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Power Apparatus and Systems, IEEE Transactions on

Issue 7 • Date July 1985

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Displaying Results 1 - 25 of 55
  • IEEE Transactions on Power Apparatus and Systems - Table of contents

    Page(s): c1 - 1936-b
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    Freely Available from IEEE
  • IEEE Power Engineering Society

    Page(s): c2
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    Freely Available from IEEE
  • Video-Based Master Degree Power Program at Georgia Institute of Technology

    Page(s): 1585 - 1591
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    This paper describes an innovative video-based master degree program in power engineering developed at Georgia Tech. The program, which is delivered to students at fifty remote locations, has been, in operation for three years. View full abstract»

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  • Power Plant Availability Prediction Using Standard Bayesian Analysis of NERC/GADS Component Cause Code Failure Data

    Page(s): 1592 - 1601
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    Prediction of power plant outage hours by cause can be very, effective in implementing a cost effective availability improvement program. If the predictions identify those causes for lost generation due to either full, pr partial outages most likely to happen in the next 3 years or less, attention can be focused on making improvements only in these areas and not for other causes that are not expected to be troublesome until later on in the life of the unit. With this approach, cognizance is given to the time value of money and overall less cost results because expenditures are deferred as long as possible. The necessity to differentiate between near-term causes of lost generation and long-term average expected performance, coupled with an incomplete data set, argues for the use of Bayesian analysis. A method of applying standard Bayesian analysis is demonstrated which uses as input only readily available data and produces as output, pre-dictions of forced outage hours (full or partial) for a unit during its next year of operation. The down hours are by cause and uncertainty of the predictions are indicated by plotting the results as probability densities (PD). How these PD can be used in an economic analysis to identify candidate availability improvement projects is demonstrated. Finally, a 7-year comparison between actual and predicted unit outage hours for sixth thermal units is presented as a measure of the "goodness" of the predictions and to serve as a base to measure future improvements to the prediction technique. View full abstract»

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  • Distribution Substation Load Impacts of Residential Air Conditioner Load Control

    Page(s): 1602 - 1608
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    An ongoing experiment to monitor the substation-level load impacts of end-use load control is described. An overview of the data acquisition system, experimental procedures and analysis techniques are provided. Results of the 1983 and 1984 experiments demonstrate the value of aggregate load impact monitoring as a means of verifying load research results, calculating the diversity of end-use loads, and predicting the impacts of load management on the transmission and distribution systems. View full abstract»

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  • User-Oriented Simulation of HVDC Control in a Transient Stability Program

    Page(s): 1609 - 1616
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    In view of the wide variety of HVDC controls, which can differ from one application to another, their simulation in transient-stability programs poses a specific problem. The simulation method described in this paper allows HVDC system representation in transient-stability programs by means of user-defined block diagrams for the control functions. The user enters the control specifications in the form of a data file which can be accessed by any users. Thus a bank of models is created which can be easily updated. An example of model creation using this method is also shown. View full abstract»

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  • Efficient Calculation of Frequency and Duration Models for Large Composite Electric Generating Plants

    Page(s): 1617 - 1623
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    This paper describes a new technique that has been developed to facilitate the preparation of frequency and duration models for large composite systems. These models are required for power system reliability and probabilistic production cost evaluations. The technique is based on the sequential composition and state aggregation of component subsystems and composite partial systems. A significant feature is the fact that state aggregation is performed at the subsystem level rather than the final system level. This has important computational consequences since it greatly reduces the number of states that must be stored and manipulated during the computational process. View full abstract»

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  • Fast Economic Dispatch Based on the Penalty Factors From Newton's Method

    Page(s): 1624 - 1629
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    An extremly fast, simple, efficient and reliable economic dispatch algorithm is presented. The algorithm utilizes a closed form expression for the calculation of the Lambda, as well as taking care of total transmission loss changes due to generation change, thereby-avoiding any iterative processes in the calculations. The closed form expression presented for Lambda can be used with any type of incremental transmission loss calculation. For this algorithm, penalty factors are derived based upon the Newton's method. An efficient method to implement the algorithm in power control centers is discussed. The algorithm presented has excellent convergence properties. View full abstract»

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  • A Modified Unit Commitment and Generation Control for Utilities with Large Wind Generation Penetrations

    Page(s): 1630 - 1636
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    A modified unit commitment is proposed in this paper that would be updated on three different cycles (daily, quarter-hourly and every minute). The 24 hour updated unit commitment would include the effects of load and slow trend wind power change that could be predicted 24 hours ahead. The quarter- hourly updated unit commitment would handle the fast trend and cyclic change in wind power that could be predicted one hour ahead and would commit peaking, regulation, and quick pickup and possibly economic units to handle these wind power changes. View full abstract»

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  • A Developed Database Management System for Operation and Planning Applications

    Page(s): 1637 - 1643
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    A database management system (DBMS) has been developed to support a major electric utility's operating and planning information requirements. Its structure is of the relational type, extended to suit the records relationship commonly found in power system applications. It has been tested to meet the real-time performance requirements of giving control responses within, 1-second, and providing a control system availability of 99.9 % or higher. View full abstract»

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  • Evaluation of Spot Price Based Electricity Rates

    Page(s): 1644 - 1655
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    It is necessary to be able to evaluate the cost of providing electric service on a hour by hour basis in order to effectively market electric energy in a fashion which meets both the utility's and its customer's needs; i. e. to offer appropriate rates, contracts, and load management options to the customers. This paper provides a methodology which uses the theory of spot prices to evaluate the variable costs of electric energy on an hourly basis. The methodology decomposes variable costs in components corresponding to generation fuel and maintenance, T and D network losses and maintenance, and generation and network quality of supply components arising from unserved energy caused by shortages of generation and network capacity. The methodology provides a choice between four different methods of revenue reconciliation to cover the capital and fixed costs of generation and the T and D network. Planning studies can be done using the methodology without developing large new computer programs. A numeric example is presented which exhibits large price variations depending on random weather and generator outages View full abstract»

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  • On-Line Computation of Phase Shifter Distribution Factors and Lineload Alleviation

    Page(s): 1656 - 1662
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    This paper presents a new method for the computation of phase shifter distribution factors required for adjusting the phase angles of phase shifters to control the line flows. These factors are computed usingusing the sensitivity matrix, which is tversee in- of the constant Jacobian matrix. Computation of these factors is carried out for both the base case system and the outaged system using the same-sensitivity matrix. The factors so computed are used to alleviate the line overloads leaving the economic generation schedules unaffected. In case the phase angle adjustments of the phase shifters do not reduce the line overloads completely, generation rescheduling and/ or load curtailment is proposed, thus ensuring a secure system operation. The proposed techniques are validated by testing on different test systems. View full abstract»

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  • Implementation of a Large-Scale Direct Load Control System-Some Critical Factors

    Page(s): 1663 - 1669
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    This paper describes several aspects of the implementation of a large-scale direct load control system. The need to maintain flexibility, and to carefully monitor critical variables affecting the overall implementation, is discussed. The existing Direct Load Control system at Florida Power Corporation is described, and factors relating to its integration to the bulk power supply operation are considered. View full abstract»

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  • A Preventive Strategy Method For Voltage and Reactive Power Dispatch

    Page(s): 1670 - 1676
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    A preventive control program for voltage and reactive power dispatch is developed to enhance a system's capability to cope with outages. In this program, not only the base case but also associated contingency cases have been considered. Therefore, it is referred to as the Global VAR Dispatch Method. View full abstract»

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  • Penetration of Wind Electric Conversion Systems into the Utility Grid

    Page(s): 1677 - 1683
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    This paper is concerned with the development of appropriate models for the interconnected operation of wind generator clusters with an autonomous power system and simulation techniques for the study of the degree of penetration of such wind electric conversion devices when operating in parallel with the utility grid. The quality of the interconnected system performance is specified in terms of operational constraints and the resultant penetration strategy is implemented via a microprocessor-based control scheme. The strategy assures a satisfactory level of system performance while optimizing the available energy transfer from the wind generators to the utility grid. View full abstract»

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  • A Solution of the Unit Commitment Problem Via Decomposition and Dynamic Programming

    Page(s): 1684 - 1690
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    Each day power generating units have to be selected to realize a reliable production of electric energy with the fewest fuel costs. This paper proposes decomposition and dynamic programming as techniques for solving the unit commitment problem, a high- dimensional non-linear, mixed-integer optimization problem. Experiments indicate that the proposed methods locate in less time a better solution than many existing techniques. View full abstract»

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  • Practical Optimization

    Page(s): 1691 - 1695
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    The recent escalation in fuel costs has resulted in a host of optimization problems which were non-existent when fuel was relatively inexpensive. Coupled with the increased costs have been more difficult operational constraints imposed by fuel vendors. These problems are particularly acute in natural gas fired units which cannot rely on reserve storage of fuel to meet demand. This research addresses the problem of optimal system operation subject to more contemporary operating constraints. The solution algorithm is based on a new optimization algorithm termed "practical optimization". View full abstract»

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  • Enhancement of the Transient Stability of Integrated AC/DC Systems Using Active and Reactive Power Modulation

    Page(s): 1696 - 1702
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    Active power modulation has been successfully used to improve the dynamic performance of interconnected AC/DC systems. This, however, results in uncoordinated reactive power modulation which, in the case of weak systems, reduces the effectiveness of the method. View full abstract»

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  • Residential Load Shape Modelling Based on Customer Behavior

    Page(s): 1703 - 1711
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    A model of residential electric load is developed. It includes psychological factors which affect individual use of the various electrical appliances. Specifically, the concepts of an "availability" function which statistically estimates the number of people in a household available to use an appliance, and a "proclivity" function which gives the probability that an individual will use that appliance at any given time of day are developed. These functions are then used to drive "physical" models of the various appliances and these are incorporated into a "combined" model which is used to estimate load on a time of day basis. Results of a computer simulation of the model are compared to actual load test data. View full abstract»

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  • Closed Loop Control of Phase Angle Regulators Using a Programmable Controller

    Page(s): 1712 - 1717
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    In order to provide positive control at all times on a 345-kV underground cable interface designed to transfer up to 1000-MW a Programmable Controller (PC) has been installed at PSE&G's Waldwick Switching Station. This PC will independently take corrective action by moving phase angle regulator transformer (PAR) load tap changers (LTC) upon recognition of local flows exceeding emergency ratings after a time delay of five minutes. The PC has undergone extensive testing to prove the correctness of its logic and has been in service for more than one year. View full abstract»

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  • A Textured Model for Computationally Efficient Reactive Power Control and Management

    Page(s): 1718 - 1727
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    The texture of the power system which govern, the interplay of reactive power and voltage is emulated by a textured model which assembles local groups of buses into a multi-leaf structure. Groups on the same leaf of the model are not coupled with each other, groups on different leaves overlap partially and are thus coupled. The paths of computational information are organized in an efficient manner and inefficient computation and information paths are eliminated, yet the computation converges to the exact solution, not an approximate one. The resulting model is ideally suited for parallel processing especially since there is no sequential component in the computation no computation overhead and (if the size of the groups and their numbers per leaf are uniform) there is no waiting time. Computation time savings of as much as 100รท1 (i.e. a hundred fold saving) were observed in experiments on steepest descent algorithms with systems of around 100 buses. Computation times also favorably compare with existing speed up techniques such as block pivoting. Computation times for common algorithms (like matrix manipulations, Newton-Raphson, linear and nonlinear programming) increase with the system size at a fast non- linear rate. The computation times remain essentially constant for the textured model in parallel processing. Thus very large computation time savings are implied on larger systems. Consequently this new model should prove to be a valuable tool for on line computations in the course of reactive power control and management. View full abstract»

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  • Reactive and Real Power Control for Computationally Effective Voltage and Thermal Management

    Page(s): 1728 - 1737
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    This paper introduces a new efficient way of controlling or "managing" the active and reactive resources of the system on line in such a way as to maintain viable voltage and current "profiles", that is to keep all voltages within normal limits and all currents within their thermal limits. The disruption to system operation is minimized by using tools of control in priority order. The computational burden is minimized by restricting the computations to moderate size clusters within the large system. The clusters consist of sets of violations and control tools which are effective on these violations along with such nonviolated elements which are responsive to the controls within the cluster. A novel, simple and effective method for finding the clusters is introduced. Because of the limited size of the clusters the computation of the controls is inherently fast but in addition a fast and efficient algorithm is introduced. This overall approach can be operated as an "emergency control" or an ongoing dispatch. In the latter case it will routinely handle any emergencies of the type consisting of more or less widespread voltage and current problems within segments of the system. On the other end of the spectrum these techniques can be used effectively in establishing a restoration sequence or plan for a failed system (with or without blackout). View full abstract»

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  • A Transformation-Decoupled Estimator for Power System State Estimation

    Page(s): 1738 - 1744
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    This paper presents a new decoupled power system state estmator. The decoupling is achieved via simple linear transformations on power measurements in contrast with the fast decoupled state (FDS) estimators which assume decoupling by direct negligence of the off- diagonal blocks of the Jacobian of the observation functions. The new estimator is compared with the conventional weighted least-squares (WLS) estimator and the fast decoupled state estimator against test systems ranging from 6-bus to 30-bus in size and different system loading conditions, network parameters, measurement types and redundancies. View full abstract»

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  • D.C. Insulation Analysis: A New and Better Method

    Page(s): 1745 - 1749
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    A recently developed method provides better analysis of insulation when testing with direct current. The problems of insulation analysis are first reviewed as background to the discussion. The paper then explains the new method in this context. Comparison is made between the new method and existing techniques. The circuit design of a new instrument based on this method is described. There is a discussion of the problems of measuring capacitive specimens with a recent history of voltage applications. Finally, there is a brief comment on practical results obtained by application of the method. View full abstract»

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  • Harmonic Resposnse Tests on Voltage Transducers for the New Zealand Power System

    Page(s): 1750 - 1756
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    This paper presents the results of harmonic response tests carried out on capacitive voltage transformers, as used on the New Zealand 220 kV a.c. network. It is shown that the harmonic response measured using low voltage test equipment is considerably different from that obtained at high voltage. The latter is highly non-linear and is affected by the specific magnetization characteristic of the CVT tested. It is concluded that for field measurement of harmonics at rated voltage, the transformer of a CVT unit should be disconnected and the CVT used as a purely capacitive or resistor-capacitor divider. View full abstract»

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Aims & Scope

This Transactions ceased production in 1985. The current retitled publication is IEEE Transactions on Energy Conversion and IEEE Transactions on Power Delivery, and IEEE Transactions on Power Systems.

Full Aims & Scope