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Power Delivery, IEEE Transactions on

Issue 3 • Date July 2002

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Displaying Results 1 - 25 of 31
  • Strategies for selecting monitoring of circuit breakers

    Publication Year: 2002 , Page(s): 742 - 746
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (182 KB) |  | HTML iconHTML  

    Diagnostics and monitoring can be used to optimize maintenance practices, replacement, and utilization of aged circuit breakers. Monitoring practices should be selected with realistic expectations. Monitoring techniques and strategies for circuit breakers can vary depending on the application. Some monitoring techniques do not provide sufficient benefit to justify the cost and effort. Conversely, appropriate selection of monitoring can provide significant benefits. A new "IEEE Guide for the Selection of Monitoring for Circuit Breakers" has been published. It outlines the majority of monitoring options, and includes the important role and application of failure modes and effect analyzes. Various monitoring techniques and strategies are reviewed using the new guide as a reference for selecting the most appropriate monitoring for a given application. View full abstract»

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  • Design and analysis of the inverter-side filter used in the dynamic voltage restorer

    Publication Year: 2002 , Page(s): 857 - 864
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (351 KB)  

    The role of the inverter-side filter used in the dynamic voltage restorer (DVR) is examined. Using circuit analysis method, it is shown that the selection of the filter parameters can affect the DVR inverter rating. Furthermore, with the DVR filter-series injection transformer combination, the loading effect of the filter on the restorer and the primary supply system has been quantified under normal as well as voltage sag conditions. A systematic filter design method is then proposed, the primary objective of which is to achieve specific harmonic performance while ensuring that the DVR inverter rating and the loading effect are minimized. Illustrative examples are also included. View full abstract»

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  • Pattern recognition applications for power system disturbance classification

    Publication Year: 2002 , Page(s): 677 - 683
    Cited by:  Papers (35)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (262 KB) |  | HTML iconHTML  

    This paper presents an automated online disturbance classification technique. This technique is based on wavelet multiresolution analysis and pattern recognition techniques. The wavelet-multiresolution transform is introduced as a powerful tool for feature extraction in order to classify different disturbances. Minimum Euclidean distance, k-nearest neighbor, and neural network classifiers are used to evaluate the efficiency of the extracted features. View full abstract»

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  • An accurate fault classification technique for power system monitoring devices

    Publication Year: 2002 , Page(s): 684 - 690
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (247 KB) |  | HTML iconHTML  

    This paper presents a novel method of classifying transmission line shunt faults. Most algorithms employed for analyzing fault data require that the fault type be classified. The older fault-type classification algorithms are inefficient because they are not effective under certain operating conditions of the power system and may not be able to accurately select the faulted transmission line if the same fault recorder monitors multiple lines. The technique described in this paper has been proven to accurately identify all ten types of shunt faults that may occur in an electric power transmission system. The other advantage of this technique is that it can be used where multiple transmission lines are present. It is able to identify the faulted line even if secondary effects are recorded in the unfaulted lines. View full abstract»

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  • An adaptive distance relay and its performance comparison with a fixed data window distance relay

    Publication Year: 2002 , Page(s): 691 - 697
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (259 KB) |  | HTML iconHTML  

    This paper describes the design, implementation and testing of an adaptive distance relay. The relay uses a fault detector to determine the inception of a fault and then uses data windows of appropriate length for estimating phasors and seen impedances. Hardware and software of the proposed adaptive relay are also described in this paper. The relay was tested using a model power system and a real-time playback simulator. Performance of the relay was compared with a fixed data window distance relay. Some results are reported in this paper. These results indicate that the adaptive distance relay provides faster tripping in comparison to the fixed data window distance relay. View full abstract»

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  • Load and voltage balancing in harmonic power flows by means of static VAr compensators

    Publication Year: 2002 , Page(s): 761 - 769
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (354 KB) |  | HTML iconHTML  

    In special applications, static VAr compensators (SVCs) with thyristor-controlled reactors (TCRs) are used to balance unbalanced loads or to eliminate voltage unbalances at the terminals of the SVC. In both cases, load balancing and voltage balancing, the TCR can present a significant unbalanced behavior which produces important quantities of noncharacteristic harmonics. In this paper, the formulation and solution of the load and voltage balancing problems are developed for harmonic power flows obtained from a combination of two blocks: (1) a conventional load flow (CLF) and (2) an iterative harmonic analysis (IHA). In both blocks, the treatment of load and voltage balancing is described in detail. Load flow (LF) calculations and harmonic analysis show the presence of noncharacteristic harmonics in these two situations. View full abstract»

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  • Adaptive power flow method for distribution systems with dispersed generation

    Publication Year: 2002 , Page(s): 822 - 827
    Cited by:  Papers (81)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (227 KB) |  | HTML iconHTML  

    There has been great interest in the integration of dispersed generation units at the distribution level. This requires new analysis tools for understanding system performance. This paper presents an adaptive distributed power flow solution method based on the compensation-based method. The comprehensive distributed system model includes 3-phase nonlinear loads, lines, capacitors, transformers, and dispersed generation units. The numerical properties of the compensation-based power flow method are compared and analyzed under different situations, such as load unbalance, sudden increase of 1-phase loads, degree of meshed loops, number of generator nodes, and so on. Based on these analyses, an adaptive compensation-based power flow method is proposed that is fast and reliable while maintaining necessary accuracy. It is shown that this adaptive method is especially appropriate for simulation of slow dynamics. View full abstract»

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  • IEEE Task Force Report: brittle fracture in nonceramic insulators

    Publication Year: 2002 , Page(s): 848 - 856
    Cited by:  Papers (20)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (266 KB) |  | HTML iconHTML  

    A description of the composite insulator brittle fracture phenomenon suitable to allow correct diagnosis of a failure is provided. This paper reports on the number of brittle fractures that have occurred around the world and contains specific empirical data surrounding composite insulator brittle fractures in the US. It also includes several case studies of in-service failures to inform the reader of the diversity of initiating causes. The current state-of-knowledge on the brittle fracture mechanism is presented. Based on what was learned during the study, possible actions that can be taken by manufacturers and users to reduce frequency of occurrence are suggested. View full abstract»

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  • Accuracy limits in the computed transients on overhead lines due to inaccurate ground return modeling

    Publication Year: 2002 , Page(s): 872 - 878
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    Electromagnetic transients on overhead transmission lines are strongly affected by the resistivity ρ of the ground return which, however, is often poorly known. Therefore, the calculation of transients with very high accuracy for a given ρ may not make good engineering sense if it entails loss of computational efficiency. The effect of ρ on the transients comes primarily via the ground return impedance. In order to judge what accuracy is reasonable, this paper derives the sensitivities of the ground return impedances for line and ground modes with respect to the resistivity ρ. The results are simple and may assist decidions on the accuracy of computations in EMTP-type simulation programs. View full abstract»

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  • A Bayesian approach for short-term transmission line thermal overload risk assessment

    Publication Year: 2002 , Page(s): 770 - 778
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (322 KB) |  | HTML iconHTML  

    An on-line conductor thermal overload risk assessment method is presented in this paper. Bayesian time series models are used to model weather conditions along the transmission lines. An estimate of the thermal overload risk is obtained by Monte Carlo (MC) simulation. We predict the thermal overload risk for the next hour based on the current weather conditions and power system operating conditions. The predicted risk of thermal overload is useful for on-line decision making in a stressed operational environment. View full abstract»

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  • Experimental results of a supplementary technique for auto-reclosing EHV/UHV transmission lines

    Publication Year: 2002 , Page(s): 702 - 707
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (255 KB) |  | HTML iconHTML  

    A technique to discriminate between the line charging inrush current and the current resulting on closing or auto-reclosing a faulted EHV/UHV transmission line has been implemented on a 32-b digital signal processor (DSP) board. The technique is based on the voltage signals before switching and the current signals. This technique is proposed to be a supplement to the main protection schemes for both single-circuit and double-circuit lines. The scheme is tested on a physical model of a transmission system with a source at each end. Laboratory tests show that the proposed technique is effective for three-pole and single-pole reclosing on a faulted or healthy line. View full abstract»

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  • Frequency-dependent transmission line modeling utilizing transposed conditions

    Publication Year: 2002 , Page(s): 834 - 839
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (230 KB) |  | HTML iconHTML  

    Existing phase domain transmission line models are capable of producing highly accurate results for both overhead lines and underground cables. This paper introduces a hybrid line model which gives substantial savings in computation time without loss of accuracy, when one or more circuits of a transmission system are treated as continuously transposed. This is achieved by means of a constant transformation matrix in combination with a reduced-size phase domain line model and a number of single-phase (modal) line models. The calculated examples demonstrate a potential speed increase over a full phase domain model between three and four. If none of the circuits are transposed, the line model degenerates into a full phase domain line model. View full abstract»

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  • Unbalance protection of fuseless, split-wye, grounded, shunt capacitor banks

    Publication Year: 2002 , Page(s): 698 - 701
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB) |  | HTML iconHTML  

    In recent years, a large number of electric utilities have been implementing fuseless split-wye grounded capacitor banks in lieu of the traditional externally fused bank. This change in philosophy has forced many protection engineers to research new methods of calculating the quantities needed to apply unbalance protection. This paper presents a novel method of calculating the unbalance current produced by fuseless capacitor unit failures as well as some general background information regarding fuseless split-wye grounded capacitor bank technology and unbalanced protection. View full abstract»

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  • Application of immune-based optimization method for fault-section estimation in a distribution system

    Publication Year: 2002 , Page(s): 779 - 784
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (221 KB)  

    In this paper, an immune algorithm-based (IA-based) optimization approach for the fault-section estimation of a distribution system is proposed. To apply the method to solve this estimation problem, each section of a power system model can be considered as an antibody. Through the immunology evolution, an antibody that most fits the antigen of concern becomes the solution. An affinity calculation has been employed in this computation process to measure the combination intensity. As this method can operate the population of antibodies simultaneously, the process stagnation can be better prevented. The proposed approach has been tested on Taiwan Power System (Taipower) through the utility data. Test results demonstrated the feasibility and effectiveness of the method for the applications. View full abstract»

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  • The design of power acceptability curves

    Publication Year: 2002 , Page(s): 828 - 833
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (250 KB) |  | HTML iconHTML  

    The concept of "standards" is introduced for the design of power acceptability curves. The power acceptability curves are aides in the determination of whether the supply voltage to a load is acceptable for the maintenance of a load process. The construction of the well-known Computer Business Equipment Manufacturing Association (CBEMA) power acceptability curve is discussed, and issues of 3-phase and rotating loads are discussed. View full abstract»

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  • Using Bayesian network for fault location on distribution feeder

    Publication Year: 2002 , Page(s): 785 - 793
    Cited by:  Papers (36)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (359 KB)  

    The Bayesian network is a probabilistic graphical model in which a problem is structured as a set of variables (parameters) and probabilistic relationships among them. The Bayesian network has been effectively used to incorporate expert knowledge and historical data for revising the prior belief in the light of new evidence in many fields. However, little research has been done to apply a Bayesian network for fault location in power delivery system. We construct a Bayesian network on the basis of expert knowledge and historical data for fault diagnosis on a distribution feeder in Taiwan. The experimental results validate the practical viability of the proposed approach. View full abstract»

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  • IEEE-519-based real-time and optimal control of active filters under nonsinusoidal line voltages using neural networks

    Publication Year: 2002 , Page(s): 815 - 821
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (280 KB) |  | HTML iconHTML  

    In this paper, a fast and simple neural network (NN)-based control system for shunt active power filters operating under distorted voltage conditions is developed. The proposed system is an enhanced version of the optimal and flexible control (OFC) strategy with very fast and simple structure. In the proposed system, the time-consuming and complex nonlinear optimization algorithm required by OFC is replaced by a simple 3-layer perceptron NN. The NN is trained off-line using some random data based on the IEEE-519 Standard, while it can be used for a very wide range of new voltage waveforms in practice. The proposed system has been developed after introducing a new version of the OFC strategy in a-b-c frame of reference. This system satisfies both theoretical and practical requirements. Several simulation results using MATLAB toolboxes under highly distorted and unbalanced voltages have been provided to validate the ability of the proposed control system. View full abstract»

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  • Structure of transfer function of transformers with special reference to interleaved windings

    Publication Year: 2002 , Page(s): 754 - 760
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (265 KB) |  | HTML iconHTML  

    A transfer function (TF) is computed during impulse tests on transformers. The structure and shape of TF depends on the type of winding, namely, disc, layer-type, or interleaved winding. There are certain features specific to TF of an interleaved winding, which has, over the years, been attributed to its increased series capacitance. However, reasons for why an increase in series capacitance should introduce such differences, the presence of only a few (lower frequency) poles in interleaved windings, etc., is as yet unknown. By analytically solving the equivalent circuit model, mathematical explanations are deduced. It is demonstrated, for the first time, how pole-zero cancellation and winding resistance are both instrumental in determining the structure of TF of interleaved windings. View full abstract»

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  • Thin wire representation in finite difference time domain surge simulation

    Publication Year: 2002 , Page(s): 840 - 847
    Cited by:  Papers (96)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (322 KB) |  | HTML iconHTML  

    Simulation of very fast surge phenomena in a three-dimensional (3-D) structure requires a method based on Maxwell's equations, such as the finite difference time domain (FDTD) method or the method of moments (MoM), because circuit-equation-based methods cannot handle the phenomena. This paper presents a method of thin wire representation for the FDTD method which is suitable for the 3-D surge simulation. The thin wire representation is indispensable to simulate electromagnetic surges on wires or steel flames of which the radius is smaller than a discretized space step used in the FDTD simulation. Comparisons between calculated and laboratory test results are presented to show the accuracy of the proposed thin wire representation. The development of a general surge analysis program based on the FDTD method is also described in the present paper. View full abstract»

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  • Narrowband, low data rate communications on the low-voltage mains in the CENELEC frequencies. I. Noise and attenuation

    Publication Year: 2002 , Page(s): 718 - 723
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB) |  | HTML iconHTML  

    This is the first part of a two-part series on communications over the European 240 V domestic powerline in the frequencies identified by the CENELEC European mains signalling standard using low-cost equipment for applications requiring data rates of no more than hundreds of bits per second (bits/s). To minimize costs, narrow-band modem techniques are considered. The series of papers identifies the key impairments introduced by the channel, proposes a novel model structure to simulate them, and gives quantitative values for simulation based on empirical measurements. The first paper describes the principal linear impairments; noise whose intensity cycles at twice the AC line rate, and linear signal attenuation. The second paper describes nonlinear multiplicative fading. Both papers present suitable modulation schemes based on orthogonal frequency division modulation (OFDM). View full abstract»

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  • Stability domain calculations of period-1 ferroresonance in a nonlinear resonant circuit

    Publication Year: 2002 , Page(s): 865 - 871
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (315 KB) |  | HTML iconHTML  

    Catastrophic equipment failures continue to occur today due to ferroresonance even though this phenomenon has been extensively studied over the past 90 years. This paper is concerned with comparing analytical nonlinear dynamics methods with a two-dimensional (2-D) brute-force bifurcation diagram for displaying safety margins in a 2-D parameter space. A simplified single-phase model is used to represent the case of ferroresonance between a transformer and circuit breaker grading capacitor. Comparisons are made between the analytical method and EMTP simulations of an actual ferroresonant event. View full abstract»

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  • A parameter identification technique for metal-oxide surge arrester models

    Publication Year: 2002 , Page(s): 736 - 741
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (293 KB) |  | HTML iconHTML  

    A simple numerical technique to identify the parameters of metal-oxide arrester models is described. Using measured arrester voltage obtained under impulse test conditions the arrester parameters are determined using an optimization technique. The validity and the accuracy of the model are then assessed by comparing the predicted against the measured values of arrester energy, initial slope, residual voltage, and the overall deviation. Application of the arrester model on network system studies is illustrated. View full abstract»

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  • Unit commitment of main transformers for electrified mass rapid transit systems

    Publication Year: 2002 , Page(s): 747 - 753
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (302 KB) |  | HTML iconHTML  

    This paper proposes the transformer planning for an electrified mass rapid transit (MRT) system so that the overall cost of main transformers is minimized over the life cycle. The unit commitment is applied to derive the optimal transformer capacity to meet the annual peak demand and provide reserve for service reliability. The motion equation of train sets is used to derive the dynamic power consumption and travel distance as each time snapshot. The Simulink package is applied to solve the power demand of each train set by the simulation of VVVF inverters and induction motors. The DC/AC load flow analysis is performed to find the annual power loading of traction substations (TSS) and whole Taipei MRT network. The transformer loss, investment, and service reliability are used to define the equivalent cost of all feasible states for each dynamic programming (DP) stage. According to the computer simulation, very significant cost saving is obtained by the proposed methodology for transformer capacity planning of an MRT network. View full abstract»

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  • A composite exponential and linear MOA model for switching transient simulation

    Publication Year: 2002 , Page(s): 730 - 735
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (239 KB) |  | HTML iconHTML  

    The multiexponential metal oxide surge arrester (MOA) model currently used to simulate switching transients (current model), approximates the V-I characteristic of an MOA with several exponential segments. A test case illustrates a numerical oscillation caused by this model. The source of the oscillation is identified as the value jump of the derivative of the approximating function at the boundary point of adjacent exponential segments. The problem can be solved by using the Quasi-Newton method, but at the expense of computing time. A modified model is presented in this paper. This new model (proposed model) features a composite exponential and linear approximation to the V-I characteristic, and a monotonic derivative of the approximating function. The combination of the Newton method of iteration and the proposed model not only avoids numerical oscillation, but also has a better performance on computing time than the combination of the Quasi-Newton method and the current model. View full abstract»

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  • Experimenting remote kilowatthour meter reading through low-voltage power lines at dense housing estates

    Publication Year: 2002 , Page(s): 708 - 711
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (228 KB)  

    Deregulation, freer customer choice, and open market competition are occurring in the energy supply market. These changes necessitate the automating of kilowatthour (kWh) reading for most energy suppliers. Power lines are readily available and making the full use of them is most desirable to the energy suppliers. However, power line is a hostile communication environment and it is imperative to know its characteristics. This paper describes a prototype automated meter reading system using the power lines and frequency shift keying modulation operating in the EN 50065-1 A Band. Its performance and reliability aspects are also presented. View full abstract»

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Aims & Scope

Installation and operation of apparatus, equipment, structures, materials and systems for the safe, reliable and economic generation, transmission, distribution, conversion, measurement and control of electric energy.

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Meet Our Editors

Editor-in-Chief
Wilsun Xu
Ph.D., P.Eng.
Dept. Electrical and Computer Eng.
University of Alberta
(9107 - 116 Street)
Edmonton, Alberta T6G 2V4 Canada
wxu@ualberta.ca
Phone:780-492-5965
Fax:780-492-1811