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Power Engineering Society Winter Meeting, 2001. IEEE

Date Jan. 28 2001-Feb. 1 2001

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  • 2001 IEEE Power Engineering Society Winter Meeting [front matter]

    Publication Year: 2001 , Page(s): i - xxxiii
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  • Author index

    Publication Year: 2001 , Page(s): 1541 - 1545
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  • Steady-state performance of a grid-connected rooftop hybrid wind-photovoltaic power system with battery storage

    Publication Year: 2001
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    Summary form only given, as follows. This paper reports the performance of a 4-kW grid-connected residential wind-photovoltic system (WPS) with battery storage located In Lowell, MA, USA. The system was originally designed to meet a typical New-England (TNE) load demand with a loss of power supply probability (LPSP) of one day in ten years as recommended by the utility company. The data used in the calculation was wind speed and irradiance of Logan Airport Boston (LAB) obtained from the National Climate Center In North Carolina. The present performance study is based on two-year operation (May 96-Apr 98) of the WPS. Unlike conventional generation, the wind and the sunrays are available at no cost and generate electricity pollution-free. Around noontime, the WPS satisfies its load and provides additional energy to the storage or to the grid. On-site energy production is undoubtedly accompanied with minimization of environmental pollution, reduction of losses in power systems transmission and distribution equipment, and supports the utility in demand side management (DSM). This paper includes discussion on system reliability, power quality, loss of supply, and effects of the randomness of the wind and the solar radiation on system design View full abstract»

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  • Performance implications of rapid load changes in carbonate fuel cell systems

    Publication Year: 2001 , Page(s): 979 - 984 vol.3
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1040 KB) |  | HTML iconHTML  

    There are several key performance objectives of molten carbonate fuel cell systems operating under load perturbations. Among these include: regulation of stack temperature, regulation of differential pressure between anode and cathode, maintaining acceptable fuel utilization and steam-carbon ratio, and electrical load tracking. Utilities are interested in rapid load cycling of carbonate fuel cell systems while the military is interested in the response of carbonate fuel cell systems under sudden application and removal of electrical load. An integrated fuel cell system may endure these types of disturbances while satisfying performance goals, depending largely on the control system. In this paper, the authors examine two important performance variables: fuel utilization and steam-carbon ratio, under both ramping operation and sudden increase in load. Setpoint control laws are proposed for determining the proper steam and natural gas flows corresponding to steady state or transient conditions. In the case of a sudden load increase, they illustrate a trade-off between good load tracking and good utilization/steam-carbon ratio when considering rate constraints on valves View full abstract»

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  • Time dependence of controls to avoid voltage collapse

    Publication Year: 2001
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    Summary form only given, as follows. In this paper, the effect of time dependence of control actions used to avoid voltage collapse, such as reactive power compensation and load shedding, is studied. A thorough justification of the phenomena under study is first presented with the help of a simple test system. The time dependence of the control actions is then studied in a real voltage collapse scenario of the Chilean interconnected system (CIS), based on a reduced system model View full abstract»

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  • A quick and practicable power flow tracing method on electric energy market. II. A new practicable method

    Publication Year: 2001 , Page(s): 1238 - 1243 vol.3
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB) |  | HTML iconHTML  

    For pt.I see ibid., vol.2, p.1244-9 (2001). Based on the theoretical proof in part I, a proportional sharing principle is incorporated with the load-flow tracing method for solving practical problems, such as the allocation of network loss, etc. Part II first analyzes the theoretical background of load-flow tracing, then advances sequences of load-flow tracings (downstream and upstream tracings), and calculates the contributing factor (of generators) and deriving factor (of loads). By applying the method to an IEEE 14-bus sample network computation, not only can this method be used to analyze the relations of load flow in the actual system, it can also well and truly reflect the nonlinearity of this problem since it is based on alternating current circuit theory View full abstract»

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  • The Brazilian interconnected system: a study on transfer limits, reactive compensation and voltage collapse

    Publication Year: 2001 , Page(s): 1147 - 1153 vol.3
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (644 KB) |  | HTML iconHTML  

    On April 1999 the S+SE (~40 GW load) and N+NE (~12.5 GW) systems in Brazil were interconnected over a single-circuit 500 kV line. The line has been operating with an average transfer of 600 MW and peak loading of almost 1000 MW. In order to improve reliability and increase transfer capability the interconnection will be expanded in 2002 with a second parallel line (North-South) and a new Southeast-Northeast 500 kV line. This paper summarizes results of studies conducted to determine the compensation and/or reinforcements that are necessary to secure those benefits. The results show that voltage stability is the most limiting constraint, with transient stability a distant second. The paper shows how OPF techniques were employed to develop compensation strategies to increase transfer capability from 1000 to 3000 MW. Steady-state results demonstrating voltage collapse conditions were confirmed using long-term dynamic simulation. That analysis demonstrated the possibility of utilizing mechanically switched capacitors instead of more expensive compensation alternatives View full abstract»

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  • Making unit commitment decisions when electricity is traded at spot market prices

    Publication Year: 2001 , Page(s): 1509 - 1512 vol.3
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB) |  | HTML iconHTML  

    We present a new formulation to the unit commitment problem suitable for an electric power producer in a deregulated market and consider computationally efficient procedures to solve it. When the option of selling or buying electric power at spot market prices is included in unit commitment decisions, the optimal solution of a UCP with M units under standard operating and load constraints can be obtained by solving M uncoupled sub-problems. We account for the volatility of the spot market price of electricity by using a stochastic model. The model incorporates both the stochastic features of the availabilities of generating units participating in the market and the uncertainty of the aggregate load. We use probabilistic dynamic programming to solve the stochastic optimization problem. We show that for a market of 150 units the unit commitment problem can be accurately solved in a reasonable time by using the normal, Edgeworth, or Monte Carlo approximation methods for estimating the needed probability distributions View full abstract»

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  • High efficiency and high performance motor for energy saving in systems

    Publication Year: 2001 , Page(s): 1413 - 1418 vol.3
    Cited by:  Papers (6)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (968 KB) |  | HTML iconHTML  

    Recently, increasing importance has been placed on energy saving in various systems. This has created a need for a motor with high efficiency that is capable of operation over a wide range of speeds. The authors have developed a novel permanent magnet reluctance motor (PRM) that has permanent magnets embedded in the isotropic rotor to increase the power density and the power factor. The PRM produces reluctance torque and torque by permanent magnet (PM) flux. The reluctance torque is 1 to 1.5 times larger than the PM torque. It is clarified that the PRM operates at a wide variable-speed range (1:5) and at high efficiency (92-97%). With an output power of 8 to 250 kW, the motor is suitable for application to electric vehicles, railway systems and elevator systems View full abstract»

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  • Enhancing power engineering education through the use of Power System Simulator

    Publication Year: 2001 , Page(s): 1467 - 1472 vol.3
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB) |  | HTML iconHTML  

    This paper describes a newly installed education facility “Power System Simulator” (PSS) based on Taiwan Power Company's system. It includes five modules: generation units, 345/161 kV switching yard, 161/69 kV switching yard, 69/22.8/11.4 kV switching yard, and load units. The PSS was developed as a “core course” introduction to power systems intended for both power and nonpower majors at I-Shou University (ISU), Taiwan. Through the use of the PSS, it can enhance student's understanding of the fundamental concept as well as the practical phenomena in power systems. This will hopefully help them in a better understanding of the practical aspects of power engineering, and therefore increase enrollments in power engineering courses at ISU. The purpose of this paper is to describe three laboratories through the use of PSS. They are (1) normal operation, (2) load transfer, and (3) transformer overload in power systems View full abstract»

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  • A quick and practicable power flow tracing method on electric energy market. I. Theoretic fundament

    Publication Year: 2001 , Page(s): 1244 - 1249 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB) |  | HTML iconHTML  

    In a competitive market environment, to “fairly allocate the total cost of transmission”, which is identical with the actual utilization of the network, is most important. Based on network theory and graph theorem, this paper theoretically proves and extends the proportional sharing principle. With it, the employment of transmission lines by different generators and loads can be confirmed theoretically, while energy consumers can be impartially, rationally charged, and quickly and truly ascertained according to the actual utilization of the network. Also based on this principle, many problems in the electricity energy market field can be settled View full abstract»

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  • Consideration of DC capacitor and line inductance in the design of UPFC to improve transient stability

    Publication Year: 2001 , Page(s): 1277 - 1282 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (516 KB) |  | HTML iconHTML  

    Practical application of the unified power flow controller requires proper design of each component of the UPFC device in order to satisfy both economic requirements and technical specifications. Economic and performance indices are always conflicting factors in the design of the practical devices and an acceptable design of practical device must be based on a reasonable compromise between these two factors. Although an overwhelming number of studies have been conducted on the UPFC and its application, the study at the components level is limited, especially regarding the selection of parameters of UPFC devices. Using the analysis of transient characteristics of UPFC installed in a power system, this paper attempts to identify the effects of the size of DC capacitor and equivalent line inductance. The relationship between the transient stability of the power system and these parameters is studied at the components-level simulation. The findings of this study can be useful in the determination of UPFC parameters for the purpose of improving transient stability, and highlight some of the practical considerations in UPFC implementation View full abstract»

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  • Analysis of harmonic for 12-pulse converter under unbalanced voltage operation due to lightning related voltage sags and short interruption

    Publication Year: 2001 , Page(s): 1009 - 1014 vol.3
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1356 KB) |  | HTML iconHTML  

    This paper presents a summary of power quality related concerns associated with the applications of 12-pulse converter with DC motor drives in industrial plants. These concerns include power system harmonics and harmonic distortion under unbalance voltage condition during voltage sags occurrence. The definition proposed focuses on system faults due to lightning. The voltage unbalance causes large unbalance source currents resulting in excessive input current and high distortion. The percentage of total harmonic distortion of input current (THDi) increased approximately 47% at 6 per unit of normal peak current. The measurement and analysis of such events has been performed. Finally, the new phase-angle jump concept based on measured techniques is introduced View full abstract»

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  • Forecasting power market clearing price and its discrete PDF using a Bayesian-based classification method

    Publication Year: 2001 , Page(s): 1518 - 1523 vol.3
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (636 KB) |  | HTML iconHTML  

    In this paper, a classification method combined with a simple regression model is presented to predict the discrete PDF of power market clearing prices (MCP), which is critical for much decision-making such as optimizing bidding strategies, and is very difficult to predict because of high market uncertainties. Our basic idea is to form a number of classes by discretizing the variable to be predicted, and thus convert the time series prediction problem into a pattern classification problem. The classes are clustered based on historical data, and the input statistics (e.g., input mean and covariance matrix, etc.) corresponding to each class are obtained via clustering. Given a new input, these classes are sorted according to the posterior probabilities calculated by using the Bayes' formula. The prediction is then generated by using an auto-regression method (AR) for the classes with high posterior probabilities. The classes are then updated after the actual output is available. The method developed can be seen as an RBF with variable structure. The posterior probabilities can be viewed as an approximation of the discrete PDF, providing valuable information for decision-makers and for what if analysis. The developed method has been used to predict the on-peak and off-peak average MCPs in the New England market. The testing results show that it outperforms the RBF network in terms of prediction accuracy and computational time View full abstract»

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  • Evaluation of transmission line arresters against winter lightning

    Publication Year: 2001
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    Summary form only given as follows. The authors have tested 154 kV class transmission line arresters by installing them on an instrumented lower of a double-circuit test transmission line during winter seasons since 1993. The tower is struck by natural and artificially-triggered lightning several times during each winter season. The conventional transmission line arrester designed against summer lightning was effective against winter lightning. The authors developed a new transmission line arrester of reduced rating, and investigated its applicability against winter lightning based on EMTP analysis, taking account of measured lightning current waveforms in winter. Although omission of an earth wire is not feasible on transmission towers having high footing resistance, the new arrester of reduced rating is a reasonable option to realize a line of high lightning performance View full abstract»

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  • Equivalent circuit of single phase permanent magnet synchronous motor

    Publication Year: 2001 , Page(s): 1378 - 1381 vol.3
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB) |  | HTML iconHTML  

    Growing consumer and legislative pressures are increasing the demand for improved efficiency of fractional horse power motors. The single phase line start permanent magnet synchronous motor has been shown to have potential for high efficiency. An equivalent circuit for this motor is proposed to predict the steady state performance of this machine. Criteria for estimating the value of capacitor required for balanced operation for desired load is outlined. The analysis is analytically validated View full abstract»

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  • Steady-state model for VSC based HVDC and its controller design

    Publication Year: 2001 , Page(s): 1085 - 1090 vol.3
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (980 KB) |  | HTML iconHTML  

    In this paper, a steady-state model of a VSC (voltage source converter) based HVDC system has been developed. According to this model, the corresponding relationship between the two controlling and the two controlled variables of the VSC is determined. Furthermore, a nonlinear control strategy combining an inverse model controller with a PI controller is proposed, and a nonlinear compensation method is adopted for the DC voltage PI controller. Digital simulation shows the validity of the established steady-state model and the feasibility of the proposed control strategy View full abstract»

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  • Accurate modeling and simulation of transmission line transients using frequency dependent modal transformations

    Publication Year: 2001 , Page(s): 1443 - 1448 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (528 KB) |  | HTML iconHTML  

    The frequency dependent line model (also known as the J. Marti model) which is currently used in most electromagnetic transient programs, is very efficient and accurate for most simulation cases. However, it makes an approximation in choosing the modal transformation matrix that is used to switch variables between the phase and modal domains at each simulation time step. This approximation may not hold true for certain tower configurations and/or conductor types where line parameters vary drastically with frequency. In this paper, a wavelet based alternative solution, which incorporates frequency dependence of transformation matrices into the simulation process is presented View full abstract»

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  • Tracing the path of electric power flow-a study for deregulated power systems

    Publication Year: 2001 , Page(s): 1479 - 1484 vol.3
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB) |  | HTML iconHTML  

    Tracing the flow of electricity in power systems is an old issue, but it has become important now especially after deregulation. There is no simple solution to this problem because clearly it is not possible to identify the electrons originating from each generator. If this could be done it would be possible to trace the flow of electric power in a network in a definitive manner. However, it is possible to approach the desired goal with the implementation of the tracing algorithms discussed in this paper. Till now, the issues related with the electricity path are generally solved by employing the DC distribution factors method. Recently, two other methods have been proposed for tracing the flow of electric power. The two methods are identified as the `commons method' and the `node method'. This work analyzes the methods based on their assumptions and simulation results for different systems. The reliability of the different methods is then discussed. A methodology for improving the results of electricity tracing is proposed View full abstract»

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  • Overall control of fossil-fuel power plants

    Publication Year: 2001 , Page(s): 1209 - 1214 vol.3
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (768 KB) |  | HTML iconHTML  

    Under the trend toward market deregulation, effective plant-wide automation systems for operation and control of power units are of paramount importance for the survival and profitable operation of any electric utility. This paper identifies the overall unit control scheme as the core of any integral automation system for fossil-fuel power units and reviews several control strategies towards the implementation of such a scheme. The current trend in the design of overall control systems is shown, and several research niches are pointed out. It is concluded that the general problem of overall power unit control may be recast as the wide-range multi-objective optimal control of a nonlinear multivariable (large-scale) process with highly interactive dynamics, and the trend on the development of overall controls is that of incorporating different techniques into hybrid systems to make use of the good characteristics of each technique in a consistent symbiosis View full abstract»

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  • Sequential timestep unit commitment

    Publication Year: 2001 , Page(s): 1524 - 1529 vol.3
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (716 KB) |  | HTML iconHTML  

    This paper presents a method for solving the unit commitment problem sequentially in time. By decomposing the problem in time, each timestep is solved individually using a free market model of the power system. The corresponding market clearing handles both energy demand, primary reserve demand and secondary reserve demand, and is performed using an extended economic dispatch algorithm that determines both the unit dispatch decisions and the unit commitment decisions. The paper focuses on describing the formulation and the solution of the problem, and includes explicit formulations of both the unit dispatch decision and the unit commitment decision as functions of the system prices. Comparisons with results provided by other methods show that the method is very competitive View full abstract»

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  • An aggregation method for improving Lagrangian relaxation-based auction implementation and generation scheduling

    Publication Year: 2001 , Page(s): 1491 - 1496 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (840 KB) |  | HTML iconHTML  

    Lagrangian relaxation has been widely used in hydrothermal scheduling. A well recognized deficiency of Lagrangian relaxation is solution oscillation caused by the existence of integer decision variables and linear or piece-wise linear subproblem cost functions, resulting in slow convergence. When there are identical or similar subproblems, this deficiency becomes serious, intensifying the slow convergence and creating an arbitrary nature of primal solutions. The latter may cause difficulty in using LR to solve the independent system operator's auction problems because of the unfair treatment of identical or similar bids submitted. In this paper, an aggregation method is developed to reduce the oscillation of subproblem solutions in the primal space and to improve the convergence of the dual problem. For convex hydro subproblems, aggregation is performed as a convex combination of subproblem solutions across iterations. For mixed-integer thermal subproblems, the aggregation is applied to each operating region, and dynamic programming is then used to optimize the states across the time horizon. The multipliers are updated at the high level based on the aggregate solutions after solving a portion of subproblems rather than solving all the subproblems. The convergence is established. Compared with the solution obtained without aggregation, the new solution is less sensitive to the perturbation of multipliers, is more feasible, and generally leads to better feasible schedules. Identical or similar units could be differentiated as they are solved with different multipliers, and more commitments with the similar costs can be obtained. Alternative solutions are thus fairly selected in a probabilistic sense. Consequently the unfairness difficulty is alleviated, making LR practical in solving ISO's auction problem. Extensive numerical testing demonstrates the above properties of method, and better schedules are obtained without increasing computational requirements View full abstract»

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  • A technical review of the power outage on July 29, 1999 in Taiwan

    Publication Year: 2001 , Page(s): 1353 - 1358 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB) |  | HTML iconHTML  

    One of the severest power outages occurred at 11:31 p.m. on July 29, 1999 in Taiwan when the #326 transmission tower collapsed due to a landslide, which disconnected around 8.46 millions of the electricity consumers from the energy supply. This paper provides a technical review of the power outage event on July 29, 1999. The authors summarize the power system characteristics and the network conditions prior to, during, and after the incident. Finally, the lessons learned from the power failure and future strategies to be adopted by Taiwan Power Company are concluded View full abstract»

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  • Damping algorithm based on phasor estimation

    Publication Year: 2001 , Page(s): 1160 - 1165 vol.3
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1076 KB) |  | HTML iconHTML  

    The paper describes a new method to generate the reactance reference for a TCSC, which has been installed in order to provide damping in a power system. The knowledge of the expected oscillation frequency in the power system is used to create a coordinate system, which rotates with that frequency. In this coordinate system a phasor representing the power swing is being extracted from the input power signal. A reactance reference signal with arbitrary gain and phase shift can easily be created using the phasor. The phase of the reactance reference is preserved during limiting. Gain and phase-shift may comfortably be scheduled due to measured parameters like average power, power swing amplitude etc. Frequency compensation has been implemented, and adapts the frequency in the measuring system when a power oscillation occurs. The new approach has been implemented and successfully tested in the North-South Interconnection in Brazil in March 1999 and has been in operation since then. The scheme is applicable for PSS and other FACTS damping systems View full abstract»

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  • A multi-agent system for power system restoration

    Publication Year: 2001 , Page(s): 1359 - 1364 vol.3
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB) |  | HTML iconHTML  

    This paper proposes a multi-agent approach to power system restoration. The proposed system consists of several bus agents (BAGs) and a single facilitator agent (FAG). A BAG is developed to decide a sub-optimal target configuration after faults occur by interacting with other BAGs, while a FAG is developed to act as a manager for the decision process. The interaction of several simple agents leads to a dynamic system allowing efficient approximation of a solution. It is shown from simulation results that this method is able to obtain sub-optimal target configurations which are the same as ones obtained by a mathematical programming approach View full abstract»

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