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Clean Electrical Power, 2007. ICCEP '07. International Conference on

Date 21-23 May 2007

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Displaying Results 1 - 25 of 136
  • Simulation-based decision support tool for electrification of isolated areas using a network with multiple renewable sources

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (710 KB) |  | HTML iconHTML  

    The Ecole Polytechnique Federale de Lausanne (EPFL), the Hassan II Institute of Agronomics and Veterinary Science (IAV) and Targa-Aid association (Rabat/Morocco) undertook a joint project to implement an electrification technique from different types of renewable sources, supplying small networks of isolated consumers. To help select the best solution among several production variants for satisfying the consumption, taking all of the constraints into account, the EPFL developed the OptElDec software, a simulation based decision support tool. This tool allows modeling consumers, energy production and storage elements. Furthermore, a priority system applied to consumers and power stations is introduced for acting on operation strategy of the production and storage elements. Thus, it gives an eloquent prediction of the performance of one production network variant. Once simulations are carried out, the decision support layer allows comparing several simulated variants regarding quantitative and qualitative criteria in order to find the optimum variant. View full abstract»

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  • The Impact of Small Scale Wind Generators on LV Distribution System Voltage

    Page(s): 9 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (218 KB) |  | HTML iconHTML  

    This paper describes research carried out at Durham University to investigate the effects of high penetrations of Small Scale Wind Turbines (SSWTs) on LV distribution networks. This work aims to develop techniques to overcome network constraints and increase the value of Small Scale Embedded Generators (SSEGs). The paper concentrates on the effects of high levels of SSWTs on the voltage quality of LV distribution systems. The investigation is carried out using a dynamic electrical model of LV distribution network and an urban wind turbine model developed using PSCAD/EMTDC software package. Initial steady state simulation results show that at around 40% penetration of urban wind turbines it is possible that the statutory voltage limits will be exceeded. However when a dynamic simulation is considered it can be seen that slight variations in wind regimes mean this limit would only be met at higher penetrations. View full abstract»

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  • Energy management of solar panel and battery system with passive control

    Page(s): 14 - 19
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB) |  | HTML iconHTML  

    The objective of this paper is to determine a simple controller for street lighting application using an energy shaping method (Passivity-Based Control (PBC)). The idea is to supply such lights with clean electricity and isolated from the network. To answer this problem, one solution consists on the association of photovoltaic (PV) panel and battery. Battery can store energy from PV panel during the day and give it back during the night. First, the system model is presented then Port-Controlled Hamiltonian (PCH) form is written. This form allows to exhibit system characteristics and to simplify the stability proof. Then the control law is deduced using passivity theory and simulation results are shown. Contrary to PI or hysteresis control usually applied for these systems, here no sensor device is used for the control. View full abstract»

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  • DC Link Voltage Stabilisation in Hybrid Renewable Diesel Systems

    Page(s): 20 - 25
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (274 KB) |  | HTML iconHTML  

    Constant Speed diesel generators have been used in remote and isolated areas to provide electricity for over half a century and in this time they have remained largely unchanged. Although they have been mated with other forms of generation, especially wind and photovoltaic successfully but generally to the detriment of the diesel generator. To alleviate this problem in this paper a modelled a variable speed diesel generator (VSDG) has been modelled as part of a hybrid renewable system. The benefits of a VSDG are explained and results show the fuel savings possible over a standard diesel generator. An experimental test rig has been built and the DC link stability has been assessed with and without different forms of short term energy storage. It is shown that supercapacitors can be utilised for maintaining the DC link voltage effectively. View full abstract»

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  • MicroGrids Dynamic Security Assessment

    Page(s): 26 - 32
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (362 KB) |  | HTML iconHTML  

    MicroGrids comprise low voltage distribution systems with distributed energy sources, storage devices and controllable loads, operated interconnected with the main power grid or autonomously, in a controlled coordinated way. Storage devices are absolutely essential for MicroGrid autonomous operation. However, depending on the operating conditions, their limited storage capacity is a major drawback and might compromise successful MicroGrid islanded operation. In this paper is proposed an index to evaluate MicroGrids security regarding an unplanned transition to islanded operation due to disturbances in the upstream Medium Voltage network. An Artificial Neural Network tool is proposed to forecast the security index for a credible range of operating scenarios. The usage of Artificial Neural Networks is emphasized due to its computational speed for on-line performance and its flexibility for providing corrective actions for insecure operating conditions in order to achieve a seamless transition from interconnected to islanded operation. View full abstract»

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  • Electrification of isolated areas by interconnecting renewable sources: a sustainable approach

    Page(s): 33 - 40
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (138 KB) |  | HTML iconHTML  

    The Ecole Polytechnique Federale de Lausanne, the Hassan II Institute of Agronomics and Veterinary Science (IAV), and Targa-Aid association undertook a joint project to develop a technique for producing electrical energy from renewable primary energy sources to supply small networks of isolated consumers. Specific attention was paid to sustainable development issues, namely, the integration of social, environmental, and technical components. The project was carried out in the Ouneine Valley (Morocco). The project aimed to implement a technical transfer program and to improve the population's ability to absorb innovations such as rural electrification by isolated micro-grid. In seven selected villages the infrastructures for the network connections were successfully implemented through a participatory process. The project also comprised a research component aimed at gaining an understanding of the interfaces between the technical and sociological levels. It was felt that such an understanding was critical to the implementation of local development projects. View full abstract»

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  • The Clausthal Demonstration Plant for Decentralised Renewable Energy Supply Systems - Clausthal Energy Park -

    Page(s): 41 - 44
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (639 KB) |  | HTML iconHTML  

    Climatic changes, environmental issues and Unite resources are keywords in the current discussion about the future of the energy sector. Because of the liberalisation of the energy markets a stronger tendency to decentralisation and to the combined generation of heat and power has become evident, and thus the opportunities of utilising renewable sources will increase. It is the task of the "Demonstration Plant for Renewable Energy Supply Systems" (www.dresy.de) to provide reliable data and facts for this effort. The building of the Clausthaler Umwelttechnik-Institut GmbH (CUTEC) is to rely solely on the supply of renewable energy, not just on a general basis but dynamically and demonstrably at any given moment in time even under off-grid conditions. Partners in this long-term joint venture are the Clausthal University of Technology (TUC) with the following two institutes, Institute of Electrical Power Engineering (IEE) and Institute of Energy Process Engineering and Fuel Technology (IEVB), the Stadtwerke Clausthal-Zellerfeld GmbH and CUTEC. View full abstract»

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  • Insulation System and Thermal Design of a Hermetically Sealed Turbo-Generator Operating in a Small-Power CHP Plant

    Page(s): 45 - 50
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB) |  | HTML iconHTML  

    Small CHP plants within the range of one megawatt electric power and a few megawatts thermal power might be well suited in supplying heat and electricity for small communities. Hermetically sealed turbo-generator improves the cost-effectiveness of such small-power CHP plants. In such a structure, the low pressure, low temperature steam from the turbine flows through the air-gap of the generator. On the other hand, a hermetically sealed turbo-generator sets very high demands for the generator design. Steam in the air-gap is a substance, which traditional insulating materials cannot tolerate. Also, the thermal design of the machine requires special attention. This paper introduces a turbo-generator design with steam-resistant insulation system and proper thermal design to operate in a hermetic small-power CHP plant. View full abstract»

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  • Overview and Comparisons of Existing DG Interconnection Standards and Technical Guidelines

    Page(s): 51 - 54
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (107 KB) |  | HTML iconHTML  

    Owing to technology innovations, electricity market liberalization and environmental concern, many small-scale generators, or distributed generation (DG), using both renewable energy and fossil fuel resources, are rapidly brought to the power networks. The connection of DG may change the operation and the topology of distribution systems. This may influence voltage control, protection regime, safety issues, etc. of the system when coupling, operating, and shutting down small generator units. Technical requirements and standards of DG interconnection are different from country to country, making international harmonization difficult. This paper aims to give an overview and to discuss those differences. View full abstract»

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  • Electrical Train Feeding By Association Of Supercapacitors, Photovoltaic And Wind Generators

    Page(s): 55 - 60
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1154 KB) |  | HTML iconHTML  

    Because of their appropriate characteristics (huge capacitance, weak serial resistance), of direct storage (energy ready for use) and of easy control through the power electronic conversion, the use of supercapacitors as a storage element is quite suitable to the embarked electrical energy management. This new supercapacitive device of storage having high dynamic performances offers the possibility of the peak load shaving but also the compensation of the intrinsic limitations especially when it is joined to a main sources as an auxiliary power unit as for example its combination with fuel cell devices. This paper deals with the conception of an embarked power source using supercapacitors which are charged by means of the combination of a photovoltaic source and an aerogenerator. These supercapacitors ensure the power supply of a miniature train of 150 W of power. The design of this device, its control strategy and the obtained simulation with some experimental results are presented. View full abstract»

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  • Fuel-Cell Supplied Vehicle Drive with Synchronized Space-Vector Modulation

    Page(s): 61 - 68
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (343 KB) |  | HTML iconHTML  

    Analysis of operation of the six-phase traction drives with two isolated DC sources, controlled in accordance with basic schemes of synchronized pulsewidth modulation (PWM), has been performed. The analyzed drive topology uses two three-phase inverters having different DC link voltages. Two basic control schemes for the six-phase drives with synchronized PWM have been investigated: (1) control on the base of power balancing of the DC sources, and (2) PWM control with unequal power of two DC voltage sources. Special attention has been given to analysis of operation of six-phase drives in the zone of over modulation. The spectra of the phase voltage of the six-phase vehicle drives with synchronized PWM do not contain even harmonics and sub-harmonics during the whole control range, which is especially important for the high power/current applications. Simulations give the behavior of the dual-source fed six-phase motor drives with low switching frequencies, controlled in accordance with algorithms of continuous and discontinuous versions of synchronized PWM. View full abstract»

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  • Ultracapacitors application for energy saving in subway transportation systems

    Page(s): 69 - 73
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (131 KB) |  | HTML iconHTML  

    The presented research project is inserted in the energy management field, focusing the attention on the electric power recovery during the train operation in the subway transportation systems, in order to use part of the energy coming from the vehicles during the many braking phases that characterize the vehicle operating cycle. The goal of this research is to find out the best suitable solution in order to exploit the maximum energy available, by deepening the field of the new energy storage technologies, such as the super capacitors, already in development phase in some industrialized countries. View full abstract»

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  • Evaluation of a Fuel Cell for Powering the Electrical Load of ICE Vehicles

    Page(s): 74 - 77
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (640 KB) |  | HTML iconHTML  

    This paper describes the implementation and testing of a fuel cell system for powering the on-board electrical load of a pick-up truck that is being converted to a hydrogen-internal combustion engine. The fuel cell is assisted by a supercapacitor bank during engine starting which requires a much larger current. The sizing of the system components is determined from actual current demand of various loads. This new power source will replace the 12 Volt battery and alternator found in the conventional vehicle. Laboratory tests including supercapacitor charging, engine starting, and load switching are presented. View full abstract»

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  • Darwin project Use of renewable energy and Hydrogen on a sailing boat

    Page(s): 78 - 81
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (324 KB) |  | HTML iconHTML  

    The Darwin project is a six months journey on the sailing boat Adriatica that follows, in the backward direction, the Darwin's route towards Galapagos islands aboard Beagle. Enel is contributing to the project equipping Adriatica, i.e. the 22 m/50 tons sailing boat that will follow Darwin's route, with renewable energy generation systems allowing a sensible decrease of diesel fuel consumption required for aboard services, together with an hydrogen storage system based on metal hydrides. The main goal of the project is to study the suitability of the coupled use of renewable energy sources and hydrogen storage to be used for energy supply in isolated environments, with particular reference to a sailing boat, which has very strict requirements in terms of volume availability and safety regulations. View full abstract»

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  • Thermo-economic analysis of Dual-Mode Hybrid Trains: concept development and possible applications

    Page(s): 82 - 88
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1152 KB) |  | HTML iconHTML  

    The paper describes a hybrid dual mode traction system consisting of a standard catenary-supplied, high-speed electrical motor coupled with a genuine hybrid configuration consisting of a gas turbine generator and a suitable pack of accumulators. The concept is first analysed in detail from a general feasibility point of view, and expressions are derived for its energy balances on an arbitrary mission profile. A specific simulator is then employed to verify the actual performance of the train on an assigned mission, representative of the average profile in a semi-mountainous portion of the Italian railroad system. Once the technical feasibility has been verified, an economic analysis is performed, to assess the relative advantage in terms of the investment net present value, NPV. The results is positive, so demonstrating that in this case environment benefits (-19% CO2) and cost reductions can be obtained at the same time. View full abstract»

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  • Electrical energy management for low-voltage clients

    Page(s): 89 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB) |  | HTML iconHTML  

    Due to the increasing frequency of short grid failures since the liberalization of energy market and the interest for new energy recourses such as wind and sun, the idea grow to make an energy management system that combines UPS functionality and renewable energy sources to cover grid failure. We found an invertor/charger combination capable for this purpose and used lead batteries as energy buffer. Tests were performed to use small wind turbines and photovoltaic cells to charge the batteries. In Flanders very small wind turbines cannot be used economically due to the low wind speed. Photovoltaic cells are much more interesting: they generate more energy for the same installed power and the Flemish government grants a subsidy for photovoltaic installations. The final combination of photovoltaic cells and the energy buffer is practical realised in our lab. View full abstract»

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  • An Energy Resource Scheduler Implemented in the Automatic Management System of a Microgrid Test Facility

    Page(s): 94 - 100
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (505 KB) |  | HTML iconHTML  

    The paper deals with a microgrid test facility, settled at the CESI RICERCA laboratories, equipped with various distributed energy resources (DERs) and connected to a LV network. The operation of such a microgrid is supervised by a central automatic microgrid management system (MMS). The paper first reports and discusses some experimental results carried out for the assessment of DERs performance and for the implementation of specific MMS functions. Then, it describes the functions of the energy resources scheduler (ERS) implemented in the MMS. The scheduler periodically updates the set points of DERs regulators in order to achieve economic, reliability and power quality objectives, starting form the load and renewable production forecasts and from the results of the system state estimation. The ERS is composed by two main parts, namely: a day-ahead economic scheduler of active power set points during the following day for the minimization of the overall costs, and an intra-day scheduler that every 15 minutes settles the set points of the DERs regulators to optimize the voltage profile at the grid buses, taking into account both technical constraints and the day-ahead economic schedules. View full abstract»

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  • Electricity distribution network operation services - An analysis on market dynamics from the service provider's perspective

    Page(s): 101 - 109
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (377 KB) |  | HTML iconHTML  

    Market mechanisms behind electricity utilities in the field of network operation services have earlier been studied with a focus on experienced costs, risks and benefits. However, the corresponding analysis is in this study performed for the counterparts of electricity utilities, that is, the service providers. The theoretical framework of the study is based on transactional cost economics. Further, findings of an empirical North-European service provider survey are presented and analyzed. Some reasons behind the identified market gap of control room services are discussed and future market development is examined. As one result of the empirical survey, service providers in the field of electricity distribution seem to be generally positive to the business model of offering control room services. View full abstract»

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  • A Methodology for Maintenance-Interval Scheduling of Equipment Considering Maintenance Effect

    Page(s): 110 - 117
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1966 KB) |  | HTML iconHTML  

    This paper presents a methodology for maintenance-interval scheduling of equipment considering maintenance effect. By means of an operable ordering list of maintenance effects, all elements in a system can be ranked. For different purpose, maintenance intervals of elements can be scheduled as below. In order to reduce maintenance cost remarkably within a scale of system availability decrease, maintenance intervals of some elements with smaller maintenance effects are lengthened to decrease the number of system maintenance; In order to keep original system availability while reducing maintenance cost, maintenance intervals of some elements with larger maintenance effects are shortened to increase system availability, and at the same time maintenance intervals of some elements with smaller maintenance effects are lengthened to decrease the number of system maintenance. Based on this method, the maintenance intervals of equipments in thermal power stations are scheduled by use of the actual data from Kyushu Electric Power Co. of Japan, and thereby the effectiveness of the proposed method is verified. The proposed method can be adopted for many kinds of equipments or systems. View full abstract»

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  • Scaled Grid Expansion of Medium Voltage Power Systems with Decentralized Power Aggregates

    Page(s): 118 - 122
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB) |  | HTML iconHTML  

    Today the analysis of the power supply grids shows more and more that the increase of transported power and energy in the last years causes problems concerning the operation of the power grids. A combination of different measures, e.g. grid upgrading, grid toughening, economizing measures, new building of power stations or substations of suitable dimension etc. is necessary to solve those problems. In the following paper a project is introduced where the use of decentralized aggregates instead of building high-voltage power lines is analyzed. Using decentralized power aggregates can help to postpone the expansion of transmission lines and medium high voltage power grids for some years and thus achieving time for discussion with critical citizens and reduce investment costs. View full abstract»

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  • Load Balancing for Distributed and Integrated Power Systems using Grid Computing

    Page(s): 123 - 127
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (259 KB) |  | HTML iconHTML  

    The need for renewable power generation in power systems is becoming more importance. This need requires geographically-distributed power systems to be integrated as a single entity where among the main features of this integration are large data base and computing intensive. Grid Computing is a gateway to virtual storage media and processing power, this paper describes how grid computing can be utilized to perform load balancing for these distributed power systems. An interface between the power systems and the Grid Computing is developed that interacts with other power systems connected to the Grid Computing. Grid Computing resources shall perform realtime load forecasting where the results will be returned to each power system for decentralized load balancing operations. In conclusion, load balancing of distributed power systems was successfully implemented using Grid Computing ensuring that appropriate and non-excessive power is generated and thus benefiting all parties especially the environment. View full abstract»

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  • Reduction of the Net Losses in Distributed Networks

    Page(s): 128 - 131
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (162 KB) |  | HTML iconHTML  

    For loss reduction In distributed networks a multiplicity of possibilities exist. The use of cables instead of overhead lines as well as larger diameters of the lines lower the arising losses in distribution networks. Likewise a more even load profile leads to a reduction of losses, so that in the consequence primary energy, costs and CO2-emissions can be saved. Unbalances through asymmetrical loads arise particularly within the low-voltage grids and they are responsible for substantial losses compared with the situation of symmetrical load conditions. In this paper investigations are presented, which show that considerable loss reductions can be obtained by decentralized compensation. For the computation of the losses in urban distribution networks a model is developed. The parameters (standardised load profiles, number and kind of typical consumers, line data etc..) can be varied. Results of model computations are presented. View full abstract»

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  • Probabilistic Load Flow for Distribution Networks with Photovoltaic Generators Part 1: Theoretical Concepts and Models

    Page(s): 132 - 136
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (158 KB) |  | HTML iconHTML  

    Connections of distributed generation (DG) systems to distribution systems are increasing in number, though they may often be associated with the need of costly grid reinforcements or new control issues to maintain optimal operating conditions. Appropriate analysis tools are required to check distribution networks operating conditions in the evolving scenario. Load flow (LF) calculations are typically needed to assess the allowed DG penetration level for a given network in order to ensure that voltage and current limits are not exceeded. The present paper deals with the solution of the LF problem in distribution networks with photovoltaic (PV) DG. Suitable models for the active power produced by PV DG units and the power absorbed by the loads are to be used for representing the uncertainty for solar energy availability and loads variation. The proposed models have been incorporated in a radial distribution probabilistic load flow (PLF) program that has been developed by using Monte Carlo techniques. In this paper the theoretical concepts and the software implementation are described. The developed program allows probabilistic predictions of power flows at the various sections of distribution feeders and voltage profiles at all nodes of a network. In the second part of the paper the application to a practical case study is presented to show the results of the proposed method. View full abstract»

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  • Probabilistic Load Flow for Distribution Networks with Photovoltaic Generators Part 2: Application to a Case Study

    Page(s): 137 - 141
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (177 KB) |  | HTML iconHTML  

    Connections of distributed generators (DG) to distribution systems are increasing in number, though they may often be associated with the need of costly grid reinforcements or new control issues to maintain optimal operating conditions. Appropriate analysis tools are required to check distribution networks operating conditions in the evolving scenario. For example, load flow (LF) calculations are typically needed to assess the allowed DG penetration level for a given network in order to ensure that voltage and current limits are not exceeded. In the first part of this paper the solution of the LF problem in distribution networks with photovoltaic (PV) DG has been dealt with. Suitable models for the active power produced by PV DG units and the power absorbed by the loads have been used for representing the uncertainty for solar energy availability and loads variation. The proposed models have been incorporated in a radial distribution probabilistic load flow (PLF) program that has been developed by using Monte Carlo techniques. In this paper a practical case study is presented to show the results of the proposed method used for probabilistic predictions of power flows at the various sections of distribution feeders and voltage values at all nodes of a given network. View full abstract»

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  • A novel integrated configuration of Grid-connected photovoltaic plant with UPS: reliability estimation

    Page(s): 142 - 147
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (206 KB) |  | HTML iconHTML  

    This paper proposes a novel configuration of an electrical system, in which a photovoltaic plant (PV), used as support and integration, is interconnected to the DC-side of a conventional uninterruptible power system (UPS). The proposed configuration introduces important advantages compared to the configuration, in which no direct PV-UPS interconnection exists. In the paper, the attention is focused on the estimation of the reliability improvement as regards the supply of the critical loads. In particular, the reliability estimation is performed in terms of the number of the critical loads interruptions over a certain period of time by using the Monte Carlo simulation method. View full abstract»

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