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Power Delivery, IEEE Transactions on

Issue 2 • Date April 2012

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Displaying Results 1 - 25 of 75
  • Table of contents

    Publication Year: 2012 , Page(s): C1 - 458
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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
  • Overcurrent Protection for the IEEE 34-Node Radial Test Feeder

    Publication Year: 2012 , Page(s): 459 - 468
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (350 KB) |  | HTML iconHTML  

    The IEEE 34-node radial test feeder is a benchmark circuit for validating results from existing and novel load-flow algorithms. This paper discusses the addition of overcurrent protection (OCP) to the test feeder using off-the-shelf protective devices. The OCP scheme includes a recloser near the substation and fuses at the laterals. These OCP devices represent the conventional types present in most distribution systems. DIgSILENT Power Factory 13.1 was used to conduct the load-flow analysis, customize the OCP devices, and perform overcurrent protection studies on the test feeder. Recloser-fuse and fuse-fuse coordination tests were conducted. Results from the coordination studies showed that the assigned OCP devices provided adequate trip coordination for all fault types on the test feeder. The short-circuit results and overcurrent protective device data provided in this paper may serve as an extension to the test feeder's existing load-flow data. View full abstract»

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  • A Novel Fuzzy-Logic Approach for Furan Estimation in Transformer Oil

    Publication Year: 2012 , Page(s): 469 - 474
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (921 KB) |  | HTML iconHTML  

    An ultraviolet-to-visible (UV-Vis) spectroscopic analysis based on the fuzzy-logic approach has been developed for furan content measurement in transformer oil. Following the successful identification and quantification of furan derivatives in transformer oil by the ASTM D 5837 standard, the new approach is able to approximate the furan content with a more convenient and economical method. Since the furan concentration level would determine the absorption intensity in the UV-Vis spectral range, the fuzzy-logic software model developed would exploit this characteristic to aggregate the furans content level in transformer oil. The UV-Vis spectral response sensitivity to ambient temperature was also studied. The proposed technique provide a convenient alternative to conventional techniques, namely: high-performance liquid chromatography (HPLC) or gas chromatography-mass spectrometry (GC/MS) methods. View full abstract»

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  • A Real-Time Conductor Sag Measurement System Using a Differential GPS

    Publication Year: 2012 , Page(s): 475 - 480
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1088 KB) |  | HTML iconHTML  

    A real-time and “direct” method of measuring the absolute value of sag on a transmission-line conductor using a differential global positioning system (DGPS) is presented. The method includes a real-time data-processing module integrated into the DGPS system. The GPS signals corresponding to physical movement of the midspan of a transmission-line conductor were obtained so that conductor-to-ground clearance could be recorded in real time. Several field tests were designed and implemented to test the DGPS method under varying conditions of the transmission-line current. A comparison of results obtained from the DGPS method with those from a laser-range finder indicates an accuracy of 1 in. View full abstract»

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  • Multiobjective Optimal Location of FACTS Shunt-Series Controllers for Power System Operation Planning

    Publication Year: 2012 , Page(s): 481 - 490
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1430 KB) |  | HTML iconHTML  

    This paper develops appropriate models of flexible ac transmission systems (FACTS) shunt-series controllers for multiobjective optimization and also presents a multiobjective optimization methodology to find the optimal location of FACTS shunt-series controllers. The objective functions are the total fuel cost, power losses, and system loadability with and without minimum cost of FACTS installation. The ε-constraint approach is implemented for the multiobjective mathematical programming (MMP) formulation, including the FACTS shunt-series controllers (i.e., phase-shifting transformer (PST), hybrid flow controller (HFC), and unified power-flow controller (UPFC)). Simulation results are presented for the IEEE 14-bus system. The optimization method is numerically solved using Matlab and general algebraic modeling system (GAMS) software environments. The solution procedure uses nonlinear programming (NLP) and mixed-integer nonlinear programming (MINLP) to solve the optimal location and setting of FACTS incorporated in the optimal power-flow problem considering these objective functions and improving the power system operation. Furthermore, the results demonstrate that the HFC is outperformed by PST and UPFC from the analytical and technical point of views. View full abstract»

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  • Partial-Discharge Magnitude Estimation With Three-Dimensional Finite-Element Methods

    Publication Year: 2012 , Page(s): 491 - 496
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (948 KB) |  | HTML iconHTML  

    Prediction of partial-discharge (PD) magnitude for ellipsoidal and spheroidal cavities in bulk insulation is easily addressed using axisymmetric 2-D finite-element methods (FEM), with the cavity on-axis. The introduction of an arbitrary defect even within an axisymmetric device breaks the 2-D symmetry, which makes prediction of PD magnitudes impossible without the use of 3-D FEM. A separable connector with tracks along various interfaces was modeled using 3-D FEM, and the apparent PD magnitude was estimated by multiplying the change in capacitance during discharges and the PD extinction voltage. Experimental PD measurements for the separable connector show good agreement with predictions. Since failure of separable connectors can cause significant damage, knowledge of the PD magnitude as a function of defect severity is useful to investigate diagnostics for defective connectors. View full abstract»

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  • Mitigating the Impacts of CCVT Subsidence Transients on the Distance Relay

    Publication Year: 2012 , Page(s): 497 - 505
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (890 KB) |  | HTML iconHTML  

    This paper presents a comprehensive time-domain model of the coupling capacitor voltage transformer (CCVT) to investigate the effect of CCVT subsidence transients on the distance relay. The studies show that voltage-zero subsidence transients can adversely impact the performance of the distance relay and result in the overreach problem. This paper also introduces a new approach to mitigate the effect of CCVT voltage-zero subsidence transients on the distance relay. The method is based on improving the degree of accuracy of the voltage phasor estimation during the CCVT subsidence transients. The proposed method is not affected by harmonics and high-frequency transient distortions of the voltage, and prevents the relay overreach problem even under high source impedance ratio (SIR). Moreover, the proposed method noticeably decreases the close-in fault clearance time under low SIR conditions, based on a fast current phasor estimation approach. The reported studies are conducted in the PSCAD/EMTDC software environment. View full abstract»

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  • Modeling of Replacement Alternatives for Power Transformer Populations

    Publication Year: 2012 , Page(s): 506 - 513
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (651 KB) |  | HTML iconHTML  

    The age of the majority of power transformers installed in the western electricity network reaches 30 to 60 years and replacement on short term seems eminent. A technically sound policy concerning the replacement of these assets requires a model that estimates the life expectancies of individual components and from that calculates parameters related to the behavior of a population of assets as a whole. A probabilistic approach is adopted and is applied to thermal degradation of the transformer paper insulation. In this paper, we will focus on the determination of the population reliability from individual reliabilities. These individual reliabilities are based on Arrhenius modeling of paper insulation degradation, including the inherent uncertainty in the parameters involved. A statistical failure model is used to obtain the population reliability figures. The modeling method is demonstrated on two populations of power transformers in The Netherlands to evaluate the different replacement alternatives. Using the model, strategies can be defined to maximize transformer utilization and postpone replacement. The downside is the need to replace the complete fleet in a relatively short time afterwards. View full abstract»

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  • Methanol: A Novel Approach to Power Transformer Asset Management

    Publication Year: 2012 , Page(s): 514 - 520
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (700 KB) |  | HTML iconHTML  

    All electrical utilities deal with the task of determining the residual life of their in-service power transformers. Given the difficulties experienced with the use of first and second generations of markers (carbon oxides and 2-furfuraldehyde), several organizations are now considering the use of methanol for this purpose. Hydro-Québec, which discovered this approach, uses this molecule on a regular basis to evaluate the state of the cellulose insulation of in-service power transformers and applies it to Électricité de France's nuclear power plant transformers. In this paper, some examples of the application of methanol in the field are presented against the information received from the early marker generations. View full abstract»

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  • Effective Voltage Flicker Calculation Based on Multiresolution S-Transform

    Publication Year: 2012 , Page(s): 521 - 530
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1116 KB) |  | HTML iconHTML  

    This paper introduces a new method for calculating the voltage flicker characteristics. A voltage waveform envelope, which captures the main flicker characteristics, is obtained by calculating rms values instantaneously using a moving window approach. The S-transform (ST) is then used to extract the voltage flicker components for each frequency. The multiresolution characteristic of the ST provides timing data which presents a “Magnitude-Time” and “Frequency-Time” contour for tracking flicker. The effects of signal sampling rate, voltage harmonics, and frequency variation on the calculation results are considered. The results show that the proposed method can identify the frequency and magnitude of flicker components in a short time and with very good precision. This method is independent of calculating the fundamental frequency of the system, which has been used for flicker index calculation. Finally, the method is tested on a real voltage flicker signal sampled from the voltage signal of an electric arc furnace. The results are quite promising. View full abstract»

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  • An SSSC-Based Hybrid Series Compensation Scheme Capable of Damping Subsynchronous Resonance

    Publication Year: 2012 , Page(s): 531 - 540
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (561 KB) |  | HTML iconHTML  

    The recently proposed phase-imbalanced series capacitive compensation concept has been shown to be effective in enhancing power system dynamics since it has the potential to damp power swings as well as subsynchronous resonance oscillations. In this paper, the series capacitive compensation concept is investigated for damping subsynchronous resonance oscillations using a static synchronous series compensator (SSSC)-based hybrid series-capacitive compensation scheme. In this scheme, the series capacitive compensation in one phase is created by using a single-phase SSSC in series with a fixed capacitor , and the other two phases are compensated by the fixed series capacitors (C). The validity and effectiveness of the proposed scheme are evaluated on the IEEE first and second benchmark models for computer simulation of subsynchronous resonance by means of time-domain simulation analysis using the Electromagnetic Transients Program-RV program. View full abstract»

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  • A Noninvasive Method for Detecting Restriking: Application to the Switching of HV Shunt Reactors

    Publication Year: 2012 , Page(s): 541 - 547
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1019 KB) |  | HTML iconHTML  

    Modern circuit breakers (CBS) may be susceptible to catastrophic failure possibly because they are designed to be more highly stressed than earlier CB designs with multiple interrupters per pole. Improved performance is obtained with dielectrically well-designed interrupters by taking advantage of advanced controlled switching to achieve a reignition-free window during opening to minimize the risk of nozzle puncture. On occasion, CB owners may wish to check whether equipment is performing satisfactorily and whether controllers are producing reliable and repeatable stress control. The monitoring of voltage waveforms during switching using established methods will provide information about the magnitude and frequency of small reignitions and restrikes. However, waveform measurements at a moderately high signal frequency require plant outages to connect specialized equipment. A nonintrusive measurement technique has been developed to measure the high- and low-frequency voltage waveforms occurring during reactor switching operations without the need for an outage. Results of tests performed in the laboratory and in a 275-kV substation demonstrating the capability of this new method to detect reignitions are presented. View full abstract»

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  • Distinguishing Internal Winding Faults From Inrush Currents in Power Transformers Using Jiles-Atherton Model Parameters Based on Correlation Coefficient

    Publication Year: 2012 , Page(s): 548 - 553
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB) |  | HTML iconHTML  

    This study proposes a novel method using Jiles-Atherton model parameters to identify small fault current results from winding turn-to-turn short circuit in power transformer inrush current. The waveform symmetry and hysteresis curve shapes of inrush current with fault current are different from inrush current without fault current; that means the magnetic parameters of transformer cores and windings are influenced. Moreover, cycle leakage inductance and cycle winding resistance also can be used to distinguish inrush current and internal fault current due to changes of permeability and the winding current density caused by transformer core or winding state changes. Jiles-Atherton parameters per cycle, leakage inductance per cycle, and the winding resistance per cycle are estimated from the exciting inrush current per cycle under no-load conditions using the differential evolution algorithm. This study uses two types of parameters: the first is the correlation coefficient of Jiles-Atherton parameters of a transformer under no-load exciting condition. The second type is the variation trend of the cycle leakage inductance and the cycle winding resistance. The study uses cross validation of the two methods to distinguish whether inrush current contains small fault current. The experiment has verified the feasibility and accuracy of the proposed methods in this study. View full abstract»

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  • A Thermodynamic Approach to Evaluation of the Severity of Transformer Faults

    Publication Year: 2012 , Page(s): 554 - 559
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB) |  | HTML iconHTML  

    Dissolved gas analysis (DGA) has been used to classify the type and severity of faults in transformers. The method commonly used to identify severity is to measure the total fault gas concentration and its rate of change, without regard to the relative concentrations of individual gases. Thermodynamic analysis indicates that the energy required to form gases increases in the order CH4 <; C2H6 ≤ CO ≤ C2H4 <; H2 ≪ C2H2. Based on these results, an energy-weighted dissolved gas analysis (EWDGA) is proposed, where concentrations of individual gases are multiplied by a weighting factor that is proportional to the energy required to produce each gas. Statistical calculations are used to show that EWDGA is more sensitive to high-energy faults than simple DGA, hence minimizing the damage caused by those faults. View full abstract»

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  • Electrodynamics Simulation of Overhead Power Lines

    Publication Year: 2012 , Page(s): 560 - 567
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (808 KB) |  | HTML iconHTML  

    Electrical overhead power lines are important installations today. They are the main part of electric transmission and distribution systems that are vital to developed societies. A key factor for proper operation is correct clearance between conducting parts and earthed parts. These separations can be altered by the movement in the conductors caused by various phenomena and this can lead to faults and subsequent supply outages. Furthermore, these situations can increase mechanical stress on conductors and cause breakages or structural faults in supports. In this paper, a multiphysic model is presented which includes three types of phenomena together: 1) electromagnetic; 2) thermal; and 3) mechanical. This model is used to study conductor movement and mechanical stress and takes the different types of stationary and transitory disturbances into consideration. View full abstract»

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  • Thermal Effect of the Recloser Operation Cycle on Bare Overhead Conductors

    Publication Year: 2012 , Page(s): 568 - 574
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (593 KB) |  | HTML iconHTML  

    A new calculation method of the temperature rise generated from multiple (consecutive) short circuits, to which bare overhead conductors are subjected, is proposed in this paper. Multiple short circuits are common in medium-voltage lines protected by reclosers due to their operation cycle. The proposed method treats each short circuit as a separate event. In additiony, the cooling between each short circuit is taken into account. The results of the proposed method are compared to the results given by the method of the IEC 60865-1 standard. The application of the proposed method results in greater temperature rises when the equivalent thermal current density is greater than a threshold. Furthermore, alterations to the recloser operation cycle are performed in order to investigate its effect on the generated temperature rise, namely, alterations to the reclosing interval between successive tripping operations and the ratio of fast to delayed trips. Finally, the proposed method was compared to an exact numerical solution of the heating process. View full abstract»

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  • Neuro-Prony and Taguchi's Methodology-Based Adaptive Autoreclosure Scheme for Electric Transmission Systems

    Publication Year: 2012 , Page(s): 575 - 582
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (749 KB) |  | HTML iconHTML  

    This paper presents a novel intelligent autoreclosure technique to discriminate temporary faults from permanent faults, and to accurately determine fault extinction time. A variety of fault simulations is carried out on a specified transmission line on the standard IEEE 9-bus electric power system by using MATLAB/SimPowerSytems. Prony analysis is employed to extract data features from each simulated fault. The fault identification prior to reclosing is accomplished by an artificial neural network trained by Levenberg Marquardt and resilient backpropagation algorithms, which are developed by using MATLAB. Some important parameters which strongly affect the entire training process are fine-tuned to their corresponding best values with the help of Taguchi's method. Test results show the robustness and efficacy of the proposed autoreclosure scheme. View full abstract»

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  • Ultrasound and Artificial Intelligence Applied to the Pollution Estimation in Insulations

    Publication Year: 2012 , Page(s): 583 - 589
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1166 KB) |  | HTML iconHTML  

    This paper presents an electrical insulator pollution estimation technique based on the ultrasonic noise emitted by these insulators when connected to energized electrodes. The spectral subband centroid energy vectors (SSCEV) algorithm was employed in the signal processing. This algorithm can be understood as being a spectral compression, capable of selecting the most significant frequency bands. The processed audio, changed into SSCEV, constituted a database which was fed into an artificial neural network (ANN), capable of distinguishing with remarkable precision a SSCEV from a polluted insulator from a SSCEV from a less polluted insulator. Finally, in order to validate the technique in the field, measurement campaigns were performed at the Campina Grande 2 substation, belonging to the São Francisco Hydroelectric Company. During these campaigns, ultrasonic noise from several electrical equipments, exposed to different natural pollution degrees, was obtained, and the processing, based on SSCEV and the artificial neural network, was once again applied. As a result, the success rates of more than 80% were generally obtained by the ANN. View full abstract»

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  • Modeling Impact of Cold Load Pickup on Transformer Aging Using Ornstein-Uhlenbeck Process

    Publication Year: 2012 , Page(s): 590 - 595
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (243 KB) |  | HTML iconHTML  

    Thermostatically controlled devices, such as air conditioners, heaters, and heat pumps may cause cold load pickup (CLPU) problems after a prolonged blackout. This causes an increased load on the power components in the electrical grid. The result is unpredictable aging and increased risk of failure. Quantifying this risk is crucial for efficient asset management for cost-intensive components such as the transformer. This paper presents a new approach to model the loading profile of a CLPU using stochastic differential equations. The realization of the loading profile is used to determine the aging of a transformer. Two models for the deterioration of transformer solid insulation represent the loss of life due to the CLPU. A comparison between two models for the aging of the solid insulation in the transformer is made in a case study. Due to the stochastic behavior of the load, there is a probability for loading the transformer above the recommended ratings, and this probability is estimated with Monte Carlo simulations. View full abstract»

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  • Mechanical Fault Diagnostics of Onload Tap Changer Within Power Transformers Based on Hidden Markov Model

    Publication Year: 2012 , Page(s): 596 - 601
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (788 KB) |  | HTML iconHTML  

    Online monitoring of the mechanical performance of onload tap changers (OLTCs) within high-voltage (HV) power transformers is of utmost significance for a safe, stable, and reliable operation of the power systems. This paper investigated a novel strategy based on a Hidden Markov Model (HMM) for mechanical fault diagnosis of OLTCs. With partition, normalization, and vector quantization of the power spectral density of the obtained vibration signals, a feature vector extraction methodology was presented for the discrete power spectrums which, to the farthest extent, could retain the unique features and difference of various mechanical condition modes, and well meet the requirement for the HMM exemplar training. With the sampled data series from experimental study and onsite measurements, a trained HMM norm modes library was established for different mechanical conditions of the OLTC. A large amount of function verifications demonstrated that the proposed HMM-based mechanical fault diagnosis scheme for OLTC is feasible and effective, with outstanding behavior for fault classification plus an identification rate of 95% in accuracy. An Internet-based program with preferable expandability has also been developed for practical applications of the proposed strategy in HV substations. View full abstract»

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  • A Traveling-Wave-Based Amplitude Integral Busbar Protection Technique

    Publication Year: 2012 , Page(s): 602 - 609
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (405 KB) |  | HTML iconHTML  

    This paper proposes an extra high-speed busbar protection technique according to the propagation theory of traveling wave. When the fault occurs on the busbar, the detected initial traveling waves on all connected lines will come from their back, which are defined as positive direction traveling waves. While a fault occurs on any one of these lines, the detected initial traveling waves on all healthy lines are positive direction traveling waves; however, the traveling wave direction on the faulted line is negative. Within a short duration of postfault, a criterion discriminating fault direction can be established according to the amplitude integral relationships between the positive direction traveling wave and the negative direction traveling wave. Analyzing the detected traveling wave directions for all lines, a distributed busbar protection scheme can be constructed. To evaluate the proposed technique, a typical busbar model was built. Simulation results show that the proposed method can rapidly and reliably discriminate the internal faults from external faults, and the protection performances are immune to fault resistances, fault inception angles, fault types, and current-transformer saturation. View full abstract»

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  • Reliability Study of HV Substations Equipped With the Fault Current Limiter

    Publication Year: 2012 , Page(s): 610 - 617
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB) |  | HTML iconHTML  

    Of particular interest to restrict the short-circuit level of interconnected power systems is to exploit fault current limiter (FCL) technologies. FCLs let the system planners devise new reliable and rather economical substation configurations and provide the possibility of proposing a promising cost-effective and prompt solution to the fault current over duty problem in the existing substations. This paper attempts to assess reliability of substation architectures accommodating the FCL operation and, besides, numerically investigates the FCL's impacts on the substation reliability indices. In order to clarify the proposed approach, two case studies with and without FCL are analyzed and compared. Although the discussions raised here are applicable for reliability modeling of all structures, five common substation configurations, namely: (1) single-bus single-breaker; (2) double-bus single-breaker; (3) ring bus; (4) one breaker and a half; and (5) double-bus double-breaker are considered in this paper. Numerical studies reveal that FCL deployment, while keeping the maximal flexibility of substation, may deteriorate the reliability indices of the substation due to the possible failures of FCLs. View full abstract»

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  • Ratings of Oil Power Transformer in Different Cooling Modes

    Publication Year: 2012 , Page(s): 618 - 625
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (632 KB) |  | HTML iconHTML  

    This case study shows the application of the calculation method based on the detailed thermal-hydraulic network model. The method is applied for the thermal design of oil power transformer of rated power 750 MVA in oil-directed, air-forced cooling mode; rated powers are also specified for oil-natural, air-forced and oil-natural, air-natural cooling modes. The results of the calculations using developed software for three cooling modes are compared with the results of the heat-run test of the transformer equipped with fiber-optic sensors. In addition to confirmation of the accuracy of the model, this paper demonstrates the full power of the integrated method (inner heating and outer cooling) for thermal calculations. All relevant components (pressure drops, oil flows, oil temperatures, etc.) in different cooling modes are obtained from the model and exposed in this paper. View full abstract»

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  • Phase-Domain Transmission-Line Modeling With Enforcement of Symmetry Via The Propagated Characteristic Admittance Matrix

    Publication Year: 2012 , Page(s): 626 - 631
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (452 KB) |  | HTML iconHTML  

    Transmission-line models for electromagnetic transient simulation are usually based on the traveling-wave method. While recent developments have focused on phase-domain formulations with an emphasis on accuracy and passivity enforcement, no consideration has been given to ensure the symmetry of the model. In this paper, we introduce the symmetry preserving property (SPP) of the propagation matrix H as a way of enforcing a symmetrical model. This property is enforced by replacing the (unsymmetrical) propagation matrix H with the (symmetrical) propagated characteristic admittance matrix during the process of rational fitting. The propagation matrix H is recovered analytically for use in the final line model. We show a procedure for enforcement of SPP and the resulting model is implemented in an Electromagnetic Transients Program-like simulation environment. Although the computational efficiency decreases somewhat with the new approach, the symmetry of the model offers significant advantages. Besides being physically correct, it avoids confusion when performing sanity checking of complex network models. 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