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Power Engineering, 2001. LESCOPE '01. 2001 Large Engineering Systems Conference on

Date 11-13 July 2001

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Displaying Results 1 - 25 of 39
  • 2001 Large Engineering Systems Conference On Power Engineering [front matter]

    Page(s): i - vii
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    Freely Available from IEEE
  • 2001 Large Engineering Systems Conference On Power Engineering [front matter]

    Page(s): i - vi
    Save to Project icon | Request Permissions | PDF file iconPDF (269 KB)  
    Freely Available from IEEE
  • Load management and control of the photovoltaic (PV) system using fuzzy logic

    Page(s): 184 - 188
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1420 KB) |  | HTML iconHTML  

    This paper provides a fuzzy logic control scheme for PV power systems under faults and load disturbances. The classical model using microprocessors, power electronics and DC-DC converters can be made less complicated with the application of a fuzzy logic controller, which is robust and good for nonlinear systems. Inputs to the fuzzy logic controller are the optimal power tracked (using a genetic algorithm), the state of charge of the battery and the load current. The output controls the rate of current injection into the battery for energy storage or increases or decreases the load in priority order to match the optimal requirement. The fuzzy design scheme is developed around an in-house PV program using Matlab software. View full abstract»

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  • Author's index

    Page(s): 213 - 214
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    Freely Available from IEEE
  • Reactive power pricing in deregulated electrical markets using a methodology based on the theory of marginal costs

    Page(s): 7 - 11
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    In this paper, a flexible formulation about the pricing of active and reactive power is presented. This proposal is developed using a decoupled formulation identifying the active and reactive subproblems. A model for the price calculation of the reactive power which is intended to incentive the participation of agents of the electricity markets is analyzed. An optimal power flow (OPF) to solve the reactive power subproblem which considers the production costs of the reactive power and the active losses minimization in the objective function, has been implemented. In order to solve the OPF and consequently obtaining the active and reactive power marginal cost prices has been adopted a nonlinear programming methodology. Tests using a 9-bus system for several load conditions show the validity of the methodology View full abstract»

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  • Supporting distance engineering education is greatly needed

    Page(s): 69 - 72
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    Academia has had enough modeling efforts and enough pilot projects of distance learning. What is needed now is long-term, sustaining efforts that truly can grow and be a substantial part of the education business. Some places are doing that, and others are struggling with it, but distance learning is certainly headed in that direction. Colleges have a long way to go before they get the support at a level that will help organizations learn enough to create sustaining programs. For distance learning to succeed, it has to have institutional reward systems that reflect distance-learning activity View full abstract»

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  • An intelligent system for monitoring the nuclear refuelling process

    Page(s): 49 - 53
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    Certain types of nuclear reactors contain over 300 fuel assemblies that over time will become depleted and require replacement with new fuel assemblies-this process is known as refuelling. When refuelling a nuclear reactor, the data produced must be evaluated to ensure that the fuel assembly has landed properly in its position, thereby allowing the continued and safe operation of the station. The process of evaluation is time consuming because of the manual interpretation required and the large amount of data produced. This manual interpretation also requires considerable domain experience due to the nature of the domain. This paper presents an intelligent system to automate the process of the data analysis, thereby shortening the evaluation time and providing an explanation of the reasoning behind its conclusions. The intelligent system utilises a knowledge based system, neural network based classification, K-means clustering techniques and rule induction methods to evaluate the data and inform the operator of any errors encountered View full abstract»

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  • Modeling of legacy intelligent electronic devices for UCA based substation integration systems

    Page(s): 38 - 43
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    Intelligent electronic devices (IED) are the standard protection and control equipment in today's substations. UCA2 based protection and control systems integrate devices that are designed to support the UCA object models. However, there is a huge installed base of legacy protection and control IEDs that are still going to be available for many years and will have to be integrated in UCA based systems. The paper describes in detail the complex object model of multifunctional legacy protection and control IEDs. The models are based on the existing UCA 2 documents (Generic Object Models for Substation and Feeder Equipment-GOMSFE). It presents the basic building blocks and their grouping in order to model such a protective device. The challenges of modeling different multifunctional legacy devices in a single gateway are discussed. The object-oriented approach to peer-to-peer communications for high speed protection and control functions and issues related to gateway based applications are covered in another section of the paper. They are based on Generic Object Oriented Substation Event (GOOSE) messages exchanged between protective relays connected to the substation LAN View full abstract»

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  • Intelligent engineering support for protection scheme design

    Page(s): 54 - 58
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    This paper describes a research project focusing on the provision of 'intelligent' engineering support facilitating two major UK utilities in the design of complex protection schemes associated with electrical transmission networks. The development and functionality of the Engineering Design Knowledge Application System (DEKAS) is described within the paper. In addition, broader issues concerning the capture of design rationale for design re-use and the application of knowledge engineering techniques in the development of expert systems and the general promotion of knowledge management are explored View full abstract»

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  • A structured methodology for intelligent system selection in nuclear power industry applications

    Page(s): 44 - 48
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB) |  | HTML iconHTML  

    As the number of successful implementations of intelligent systems (ISs) to perform nonsafety related operations increases, so the desire has grown to assess the possibility for use of ISs to support safety related functions. This interest has been recognised by the nuclear industry who wish to determine if ISs can be successfully and reliably used for performing condition monitoring of critical data. Therefore, in order to test the applicability of ISs in the nuclear domain, it is necessary to create a structured development methodology that explains why and how development decisions have been made. At the top level of this IS development methodology, it has consequently been necessary to develop a generic IS selection methodology which can be applied to any relevant problem. This paper has presented a methodology, to aid a decision maker in choosing an appropriate intelligent system as the solution to a given problem. This methodology provides a formal framework for justification of the decisions made and provides the facility for traceability and subsequent justification of these decisions. This is therefore useful for nuclear power software applications where it is desirable to make well-planned and justifiable decisions when the IS is to be used in safety-related applications View full abstract»

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  • Power cable on-line diagnosis using partial discharges ultra wide band techniques

    Page(s): 201 - 205
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    A noninvasive ultra-wide band (UWB) partial discharge technique was employed in cable diagnosis of Mexico City underground distribution feeders. The technique presented here was applied to over 2000 joints, 400 terminals and thousands of meters of installed paper insulated impregnated cables rated at 23 kV. The technique allowed circuit classification according to electromagnetic field levels produced by partial discharges and recorded on each manhole with a joint along the circuits evaluated in 12 substations. The PD detection technique employs near field sensors working within the 80 MHz range and whose information is digitized and fed to a conventional PD digital detector, where a PD pattern is obtained. This pattern is correlated to the phase current by using an inductive sensor; therefore corona and interference problems could be disregard during measurements. To attain repetitive values, calibration was performed using a very fast pulse (less than 50 ns front) injected in a small cable loop. Results demonstrate a great signal to noise ratio, high selectivity and great noise discrimination. The large amount of measurements allowed the determination of limit values to differentiate areas in acceptable state from those requiring attention. Those results include detection of bad joints, cable deformation due to ducts collapse and damaged terminals, besides aged cable detection caused by overheating operation conditions. The results obtained had been confirmed by subsequent faults following the detection of very high levels of PD View full abstract»

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  • Voltage stability constrained VAr planning-a case study for New Zealand

    Page(s): 86 - 91
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    This paper discusses a VAr planning optimisation model that takes into account voltage stability constraint, and proposes an efficient solution algorithm to solve it. A contingency constrained optimal power flow (OPF) based model incorporating (static) voltage stability constraints is developed to analyse optimal VAr support decisions. Given a set of contingencies, the model performs the contingency ranking, decides optimal location and quantity of VAr support to simultaneously cover all the contingencies. DICOPT++, a state-of-the-art mixed integer nonlinear programming (MINLP) algorithm, is proposed to solve the model efficiently. The model is implemented for a 17 bus reduced New Zealand North Island system. The modal analysis is also conducted and the result is discussed View full abstract»

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  • Modelling and simulation of a PV-inverter-asychronous motor association in photovoltaic pumping systems

    Page(s): 146 - 151
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    In this paper, we introduce a method of control and sizing of photovoltaic systems in stand alone PV pumping plants. This approach is based on the dynamic model of the PV-DC/DC inverter-asynchronous motor. The DC-DC converter ensures an impedance adaptation between the PV and the load and an optimal PV panel output power extraction. However, the DC/AC converter ensures a PWM control of the induction motor and a sinususoidal output signal. This methodology allows an optimal control and monitoring of continuous-continuous and continuous-alternative converters by calculating respectively the DC/DC cyclic ratio and the DC/AC frequency. Contrary to classic methods, this method, which is based on the parametric model of the PV system, leads to a best prediction of the the PV installation especially with load and climatic fluctuations View full abstract»

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  • Effect of distributed generation on protective device coordination in distribution system

    Page(s): 115 - 119
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    Protection of a power system is an extremely important aspect as the duality and scheme of protection decides system reliability, controllability and stability. This paper concentrates on the protection of a distribution system in the light of developments in distributed generation (DG). The conventional distribution system is radial in nature, characterized by a single source feeding a network of down-stream feeders. The protection system has traditionally been designed assuming the system to be radial. After connecting DG, part of the system may no longer be radial, which means the coordination might not hold. The effect of DG on coordination will depend on size, type and placement of DG. This paper explores the effect of DG on protective device coordination such as fuse-fuse, fuse-recloser and relay-relay. In each case, depending on size and placement of DG, there are some margins in which the coordination may hold and certain cases, where no margin is available. These conditions are identified for each case through coordination graphs View full abstract»

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  • Implementation and performance analysis of very short term load forecaster based on the electronic dispatch project in ISO New England

    Page(s): 98 - 104
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (532 KB) |  | HTML iconHTML  

    With deregulation in the electric power industry, an accurate very short-term load forecasting (VSTLF) function is increasingly important and becomes an integral component of the real-time (spot) market. VSTLF, dealing with the forecast horizon of one to several minutes ahead, is a relatively new division of the load forecasting which is of special importance in resource dispatch function and correction of area control error (ACE). This paper reports upon the implementation and performance analysis of very short term load forecast (VSTLF) in the electronic dispatch project in ISO New England View full abstract»

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  • Two digital filtering algorithms for fast estimation of symmetrical components in power system: a static estimation approach

    Page(s): 125 - 130
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    This paper presents the application of two digital filters working together for fast estimation of the system symmetrical components. The three-phase unbalanced system is transformed into αβ-transformation. Using such a transformation, harmonics of order 3 and their multiples can be eliminated from the input signal. Having identified the two-phase voltage, the positive and negative sequence phase voltage can be calculated using a constant transformation matrix as well. The zero sequence is easily estimated by averaging the unbalanced three-phase voltage at any sample instant. The least error square algorithm is the parameter estimation algorithm used to identify the magnitude and phase angle of each sequence component from the available samples of the specified component View full abstract»

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  • Challenges and opportunities facing electricity distribution utilities

    Page(s): 167 - 171
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    UK electricity distribution utilities will be faced with a number of challenges and opportunities as a result of distributed generation appearing on their networks. It is argued that the current approach to distribution network design, which relies on network reinforcement practices, will not be conducive for designing networks in the future. Especially to take advantage of the opportunities while at the same time mitigating the challenges, network designers should be in a position to consider all solutions that can solve a particular design problem. This means that they should consider both network reinforcement and contemporary design solutions. Contemporary solutions include the wide range of power electronic controller devices on the market. A new framework is presented to facilitate the design of distribution networks in the future View full abstract»

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  • GENCOs portfolio management using “STRATEGIST” in deregulated power markets

    Page(s): 12 - 17
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    STRATEGIST is a software package that is coded in FORTRAN and C++ for GENCOs' portfolio management in deregulated power markets utilizing COUGER which is a unit commitment software package coded in FORTRAN for profit maximization. STRATEGIST incorporates a probabilistic approach for the evaluation of composite reliability of generation, load forecast and fuel prices using different probability distributions. STRATEGIST analyses the risk in an uncertain power market. This package is to be used by GENCOs to maximize their profit as well as to hedge the GENCOs to against crucial loss of profit. A typical scenario for applying this package is a GENCO which tries to supply its native load and trade bilateral transactions and would be interested in determining the risk associated with different alternatives. STRATEGIST is designed based on a comprehensive analysis of various risks in a portfolio View full abstract»

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  • Simple power distribution load forecasting method based on fuzzy modelling

    Page(s): 93 - 97
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (472 KB) |  | HTML iconHTML  

    During the last three and a half decades various load forecasting methods have been created. However, these methods cannot forecast future loads in case of severe lack of data, when only few loads are measured in nonconsecutive years. This paper presents two simple methods developed specially to handle such a situation: a simple trending method and a method based on fuzzy modelling. Fuzzy modelling is carried out using a subtractive fuzzy clustering algorithm and recursive least-squares estimator. Both load forecasting methods are illustrated by a numerical example View full abstract»

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  • A Norton equivalent model for nonlinear loads

    Page(s): 63 - 67
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    In this paper, a new model for the distribution system including nonlinear loads is introduced. The model is based on measurements, where current and voltage measurements at two different operating conditions are used to derive an equivalent Norton model for the distribution system. An advantage of such a model is that knowledge of the distribution system details is not necessary. Another advantage is that the model can simulate the performance of the modeled part of the distribution over a reasonable range of variations in the operating conditions. Moreover, the amount of measurements required is significantly decreased. The proposed model has proved its accuracy in representing the performance of the distribution system including nonlinear loads as well as its simplicity and minimum required measurements View full abstract»

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  • Software engineering in power systems: practices and challenges

    Page(s): 25 - 30
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    This paper presents an overview of applying software engineering concepts in development of software for use in deregulated power markets. An overview of power system deregulation is presented and the importance of software requirements management and software testing, in particular, in the development of power systems software is underlined. Practices adopted for the purpose are enumerated. Sample illustrations for managing power software requirements and enhancing testing practices to improve software quality are also presented. Challenging issues related to power system software are briefly outlined View full abstract»

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  • Linear programming based algorithm for reactive power constrained real power dispatch and pricing

    Page(s): 2 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (396 KB) |  | HTML iconHTML  

    This paper presents a linear programming based algorithm for dispatch and pricing in electricity markets. The proposed algorithm takes reactive power and voltage magnitude constraints into account, unlike most commonly used dispatch and pricing algorithms. A case study with IEEE 30 bus system shows that the algorithm gives very accurate answers for dispatch and prices when compared with a full nonlinear model. The paper also presents insights on the relationships between nodal prices in the presence of constraints View full abstract»

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  • Distribution network reconfiguration and reactive power compensation

    Page(s): 177 - 183
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    Electric utilities and customers are all interested in power quality. The use of automation and energy efficient equipment with electronic control would greatly improve industrial production. These new devices are more sensitive to supply voltage deviation and the characteristics of the power system that was previously ignored are now very important. Hence the benefits of distribution automation have been widely acknowledged in recent years. This paper proposes an efficient load flow solution technique extended to find optimum location for reactive power compensation and network reconfiguration for planning and day-to-day operation of distribution networks. This is required as a part of the distribution automation system (DAS) for taking various control and operation decisions. The method exploits the radial nature of the network and uses forward and backward propagation technique to calculate branch currents and node voltages. The proposed method has been tested to analyze several practical distribution networks of various voltage levels and also having high R/X ratio View full abstract»

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  • Location of FACTS devices for enhancing power systems' security

    Page(s): 162 - 166
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    A stressed power system, either due to increased loading or due to severe contingencies, often lead to situations where the system no longer remains in the secure operating region. Under these situations, it is a primary objective of the operator to apply control action to bring the power system into a secure region. Any delay or unavailability of suitable control, and the system may become unstable. FACTS devices can play a very important role in power system security enhancement. Due to high capital investment, it is necessary to locate these devices optimally in the power system. In this paper, a suitable approach has been suggested based on the sensitivity analysis on FACTS device control parameters with respect to reduction in a real power flow performance index to enhance the security of the power system. The proposed approach has been illustrated on a sample system View full abstract»

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  • Assessment of the small signal stability of the European interconnected electric power system using neural networks

    Page(s): 158 - 161
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    This paper deals with a new method based on neural networks for eigenvalue predictions of critical stability modes of power systems. Our special interest is focused on interarea oscillations in the European interconnected power system. The existing methods for eigenvalue computations are time-consuming and require the entire system model that includes an extensive number of states View full abstract»

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