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Power Engineering 2002 Large Engineering Systems Conference on, LESCOPE 02

Date 26-28 June 2002

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  • LESCOPE'02. 2002 Large Engineering Systems Conference on Power Engineering. Conference Proceedings

    Publication Year: 2002
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (187 KB)  

    The following topics are dealt with: power system economics; power system deregulation; distribution systems; power electronics; power system stability; power system protection; power system fault analysis; and power quality. View full abstract»

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  • Author's index

    Publication Year: 2002
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    Freely Available from IEEE
  • State of the art in optimal capacitor allocation for reactive power compensation in distribution feeders

    Publication Year: 2002 , Page(s): 61 - 75
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1819 KB) |  | HTML iconHTML  

    The application of capacitors in electric power systems is intended for the control of power flow, improvement of stability, voltage profile management, power factor correction, and loss minimization. This paper presents a review of different solution methods found in the literature and is intended as a guide for those interested in the problem or intending to do additional research in the area. The assumptions made and brief descriptions of the solution methods are presented. View full abstract»

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  • Recent progress in sensorless vector-controlled induction motor drives

    Publication Year: 2002 , Page(s): 80 - 85
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (613 KB) |  | HTML iconHTML  

    This paper reports the basic concept and recent progress in sensorless vector-controlled inverter fed induction tor (IM) drives. In field oriented control, a rotational transducer such as a tachometer, an encoder or a resolver, was often mounted on the IM shaft. However, a speed sensor cannot be mounted on a shaft in some cases such as motor drives in a hostile environment or high-speed motor drives. Further, these sensors suffer from low reliability, high cost and noise. Therefore, a sensorless speed drive is increasingly employed in modern industrial applications. This paper gives a short review of sensorless vector control of an induction motor drive. View full abstract»

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  • Double-circuit line adaptive protection based on Kohonen neural network considering different operation and switching modes

    Publication Year: 2002 , Page(s): 153 - 157
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB) |  | HTML iconHTML  

    This paper deals with problems connected to the distance protection of double-circuit transmission lines. Because of the zero sequence mutual coupling of parallel circuits, the relay "sees" incorrect impedance. In this paper, the authors develop an adaptive model which solves problems of single-line-to-ground faults on a single line. Different operation modes change short circuit currents (Ik1 - phase-to-earth short circuit current and Ik3 - three-phase short circuit current) on both ends. In fact, the parameters of the active network will be changed. The idea was to develop an adaptive model with different independent Kohonen networks. Each network is trained with short-circuit examples according to the switching mode and operation mode. Input parameters are voltage, current, switching mode and operation mode. The developed adaptive model was tested on a double-circuit 400 kV transmission line. View full abstract»

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  • The phase plane: a tool to solve the transient stability problem

    Publication Year: 2002 , Page(s): 120 - 124
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (431 KB) |  | HTML iconHTML  

    One of the most important problems in the study of transient stability of power systems is the determination of perturbation's maximum time of permanence without losing the synchronism of the generators that feed the network. The problem is generally solved by either the application of the equal-area criterion or through numerical integration methods. In the present work, the phase-plane is proposed as an alternative tool to solve the above-mentioned problem with greater efficiency. View full abstract»

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  • The electricity crises of California, Brazil and Chile: lessons to the Chilean market

    Publication Year: 2002 , Page(s): 7 - 12
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (774 KB) |  | HTML iconHTML  

    Many countries have deregulated their electricity markets, boosting competition and participation of private enterprises in generation. The recent electricity crises of Chile, California and Brazil, and the problems that other countries have faced, have interrupted the development of these reforms. In this paper the fundamentals of each market are analyzed, as well as each deregulated legislation. The authors also studied the crises, and the influence on them of each legislation. They found that besides circumstantial situations in each case, there are common aspects in the three crises. In all of them they found that the price signals in shortage situations were wrong, and that the performance of the regulators was deficient. They conclude that a deregulated electricity market will not work properly in a scarcity situation if consumers are isolated from the real cost of energy, and if it does not have independent regulators, that are not influenced by short-term political interests. Finally, based on the study, they propose improvements to the Chilean electricity legislation. View full abstract»

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  • FERC Order 2000

    Publication Year: 2002 , Page(s): 13 - 17
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (586 KB) |  | HTML iconHTML  

    This paper discusses FERC order 2000 and the necessity for the formulation of the Regional Transmission Organizations (RTOs). The advantages, problems and implications of RTOs are discussed. RTOs are beneficial in terms of market operation as well as system operation. No doubt that RTOs will affect some participants' interests. However, with so many benefits to the participants and to the system reliability, voluntarism should not be over emphasized and RTOs should be implemented in a more active way. View full abstract»

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  • Fast acting load control

    Publication Year: 2002 , Page(s): 23 - 28
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (525 KB) |  | HTML iconHTML  

    As open access market principles are applied to power systems, stability margins have been steadily decreasing. This has lead to events such as rolling black-outs in several power systems, for example, California, and has generally resulted in increased electricity prices. A novel approach to reduce the tension in electrical systems is to establish a fast acting load control program for price and system stability. This differs from traditional approaches where additional transmission lines and generators need to be installed. Using this approach, load can be modeled and controlled similar to a generator, proving spinning reserve. The paper reviews existing implementations of fast acting load control. Furthermore, in this paper, two Lagrangian based approaches are used to determine optimal locations for fast acting load control. The approaches are formulated to consider economic cost and stability limits. The effects of applying these approaches are analyzed using a 30-bus system, which is derived from the IEEE 30-bus test system. View full abstract»

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  • Genetic algorithm and GIS enhanced long term planning of large link structured distribution systems

    Publication Year: 2002 , Page(s): 55 - 60
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB) |  | HTML iconHTML  

    In order to enhance the serviceability in the distribution system genetic algorithm and GIS based method is proposed in this article for planning the link distribution networks. All practical issues such as cost parameters (investments, line losses, maintenance), and technical constraints (voltage drop, thermal limit, reliability) as well as physical routing constraints (obstacles, high cost passages, existing line sections) are taken into consideration. Fuzzy set concept and scenario representation (tree of futures) to model uncertainties, as well as decision making guided by a paradigm of multi-criteria risk analysis are discussed. The merits of the approach are discussed by analyzing its application to a study case based on a real case in a Croatian utility. View full abstract»

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  • Improved branch-based voltage stability proximity indices. Part I: Theoretical background

    Publication Year: 2002 , Page(s): 109 - 114
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (671 KB) |  | HTML iconHTML  

    In this paper improved branch-based voltage stability proximity indices are proposed. Their computation does not require the use of equivalents nor matrix handling, being straightforward and fast. They can be a very useful tool for power systems operators and planners both to evaluate systems operating conditions, and to determine system reinforcement actions. Also, the indices can be used to compare different operating situations as far as voltage stability is concerned. View full abstract»

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  • Unit commitment using the ant colony search algorithm

    Publication Year: 2002 , Page(s): 2 - 6
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (527 KB) |  | HTML iconHTML  

    The paper presents an ant colony search algorithm (ACSA)-based approach to solve the unit commitment (UC) problem. This ACSA algorithm is a relatively new meta-heuristic for solving hard combinatorial optimization problems. It is a population-based approach that uses exploitation of positive feedback, distributed computation as well as a constructive greedy heuristic. Positive feedback is for fast discovery of good solutions, distributed computation avoids early convergence, and the greedy heuristic helps find adequate solutions in the early stages of the search process. The ACSA was inspired from natural behavior of the ant colonies on how they find the food source and bring them back to their nest by building the unique trail formation. The UC problem solved using the proposed approach is subject to real power balance, real power operating limits of generating units, spinning reserve, start up cost, and minimum up and down time constraints. The proposed approach determines the search space of multi-stage scheduling followed by considering the unit transition related constraints during the process of state transition. The paper describes the proposed approach and presents test results on a 10-unit test system that demonstrates its effectiveness in solving the UC problem. View full abstract»

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  • A Monte Carlo technique for the evaluation of voltage sags in series capacitor compensated radial distribution systems

    Publication Year: 2002 , Page(s): 41 - 46
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (457 KB) |  | HTML iconHTML  

    Voltage sags, also known as dips, are important to industrial reliability. This paper presents a Monte Carlo based approach to evaluate the maximum voltage sag magnitudes in series capacitor compensated radial distribution systems. In this context, investigations have been conducted on a sample distribution system model taking into consideration the uncertainty of several factors associated with the practical operation of a power system. The Power System Blockset of MATLAB is used in the simulation studies. View full abstract»

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  • Inverters without filters

    Publication Year: 2002 , Page(s): 93 - 97
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (410 KB) |  | HTML iconHTML  

    This paper presents the optimized conditions for stepped wave inverters in order to minimize the total harmonic distortion present in the output waveform. It is shown that one- and two-level waveforms do not have sufficient degrees of freedom to meet harmonic standards like the IEEE 519. However three-level waveforms can be constructed, which meet such power quality standards and as a result, do not require output filtering. View full abstract»

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  • Complex and multiple unsymmetrical fault analysis

    Publication Year: 2002 , Page(s): 158 - 163
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (411 KB) |  | HTML iconHTML  

    A systematic procedure to solving complex and multiple fault problems of power systems is proposed in this paper. Complex faults are combinations of different common unsymmetrical faults that occur at a single bus. Multiple faults are a series of complex faults that occur at several buses at the same time. The proposed method utilize the well known bus impedance matrix method for fault analysis. Examples of both types of faults are given to demonstrate the proposed procedure. View full abstract»

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  • Improved branch-based voltage stability proximity indices. II. Application in security analysis

    Publication Year: 2002 , Page(s): 115 - 119
    Cited by:  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (495 KB) |  | HTML iconHTML  

    In this paper, a method for contingency ranking for voltage stability is proposed. Contingencies are ranked according to a performance index defined in terms of branch-based voltage stability proximity indices. Simulation results show that the most critical contingencies can be correctly identified. View full abstract»

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  • Artificial neural network application to alleviate voltage instability problem

    Publication Year: 2002 , Page(s): 133 - 141
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB) |  | HTML iconHTML  

    This paper argues that the artificial neural network (ANN) is an important technique and can be applied to control voltage instability problems in two ways. The first is to control voltage collapse by using load shedding. In this way the minimum and optimal ratio of load shedding can be calculated. The second is to calculate the reactive power required to control sources in the electric power system. The strengths of this powerful technique lie in its ability for modeling and solving many types of problems. The ANN is designed for those two mentioned ways. A multi-layer feed forward ANN trained with error backpropagation learning is proposed. This network is applied to a stressed power system at different load levels. Simulation results on a test system are reported in this paper. View full abstract»

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  • Security-constrained price-based unit commitment in the deregulated power market

    Publication Year: 2002 , Page(s): 18 - 22
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB) |  | HTML iconHTML  

    This paper describes a coordination process between GENCOs and the ISO for congestion management and reducing the risk of failure to supply loads. The algorithm underlining the coordination technique is the security-constrained price-based unit commitment (SPUC) which is implemented in two states. At first, GENCOs apply priced-based unit commitment (without transmission security constraints), schedule their generating units and submit their energy and capacity bids to the ISO for maximizing their revenues. The ISO obtains transmission information as well from TRANSCOs via OASIS. Using the two sets of generation and transmission data, the ISO executes inter-zonal and intra-zonal congestion management and contingency analysis for minimizing line flow violations and the risk supplying loads. As part of this package, the ISO would have a chance to minimize both transmission flow and reactive (bus voltage) violations. If transmission flow violations persist after the adjustments are made, the solution would provide a signal to GENCOs, based on Benders decomposition, for modifying their initial bids. Accordingly, additional constraints will be introduced in GENCOs for rescheduling generating units and submitting modified bids to the ISO. View full abstract»

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  • PSO-based neural network for dynamic bandwidth re-allocation [power system communication]

    Publication Year: 2002 , Page(s): 98 - 102
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (414 KB) |  | HTML iconHTML  

    A high-speed network needs to assign a fixed bandwidth for each connection some where between its mean and peak rates. Most of the time this assigned bandwidth will not handle all the traffic received and creates traffic loss. This paper introduces a new algorithm to avoid network congestion. The algorithm mainly considers online measurements of the relative contents of each buffer in the network. An adaptive bandwidth reallocation is simply done by recalling an evolved neural network. A particle swarm optimizer (PSO) is used to adjust both weights matrix and the number of nodes for the hidden layer providing that input and output layers are fixed at one node (ratio of relative contents and bandwidth proportion respectively). The results are compared with static bandwidth allocation in terms of number of traffic drop. View full abstract»

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  • Harmonic flow study and evaluation of a petrochemical plant in Saudi Arabia

    Publication Year: 2002 , Page(s): 165 - 172
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (515 KB) |  | HTML iconHTML  

    Nowadays, the concern about power quality is continuously increasing, due to industry automation and use of nonlinear devices introduced in the power system. These nonlinear control devices or loads may cause harmonics or distortion to the current waveform. Such distortions will cause malfunction to the sensitive devices such as metering instruments, on-line process analyzers, and measuring devices, and false readings may be displayed. These false readings are going to affect the operation of the plant and may cause shut down and large monetary losses. The purpose of this paper is to outline the subject of harmonics and to conduct and demonstrate harmonic study on a petrochemical company power system in Saudi Arabia. The study will insure that the harmonic flows between different buses are within standards for industrial plants, and emphasize that the plant can be safely operated from the harmonics effects point of view. Also, to determine the THD values, and conduct mitigation if high THD, TIF values obtained to that are beyond the recommended practices by IEEE-519-1992. View full abstract»

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  • Stator-winding fault diagnosis of PM brushless DC motor drives

    Publication Year: 2002 , Page(s): 147 - 152
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (508 KB) |  | HTML iconHTML  

    A model-based diagnostic system for stator winding inter-turn faults of PM brushless DC motor drives is presented. A transient model of the drive system is set up and run under different healthy and faulty conditions. The steady-state supply current is selected as the diagnostic signal to compare the healthy operation to the faulty operation under different loads. The supply current signal is transformed to the frequency domain using the discrete Fourier transform (DFT). Appropriate diagnostic indices are extracted from the supply current spectrum to differentiate between healthy and different faulty conditions. View full abstract»

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  • Visualization of UPFC control parameters effects on the tie-line power flow

    Publication Year: 2002 , Page(s): 103 - 107
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (407 KB) |  | HTML iconHTML  

    This paper investigates the ability of unified power flow controller (UPFC) on controlling the tie line power transfer of an interconnected system. A form of vector presentation in complex power plane is used to visualize the effect of different control parameters of UPFC on tie line power transfer. This visualization helps to identify the effectiveness of each control parameters on power control region. View full abstract»

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  • Skin effect on optimal power factor

    Publication Year: 2002 , Page(s): 76 - 78
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (371 KB) |  | HTML iconHTML  

    Optimization criteria are presented which allow proper calculation of optimal power factor. Optimization minimizes the line loss, maximizes the power factor and maximizes the efficiency, taking into consideration the skin effect. The performance of the obtained capacitor is discussed by means of a numerical example. View full abstract»

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  • A new tabu search algorithm for the long-term hydro scheduling problem

    Publication Year: 2002 , Page(s): 29 - 34
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB) |  | HTML iconHTML  

    A new efficient algorithm to solve the long-term hydro scheduling problem (LTHSP) is presented in this paper. The algorithm is based on using the short-term memory of the tabu search (TS) approach to solve the nonlinear optimization problem in continuous variables of the LTHSP. The paper introduces new rules for generating feasible solutions with an adaptive step vector adjustment. Moreover an approximated tabu list for the continuous variables has been designed. The proposed implementation contributes to the enhancement of speed and convergence of the original tabu search algorithm (TSA). A significant reduction in the objective function over previous classical optimization methods and a simulated annealing algorithm has been achieved. Moreover the proposed TS requires less iterations to converge than simulated annealing. The proposed algorithm has been applied successfully to solve a system with four series cascaded reservoirs. Numerical results show an improvement in the solution compared to previously obtained results. View full abstract»

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  • Five level diode clamped voltage source inverter and its application in reactive power compensation

    Publication Year: 2002 , Page(s): 86 - 92
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (600 KB) |  | HTML iconHTML  

    This paper deals with multilevel diode clamped voltage source inverter applied as STATCOM. The authors use "offline" optimization of switching angles together with fundamental frequency modulation switching strategy (FFM). They show that reactive power compensation is achieved by controlling the exchange of active power between the DC side of the inverter and the AC system. Moreover, they show that it is not possible to achieve the proper compensation during unbalanced conditions of the system while an FFM switching strategy is used together with "offline" optimization of switching angles. Simulation and experimental results are presented. View full abstract»

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