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Power Delivery, IEEE Transactions on

Issue 1 • Date Jan. 2006

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Displaying Results 1 - 25 of 90
  • Table of contents

    Publication Year: 2006 , Page(s): c1 - 3
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    Freely Available from IEEE
  • IEEE Transactions on Power Delivery publication information

    Publication Year: 2006 , Page(s): c2
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    Freely Available from IEEE
  • Nonlinear-coupled electric-thermal modeling of underground cable systems

    Publication Year: 2006 , Page(s): 4 - 14
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB) |  | HTML iconHTML  

    An original nonlinear-coupled electric-thermal model of underground cables with the solid sheaths is proposed. The model deals with the numerical evaluation of losses, heating, and ampacity. The computation of the current dependent losses is undertaken by means of the filament method, where conductors and sheaths are represented by a number of smaller subconductors or filaments. Furthermore, heat-transfer phenomena through an "infinite" domain beneath the soil surface are modeled combining the finite and the mapped infinite elements, respectively. The corresponding finite-element meshes are generated by the advancing front method. The numerical results presented throughout this work suggest that the International Electrotechnical Commission relation concerning the external thermal resistance for touching cables, placed in flat formation, having appreciable sheath losses, should be re-examined. View full abstract»

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  • Recursive algorithm for real-time measurement of electrical variables in power systems

    Publication Year: 2006 , Page(s): 15 - 22
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB) |  | HTML iconHTML  

    In this paper, a novel complex bandpass filter is presented which overcomes the pitfalls of the techniques in common use. This complex bandpass filter can correctly extract the phasor of the fundamental component and symmetrical components in voltage or current waveforms and then accurately estimate their instantaneous amplitude, phase angle, and frequency, even encountering various power disturbances. Further, a recursive algorithm is also developed for the complex bandpass filtering that updates current filtering output only using several previous sample values and filtering outputs. This attribute greatly reduces the computational complexity of complex bandpass filtering, which is the weakness of the continuous wavelet transform based on the well-known Morlet Wavelet. Thus, this recursive algorithm is highly desirable for real-time applications. The performance of the proposed technique is ascertained by using both simulated and practical power disturbance waveforms. View full abstract»

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  • Third zone revisited

    Publication Year: 2006 , Page(s): 23 - 29
    Cited by:  Papers (48)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB) |  | HTML iconHTML  

    Zone 3 of a step-distance protection scheme has been identified as one of the contributing causes of cascading failures in power systems. The National Electric Reliability Council (NERC) has issued rules, and the IEEE Power System Relaying Committee (PSRC) has discussed recommendations to reduce the undesirable operation of this component of the protection chain. It is the purpose of this paper to reexamine the application of zone 3, to describe situations where it can be properly utilized, where it can be removed without reducing the reliability of the system protection and, if used, how it can be modified or set. A table is presented for a variety of station designs and protection schemes including two common local backup relay systems and the associated application of a remote third zone. Finally, the concept of critical locations is introduced which can assist the relay engineer in determining if potential zone 3 undesirable operations are a serious threat to the system and help determine if the expense and difficulty of removing zone 3 or modifying the relay or its associated station is justified. View full abstract»

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  • An open-system approach to power system protection and control integration

    Publication Year: 2006 , Page(s): 30 - 37
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB) |  | HTML iconHTML  

    Data packets based high-speed digital communications have opened the door for new types of applications in power system protection and control. The main obstacle in adopting Ethernet-type networks for time-sensitive communications was the data transfer characteristic of these networks. With baud rates in the gigabit-per-second range, the industry has started adopting the Ethernet networks as a viable alternative, not only because of their lower cost. This paper presents an open-system approach in which protective hardware equipment is designed to work in a clustered environment, sharing resources, data, and diagnostic functions with similar units. The Ethernet network, being capable to accommodate transparently a wide range of protocols, is used to connect the protective hardware. A model was developed for the Ethernet network to be incorporated into the power system simulation. The characteristics required from a digital relaying algorithm to be able to work with signal samples sent across data packets based networks are described in this paper. The proposed solution is implemented using a modified adaptive least-square-error algorithm and tested on a protection system that was integrated into the power system model. View full abstract»

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  • A CT saturation detection algorithm using symmetrical components for current differential protection

    Publication Year: 2006 , Page(s): 38 - 45
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB) |  | HTML iconHTML  

    A method of symmetrical component analysis for the detection of current-transformer (CT) saturation in a numerical current differential feeder protection relay is presented in this paper. The performance of the differential relay is investigated for various faults on a typical Electro-Magnetic Transients Program/Alternative Transients Program (EMTP/ATP) simulated transmission feeder. The simulator includes the effects of CT saturation. A comparison between simulation and tests conducted on an analog model testbench are also evaluated. The results show a high degree of similarity and illustrate the effect that CT saturation imposes on the sensitivity and stability of the protection scheme. An algorithm is presented that shows significant improvement in sensitivity on internal faults while still maintaining a high level of stability on external faults and nonfault events. View full abstract»

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  • Online detection of loss of synchronism using energy function criterion

    Publication Year: 2006 , Page(s): 46 - 55
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (376 KB) |  | HTML iconHTML  

    Maintaining dynamic security of a power system subjected to large disturbances is of utmost importance. Fast and accurate online detection of instability is essential in initiating certain emergency control measures. The techniques reported in the literature involve mainly the application of global phasor measurements and heuristic algorithms. In this paper, an accurate technique for the online detection of loss of synchronism based on voltage and current measurements in a line is presented. The technique makes use of the concept of potential energy in a line. The conditions for the system instability are derived from energy function analysis. However, no assumptions are made regarding the power-angle relationship in a line, nor are any data on the system equivalents necessary in implementing the detection scheme. View full abstract»

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  • Bibliography of relay Literature, 2003 IEEE committee report

    Publication Year: 2006 , Page(s): 56 - 65
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (141 KB)  

    The latest of a series of classified lists of power system relaying references, begun in 1927, is presented. This bibliography is in continuation to the bibliographies of relay literature, which were published previously and are contained in the following volumes of the IEEE Transactions. View full abstract»

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  • Comparative analysis on current percentage differential protections using a novel reliability evaluation criterion

    Publication Year: 2006 , Page(s): 66 - 72
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB) |  | HTML iconHTML  

    A novel reliability evaluation criterion, designated as consistent security, is proposed in this paper to compare the comprehensive performance between the current differential protections in various bias current designs. It is initially based on the investigations of the comparative analysis between the complex percentage differential criterion, which is a kind of compensated bias current design, and normal percentage differential criterion. A variety of fault scenarios is included in these comparisons (e.g., current-transformer (CT) saturation induced by a severe external fault resulting in false differential current, various internal fault scenarios leading to possible ratio, and phase differences of outgoing current to the incoming current). Based on investigations on the CT saturation due to external faults, a novel baseline, "consistent security", is thus put forward to evaluate the comprehensive performances of the differential protections implemented with different bias current designs. On the basis of consistent security, it can be proved that the complex differential criterion is better than normal differential criterion in most operation conditions. View full abstract»

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  • Correction of saturated current transformers secondary current using ANNs

    Publication Year: 2006 , Page(s): 73 - 79
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB) |  | HTML iconHTML  

    Current transformers (CTs) provide instrument-level current signals to meters and protective relays. Protective relays' accuracy and performance are directly related to steady-state and transient performance of CTs. CT saturation could lead to protective relay maloperation or even prevent tripping. This paper proposes the use of an artificial neural networks scheme to correct CT secondary waveform distortions. The proposed module uses samples of current signals to achieve the inverse transfer function of CT. Simulation studies are preformed and the influence of changing different parameters is studied. Performance studies results show that the proposed algorithm is accurate and reliable. The proposed algorithm has also been implemented and tested on a digital signal processor board. Details of the implementation and experimental studies are provided in this paper. View full abstract»

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  • Impact of TCSC on the protection of transmission lines

    Publication Year: 2006 , Page(s): 80 - 87
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (640 KB) |  | HTML iconHTML  

    This paper presents a comprehensive analysis of the impact of TCSC on the protection of transmission lines. The TCSC is considered as a dynamical device and its transient process is modeled in order to have the response to disturbances based on its own control strategy. It is shown that not only the TCSC affects the protection of its line, but also the protection of adjacent lines would experience problems. The analysis is done first analytically by using simple models, then the power system and the protective relays are simulated in detail by Real Time Digital Simulator (RTDS). Finally, the simulation results are validated by using a commercial relay. View full abstract»

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  • Experience of numerical protective relays operating in an environment with high-frequency switching surge in Japan

    Publication Year: 2006 , Page(s): 88 - 93
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB) |  | HTML iconHTML  

    This paper intends to provide general information about the experiences of numerical relay operation under many different kinds of surges from switchyards in Japan. The main focus of this paper is to investigate the immunity of numerical relays against a switching surge with relatively high frequency in a gas-insulated substation that is considered to be severe for the relay's correct operation. It is concluded that the reliability of today's numerical relays in Japan against the switching surge is almost sufficient due to the effectiveness of the immunity test standard adopted and countermeasures against the switching surge in Japan. View full abstract»

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  • Impulse noise mitigation based on computational intelligence for improved bit rate in PLC-DMT

    Publication Year: 2006 , Page(s): 94 - 101
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    This paper introduces a modified version of the discrete multi-tone transceiver (DMT) to increase the data rate in broadband power-line communications (PLC). Basically, a computational-intelligence technique trained by a second-order optimization method is applied to mitigate the high-power impulse noise, while the DMT copes with the severe intersymbol interference observed in power-line channels. The masking of the impulse noise enhances the signal-to-noise ratio in each DMT subchannel. As a result, a high number of bits can be allotted to each subchannel for a given error probability. The simulation results reveal that the proposed PLC-DMT solution outperforms, in terms of the data rate, traditional PLC-DMT over different environments, especially in the presence of additive high-power impulse noise. View full abstract»

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  • A reliable energy information system for promoting voluntary energy conservation benefits

    Publication Year: 2006 , Page(s): 102 - 107
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB)  

    This paper presents the design and development of a reliable PLC/RF ENergy Information System (ENIS) for promoting voluntary energy conservation benefits. With the help of monitoring and browsing energy information immediately, the price signal and visible energy saving profile can provide incentives for customers to migrate peak demand elastically and economically. Two real-world applications of the ENIS are then reported. First, shedding peak load and diminishing energy consumption at NCTU University are explored by managing air conditioners through debit cards and energy meters (EMs). Second, in an aggregate community, the real-time pricing signals can motivate end users to shift peak demand by means of manual or automatic load controls. These examples illustrate that EMs and energy information displays with enhanced reliability are highly applicable for voluntary energy conservation in densely populated areas. View full abstract»

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  • A broadband wide-area network as an enabler of improved power system maintenance

    Publication Year: 2006 , Page(s): 108 - 112
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB) |  | HTML iconHTML  

    Wide-area networks (WANs) are being deployed worldwide at power utilities. By replacing vintage narrowband solutions, broadband communications can now be used for an entire utility enterprise. One new possibility that has opened up is to improve power system maintenance. During the last ten years, the benefits of adequate asset management have become increasingly clear in the power industry due to the economic pressures and aging infrastructure. An apparent tool to improve the asset-management strategies is the implementation of information technology systems that support the operational processes. The impact of these systems can be further enhanced by efficient communications, allowing the proliferation of functionality and data access. This paper describes the initial stages in analyzing the combined effects of enhanced communication and maintenance requirements. It provides a useful maintenance categorization, based on empirical data. Also, areas of improvement for power system maintenance are elucidated together with the benefit of enhanced communications. View full abstract»

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  • Development of polymeric surge ZnO arresters for 500-kV compact transmission line

    Publication Year: 2006 , Page(s): 113 - 120
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (536 KB) |  | HTML iconHTML  

    The 500-kV polymeric ZnO surge arresters for compact transmission line against lightning overvoltage were developed and have been put into operation, which consists of arrester unit and series gap. The design of the arrester unit, including structure design, selection of ZnO varistor, parameter determination, polymeric housing design, and mechanical structure design was discussed. The design of the series gap and the determination of the series gap length were presented. The calculated results state the line surge arrester can highly improve the lightning withstand level of the compact transmission line, and the line surge arrester can withstand the effects of lightning. View full abstract»

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  • An interpolation model to accelerate the frequency-domain response calculation of grounding systems using the method of moments

    Publication Year: 2006 , Page(s): 121 - 128
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB) |  | HTML iconHTML  

    The transient characteristics of grounding systems are essential for their designs and related electromagnetic-compatibility problems in power systems. Although the method of moments (MoM) is a popular way to analyze the characteristics of grounding systems, it is time-consuming. In this paper, a two-stage method is presented to construct fitted models of the frequency-domain responses of grounding systems to accelerate the calculations of the MoM. In the first stage, the adaptive model-based parameter estimation is used to adaptively choose the most valuable frequency sampling points to construct the initial fitted functions, and then the fitted functions are adjusted in the second stage by comparing the fitted results with those computed by the first principle model at some points. The validation was achieved by a comparison of the numerical results and those obtained by inverse fast Fourier transformation. View full abstract»

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  • Inherent transient recovery voltage of power transformers-a model-based determination procedure

    Publication Year: 2006 , Page(s): 129 - 134
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB) |  | HTML iconHTML  

    Knowledge of the inherent transient recovery voltage (TRV) associated with power-transformer terminal faults is essential for correct application of circuit breakers. Instead of establishing standards for TRV parameters as a function of power transformer ratings, standardized model-based determination procedures are proposed. The dynamic properties of the transformer short-circuit impedance Zx allow a straightforward calculation of the TRV waveshape without high computational effort. Test setups for lightning impulse (LI), frequency response analysis (FRA) and low-voltage current injection (LVCI) are presented and discussed. A sample calculation introduces the TRV calculation from LI test data and comparison with LVCI and FRA results. It is concluded that the presented procedure should be incorporated into the transformer type-test routines to provide highly valuable information about the TRV of each specific transformer. View full abstract»

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  • Computational investigation of the magnetic-field distribution in a 145-kV/40-kA rotary-arc circuit breaker

    Publication Year: 2006 , Page(s): 135 - 141
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1264 KB) |  | HTML iconHTML  

    Rotary-arc circuit breakers (CBs) rely on an externally imposed magnetic field to move the arc column in the arcing chamber, hence reducing contact erosion and enhancing the interruption capability. The three-dimensional computation of the magnetic field was carried out for a prototype 145-kV/40-kA rotary-arc CB and the influencing parameters were identified. It is shown that the presence of an arc column in the arcing chamber, whether at high or low currents, does not impose significant distortion to the magnetic field that has a dominant component in the axial direction and for design purposes, its effects can be neglected. Strong eddy current is induced in the ring-shaped copper arc runner distorting the local magnetic field. Reducing the electrical conductivity of the arc runner material by a factor of three, effectively suppresses the influence of this eddy current on the magnetic field. The assumption of a steadily alternating magnetic field lagging the exciting ac current by a fixed phase angle may not be safe in the design of such CBs since the phase angle varies remarkably in the arcing chamber and the transient effects of exciting current can significantly affect the magnetic field for a period of up to 5 ms. View full abstract»

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  • Analytical approach to internal fault simulation in power transformers based on fault-related incremental currents

    Publication Year: 2006 , Page(s): 142 - 149
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB) |  | HTML iconHTML  

    A new method for simulating faulted transformers is presented in this paper. Unlike other methods proposed in the literature, this method uses the data obtained from any sound transformer simulation to obtain the damaged condition by simply adding a set of calculated currents. These currents are obtained from the definition of the fault. The model is fully based on determining the incremental values exhibited by the currents in phases and lines from the prefault to the postfault condition. As a consequence, data obtained from simulation of the sound transformer may be readily used to define the damaged condition. The model is described for light and severe faults, introducing this latter feature as a further add-on feature to the low-level faults simulation. The technique avoids the use of complex routines and procedures devoted to specially simulate the internal fault. Of prompt application to relay testing, the proposed analytical model also gives an insight into the fault nature by means of the investigation of symmetrical components. In contrast with its low complexity, the method has shown to present large accuracy for simulating the fault performance. View full abstract»

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  • Transformer insulation life assessment

    Publication Year: 2006 , Page(s): 150 - 156
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB)  

    This paper presents novel techniques for life assessment of the insulation of the generator stepup units in power plants. Load and ambient temperatures are two important factors that influence the life of insulation in transformers. Hourly load and ambient temperatures obtained through condition monitoring are used to assess the operating profile of the equipment. Modeling techniques for estimating load factors and the ambient temperatures using the operating history are discussed in this paper. The estimated load factors and ambient temperatures are input to the IEEE life consumption models to assess the consumed life of insulation. A full simulation approach and a renewal process approach have been presented to evaluate the time to failure of the insulation. Estimation of some relevant reliability parameters such as BX life, time-to-reach design life, and probability of failure at a given time are also presented. The methods discussed are useful for estimating residual life of insulation to support the repair and maintenance policies of transformers. View full abstract»

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  • Transformer tank vibration modeling as a method of detecting winding deformations-part I: theoretical foundation

    Publication Year: 2006 , Page(s): 157 - 163
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB) |  | HTML iconHTML  

    In this paper, a model developed for a transformer monitoring system to estimate transformer tank vibration is presented. The model calculates vibration on the transformer tank starting from some input variables that can be easily measured on the transformer. Tank vibration is also measured, showing a good concordance between estimated and measured values if the transformer is healthy. In case of a winding deformation winding vibration and, consequently, that of the tank, changes and a big difference between estimated and measured vibration appear. To estimate tank vibration, the model takes into account the main physical phenomena generating vibrations in the different transformer elements and how these vibrations are superposed and transmitted to the tank. The model has been tested experimentally on a test transformer fitted with internal and external accelerometers. A deformation has been provoked in the test transformer winding with the aim of testing the model's ability to detect it. The model has been also tested on several in-service grid transformers. The results of the experimental validation are shown in Part II of the paper. View full abstract»

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  • Transformer tank vibration modeling as a method of detecting winding deformations-part II: experimental verification

    Publication Year: 2006 , Page(s): 164 - 169
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1496 KB) |  | HTML iconHTML  

    In Part I of the paper, a tank vibration model was proposed as a method to detect the winding deformations in power transformers. This model is incorporated in a model-based monitoring system for power transformers. In this paper, the experimental verification of the proposed model that calculates vibration on the transformer tank is reported. The model was validated in a 1500-kVA experimental transformer constructed as a reduced scale model of a 60-MVA 220-kV unit. In order to load the test transformer, the opposition method described in IEC 60076-2 Standard was used allowing to vary the load and power factor over a wide range. Sensors to measure vibrations and temperature were installed in the test transformer. The model was validated under different test transformer operating conditions. In order to verify the model's ability to detect failures, a deformation was provoked in the test transformer winding. Model predictions were compared with the measured vibration in that situation. The model has also been applied to four (30-40 MVA) grid transformers. Some results of this field validation are presented in this paper. View full abstract»

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  • Estimation of transformer saturation characteristics from inrush current waveforms

    Publication Year: 2006 , Page(s): 170 - 177
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (528 KB) |  | HTML iconHTML  

    This paper presents a novel method to estimate transformer saturation characteristics that extend to the 'deep' saturation region. The basic idea of the method is to use recorded inrush voltage and current waveforms to estimate the saturation characteristics. Accurate representation of a transformer's 'deep' saturation region is important for studying the impact of transformer energization and its inrush currents. The performance and accuracy of the proposed method have been verified by a close agreement between simulation results and recorded inrush waveforms. 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.

Full Aims & Scope

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