power supply. [ABSTRACT FROM AUTHOR]

Piezoelectric energy harvesting technology has received a great attention during the last decade to activate low power microelectronic devices such as wireless sensor nodes (WSN). This paper investigates the necessary conditions to enhance the extracted AC electrical power from the exciting vibration energy using piezoelectric material. The effect of tip mass and its mounting position on maximum power extraction are investigated theoretically and experimentally. The optimal load impedance is also investigated to maximize the output power. The experimental results validated the theoretical and concluded remarks in the paper. [ABSTRACT FROM AUTHOR]

In this paper, the robust algorithm based on the coupling of sliding mode control and the fuzzy logic control is concerned to ameliorate the robustness and the performances of a variable speed wind energy conversion system (WECS) based on vertical axis wind turbine (H-darrieus) with direct attack, connected to electric power grid with a doubly fed induction generator (DFIG). The control independently of stator active and reactive powers is used by stator flux orientation strategy. The active power reference derived from turbine’s mechanical power. The hybrid fuzzy sliding mode control permits to enjoy the advantages of these two techniques in order to reduce the chattering phenomenon. The proposed approach is analysed and compared between SMO and SMOF by Simulink/Matlab environment. The simulation results show good performances and robustness of SMOF. [ABSTRACT FROM AUTHOR]

The implementation of the requirements of the European Parliament Directive 2009/28 / EC requires efficient use of the water supply of a hydropower plants installation in order to obtain a higher amount of electricity by producing the same volume of water. In order to achieve efficient utilization of the energy of the water is necessary framing the operation of hydropower plants in the ranges of head course and the electric power so that the energy conversion is carried out in the optimum efficiency characteristic operation of the system. In order to determine as accurately the actual operating characteristics of a hydro- unit, in situ tests are required to determine the actual operating parameters of the hydrounit. These parameters, the flow rate is the parameter that requires the most complex methodologies to determine. The paper presents a way of improvement but also a simplification of the methodology for in situ determination of the flow to small hydropower plants by using a mobile frame that has implemented a wireless data transmission system. [ABSTRACT FROM AUTHOR]