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Energy Conversion, IEEE Transactions on

Issue 1 • Date Mar 1991

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Displaying Results 1 - 25 of 28
  • Benefits of excitation control system testing at AEP's Rockport plant

    Publication Year: 1991 , Page(s): 21 - 28
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB)  

    Excitation control systems (ECS) play an important role in the transient and oscillatory stability of generating units and interconnected systems. For this season, comprehensive testing of the ECS was conducted at AEP's Rockport plant, Indiana. Analyses of the ECS tests indicate that, with the ECS equipment as found, a permanent 100 MW plant curtailment would have been needed during two-unit plant operation to assure satisfactory stability performance. This curtailment was avoided by retuning the voltage regulators of both Rockport units before the second unit was placed in service. The Rockport ECS testing, analysis, and tuning efforts are described View full abstract»

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  • Development and implementation of high performance variable structure tracking control for brushless motors

    Publication Year: 1991 , Page(s): 114 - 119
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    A high-performance controller for DC brushless motors is proposed. The controller is based on the theories of variable structure tracking. With the proposed method, the rotor position can trace any arbitrarily selected track with a high degree of accuracy, and without overshooting or overstressing the hardware of the system. The control strategy is adaptive and very robust. External disturbances and variations in system parameters are adaptively compensated by the tracking controller. The proposed controller is suitable for such applications as robotics, actuation and manipulation, where most of the present fixed-parameter positional control methods are inadequate. The system is designed and implemented in the laboratory. Test results are presented and discussed View full abstract»

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  • Performance analysis of permanent magnet synchronous motors. II. Operation from variable source and transient characteristics

    Publication Year: 1991 , Page(s): 83 - 89
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (444 KB)  

    For pt.I see ibid., vol.5, no.2, p.366-73 (1990). A comprehensive analysis of the transient performance of a permanent magnet (PM) synchronous motor operating from a variable source is described. Internal damping is modeled, and optimum values of design parameters which improve transient performance are obtained. The effects of varying the supply voltage and frequency on the optimum values of these parameters are demonstrated. Simulated nonlinear response to a load change and starting performance are discussed. The results illustrate that significant improvement in transient performance can be achieved over a wide range of voltage and frequencies when some parameters are properly chosen View full abstract»

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  • A new method for determining the armature leakage reactance of synchronous machines

    Publication Year: 1991 , Page(s): 120 - 125
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB)  

    A method for determining the armature leakage reactance of synchronous machines is presented. In this method, the terminal voltage/armature current characteristic with the machine unloaded and unexcited is needed, together with the open-circuit characteristic of the machine. The armature leakage reactance is derived from these two curves using an iterative technique. The armature leakage reactances of five synchronous machines of different designs are obtained using this method. Their values are compared with those of the Potier reactance of these machines measured at various terminal voltages View full abstract»

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  • Proven criteria imperative to the application of ASDs to large power plant motor systems

    Publication Year: 1991 , Page(s): 90 - 98
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (572 KB)  

    A seven-step systematic approach for successfully applying adjustable speed drives (ASDs) to large power plant motors is presented. The seven steps are: preliminary study for retrofit economics; detailed analysis and budget preparation; budget approval; design engineering; installation; start-up; and post start-up tests for ASD evaluation. A discussion of each step is presented View full abstract»

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  • Minimum excitation limiter effects on generator response to system disturbances

    Publication Year: 1991 , Page(s): 29 - 38
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (820 KB)  

    Minimum excitation limiters (MEL) have been in use since the first applications of voltage regulators to synchronous machines, and are presently in widespread use throughout the power industry. However, a cursory literature search indicates scant examination of the dynamic behavior of these devices. Although the minimum excitation limiter is rarely called into action, its effect can be particularly significant to the final outcome of some severe disturbances. The digital computer modeling of two common MEL devices is described, and their effect on power system dynamics is addressed View full abstract»

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  • Damping of torsional oscillations using excitation control of synchronous generator: the IEEE Second Benchmark Model investigation

    Publication Year: 1991 , Page(s): 47 - 54
    Cited by:  Papers (15)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB)  

    A simple lead-lag excitation controller using generator shaft speed deviation (Δω) as a feedback signal to damp all of the IEEE Second Benchmark Model, system-1 torsional oscillations is presented. In order to stabilize all the torsional modes, modal control theory is used to determine the parameters of the dynamic output feedback controller. Various degrees of series compensation, different loading conditions, and torsional mode shapes for a torsional oscillations study are also investigated. In addition, time-domain simulation using a nonlinear system model are examined to demonstrate the effectiveness of the proposed countermeasure under torque disturbance conditions View full abstract»

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  • Implementation and test results of a generalized self-tuning excitation controller

    Publication Year: 1991 , Page(s): 186 - 192
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (444 KB)  

    A self-tuning excitation controller performing the functions of AVR (automatic voltage regulation) and stabilization, and an interactive man-machine interface have been implemented using two microcomputers. The general setup of the hardware and software are described. Results of experimental tests on a physical model of a power system are also presented. The results demonstrate the effectiveness of the adaptive controller View full abstract»

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  • Transient state analysis of a doubly-fed induction generator under three phase short circuit

    Publication Year: 1991 , Page(s): 62 - 68
    Cited by:  Papers (37)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (992 KB)  

    The doubly fed induction generator (DFG) is a variable-speed constant-frequency generator operating in either subsynchronous or supersynchronous mode. The transient behavior of a symmetrically loaded DFG after a three-phase short circuit is presented. Both speed and rotor excitation voltage and frequency remain unchanged during short circuit. The complete mathematical model of the transient state and experimental results are given, along with the transient state equivalent circuit View full abstract»

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  • Transient model of a doubly excited reluctance motor

    Publication Year: 1991 , Page(s): 126 - 133
    Cited by:  Papers (52)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB)  

    A transient machine model of a doubly fed reluctance motor is derived by means of winding function and d-q transformation theory. The machine consists of a double-wound stator with four and eight pole sets. The rotor is equipped with six poles. The machine, related to the Hunt motor, has the synchronous speed of a twelve-pole machine. Comparison of simulated results to test results indicates that the higher harmonics in the motor inductances are important for predicting the current waveform View full abstract»

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  • Overview of battery power regulation and storage

    Publication Year: 1991 , Page(s): 204 - 211
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (700 KB)  

    Battery energy systems are an electric utility technology whose applications are not yet fully demonstrated. The applications and benefits achieved by existing and planned facilities, and those that are possible, are discussed. The performance of existing facilities and the benefits predicted by models show that battery energy systems can be an economically attractive addition to the equipment now used to generate and transmit electric power View full abstract»

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  • Motor temperature estimation incorporating dynamic rotor impedance

    Publication Year: 1991 , Page(s): 107 - 113
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (532 KB)  

    The estimation of induction motor temperature at different system, motor, and load conditions is investigated. Motor temperature is estimated using comprehensive interactive electrical, thermal, and mechanical models. The electrical model accounts for the skin effect in the rotor bars and predicts the dynamic motor impedance as motor speed changes. The thermal model accounts for the heating and cooling process in the motor. The interactive model is used to study motor behavior during balanced system condition, unbalanced system condition, high inertia load, locked rotor, and overload situations. Motor temperature during these states is predicted. It is shown that under certain conditions motor starting time may exceed the locked rotor time. Rotor thermal limit curves during an unbalanced voltage condition are presented View full abstract»

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  • On the theory of 3-phase squirrel-cage induction motors including space harmonics and mutual slotting

    Publication Year: 1991 , Page(s): 76 - 82
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (920 KB)  

    General equations for squirrel-cage induction motors are derived based on the real geometry of the motor. The squirrel cage is described by its meshes; no equivalent windings are used. By means of complex time-dependent transformations free angles are introduced which simplify the set of equations when the specific geometrical properties of both types in which the asynchronous machines fundamentally can be divided are taken into account. The equations are general in the sense that all space harmonics are taken into account, due to the MMF and double slotting. This provides a better calculation of the synchronous, pulsating, and asynchronous torques. The final equations enable the formulation of some specific properties of both types in connection to their electromechanical behavior. Further, they are valid for star and delta connections and for any arbitrary source voltage View full abstract»

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  • Integration of steam turbine controls into power plant systems

    Publication Year: 1991 , Page(s): 177 - 185
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (760 KB)  

    The unique control and protection requirements of steam turbines are described, and the concept of a unit control system, which by itself is capable of starting, loading, and unloading, as well as protecting, a steam turbine through all operational phases, is introduced. The unit control then interfaces to the plant control at a level where the speed of response and degree of security of a plantwide network is acceptable for the turbine. Examples of unit controls for different types of turbines are given, together with methods for interfacing to plant control systems View full abstract»

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  • Magnet shaping to reduce induced voltage harmonics in PM machines with surface mounted magnets

    Publication Year: 1991 , Page(s): 155 - 161
    Cited by:  Papers (16)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    A simple methodology for reducing induced voltage harmonics in permanent magnet (PM) machines by selecting the appropriate magnet shape and dimensions is presented. The method, which uses a simplified analytical model of the magnetic circuit, is applied to three basic magnet shapes (rectangular, stepped, and trapezoidal), and can be extended to more complex geometries. The results of the analytical models are compared with results obtained from finite element analysis and with test results View full abstract»

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  • Digital simulation of an impulse turbine: the Bradley Lake Project

    Publication Year: 1991 , Page(s): 39 - 46
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    A digital simulation and stability study of the Bradley Lake (Alaska) hydroelectric project is discussed. The basic system consists of two 45-MW, multiple-jet impulse turbines supplied by a three-mile conduit. A digital governor is utilized. Once produced, the simulation is used to investigate the stability of the system. The system was found to be locally stable, but unstable to large perturbations. Due to economic constraints in plant design, the response of the system to load acceptance is poor View full abstract»

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  • Doubly fed induction machine state variables model and dynamic response

    Publication Year: 1991 , Page(s): 55 - 61
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    A state variables model in terms of d-q component displacements is deduced from linearized complex variable equations describing small-signal dynamic performance of the doubly fed induction machine. A state variables model in terms of magnitude and phase displacements of both stator and rotor voltages is deduced and studied. Transfer functions are also described. Study of the dynamics shows that the regions of instability are influenced by the variations of speed, of RMS value, and of phase angle of rotor applied voltage. This state variables model in polar coordinates eliminates the computations for the intermediate d-q components View full abstract»

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  • Maximum likelihood estimation of generator stability constants using SSER test data

    Publication Year: 1991 , Page(s): 140 - 154
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (988 KB)  

    The performance of the maximum likelihood (ML) method when used to determine simulation data for generators from standstill frequency response (SSFR) tests is evaluated. The robustness of the ML method is demonstrated by analyses made with SSFR data from tests on the Rockport 722 MVA generator. It is shown that a unique set of parameters can be obtained, and the noise effects can be dealt with effectively when the ML technique is used to estimate machine parameters View full abstract»

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  • Analysis of current source induction motor drive fed from photovoltaic energy source

    Publication Year: 1991 , Page(s): 99 - 106
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    The transient and steady-state analysis of an induction motor fed from a photovoltaic energy source through a current-source inverter is presented. It is shown that the steady-state and dynamic behaviors of the motor differ considerably from the case in which it is fed from a perfect current source. In particular, the steady-state capability of the motor is limited by the chopping ratio of the DC-DC converter and the switching frequency of the current-source inverter. Analysis of the small signal perturbation equations of the system shows that the system is lightly damped for operating voltages of the array that are less than that of the array voltage corresponding to array maximum output power. For some values of array voltage, it has a nonminimum phase characteristic due to the nonlinear relationship between the array voltage and current. This nonminimum phase characteristic adds an inherent difficulty to the design of a robust closed-loop feedback controller for the motor drive system View full abstract»

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  • Estimating the effects of harmonic voltage fluctuations on the temperature rise of squirrel-cage motors

    Publication Year: 1991 , Page(s): 162 - 169
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    A preliminary analysis of the effect of randomly varying harmonic voltages on the temperature rise of squirrel-cage motors is presented. The stochastic process of random variations of harmonic voltages is defined by means of simple statistics (mean, standard deviation, type of distribution). Computational models based on a first-order approximation of the motor losses and on the Monte Carlo method yield results which prove that equipment with large thermal time-constant is capable of withstanding, for a short period of time, total harmonic distortions larger than 5% View full abstract»

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  • Measurement of torque in steam turbine-generator shafts following severe disturbances on the electrical supply system-analysis and implementation

    Publication Year: 1991 , Page(s): 193 - 203
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1012 KB)  

    Phenomena that affects the performance of transducers that measure torque at positions along a turbine-generator shaft are reviewed, and the design of a transducer for precise measurement of torque at positions on a steam turbine-generator shaft that results from severe disturbances of the electrical supply system is discussed. Torque at shaft couplings following severe supply system events predicted using continuum models of turbine-generator shafts are analyzed and compared with that obtained over a section of the shaft by shaft twist and overall stiffness of the section. Algorithms for processing torque deduced from twist over a section to estimate true torque at specific shaft locations are discussed. Studies are performed for severe L-L-L short circuits with clearance. The design of a transient shaft torque transducer which uses disks with slits which are secured to the rotating shaft is described View full abstract»

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  • Synchronous machine steady-state stability analysis using an artificial neural network

    Publication Year: 1991 , Page(s): 12 - 20
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (660 KB)  

    In the developed artificial neural network, those system variables which play an important role in steady-state stability, such as generator outputs and power system stabilizer parameters, are used as the inputs. The output of the neural net provides the information on steady-state stability. Once the connection weights of the neural network have been learned using a set of training data derived offline, the neural net can be applied to analyze the steady-state stability of the system in real-time situations where the operating conditions change with time. To demonstrate the effectiveness of the proposed neural net, steady-state stability analysis is performed on a synchronous generator connected to a large power system. It is found that the proposed neural net requires much less training time than the multilayer feedforward network with back-propagation-momentum learning algorithm. It is also concluded from test results that correct stability assessment can be achieved by the neural network View full abstract»

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  • Loss of power supply probability of stand-alone photovoltaic systems: a closed form solution approach

    Publication Year: 1991 , Page(s): 1 - 11
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (524 KB)  

    A closed-form solution approach to the evaluation of the loss of power supply probability of stand-alone photovoltaic system with energy storage is presented. Nontracking and single-axis tracking systems are considered. In both cases, the tilt is assumed to be fixed. A numerical example is included to illustrate the usefulness of the expressions developed. Relationships between the amount of energy storage and the loss of power supply probability under various operating conditions can be investigated using the results. These relationships can be used in the design of stand-alone photovoltaic systems View full abstract»

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  • The analysis of 3-phase squirrel-cage induction motors including space harmonics and mutual slotting in transient and steady state

    Publication Year: 1991 , Page(s): 69 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1012 KB)  

    From general equations which describe the transient electromechanical behavior of the asynchronous squirrel-cage motor (and which include the influence of space harmonics and mutual slotting), simplified models are derived and compared. The models are used in examples where special attention is paid to the influence of the place of the harmonics in the mutual inductance matrix and the influence of mutual slotting. Further, the steady-state equations are derived and the back-transformation for the stator and rotor currents is given. An example is compared with the results of measurements View full abstract»

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  • Technology and application options for future battery power regulation

    Publication Year: 1991 , Page(s): 216 - 223
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (860 KB)  

    Future battery storage applications and technologies are discussed. Trends in the utility industry and the future role of battery storage are addressed, with an emphasis on power regulation options. Discussions on battery storage for specific power regulation applications are presented, as well as the status of advanced battery development in Europe, Japan, and the United States View full abstract»

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Aims & Scope

The IEEE Transactions on Energy Conversion includes in its venue the research, development, design, application, construction, installation, operation, analysis and control of electric power generating and energy storage equipment (along with conventional, cogeneration, nuclear, distributed or renewable sources, central station and grid connection). The scope also includes electromechanical energy conversion, electric machinery, devices, systems and facilities for the safe, reliable, and economic generation and utilization of electrical energy for general industrial, commercial, public, and domestic consumption of electrical energy.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Juri Jatskevich
University of British Columbia