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Power Delivery, IEEE Transactions on

Issue 4 • Date Oct. 2012

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Displaying Results 1 - 25 of 94
  • Table of contents

    Publication Year: 2012 , Page(s): C1 - 1699
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    Freely Available from IEEE
  • IEEE Transactions on Power Delivery publication information

    Publication Year: 2012 , Page(s): C2
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    Freely Available from IEEE
  • Effect of Modeling Non-Normality and Stochastic Dependence of Variables on Distribution Transformer Loss of Life Inference

    Publication Year: 2012 , Page(s): 1700 - 1709
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1577 KB) |  | HTML iconHTML  

    This paper presents a method for transformer loss-of-life inference by integrating stochastic dependence between non-normal transformer load and ambient temperature into analysis. The non-normally distributed variables are transformed to a common domain (i.e., the rank domain) by applying the cumulative density function transformation. In this domain, special functions, copulas, are used for modeling stochastic dependence between the variables. Extensive research data have been used to obtain quantitative results for realistic test cases of distribution transformers serving various types of low-voltage consumers. The results indicate that the accuracy of loss-of-life inference is very sensitive to normality and independence assumptions which are generally adopted in previous studies. It is demonstrated that such assumptions may lead to misleading results compared to the actual conditions. Thus, the proposed method, which is based on no restrictive assumption, emerges as a more accurate solution for transformer loss-of-life inference. View full abstract»

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  • Advanced Thermal Modeling and Experimental Performance of Oil Distribution Transformers

    Publication Year: 2012 , Page(s): 1710 - 1717
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1579 KB) |  | HTML iconHTML  

    This paper presents an analysis of the thermal behavior of a 15-kVA ONAN distribution transformer. Design, performance, and service-life improvements come into view from this study. The mathematical model, conceived as a 3-D solid-oil-environment extended system, considers all modes of heat transfer, including radiation. We computed oil velocity profile and oil and winding temperature distribution, patterns thereafter experimentally validated in accordance with the IEEE-1995 Loading Guide. Since this paper identifies hot-spot and flow patterns more accurately than its predecessors, and reveals a serious malfunction in refrigeration channels, it creates interesting possibilities for new designs in transformers below 75 kVA. View full abstract»

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  • Real-Time Power-Quality Monitoring With Hybrid Sinusoidal and Lifting Wavelet Compression Algorithm

    Publication Year: 2012 , Page(s): 1718 - 1726
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1766 KB) |  | HTML iconHTML  

    This paper presents a novel algorithm for real-time continuous electrical waveform compression and transmission. The proposed algorithm achieves a high data compression ratio by processing the stationary and non-stationary components of a power waveform separately. It works on integer data which simplifies the computation process, and can be run on a low-cost digital signal processor. The proposed algorithm has been implemented on a prototype meter successfully. Experimental and extensive field tests have confirmed the effectiveness of the algorithm. The prototype smart meter can communicate through a low-power, low-bit-rate sensor network protocol such as ZigBee. View full abstract»

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  • Analysis, Design and Control of a Unified Power-Quality Conditioner Based on a Current-Source Topology

    Publication Year: 2012 , Page(s): 1727 - 1736
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2857 KB) |  | HTML iconHTML  

    This paper presents a three-phase unified power-quality conditioner based on current source converters (CSC-UPQC), including the design guidelines of the key components, an appropriate control scheme, and a selection procedure of the dc current level. Particularly, the ride through capability criterion is used to define a minimum dc current level so that the CSC-UPQC achieves the same characteristics as a UPQC based on voltage-source converters in terms of voltage disturbance compensation in the point of common coupling (PCC) and load power factor compensation. A 1.17 MVA load fed from a 3.3 kV system is used to show the proposed design procedure, and a laboratory prototype is implemented to show the system compensating sags and swells using low switching frequency in the CSC and maintaining a unitary displacement power factor in the PCC. View full abstract»

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  • A Control Strategy for Enhanced Operation of Inverter-Based Microgrids Under Transient Disturbances and Network Faults

    Publication Year: 2012 , Page(s): 1737 - 1747
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2243 KB) |  | HTML iconHTML  

    This paper proposes an enhanced control strategy for electronically coupled distributed energy resources that improves the performance of the host microgrid under network faults and transient disturbances. The proposed control strategy does not require controller mode switchings and enables the electronically coupled distributed energy resources to ride through network faults, irrespective of whether they take place within the host microgrid or impact the upstream grid. Moreover, the proposed control ensures acceptable power quality for the duration of the faults, which is an important feature for protection against certain classes of faults, as well as for sensitive loads. Further, the paper proposes a supplementary control loop that improves the microgrid post-fault recovery. The effectiveness of the proposed control strategy is demonstrated through a comprehensive set of simulation studies, conducted in the PSCAD/EMTDC software environment. View full abstract»

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  • Real-Time Image-Identification-Based Anti-Manmade Misoperation System for Substations

    Publication Year: 2012 , Page(s): 1748 - 1754
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1240 KB) |  | HTML iconHTML  

    A novel antimisoperation system is proposed to prevent manmade misoperations using real-time signboard image identification technology. A portable video capture device is employed to capture real-time images of the current working bay's substation signboard. These images, with the aid of image identification, are used to determine whether the operations staff has accessed a wrong bay. The framework and workflow of the system are provided, and the implementation of the signboard image border detection, character partition, and image-matching methods are also introduced in detail. The effectiveness and engineering applicability of the proposed system are demonstrated through lab results and in-field tests. The proposed system can be used in conjunction with an active five-prevention system to further improve the validity and safety of substation operations. View full abstract»

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  • Complete Model Development for an Optical Current Transformer

    Publication Year: 2012 , Page(s): 1755 - 1762
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1189 KB) |  | HTML iconHTML  

    Optical current transformers/transducers (OCTs) produce digital and analog signals. In recent years, they have become more available, playing an increasingly important role in electric power grid upgrades. This requires developing accurate models for relay testing and relay performance evaluations to ensure that the system equipment is safe. This study presents several models developed for OCT: analog, digital, and complete models. It applies previously studied and presented frequency-response characteristics to develop a transfer function using a complex curve-fitting method. An analog circuit model is constructed from the developed transfer function via a network synthesis method. A digital model is presented by transforming the developed transfer function into a digital domain transfer function using bilinear transformation. The digital model implementation is performed by the direct form I block diagram. The optics model and electronics model of the device are developed separately and are then combined to present a complete model. The Jones calculus method is used for optical modeling, and a developed transfer function is used for electronics modeling. All of the developed models are verified through the frequency-response results and tested with PSpice and Matlab Simulink programs. The results show that the developed models can be used as legitimate OCT models. View full abstract»

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  • New Fault-Location Algorithm for Transmission Lines Including Unified Power-Flow Controller

    Publication Year: 2012 , Page(s): 1763 - 1771
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1776 KB) |  | HTML iconHTML  

    In this research, a novel fault-location algorithm for transmission lines including the unified power-flow controller (UPFC) is proposed. Since this method does not utilize model of the UPFC, the errors resulting from the fault interval model of the UPFC are avoided. In addition, the new technique does not require proposing a selector to select fault section with respect to the UPFC location. This method uses synchronous data gathered from both ends of the transmission line and takes advantage of the distributed parameter line model in time domain. One quadratic equation is obtained, assuming that the fault is located on the left-hand side of the UPFC. The same procedure is applied for the assumed fault on the right-hand side of the UPFC and another quadratic equation is achieved. These two equations are used to derive an optimization problem that the location of fault is calculated by solving this problem. A 300-km/500-kV transmission line, including a UPFC simulated in MATLAB/Simulink, has been used to evaluate the performance of the new method. The obtained results show the accuracy of the proposed algorithm. View full abstract»

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  • Direct Power Control of Series Converter of Unified Power-Flow Controller With Three-Level Neutral Point Clamped Converter

    Publication Year: 2012 , Page(s): 1772 - 1782
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2284 KB) |  | HTML iconHTML  

    A unified power-flow controller (UPFC) can enforce unnatural power flows in a transmission grid, to maximize the power flow while maintaining stability. Theoretically, active and reactive power flow can be controlled without overshoot or cross coupling. This paper develops direct power control, based on instantaneous power theory, to apply the full potential of the power converter. Simulation and experimental results of a full three-phase model with nonideal transformers, series multilevel converter, and load confirm minimal control delay, no overshoot nor cross coupling. A comparison with other controllers demonstrates better response under balanced and unbalanced conditions. Direct power control is a valuable control technique for a UPFC, and the presented controller can be used with any topology of voltage-source converters. In this paper, the direct power control is demonstrated in detail for a third-level neutral point clamped converter. View full abstract»

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  • Energy Storage System for Mitigating Voltage Unbalance on Low-Voltage Networks With Photovoltaic Systems

    Publication Year: 2012 , Page(s): 1783 - 1790
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1386 KB) |  | HTML iconHTML  

    The growth of building integrated photovoltaic (BIPV) systems in low-voltage (LV) networks has the potential to raise several technical issues, including voltage unbalance and distribution system efficiency. This paper proposes an energy storage system (ESS) for mitigating voltage unbalance as well as improving the efficiency of the network. In the study, a power system simulation tool, namely PSCAD, is used to model two generic LV networks, BIPV systems and an ESS in order to simulate the performance of the networks with various levels of BIPV penetrations. A control algorithm is developed and implemented in the energy storage model in order to study the ability of the ESS to mitigate network voltage unbalance and reduce losses. Experimental studies are carried out in the experimental small-scale energy zone to investigate the effectiveness of the energy storage system under various levels of PV penetration and load conditions. The simulation and experimental studies carried out clearly show the effectiveness of the ESS in reducing the voltage unbalance factor and improving the efficiency of the two networks considered. View full abstract»

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  • Statistical Machine Learning and Dissolved Gas Analysis: A Review

    Publication Year: 2012 , Page(s): 1791 - 1799
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1319 KB) |  | HTML iconHTML  

    Dissolved gas analysis (DGA) of the insulation oil of power transformers is an investigative tool to monitor their health and to detect impending failures by recognizing anomalous patterns of DGA concentrations. We handle the failure prediction problem as a simple data-mining task on DGA samples, optionally exploiting the transformer's age, nominal power and voltage, and consider two approaches: 1) binary classification and 2) regression of the time to failure. We propose a simple logarithmic transform to preprocess DGA data in order to deal with long-tail distributions of concentrations. We have reviewed and evaluated 15 standard statistical machine-learning algorithms on that task, and reported quantitative results on a small but published set of power transformers and on proprietary data from thousands of network transformers of a utility company. Our results confirm that nonlinear decision functions, such as neural networks, support vector machines with Gaussian kernels, or local linear regression can theoretically provide slightly better performance than linear classifiers or regressors. Software and part of the data are available at http://www.mirowski.info/pub/dga. View full abstract»

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  • Modeling and Simulation of Temporal Variation of Channel and Noise in Indoor Power-Line Network

    Publication Year: 2012 , Page(s): 1800 - 1808
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3622 KB) |  | HTML iconHTML  

    Broadband power-line communication (PLC) technologies are one of the main parameters of digital convergence voice-data-video in the home environment. These technologies use the power-line network as a propagation and a communication medium. Its transmission quality depends on the frequency behavior of the propagation medium and the connected household electrical appliances. The impedance of those devices and noise levels has a great impact on the PLC systems. In this paper, a simulator for indoor power-line channels is presented. In this paper, a new approach is presented for modeling temporal variations of noise and channel on indoor power lines. A three-conductor power cable (phase, neutral, and ground) is modeled by a circuit of four elements (resistor R, inductor L, capacitance C, conductance G). The RLCG parameters are deduced from the impedance measurement in open circuit and in short circuit. The cable model is validated in time and frequency domains. Then, the temporal variation of periodic noise is modeled by a stochastic approach. The global model, combining both channel and noise variations, is validated by comparing SPICE simulation and measurement results. View full abstract»

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  • Copula-Based Statistical Health Grade System Against Mechanical Faults of Power Transformers

    Publication Year: 2012 , Page(s): 1809 - 1819
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2119 KB) |  | HTML iconHTML  

    A health grade system against mechanical faults of power transformers has been little investigated compared to those for chemical and electrical faults. This paper thus presents a statistical health grade system against mechanical faults in power transformers used in nuclear powerplant sites where the mechanical joints and/or parts are the ones used for constraining transformer cores. Two health metrics-RMS and root mean square deviation of spectral responses at harmonic frequencies-are first defined using vibration signals acquired via insite sensors on 54 power transformers in several nuclear powerplants in 16 months. We then investigate a novel multivariate statistical model, namely copula, to statistically model the populated data of the health metrics. The preliminary study shows that the proposed health metrics and statistical health grade system are feasible to monitor and predict the health condition of the mechanical faults in the power transformers. View full abstract»

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  • Application of Power System Frequency for Digital Audio Authentication

    Publication Year: 2012 , Page(s): 1820 - 1828
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1417 KB) |  | HTML iconHTML  

    Frequency is an important parameter for the operation and control of power systems. One novel application of frequency measurements involves using this information to authenticate a digital audio/video recording presented as forensic evidence in legal proceedings. To apply this technique, called the electrical network frequency (ENF) criterion, both a reference frequency database and an accurate frequency estimation method are required. This paper briefly introduces a wide-area frequency monitoring network (FNET) as the reference frequency database and analyzes statistical features of frequency of the four North American interconnections in terms of different time scales. Combined with digital filtering and a three-sample interpolation, the short-time Fourier transform (STFT) is adjusted to estimate the ENF embedded in digital audio recordings. A procedure of using the ENF criterion, ranging from signal preprocessing to ENF estimation and reference frequency database matching, is then proposed. Further, oscillator error of the digital recording device is considered and an iterative error correction method is given to assist with the frequency database matching. Factors which influence the accuracy of frequency estimation, such as parameter selections of the STFT and signal-to-noise ratio, are also discussed. Test results show that the procedure is capable of performing digital audio authentication. View full abstract»

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  • Development of an Efficient Solid-State Fault Current Limiter for Microgrid

    Publication Year: 2012 , Page(s): 1829 - 1834
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1163 KB) |  | HTML iconHTML  

    This paper deals with the development of a resonant-type solid-state fault current limiter (SSFCL), suitable for distribution-generation (DG) units in the microgrid. The proposed SSFCL has both series and parallel resonant circuits that are tuned at the supply frequency. In normal condition, the SSFCL exhibits very low impedance through the series resonant circuit. In fault conditions, the SSFCL offers very high impedance by the parallel resonant circuit. Upon fault occurrence, an auto-triggered silicon control rectifier (SCR) inserts the parallel resonant circuit in the load current path. In addition to self-controlling capability of the proposed SSFCL, it can be controlled using an external command generated by a fault detection algorithm. Therefore, with a very simple structure, it provides adequate certainty of operation. A prototype single-phase SSFCL is simulated in the Electromagnetic Transient Program (EMTP) and tested. The results show that the proposed SSFCL can significantly reduce the fault current in a short time. View full abstract»

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  • Vibration and Audible Noise Characteristics of AC Transformer Caused by HVDC System Under Monopole Operation

    Publication Year: 2012 , Page(s): 1835 - 1842
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2818 KB) |  | HTML iconHTML  

    When the HVDC system works in monopole ground return mode, dc current flows through the neutral of ac power transformer with the neutral grounded, which will enhance its vibration and audible noise. In this paper, dc bias experiments on ac power transformers carried out on 500-kV power transformers both in the transformer factory and the substation are described; the experimental results show how the vibration and audible noise of the transformer change under the dc bias current or windings voltage. The frequency characteristics of the vibration and audible noise of the dc-biased transformer are discussed under the conditions with and without loads. The direct connections between the vibration peak value and the dc bias current, and between the sound pressure and the dc bias current are revealed. Long-term online monitoring shows that the vibration of the transformer changes seriously even if there is not a dc system operating in monopole earth return mode, so when we analyze the influence of dc bias on the vibration and audible noise of the transformer, other influential factors should be expelled. View full abstract»

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  • A Decentralized Robust Control Strategy for Multi-DER Microgrids—Part I: Fundamental Concepts

    Publication Year: 2012 , Page(s): 1843 - 1853
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2301 KB) |  | HTML iconHTML  

    This paper presents fundamental concepts of a central power-management system (PMS) and a decentralized, robust control strategy for autonomous mode of operation of a microgrid that includes multiple distributed energy resource (DER) units. The DER units are interfaced to the utility grid through voltage-sourced converters (VSCs). The frequency of each DER unit is specified by its independent internal oscillator and all oscillators are synchronized by a common time-reference signal received from a global positioning system. The PMS specifies the voltage set points for the local controllers. A linear, time-invariant, multivariable, robust, decentralized, servomechanism control system is designed to track the set points. Each control agent guarantees fast tracking, zero steady-state error, and robust performance despite uncertainties of the microgrid parameter, topology, and the operating point. The theoretical concept of the proposed control strategy, including the existence conditions, design of the controller, robust stability analysis of the closed-loop system, time-delay tolerance, tolerance to high-frequency effects and its gain-margins, are presented in this Part I paper. Part II reports on the performance of the control strategy based on digital time-domain simulation and hardware-in-the-loop case studies. View full abstract»

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  • A Decentralized Robust Control Strategy for Multi-DER Microgrids—Part II: Performance Evaluation

    Publication Year: 2012 , Page(s): 1854 - 1861
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1442 KB) |  | HTML iconHTML  

    In Part I of this two-part paper, a power-management and a control strategy for the microgrid autonomous mode of operation were presented. The strategy consists of 1) open-loop frequency control of the system and synchronization of DER units based on a GPS signal; 2) voltage reference setpoint determination for the DER units by the central power-management system; and 3) tracking the assigned setpoints and rejecting disturbances by robust, decentralized, local controllers of DER units. This Part II paper applies the envisioned strategy to a three-DER microgrid. Offline digital time-domain simulation studies in the EMTDC/PSCAD software environment demonstrate the robustness of the local controllers to parametric, topological, and unmodelled uncertainties of the microgrid, its fast performance in tracking the setpoints with zero steady-state error, and rapid disturbance rejection. The results also show the effectiveness of the proposed power-management system in achieving prescribed load sharing of DER units. The digitized algorithms of the proposed control system of the three-DER microgrid are also implemented in NI-cRIO industrial-grade platforms and tested in an RTDS-based real-time hardware-in-the-loop (HIL) environment to demonstrate the feasibility of the strategy for hardware implementation and hardware-based performance validation. View full abstract»

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  • Theoretical Study of Dielectric Breakdown in a New Composite Core HTLS Conductor

    Publication Year: 2012 , Page(s): 1862 - 1867
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (492 KB) |  | HTML iconHTML  

    The growing electrical energy demand and an aging electricity infrastructure underscore the need for new power overhead transmission lines. The need to refurbish the oldest lines has been initiated by the Working Group B2 of CIGRE, and high-temperature low-sag (HTLS) conductors seem to be one solution for uprating the power lines. In this paper, the electrical behavior of a new type of organic matrix composite conductor using carbon fibers and epoxy resin is especially investigated. Because of the insulating layer between the core and the aluminum wires preventing galvanic corrosion between carbon and aluminum and due to the non-negligible carbon fiber conductivity, a part of the total current flows through the carbon fibers core across this layer. Thus, a voltage drop appears between the inner and the outer layers of the insulating material, and dielectric breakdown may arise for high values of current in case of huge peak loads. The objective of this paper is to analyze the problem theoretically in an original way and to advise the way to prevent adverse effects. View full abstract»

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  • Reliability and Maintainability Improvement of Substations With Aging Infrastructure

    Publication Year: 2012 , Page(s): 1868 - 1876
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1742 KB) |  | HTML iconHTML  

    The increasing size, aging equipment, and complexity of power systems, coupled with present day financial constraints, have made the use of probabilistic methods and reliability indices a necessity for maintaining continuity and quality of service to customers. Proper maintenance-related decisions should address all of these issues to improve system reliability while meeting limited budget constraints. This paper proposes algorithms that enable system-level reliability assessment with detailed modeling of maintenance for aging equipment. Stochastic-based reliability modeling of substations with aging equipment is presented, which enables the study of equipment aging, failures, and maintenance and their effect on substation-level availability and frequency of failure. Several case studies are provided which describe optimization of maintenance activities and the impact on maximum substation reliability. The algorithms provide a valuable tool for processing detailed models of aging equipment and maintenance of individual pieces in system reliability assessment applications. These algorithms are consistent with existing reliability models and are capable of being integrated into utility asset-management programs. View full abstract»

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  • A Practical Method for Extraction of High-Frequency Parameters of Distribution Cables

    Publication Year: 2012 , Page(s): 1877 - 1884
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1803 KB) |  | HTML iconHTML  

    Cable parameter extraction is needed for many practical purposes. The main motivation for this research came from a need to extract high-frequency properties of cables used for indoor electricity distribution because they can be utilized for transmission of communication signals, too, by means of the power-line carrier (PLC) technology. These cables have relatively high specific losses, so that indoor broadband PLC applications can use frequencies up to some 30 MHz. In this paper, cable features in the frequency range from 5 to 30 MHz, belonging to the high-frequency band, were studied. The purpose of this paper is to describe a practical method by which the cable parameters in the mentioned indicated frequency range can be extracted rather accurately from measured complex reflection coefficients at a cable end when the other end is terminated by precise open and short terminations, using very simple equipment. The parameters extracted in this way can be used for very precise modeling of real-life multiterminal distribution networks. View full abstract»

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  • Fuzzy Dynamic Thermal Rating of Transmission Lines

    Publication Year: 2012 , Page(s): 1885 - 1892
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1348 KB) |  | HTML iconHTML  

    Dynamic thermal rating (DTR) of transmission system facilities is a way to maximally realize the equipment capacities while not threatening their health. With regards to transmission lines, the allowable current of conductors is forecasted based on the environmental situations expected in some forthcoming time periods. Due to the fact that weather conditions continuously vary, sampling points are very limited against many line spans, and the measurements have an inherent error, uncertainties must be appropriately included in the DTR determination. This paper adopts the fuzzy theory as a strong and simple tool to model uncertainties in the DTR calculation. Since DTR intends to determine the line capacity for some periods ahead, the capability of fuzzy computation in predicting future phenomena is very fruitful here. In the proposed model, variables, such as ambient temperature, wind speed, wind direction, and solar hour angle are assumed to be fuzzy numbers. Numerical simulations are provided based on inputs taken from real databases and reasonable assumptions as well. The results obtained support the validation and efficiency of the proposed model. View full abstract»

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  • A New Stochastic Model of Electric Arc Furnace Based on Hidden Markov Model: A Study of Its Effects on the Power System

    Publication Year: 2012 , Page(s): 1893 - 1901
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1033 KB) |  | HTML iconHTML  

    Electric arc furnaces (EAFs) are nonlinear and time-variant loads that cause severe fluctuations of current, voltage, and current harmonics, voltage flicker, frequency changes, etc. The requirement is to present an accurate model to analyze the function of these types of loads. In this paper, a new model based on hidden Markov model theory is presented for an electric arc. For this purpose, the characteristic of the arc voltage-current is divided into four regions. Then, on the basis of actual measured samples of an electric arc in several functioning cycles of EAF, different operating points are generated in the form of statistical probability, corresponding to hidden Markov theory in the aforementioned four regions. The arc model is designed in the form of a current-dependent voltage source. Therefore, the proposed model is without linear approximation and corresponds to the actual state. Also, in order to be accurate in flicker modeling, a voltage is randomly considered for the arc model. After designing the aforementioned model, the effects resulting from this electric load in the power system are studied and analyzed. The simulation results are compared with the measured arc to show the accuracy and soundness of the model. 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