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05053 A new accelerated aging procedure for cable life tests
06
Hard-limit induced chaos In a fundamental power 96/050&l system model Ji, W. and Venkatasubramanian, V. Electrical Power & Ettergy Sysrems, Jun. 1996, 18, (5), 279-295. The paper investtgates complex nonlinear phenomena in a fundamental power system model represented in a single-machine infinite-bus formulation. The generator electromagnetics, electromechanics and its excitation control are modelled together by fourth-order differential equations. It is shown that when excitation control gains are set high (as in common industry practice) and when the excitation hard-limits are taken into account, this representative power system model undergoes global bifurcations including period-doubling cascades which lead to sustained chaotic behaviour. Specifically sustained complex oscillations results from the interaction of hard-limits and the system transients over a large range of realistic parameter values. The emergence of strange attractors is demonstrated in the paper by detailed numerical simulations and preliminary analysis. History of MHD power plant development 96105045 Malghan, V. R. Energy Convers. Mgmr., May 1996, 37, (5) 569-590. The development of commercial MHD (magnetohydrodynamic) power plants has come a long way, from the first MHD experiment by Michael Faraday at the River Thames in 1832 to the present day efforts towards early commercialization. Over these years, development of MHD technology has seen many ups and downs. Though technically substantial progress has been achieved, today financial constraints are impeding speedy commercialization. Nevertheless, it is hoped that the MHD development community will overcome the present setback and establish commercial MHD power plants in the near future. Hybrid transient stability analysis using structure 96105046 preserving model Liu, S. et al., Electrical Power & Etlergy Systems, Aug. 1996, 18, (6) 347-352. The hybrid transient stability analysis given by Maria et al. is studied. The model differs from the usual classical model: the E’ machine mode, the arbitrarily voltage dependent loads and the network ?opology are considered. The criteria for detecting the potential energy boundary surface based on the structure preserving model are first proved. The method is applied to six-unit and 16-unit example systems. This is found to give a more reliable assessment of stability than the classical hybrid method for real utility. Induction motor drive behavior during unbalanced 96105047 faults Akpinar, K. ef al., Elecrric Power Systems Res., Feb. 1996, 36, (2) 131-138. The ability of an induction motor drive to ‘ride through’ short-term power system faults or voltage dips of several cycles is of interest in processing plants where shutdowns are expensive. In this paper, the rectitieriinverter induction motor drive is modeled to include the effects of an unbalanced supply circuit, such as that caused by a fault in the supply. A three-phase diode bridge rectifier is used to simulate the effects of the overlap angle caused by the unbalanced source reactance and associated harmonics. The filter circuit between the rectifier and inverter is included. A detailed switching function model is chosen for the inverter so that generated harmonics are included in the motor voltage. Experimental results are included. The integral motor - A new variable-speed motor 96/05048 drive Henze, M. ABE Review, 1996, (4), 4-8. Reports that ABB Motors has developed a new, energy-saving variablespeed motor drive for the 0.75 to 7.5 kW power range. A combination of standard induction motor and integrated frequency inverter, the so-called integral motor is especially well suited for industrial applications such as driving pumps or fans. The new motor is as easy to install and commission as a standard induction motor. Lighting directory 96/05049 Elect. Times, Mar. 1996. The insert contains a lighting directory giving a listing of products supplied by manufacturers. Load flow solution of distribution systems with 96/05050 voltage dependent load models Haque, M. H. Electric Power Sysfems Rex, Mar. 1996, 36, (3) 151-156. The classical constant-power load model is usually used to solve the load flow problem of a transmission or distribution system. However, the actual load of a system is not independent of voltage magnitude. Incorporation of voltage dependent load models in the load flow algorithm is essential to get better and accurate results. The paper compares the load flow results of a distribution system for various voltage dependent load models. The load flow problem of a distribution system is also formulated in terms of three sets of recursive equations to that very sophisticated voltage dependent load models can easily be incorporated in these equations. A 12.66 kV, 33bus distribution system was used to observe the effects of load models on the load flow results.
Electric
power
gene&ion
Methodology 96lO5051 In large power systems
and utilisation
for alleviation
(scientific,
of voltage
fechnical)
excursions
Singh, G. D. er al., Electrical Power & Energy Systems, Mar. 1996, 18, (3), 167-173. The paper presents a method for minimizing the sum of the square of voltage deviations by a least-square minimization technique, and thus improving the voltage profile in a given system by adjusting control variables, such as tap position of transformers, reactive power injection of VAR sources and generator excitations.
96105052 approach
Multistage
capacitor
Swain, N. K. and Bengiamin, 1996, 36, (2), 93-100.
N. N.
switching:
An
analytical
Electric Power Systems Res., Feb.
Presents a novel mathematical formulation for the multistage capacitor scheduling problem in a radial distribution feeder using a predetermined reactive load duration curve. The objective is to determine the optimal switching times of the predetermined capacitor stages to minimize the energy losses under varying load conditions. The presented methodologies are superior to previous works in generalizing the solution to avoid constraints on the number of capacitors and their switching stages, Three different models for the reactive load duration curve are considered. A closedform solution for the switching time and energy loss reduction is derived from each case. The presented methodologies are simple and efficient. They provide several capacitor control alternatives of value in distribution automation control.
96105053 tests
A new accelerated
Andjelkovic, D. and Rajakovic, 1996, 36, (l), 13-19.
aging
Teo, C. Y.
for cable
life
Electric Power Systems Rex, Jan.
N.
A new accelerated ageing procedure in this paper. The objective has been cable samples subect to the constraint should be preserved by the samples. approach based on available physical tory accelerated ageing tests.
96105054 of electrical
procedure
for cable life tests has been proposed to minimize the total test costs using that all relevant cable characteristics The procedure utilizes a combined and mathematical models and labora-
A new integrated tool for exercises Installations using a microcomputer
on the design
Electric Power Sptems Res., Feb. 1996, 36, (2). 81-91.
An innovative approach using computer-aided design tools to support the teaching of electrical installations through hands-on design exercises is described. It is implemented by an integrated package with all the built-in facilities which guide engineers/students step by step to complete the design of two sizeable electrical installations. The dedicated file structure enables students to get direct access to the building information, details of each type of load and the technical parameters of all the electrical parts required for the design exercise.
96105055 Nonlinear for transient stability adaptive control law
excitation and hase shifter controller enhancement o P power systems using
Tan, Y. L. and Wang, Y. 18, (6), 397-403.
Electrical Pou,er & Energy System., Aug. 1996,
The highly nonlinear nature of the generator and system behaviour following a severe disturbance precludes the use of classical linear control techniques, In this paper, a nonlinear adaptive excitation and static phase shifter controller is proposed to enhance the transient stability of a power system. The phase shifter is located near the generator terminal in a power system. A third-order generator model is used which is in the standard form of a nonlinear system representation. The phase shifter is represented bv a first-order model. Nonlinear feedback control laws are found which linearize and decouple the power system. An adaptive control law is used to design the controller for the excitation and phase shifter. The design of the resulting controller is independent of the operating point.
Nonlinear excitation control of a synchronous 96105056 erator with implicit terminal voltage regulation Lahdhiri, T. and Alouani, A. T. 36, (2) 101-112.
gen-
Electric Power Systems Res., Feb. 1996,
The objective of the paper is to design nonlinear excitation controllers for single-machine infinite-bus power systems. Because of the nonlinear nature of such systems, nonlinear controllers are more effective in providing larger stability margins than their linear counterparts. To take advantage of well-developed linear control techniques, the concept of feedback linearization is used. A characterization of the region over which the linearizing state transformation is guaranteed to be diffeomorphic is provided. Also, a formulation of the linear controller design is provided to solve the problem of the terminal voltage regulation.
Fuel and Energy
Abstracts
September
1996
355
Hard-limit induced chaos In a fundamental power 96/050&l system model Ji, W. and Venkatasubramanian, V. Electrical Power & Ettergy Sysrems, Jun. 1996, 18, (5), 279-295. The paper investtgates complex nonlinear phenomena in a fundamental power system model represented in a single-machine infinite-bus formulation. The generator electromagnetics, electromechanics and its excitation control are modelled together by fourth-order differential equations. It is shown that when excitation control gains are set high (as in common industry practice) and when the excitation hard-limits are taken into account, this representative power system model undergoes global bifurcations including period-doubling cascades which lead to sustained chaotic behaviour. Specifically sustained complex oscillations results from the interaction of hard-limits and the system transients over a large range of realistic parameter values. The emergence of strange attractors is demonstrated in the paper by detailed numerical simulations and preliminary analysis. History of MHD power plant development 96105045 Malghan, V. R. Energy Convers. Mgmr., May 1996, 37, (5) 569-590. The development of commercial MHD (magnetohydrodynamic) power plants has come a long way, from the first MHD experiment by Michael Faraday at the River Thames in 1832 to the present day efforts towards early commercialization. Over these years, development of MHD technology has seen many ups and downs. Though technically substantial progress has been achieved, today financial constraints are impeding speedy commercialization. Nevertheless, it is hoped that the MHD development community will overcome the present setback and establish commercial MHD power plants in the near future. Hybrid transient stability analysis using structure 96105046 preserving model Liu, S. et al., Electrical Power & Etlergy Systems, Aug. 1996, 18, (6) 347-352. The hybrid transient stability analysis given by Maria et al. is studied. The model differs from the usual classical model: the E’ machine mode, the arbitrarily voltage dependent loads and the network ?opology are considered. The criteria for detecting the potential energy boundary surface based on the structure preserving model are first proved. The method is applied to six-unit and 16-unit example systems. This is found to give a more reliable assessment of stability than the classical hybrid method for real utility. Induction motor drive behavior during unbalanced 96105047 faults Akpinar, K. ef al., Elecrric Power Systems Res., Feb. 1996, 36, (2) 131-138. The ability of an induction motor drive to ‘ride through’ short-term power system faults or voltage dips of several cycles is of interest in processing plants where shutdowns are expensive. In this paper, the rectitieriinverter induction motor drive is modeled to include the effects of an unbalanced supply circuit, such as that caused by a fault in the supply. A three-phase diode bridge rectifier is used to simulate the effects of the overlap angle caused by the unbalanced source reactance and associated harmonics. The filter circuit between the rectifier and inverter is included. A detailed switching function model is chosen for the inverter so that generated harmonics are included in the motor voltage. Experimental results are included. The integral motor - A new variable-speed motor 96/05048 drive Henze, M. ABE Review, 1996, (4), 4-8. Reports that ABB Motors has developed a new, energy-saving variablespeed motor drive for the 0.75 to 7.5 kW power range. A combination of standard induction motor and integrated frequency inverter, the so-called integral motor is especially well suited for industrial applications such as driving pumps or fans. The new motor is as easy to install and commission as a standard induction motor. Lighting directory 96/05049 Elect. Times, Mar. 1996. The insert contains a lighting directory giving a listing of products supplied by manufacturers. Load flow solution of distribution systems with 96/05050 voltage dependent load models Haque, M. H. Electric Power Sysfems Rex, Mar. 1996, 36, (3) 151-156. The classical constant-power load model is usually used to solve the load flow problem of a transmission or distribution system. However, the actual load of a system is not independent of voltage magnitude. Incorporation of voltage dependent load models in the load flow algorithm is essential to get better and accurate results. The paper compares the load flow results of a distribution system for various voltage dependent load models. The load flow problem of a distribution system is also formulated in terms of three sets of recursive equations to that very sophisticated voltage dependent load models can easily be incorporated in these equations. A 12.66 kV, 33bus distribution system was used to observe the effects of load models on the load flow results.
Electric
power
gene&ion
Methodology 96lO5051 In large power systems
and utilisation
for alleviation
(scientific,
of voltage
fechnical)
excursions
Singh, G. D. er al., Electrical Power & Energy Systems, Mar. 1996, 18, (3), 167-173. The paper presents a method for minimizing the sum of the square of voltage deviations by a least-square minimization technique, and thus improving the voltage profile in a given system by adjusting control variables, such as tap position of transformers, reactive power injection of VAR sources and generator excitations.
96105052 approach
Multistage
capacitor
Swain, N. K. and Bengiamin, 1996, 36, (2), 93-100.
N. N.
switching:
An
analytical
Electric Power Systems Res., Feb.
Presents a novel mathematical formulation for the multistage capacitor scheduling problem in a radial distribution feeder using a predetermined reactive load duration curve. The objective is to determine the optimal switching times of the predetermined capacitor stages to minimize the energy losses under varying load conditions. The presented methodologies are superior to previous works in generalizing the solution to avoid constraints on the number of capacitors and their switching stages, Three different models for the reactive load duration curve are considered. A closedform solution for the switching time and energy loss reduction is derived from each case. The presented methodologies are simple and efficient. They provide several capacitor control alternatives of value in distribution automation control.
96105053 tests
A new accelerated
Andjelkovic, D. and Rajakovic, 1996, 36, (l), 13-19.
aging
Teo, C. Y.
for cable
life
Electric Power Systems Rex, Jan.
N.
A new accelerated ageing procedure in this paper. The objective has been cable samples subect to the constraint should be preserved by the samples. approach based on available physical tory accelerated ageing tests.
96105054 of electrical
procedure
for cable life tests has been proposed to minimize the total test costs using that all relevant cable characteristics The procedure utilizes a combined and mathematical models and labora-
A new integrated tool for exercises Installations using a microcomputer
on the design
Electric Power Sptems Res., Feb. 1996, 36, (2). 81-91.
An innovative approach using computer-aided design tools to support the teaching of electrical installations through hands-on design exercises is described. It is implemented by an integrated package with all the built-in facilities which guide engineers/students step by step to complete the design of two sizeable electrical installations. The dedicated file structure enables students to get direct access to the building information, details of each type of load and the technical parameters of all the electrical parts required for the design exercise.
96105055 Nonlinear for transient stability adaptive control law
excitation and hase shifter controller enhancement o P power systems using
Tan, Y. L. and Wang, Y. 18, (6), 397-403.
Electrical Pou,er & Energy System., Aug. 1996,
The highly nonlinear nature of the generator and system behaviour following a severe disturbance precludes the use of classical linear control techniques, In this paper, a nonlinear adaptive excitation and static phase shifter controller is proposed to enhance the transient stability of a power system. The phase shifter is located near the generator terminal in a power system. A third-order generator model is used which is in the standard form of a nonlinear system representation. The phase shifter is represented bv a first-order model. Nonlinear feedback control laws are found which linearize and decouple the power system. An adaptive control law is used to design the controller for the excitation and phase shifter. The design of the resulting controller is independent of the operating point.
Nonlinear excitation control of a synchronous 96105056 erator with implicit terminal voltage regulation Lahdhiri, T. and Alouani, A. T. 36, (2) 101-112.
gen-
Electric Power Systems Res., Feb. 1996,
The objective of the paper is to design nonlinear excitation controllers for single-machine infinite-bus power systems. Because of the nonlinear nature of such systems, nonlinear controllers are more effective in providing larger stability margins than their linear counterparts. To take advantage of well-developed linear control techniques, the concept of feedback linearization is used. A characterization of the region over which the linearizing state transformation is guaranteed to be diffeomorphic is provided. Also, a formulation of the linear controller design is provided to solve the problem of the terminal voltage regulation.
Fuel and Energy
Abstracts
September
1996
355