By Hans De Keulenaer / Published on Fri, 2009-05-29 11:49
At the moment, the market is dominated by conventional cars, with a combustion engine fuelled by fossil fuel. Some car manufacturers also introduced hybrid electric vehicles (HEV), that make use of both electric motors and other types of engine. Batteries of hybrid vehicles can be charged from an external source, the so called plug-in hybrid electric vehicles (PHEV). The coming decade will show us whether the electric vehicle will be capable to oust these types of cars and will be worthy to win the trust of car drivers…
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By HDK / Published on Fri, 2009-05-29 08:41
Date & Venue: June 16, 2009 - Arnhem
A new annual congress has been established with the intention of exchanging knowledge on low carbon electricity systems. The congress invites the participation of professionals interested in developing their vision of low carbon electricity, including policy makers, utility planning managers, consultants, energy industry representatives, research journalists and academics. Participants can expect a realistic, market-oriented approach with academic validation.
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By HDK / Published on Fri, 2009-05-29 07:52
EPQU Archives
By Sergio Ferreira / Published on Thu, 2009-05-28 14:38
Energy and climate policy in the United States are being proposed at a fast pace, and it is difficult, even from people working in energy, to keep track of all the new proposals.
In this webinar, we will review the impact of some of the current proposals and bills on energy efficiency. The presentation will include both federal and state level considerations.
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By Sergio Ferreira / Published on Thu, 2009-05-28 13:41
Is it possible to reduce the risk of electrically induced fires by 50% and reduce the cost of motor breakdown's and downtime?
This webinar will shed some light over a solution for preventive maintenance and fault identification in industrial applications as tool for cost saving/avoidance and performance improvement.
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By HDK / Published on Thu, 2009-05-28 09:39
Rob Kool and Renée Bruel, SenterNovem, The Netherlands
Energy efficiency is once more at the top of the policy agenda in the Netherlands. In fact the Dutch government wants to be one of the frontrunners of the EU in this field. Reasons for this renewed attention for energy efficiency are:
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By HDK / Published on Thu, 2009-05-28 09:37
Oikonomou V., SOM, University of Groningen, The Netherlands
Becchis F., Prof., Environmental Economics, University of East Piedmont, Italy
Russolillo D., Fondazione per l’Ambiente “T. Fenoglio”, Torino, Italy
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By HDK / Published on Thu, 2009-05-28 09:35
Jiang Lin, Nan Zhou, Mark Levine, and David Fridley, Lawrence Berkeley National Laboratory, USA
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By Hans De Keulenaer / Published on Wed, 2009-05-27 13:56
After heated debates on the final agreement between the European Parliament and the Council on 9 December 2008 and within the European Council on 11 December 2008, the European Parliament, on 17 December 2008, has adopted by a large majority (685 against 25) the Renewables Directive. This important piece of legislation provides necessary tools to increase the use of renewables within the energy system. The so-called 20-20-20 EU policy by 2020 contains:
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By HDK / Published on Wed, 2009-05-27 08:10
The development of photovoltaic (PV) panels has made solar-powered pumps a reality. The pump drivers are usually direct-current (DC) motors, which are fed by power electronic converters with maximum power point tracking (MPPT) to extract the whole energy that the PV panels can generate, depending on environmental conditions including irradiation and temperature. The implementation of the MPPT algorithm essentially involves sensing both an input current and an input voltage. Understandably, such realisation is expensive.
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By HDK / Published on Wed, 2009-05-27 08:06
Based on current trends for solving complex technical problems, a new concept of power quality improvement is proposed here. It consists of creating a distributed system for improving supply conditions in a given islanding power system in, for example, geographical terms (with determined points of delivery), or as an internal installation system for an industrial consumer.
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By HDK / Published on Wed, 2009-05-27 08:03
Ferroresonance is a phenomenon usually initiated by transients in power networks resulting from, for example, switching operations or ground faults. Non linear behavior of the core of an inductive voltage transformer results in magnetic saturation. Long-lasting ferroresonant states are dangerous to equipment due to prolonged overvoltage and large overcurrents in HV windings. In the present article, numerical simulations of the ferroresonance phenomenon in a HV inductive VT are presented.
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By HDK / Published on Wed, 2009-05-27 07:57
A hybrid parallel active filter / off-line uninterruptible power supply (UPS) system is proposed here. The hybrid system contains a single inverter, which acts as a parallel active filter during the normal mode of operation (when the AC supply is available) and also supplies the load with energy from the UPS back-up battery during the back-up mode of operation (when the AC supply is not available, or is beyond the preset tolerance). In both modes of operation, the inverter is controlled in such a way that the line current is a pure sinusoid.
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By HDK / Published on Wed, 2009-05-27 07:55
Power Quality, in terms of power factor and harmonics, is greatly hampered by a three-phase rectifier used as a front-end ac-to-dc converter in many systems including a UPS. This paper presents the high power factor operation of the converter with reduced total harmonic distortion up to 4%.
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By HDK / Published on Wed, 2009-05-27 07:52
Recently, electricity consumers have shown increasing concern for power quality. Indeed, power quality standards have become higher than before for certain customers due to sensitivity of automation devices. In addition, power quality is affected by the deregulation of power markets in Turkey.
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By HDK / Published on Wed, 2009-05-27 07:49
This paper presents a method of estimating the conducted electromagnetic interference EMI emissions in soft switching inverters.
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By HDK / Published on Wed, 2009-05-27 07:45
In this paper, the method of selecting dv/dt for EMI current ringing attenuation is presented. The mechanism for attenuation is first identified using the theoretical approach. It is shown that the attenuation occurs for rise time of the voltage equal to the inverse of the frequency of current ringing. The concept has been experimentally verified in DC chopper and frequency converter arrangements.
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By HDK / Published on Wed, 2009-05-27 07:42
This paper presents an algorithm for the detection of a complex envelope of power grid signals. The algorithm is based on a Hilbert transform. It was prepared for an analysis of low-frequency disturbances, but can also be used as a compex envelope source for other applications. An implementation of the algorithm in a digital signal processor was made to prove an ability of a real-time operation. Analyses with various numerical representations and input signal quantisation were done. Execution times on a DSP were measured.
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By HDK / Published on Wed, 2009-05-27 07:38
Phase disturbances in electric power signals are neglected and only amplitude (envelope) distortions are discussed in literature. Amplitude disturbances are interpreted as Amplitude Modulation (AM) of the main 50 Hz frequency. Detailed analyses of all disturbances and their sources are presented in this paper. It is shown that AM and narrow band PM (phase modulation) take place in power networks simultaneously, and those two modulations interact with each other. Voltage variation is proposed for disturbance measurement.
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By HDK / Published on Wed, 2009-05-27 07:34
This brief communication addresses the case of a dc nonlinear load supplied with a perfectly constant instantaneous power. A careful analysis shows that this condition does not provide optimum transfer of electric energy.
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