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Universities' Power Engineering Conference (UPEC), Proceedings of 2011 46th International

Date 5-8 Sept. 2011

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Displaying Results 1 - 25 of 185
  • Design and Analysis of Heat Regeneration Technique in Combined Cycle Power Plant

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (527 KB)  

    In recent years, energy efficiency becomes one of the most frequently discussed topics in international forums and community, from which the notion of optimizing energy resources is introduced. Heat regeneration represents a mechanism to reuse the heat energy which is wasted during the energy conversion process, such practice is also known as combined cycle technique. This paper presents the analysis of a conversion from open cycle gas turbine power plant into a combined cycle power plant based on mathematical modeling and simulation. The scope is limited to the study of heat regeneration process in Heat Recovery Steam Generator (HRSG), during which the running process converts feed water into steam before it is fed into a steam turbine to generate electricity. The main concerns to be examined involve the mechanical analysis of heat transfer media and PI controller design of heat exchanger. View full abstract»

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  • Investigation of Substation Installed Shunt Active Power Filter in AC Electrified Railway Systems

    Publication Year: 2011 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    25 Kv Ac electrified railway power systems have the following shortcomings as far as the quality of their power supply is concerned: higher harmonic supply current pollution, feeder supply voltage perturbations and the demand for reactive power. These power quality issues have a detrimental impact on the railway power supply system itself as well as on the other electric power systems integrated with it. This paper investigates the performance of single phase active power filters (SAPFs) which are introduced in order to address these quality issues. These filters can be installed at either the substation end (S/S) or at the sectioning post (SP) of the railway power system. In this investigation novel control algorithms, based on the synchronously rotating frame of reference, are proposed for the case when the SAPF is installed at the substation end and its performance is assessed. The effectiveness of the proposed control algorithms are illustrated via Matlab/ PowerSim computer simulations and validated via comparisons with other publications. This investigation demonstrated that when the SAPF is installed at the substation side, it can effectively compensate for the higher harmonic supply current. In addition, the reactive power demand is fully compensated for, leading to a unity power factor. However, the voltage drop/sag at the locomotive power entry point is not fully compensated for. View full abstract»

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  • Investigation of Sectioning Post Installed Shunt Active Power Filter in AC Railway Systems

    Publication Year: 2011 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (515 KB)  

    25 Kv Ac electrified railway power systems have the following shortcomings as far as the quality of their power supply is concerned: higher harmonic supply current pollution, feeder supply voltage perturbations and the demand for reactive power. These power quality issues have a detrimental impact on the railway power supply system itself as well as on the other electric power systems integrated with it. This paper investigates the performance of single phase active power filters (SAPFs) which are introduced in order to address these quality issues. These filters can be installed at either the substation end (S/S) or at the sectioning post (SP) of the railway power system. In this investigation novel control algorithms, based on the synchronously rotating frame of reference, are proposed for the case when the SAPF is installed at the sectioning post and its performance is assessed. The effectiveness of the proposed control algorithms are illustrated via Matlab/ PowerSim computer simulations and validated via comparisons with other publications. This investigation demonstrated that when the SAPF is installed at the sectioning post end, it can effectively compensate for the voltage drop/voltage sag at the locomotive power entry point. However, the harmonic source current and the reactive power are only partially compensated for. View full abstract»

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  • Analysis and simulation of switching phenomenon in electrical networks and reduction of its undesirable effects by using close resistance and switch

    Publication Year: 2011 , Page(s): 1 - 4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (561 KB)  

    When an over head Transmission line is energized by closing the line circuit breaker, some transients states are generated in the electrical networks including the line and the supply network that can be dangerous , therefore, it would be of great importance to study the effects of the transient overvoltages. A traditional method for limiting switching overvoltages to acceptable levels is use of circuit breakers equipped with pre-insertion resistors. These resistors provide efficient limitation of the switching overvoltages. Therefore, they caused the circuit breakers more complex and un-reliable. Controlled switching of line circuit breakers using switchsync relay not need to pre-insertion resistors. The EMTP software is used to model an appropriate power system and various simulations are performed. View full abstract»

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  • Economic Load Dispatch with Daily Load Patterns Using Particle Swarm Optimization

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (463 KB)  

    Economic load dispatch (ELD) problem is one of the essential issues in power system operation. The objective of solving ELD problem is to allocate the generation output of the committed generating units. The main contribution of this work is to solve the ELD problem concerned with daily load pattern. The proposed solution technique, developed based particle swarm optimization (PSO) algorithm, is applied to search for the optimal schedule of all generations units that can supply the required load demand at minimum fuel cost while satisfying all unit and system operational constraints. The performance of the developed methodology is demonstrated by case studies in test system of six-generation units. The results obtained from the PSO are compared to those achieved from other approaches, such as quadratic programming (QP), and genetic algorithm (GA). View full abstract»

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  • Discrete Time Simulation of Electrical Power Network with Intermittent Generation

    Publication Year: 2011 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (579 KB)  

    Hybrid systems including wind, solar, batteries and diesel generation have been develop in various places to apply the complementary strengths of each source. In the daytime, when there is less wind, the solar panels will cover the extra load. At night, the wind turbines will be generating more power. If the solar panels and wind turbines do not create enough power, the diesel generator will automatically run to compensate for the deficiency and batteries, as storage, will help to reduce the burden of the diesel generator. Since the back-up generators are fuelled by diesel and turn on only when needed, this can actually save a lot on fuel cost. Such a situation can be modelled and simulated using a Stepwise Power Flow method created in the MatPower package and executed with MATLAB. Then the system can be optimized and monitored to achieve the best hybrid system. Regular power flow calculations assume balance between scheduled generation and actual load, but this is formally correct only once, or a few times, during the hour in a real power system, where the load is always changing. A basic Stepwise Power Flow method is demonstrated by using a modified IEEE 30-BUS test system as the sample system, the load is changed following the load demand through a day, while schedule generation is changed only at the change of hour. The loads on a power system consist of a variety of electrical devices. Some of them are purely resistive; some are motor loads with variable power-frequency characteristics, and others exhibit quite different characteristics. Since motor loads are a dominant part of the electrical load, there is a need to model the effect of a change in frequency on the net load drawn by the system and this will be simulated. View full abstract»

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  • Technical and Economic Assessment of Power Generation from Dairy Farm-based Biogas Plants in South Africa

    Publication Year: 2011 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (569 KB)  

    The paper reports on the technical, economic and environmental assessment of stand-alone and grid connected electricity generation from dairy-based biogas plants in South Africa. HOMER will be used assess the possibility of integrating microturbine and or diesel generator systems on small dairy farms, where grid extensions are complex and uneconomical. HOMER will also be used to assess the possibility of using these electricity generating systems on large scale dairy farms, for grid-connected applications. The decision criteria used for these assessments include, the equipment setup, energy production, financial viability, fuel consumption and CO2 emissions and the main decision parameters used are net present cost (NPC) and renewable fraction (RF). View full abstract»

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  • Technical and Economic Assessment of Landfill Gas-based CHP Plants in South Africa

    Publication Year: 2011 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (603 KB)  

    The paper reports on the technical, economic and environmental assessment of landfill gas-based stand-alone and grid-connected combined heat and power (CHP) systems in South Africa. First order decay models are used to calculate the methane production potential of three Western Cape landfill sites in order to assess their suitability for landfill gas to energy (LFGTE) projects. Then Homer package is used to simulate and assess the energy generation potential of stand-alone and grid-connected CHP configurations using landfill gas generated in all the three sites. It is assumed that stand-alone configuration is aimed at supplying heat and power to remote communities without access to grid electricity while the grid-connected configuration is aimed to generate energy during the peak load period only. The results of simulation are used to make final conclusions and recommendation about the viability of LFGTE systems in South Africa. View full abstract»

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  • Impact of Distributed Generation on Protection Coordination in a Radial Distribution Feeder

    Publication Year: 2011 , Page(s): 1 - 5
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (572 KB)  

    Integration of distributed generation (DG) in radial distribution network disturbs the coordination of the existing over-current protective devices in the network. Since coordination of protective devices is vital to a safe and secure operation of the network, the impacts of DG penetration protection coordination must be investigated in the planning and development stage. In this paper, the authors study the effects of DG penetration on protection coordination in a 66kV radial network with DG units with respect to degree of penetration and grid strength. The test network and over-current relays are simulated in Mat lab Simulink. View full abstract»

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  • Integration of Stochastic Power Generation, Geographical Averaging and Load Response

    Publication Year: 2011 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (974 KB)  

    The stochastic nature of generation from renewable sources can in certain cases increase the costs for dispatchable generation, as well as increase the amount of reserves needed for Operational Reliability. This is likely to happen when conventional generation is used to counteract for unforeseen shortages of renewable generation. The objective of this paper is to analyze how the variability of wind affects optimal dispatches and reserves in a daily optimization cycle. The Cornell SuperOPF1 with several periods optimization is used to illustrate how the system costs can be determined for a reliable network (the amount of conventional generating capacity needed to maintain System Adequacy is determined endogenously). Five cases are studied to illustrate the effects of geographical distribution, ramping costs and load response to customers payment in the wholesale market, and the amount of potential wind generation that is dispatched. The results in this paper use a typical daily pattern of load and capture the cost of ramping by including additions to the operating costs of the generating units associated with the hour-to-hour changes in their optimal dispatch. The calculations for determining endogenous up and down reserves are included, and the wind generation cost is assumed to be zero. Additionally, the maximum and minimum available capacities for all hours in the day are constrained to the optimal capacities for the hours with the highest and the lowest loads. Different scenarios are evaluated for a given hourly realization of wind speeds using specified amounts of installed wind capacity with and without ramping costs. The proposed regulatory changes for electricity markets are 1) to establish a new market for ramping services, 2) to aggregate the loads of customers on a distribution network so that they can be represented as a single wholesale customer on the bulk-power transmission network and 3) to make use of controllable load to mitigate the variability of- - wind generation as an alternative to upgrading the capacity of the transmission network. The cost of ramping reduces the amount of potential wind generation that is dispatched because of the inherent variability of wind speeds. The analysis evaluates whether the ability to dispatch some load that is not time-sensitive, such as charging the batteries in electric vehicles over night above the minimum usage requirement, can be an effective way to use more of the potential wind generation. This can help in environments where upgrading the transfer capacity of a transmission network presents political hurdles in the short term. The expectation is that more wind generation can be dispatched at times when load is relatively low and congestion on the network is not a major limitation. View full abstract»

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  • Implementation of Free Governor Action in Power Plant to Increase System Resilience of Jawa Bali Power System Network

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1170 KB)  

    Indonesia consists of many isolated power system networks. Jawa Bali power system is the main power system networks in Indonesia. It represents 80% of total Indonesia load and consists of various types of generator units. More than 50% of the generation come from coal steam. Due to acceleration project, in the next couple years the contribution of coal steam will increase up to 75%. In term of customer, there are significant numbers of industrial customer come from steel furnished industry. Their contribution is up to 20% of total load. The loading fluctuation of those customers, mixed with other customer loading characteristic, and slow reaction of coal steam power plant may cause instability of system frequency. In 2009, there are more than 200 times frequency excursions only caused by load fluctuation and the system resilience only about 2.86% or equivalent with 500 MW/Hz. This paper will explain about processes in implementing free governor action of power plant in Jawa Bali power system start from September 2009 until now and the impact to the system resilience of Jawa Bali power system. This paper will start with theoretical background of primary control in generator, including international standard for speed droop and dead band of unit generator and followed by historical background of the situation in the system. There will be explanation of the steps in implementing free governor action in all power plants, including coordination meeting, working group creation, site visit, individual test, simultaneously test and activation, and monitoring of free governor status in each power plant. Furthermore, constraints faced by the team will be covered as well. The impact of implementation of free governor action during normal and big disturbance is described comprehensively, including comparison with the similar situation before the implementation. Finally, this paper will tell about lesson learned in implementing free governor action of power plants in Jawa Bali p- - ower system. View full abstract»

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  • Performance Comparison of Frequency Based Loss of Grid Protection Schemes

    Publication Year: 2011 , Page(s): 1 - 6
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (795 KB)  

    Distributed Generation (DG) has been a great contributor to the power generation industry. It provides a lot of solutions to most of the problems encountered by the traditional centralised structure for power production but this increased adoption impacts negatively on the functionality of Protection Devices. The paper looks at the operation of different islanding detection schemes and documents their ability to detect loss of mains under different condition. It reports a comparative study of frequency based loss of grid protection schemes done on a simple network using Matlab Simulink. The study focused on three particular anti-Islanding detection schemes based on frequency, namely: ROCOF, Sandia Frequency Shift (SFS) and normal Over/Under frequency relay operation. The results show that the ROCOF relay has a relatively high success rate than the other scheme under the set conditions while Over/Under frequency has the lowest. View full abstract»

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  • Identification of the Horizontal Network Interconnecting the Portuguese and Spanish Electrical Power Systems

    Publication Year: 2011 , Page(s): 1 - 6
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1210 KB)  

    In this paper it is proposed a technique to identify the relevant neighbouring electric power systems using the Horizontal Network methodology. The relevant network of the Spanish system was established, taking into account the actual interconnections and the new cross-border tie-line in Douro International with a voltage level of 400 kV. All simulations of the Portuguese and Spanish transmission systems were performed using the computational software package PSS(R)E from Siemens/PTI. The savecases used in this study represent pictures of the real systems. From the simulation results, some conclusions that provide a valuable contribution to the understanding of the impact of the new interconnection between the two countries will be pointed out. View full abstract»

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  • A Suggestive Method for Proper Prediction of Dynamics using Bifurcation Diagram in C¿ uk Converter

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (595 KB)  

    The nonlinear phenomena in current mode controlled Cuk Converter have been studied in continuous conduction as well as discontinuous conduction mode. It has been reported that the bifurcation phenomena studied in conventional procedure give some incorrect information under certain operating condition. An alternative method has been suggested which correctly predicts the system dynamics in all operating conditions. View full abstract»

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  • A Smart Photovoltaic Generation System Integrated with Lithium-ion Capacitor Storage

    Publication Year: 2011 , Page(s): 1 - 6
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1157 KB)  

    An innovative and smart photovoltaic generation system integrated with lithium-ion capacitor storage is newly proposed for contribution to stable operation of small and isolated grid. The proposed PV generation system employs concept of virtual synchronous generator for the power control by charge/discharge of capacitor. The contribution to stable operation of small model grid was demonstrated with simulations. View full abstract»

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  • The Influences of Decoupling Elements on the Testing of Low Voltage Spark Gap and Varistor

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (705 KB)  

    This paper presents the research results of the influence of decoupling elements as representation of inductive property. The main equipment of the research were impulse generator, spark gap and varistor arresters as protective devices, storage oscilloscope and wires. The impulses were injected to the arresters through the decoupling elements, and recorded by the oscilloscope. The decoupling elements consisted of three types, namely ferrite, iron and air core decoupling elements. The wires those wound on the cores were made of copper. The results indicated that the inductances and capacitances for ferrite, iron and air cores were 133.6 microH and 8.0 microF, 14.7 microH and 38.6 microF and 2.2 microH and 27.99 microF respectively. Based on the oscilloscope display, the first, second and third highest oscillations of the impulse voltages were for the ferrite, iron and air cores of the decoupling elements respectively. As an addition, the impedance of the ferrite core decoupling element was the highest among other decoupling elements. Therefore, the ferrite core decoupling element was the most suitable for an impediment the surge overvoltages. View full abstract»

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  • Efficient Utilization of Photovoltaic Energy for Supplying of Remote Electric Loads

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (600 KB)  

    The increasing concern of environmental pollution, high oil price and limited oil reserves are pushing the substitution potential of fossil fuel by renewable energy such as wind and solar. By solar energy, electricity can be generated by photovoltaic cells, which convert the irradiance directly into electrical energy. There are many applications of solar energy in residential, commercial, industrial and agricultural sectors as well as electrification of remote areas. In this paper an efficient solar green energy scheme comprising of PV array and MPPT DC-DC converter, boost chopper to interface the PV array with the DC load. In this paper, the MPPT is achieved using DC boost converter through perturb-observe technique. In addition, on-line tuned controller is used to regulate the chopper for stabilizing the converter voltage and speed of the PMDC motor. Sliding mode control (SMC) is still the most common controlling scheme due to its simplicity, robustness and successful wide application in electronic converters. The main problem by this control strategy is the appropriate tuning of the controller parameters. In this paper, the integral minimization of time-weighted absolute error (ITAE) is used for on-line tuning of the controller parameters. The Matlab optimization toolbox offers different algorithms for solving constrained and unconstrained minimization problems. The on-line parameter tuning is achieved using unconstrained optimization technique. The proposed system with all models of its components models and the on-line tuned controller has been simulated using Simulink/Simpower environment and validated for efficient utilization of solar energy and stabilizing the motor speed and minimizing the converter voltage oscillations. View full abstract»

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  • Grid Frequency Response of Different Sized Wind Turbines

    Publication Year: 2011 , Page(s): 1 - 6
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

    In many power systems like for instance the Continental European synchronous area of the ENTSO-E, wind power is replacing conventional (thermal) generation. Because wind power does in general not show inertial response and does not provide control power, the ability of the entire system to withstand power disturbances deteriorates. Under the event of a large generation outage in a system with large scale wind power, grid frequency limits could be exceeded which affect controllability, stability, and reliability of power system operation. Therefore, there is an incentive that wind turbines participate in balancing power. Previous research showed that control systems can enable participation of wind turbines in balancing, using their kinetic energy. It was also perceived that different sized wind turbines have different capacities to support the system. This research elaborates on previous work and shows that wind turbines equipped with adequate control systems can provide nearly identical grid frequency response as conventional power plants, independently of the size of the wind turbines. This work shows that system stability can be maintained even with large scale wind power integration. The grid frequency drop which immediately originates after a large generation outage will not worsen due to wind power, which consequently will not threaten the current power system operation. View full abstract»

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  • Bad Data Identification for Voltage Sag State Estimation in Distribution System with Wind Farm Connections

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (567 KB)  

    The problem of the low voltage ride through in distribution system with wind farm connections is actually the voltage sags propagation problems. Valid voltage Sag State Estimation (SSE) can check the possible severity of the voltage faced by the wind generators. Since SSE algorithm is a 2nd curve fitting algorithm, the estimation accuracy is mostly influenced by the validity of the metered data, especially the wrong data at the key points would cause the failure of all state estimation. In response to this question, the bad data identification algorithm in SSE is introduced, and the mathematic model of bad data revisement is also proposed in this paper. The simulation results proved the good performance of the algorithm in paper. And the work in paper will help to enhance the LVRT capacity in distribution substation by improving the relay' performance. View full abstract»

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  • Effects of Distributed Generators from Renewable Energy on the Protection System in Distribution Networks

    Publication Year: 2011 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (671 KB)  

    The increasing number of distributed generators especially from renewable energy requires investigating the impact of their integration on the protection system. This paper evaluates the effects of distributed generators on protection relays functionalities (main and backup protection) in the medium voltage grids. In order to obtain profound results, simulations were done on several realistic scenarios for existing medium voltage grid. As all short circuits were simulated in the time domain by using the software Power Factory from DIgSILENT GmbH, dynamic models for distributed power generation had to be implemented. The results were analyzed graphically and tested for negative influences on the protection functions. In addition, simulation was also done to study the effects of the realistic requirements for the increasing number of distributed power generation in the future. The results from these simulations are presented and discussed. View full abstract»

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  • Optimization and Protective Distance of Surge Protective Devices in Low-Voltage AC Circuits

    Publication Year: 2011 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (569 KB)  

    Protection performances of surge protective device (SPD) in one-stage protection of low-voltage AC power circuits, depending on location of SPD and equipment under test (EUT) are analyzed in the paper. Obtained results can be used for determination of effective protective distance of SPD both in front of and after its location, and could provide optimization of surge protection. View full abstract»

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  • Water desalination with evaporation from environmental friendly waste heat source

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (672 KB)  

    Today and in the future the demand on freshwater increases and not only in sunny countries, but also in a lot of other parts of the world. Right now a lot of people do not have enough freshwater for their daily life and in the future it grows more acute. One reason is the global warming and another reason is the rise of the worldwide population. Additional the available freshwater resources are polluted more and more. Therefore possibilities must be found to produce a huge amount of freshwater without producing a lot of carbon dioxide. Only with this combination the future freshwater demand and the problem of global warming can be tackled. One possibility to produce freshwater was shown in the Sunwater project, which was undertaken between 2009 and 2011. This project was a cooperation between Germany and Egypt and was initialized by this author. During this project it was researched if solar energy can directly be used to convert saltwater into freshwater without producing electrical energy, but this is just one possibility to produce usable freshwater for the daily life in an environmental friendly way. Another possibility is to use other waste heat sources for the desalination of saltwater or brackish water. The used desalination unit can be operated with in wide range available waste heat sources. These waste heat sources can come for example from power stations like gas power stations or nuclear power stations, from air conditioners or usable thermal waste heat from the steel industry. At the moment a lot of waste heat is produced with this installations, which is unused and released to the environment. With different technology combinations the already available thermal energy can be used for the operation of the desalination unit. If the waste heat comes from an environmental friendly energy source like nuclear power stations, geo thermal or solar thermal, the freshwater is also produced complete in an environmental friendly way. This great chance of using was- - te heat will be discussed in this paper. View full abstract»

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  • A Current Hysteresis Controller for Reduction of Switching Losses in a Full-Bridge Inverter - FPGA implementation by using a custom developed 24 bit

    Publication Year: 2011 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (652 KB)  

    This work explores the feasibility of implementing IEEE 754 standard compliant, 24 bit floating point unit on reconfigurable computing systems. The floating point unit generation approach outlined in this paper allows the creation of a vast collection of floating point routines. The developed library has been tested by means a proposed hybrid current hysteresis strategy control for the reduction of the switching losses in a full bridge inverter. The proposed hysteresis current controller is compared with the conventional one. Simulated and experimental results are included to show the effectiveness of the proposed current controller and the today's FPGA devices are well suited for this operation also by using a low cost device. View full abstract»

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  • High Efficiency Predictive Control Strategy applied to a Power Factor Correction System

    Publication Year: 2011 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (560 KB)  

    This work explores the feasibility of a novel predictive control strategy on a Power Factor Correction system. The proposed control strategy allows a significant reduction of the power losses respect to a classical predictive control strategy working with a fixed execution time Ts. The proposed control strategy operates with a variable execution time Ts, it has been implemented using a low cost hardware platform based on TI(R) TMS320F2812 DSP. The chosen platform is capable to execute a control strategy code with a variable execution time Ts. This operation can be performed by setting in proper manner the timer registers of one of two Event Manager A/B blocks present on the mentioned DSP. View full abstract»

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  • Load Measurement and Analysis for Inverse Load Reconstruction

    Publication Year: 2011 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (454 KB)  

    In many applications of electric power systems like cost optimization for cost-aware consumers, load simulation and prediction, load-dependent energy generation in smart grids, and inverse load reconstruction, we need a more or less detailed understanding of the power consumption behavior of different loads. In particular, in the last challenging task of inverse load reconstruction, we want to reconstruct the individual power consumptions of different loads from the total measurements of a single or a few power meters. This would enable a convenient and cost-effective way of collecting individual load data without installing power meters on all loads. This paper makes the first step towards this direction. It performs a feasibility study by measuring and analyzing the load characteristics of different home and office electric devices and tries to answer the question, whether such an inverse load reconstruction is possible. In the companion paper (B. Yang, Z. Zhou, Joint modeling of device load and user intention), we derive models of the load behavior from the load measurements and models of the user intension and study the interactions between the user models and load models. View full abstract»

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