- Email: [email protected]
00459 Improved estimation of induction machine parameters
06 Eddy currents In superconductlng
Rutherford
Mallick, G. T. ef al., Cryogenics, Nov. 1995, 35, (lo), 653-658. Eddy currents induced in magnet cables have long been recognized as contributing to the quench rformance of superconducting accelerator magnets, and are thought to gee a major contributor to degraded performante in the superconducting super collider dipole magnets. There are several major paths which these currents might follow., however, and each path has an effect. The authors have experimentally isolated these several contributions and estimated their relative importance.
96lOW47
EMC compliance - PLCs OK?
Cheung, W. Elect. Review, Aug. 1995, 228, (16). 32-34. The author considers the requirements for electromagnetic compatibility compliance for electrical and electronic equipment in general and for programmable logic controllers. Although the EC Directive does not apply to these components, and they do not have to be CE-marked, they form part of apparatus that does have to comply with the EC Directive.
Enerav conservation with efflclent electric drlves 96lQO446 Tripathy, S. C. En&y Convers. Mgmt., Feb. 1995, 36, (2) 125-134. The paper details with the basic principle of energy efficient electric drive systems. The economic aspects, including calculation of life-cycle cost versus energy efficiency, have been highlighted. The paper also discusses the general applications of thyristor converter, inverter and chopper to the drive systems. It is expected that the paper will help engineers in industries to conserve energy in electric drives. 96lQO449 Exoert svstem based Interactive Dower svstem . planning facllitiis s
Hodgson, J. E. et al., Power Engng. J., Oct. 1995, 9, (5) 215-222. Discusses how increased demand on existing interconnected power systerns, together with the tightening of both operational and economic constraints, has led to the ootimisation of maintenance and expansion nlanninp. becoming more critical-The exoert svstem oresented in the uaoer attern& to aid the knowledge intensive iask df analysing and solving Gansient and steady-state problems associated with hypothetical network configurations.
A fast approach to transient stability estimation using an Improved potential energy boundary surfice method
96l00450
Chune. T. S. and Da-zhone,I F. Electric Power Svsrems Res.. Jul. 1995. 34, (0; 47-5s. In this paper, a new fast algorithm to perform online transient stability assessment (TSA) in a power system is proposed. The TSA is concerned with finding the critical clearing time, the stability limit, for a specified fault. The method possesses the merits of the fast speed of the potential energy boundary surface method and the accuracy of the conventional time domain simulation technique.
96lOO451 Flux jump In solid multistrand superconducting cable for fusion magnet
Kaneko, H. et al., Cryogenics, Nov. 1995, 35, (lo), 611-622. The stability criterion for flux jumps in a solid multistrand cable for a fusion magnet is investigated. Current distribution is discussed for a strand under a varying external magnetic field independent of its own current. Control of the distribution is now always possible, especially in fusion magnets. The criterion is evaluated for a single strand and also for a whole composite cable, with the condition that heat generation during current redistribution warms the conductor just up to the current sharing temperature.
96lQO452 Fuel cells for power generation Frv. M. R. and Dams. R. A. Proc. Inr. Cod Power Generation & rhe
E&ironmenr, Jun. 1994, IMech.E. 9 pp. . A review of fuel cell technology, including potential applications and status in terms of installed hardware worldwide. The authors point out that the only ‘commercially developed’ units are those found in spacecraft and submersibles, which are too expensive for civilian applications.
Electric power generation and utilisation (scientific, technical)
96100455 A enetlc algorlthm based approach to thermal unlt commitment 0 8 electric power systems Ma, X. ef al., Electric Power Systems Res., Jul. 1995, 34, (l), 29-36. The paper presents a new approach based on genetic algorithms to solve the thermal unit commitment problem of electric power systems.
Heard a flash. Saw a boom. Power quality monltorIng detlned In P1159
96lOO458
Ray, L. A. and Kina. J. A. ASHRAE Trans., Paver No.CH.95-4-I. 1995. 1Oi; (l), 659-663. -’ The paper refers to a new Institute of Electrical and Electronics Engineers Recommended Practice ‘Monitoring Electric Power Quality’ (Project No.PllS9). Reports that the document is designed to define electromag netic phenomena that can cause power quality problems and recommend methods by which to measure and record these phenomena. Summarises the definitions presented in PllS9 and describes how the document can contribute to improved operations.
The If, why and what of street llghtlng and street crime - A review
96/00457 F;
clei3P. R. and r. A revised version Conference, 1994. ship betwen street
96/00456
Gutkowski,
J. M.
Lrg. Res. Tech., 1995, 27, (2)
of a paper presented at the CIBSE National Lighting Presents a case for closer examination of the relationlighting and street crime.
The Impact of EPAct on llghtlng speclflcatlon
Yarnell, K. Consul. Specif Engr., Apr. 1995, 17, (4) 30-34. Discusses the US Energy Policy Act of 1992 (EPAct) and the way it has affected how lighting engineers write specifications.
96/00459
Improved
estlmatlon
of
Induction
machlns
parameters Akbaba, M. et al., Elecrric Power Systems Res., Jul. 1995, 34, (I), 65-73. Induction machine parameters are often estimated from no-load and blocked-rotor tests. At different machine oueratinn noints. the narameter values may vary because of the nonlinearities caused mainly b; the skin effect and saturation. Some investigators have already published techniques to estimate the parameters more accurately. Their- techniques are either complicated or involve many simplified assumptions and are valid only at specific points. The paper proposes a less complicated yet accurate technique by making use of on-load machine performance measurements as input data. The proposed technique is formulated in an interative algorithm while making few assumptions. The results obtained clearly show the influence of the skin effect and saturation on the rotor resistance, magnetizing and leakage reactances.
Improvement of enthalpy sxtractlon over 30% uslng a disk MHD generator with Inlet swirl
96/00460
Harada, N. et al., Energy Convers. Mgmt., May 1995, 36, (S), 355-364. Performance of a disk-type CCMHD generator has been investigated. In the present power generation experiments, special attention has been devoted to the effect of inlet swirl on generator performance. In order to clarify this effect, one-dimensional numerical simulation has also been performed. The results showed that the enthalpy extraction ratio was successfully improved up to 32.5% by employing inlet swirl with the swirl ratio.
Influence of an applied magnetic field on shielding current paths In a high T, superconductor
96100461
96lOO453 Furnlshlng with the electric light Harris, J. B. Power Engng. J., Oct. 1995, 9, (S), 231-232. Discusses street lighting in the United Kingdom.
Takeda, N. et al., Cryogenics, Dec. 1995, 35, (12), 893-899. The influence of an annlied maenetic field on shieldine current oaths in a bulk high T, superco&ctor was investigated. This is& is very ‘important for the quantitative analysis of levitation force, since the distortion and localization of the current paths have been found to be a major source of discrepancy between computed and experimentals results.
Further developments of the equal-area criterion for multlmachlne Dower svstems
96100462
Haque, M. H. El&;ric Pow;; Systems Rex, Jun. 1995, 33: (3), 175-183. An efficient method for determining the transient stabtltty of a multimachine power system is presented.For a given disturbance, the method identifies the critical machine by observing the variation in accelerating power of the severely disturbed machines. The critical machine is considered to be the one which has a tendency to initiate the instability. The transient stability of the system is determined by checking the stability limit of only the critical machine through a modified equal-area criterion. The stability limit or critical situation is diagnosed from the simultaneous occurrence of zero accelerating power and speed of the critical machine in the postfault period.
Tang, Y. J. et al., Cryogenics, Dec. 1995, 35, (12), 861-866. The a.c. quench current level of a superconducting cable when formed into a coil is, in general, lower than that of a short sample. The current in the coil induces a self-magnetic field on the superconducting winding. It was found from the authors experiments that the transition from the superconducting state to the normal one in a superconducting coil originates in that part of the winding where the self-magnetic flux density is estimated to be the largest. It is concluded that degradation of the a.c. quench current level in the superconducting coil is mainly brought about by the influence of the self-magnetic field.
96lQO454
Influence of self-magnetic field on a.c. quench current level of superconductlng coils
Fuel and Energy Abstracts January 1996
27
Rutherford
Mallick, G. T. ef al., Cryogenics, Nov. 1995, 35, (lo), 653-658. Eddy currents induced in magnet cables have long been recognized as contributing to the quench rformance of superconducting accelerator magnets, and are thought to gee a major contributor to degraded performante in the superconducting super collider dipole magnets. There are several major paths which these currents might follow., however, and each path has an effect. The authors have experimentally isolated these several contributions and estimated their relative importance.
96lOW47
EMC compliance - PLCs OK?
Cheung, W. Elect. Review, Aug. 1995, 228, (16). 32-34. The author considers the requirements for electromagnetic compatibility compliance for electrical and electronic equipment in general and for programmable logic controllers. Although the EC Directive does not apply to these components, and they do not have to be CE-marked, they form part of apparatus that does have to comply with the EC Directive.
Enerav conservation with efflclent electric drlves 96lQO446 Tripathy, S. C. En&y Convers. Mgmt., Feb. 1995, 36, (2) 125-134. The paper details with the basic principle of energy efficient electric drive systems. The economic aspects, including calculation of life-cycle cost versus energy efficiency, have been highlighted. The paper also discusses the general applications of thyristor converter, inverter and chopper to the drive systems. It is expected that the paper will help engineers in industries to conserve energy in electric drives. 96lQO449 Exoert svstem based Interactive Dower svstem . planning facllitiis s
Hodgson, J. E. et al., Power Engng. J., Oct. 1995, 9, (5) 215-222. Discusses how increased demand on existing interconnected power systerns, together with the tightening of both operational and economic constraints, has led to the ootimisation of maintenance and expansion nlanninp. becoming more critical-The exoert svstem oresented in the uaoer attern& to aid the knowledge intensive iask df analysing and solving Gansient and steady-state problems associated with hypothetical network configurations.
A fast approach to transient stability estimation using an Improved potential energy boundary surfice method
96l00450
Chune. T. S. and Da-zhone,I F. Electric Power Svsrems Res.. Jul. 1995. 34, (0; 47-5s. In this paper, a new fast algorithm to perform online transient stability assessment (TSA) in a power system is proposed. The TSA is concerned with finding the critical clearing time, the stability limit, for a specified fault. The method possesses the merits of the fast speed of the potential energy boundary surface method and the accuracy of the conventional time domain simulation technique.
96lOO451 Flux jump In solid multistrand superconducting cable for fusion magnet
Kaneko, H. et al., Cryogenics, Nov. 1995, 35, (lo), 611-622. The stability criterion for flux jumps in a solid multistrand cable for a fusion magnet is investigated. Current distribution is discussed for a strand under a varying external magnetic field independent of its own current. Control of the distribution is now always possible, especially in fusion magnets. The criterion is evaluated for a single strand and also for a whole composite cable, with the condition that heat generation during current redistribution warms the conductor just up to the current sharing temperature.
96lQO452 Fuel cells for power generation Frv. M. R. and Dams. R. A. Proc. Inr. Cod Power Generation & rhe
E&ironmenr, Jun. 1994, IMech.E. 9 pp. . A review of fuel cell technology, including potential applications and status in terms of installed hardware worldwide. The authors point out that the only ‘commercially developed’ units are those found in spacecraft and submersibles, which are too expensive for civilian applications.
Electric power generation and utilisation (scientific, technical)
96100455 A enetlc algorlthm based approach to thermal unlt commitment 0 8 electric power systems Ma, X. ef al., Electric Power Systems Res., Jul. 1995, 34, (l), 29-36. The paper presents a new approach based on genetic algorithms to solve the thermal unit commitment problem of electric power systems.
Heard a flash. Saw a boom. Power quality monltorIng detlned In P1159
96lOO458
Ray, L. A. and Kina. J. A. ASHRAE Trans., Paver No.CH.95-4-I. 1995. 1Oi; (l), 659-663. -’ The paper refers to a new Institute of Electrical and Electronics Engineers Recommended Practice ‘Monitoring Electric Power Quality’ (Project No.PllS9). Reports that the document is designed to define electromag netic phenomena that can cause power quality problems and recommend methods by which to measure and record these phenomena. Summarises the definitions presented in PllS9 and describes how the document can contribute to improved operations.
The If, why and what of street llghtlng and street crime - A review
96/00457 F;
clei3P. R. and r. A revised version Conference, 1994. ship betwen street
96/00456
Gutkowski,
J. M.
Lrg. Res. Tech., 1995, 27, (2)
of a paper presented at the CIBSE National Lighting Presents a case for closer examination of the relationlighting and street crime.
The Impact of EPAct on llghtlng speclflcatlon
Yarnell, K. Consul. Specif Engr., Apr. 1995, 17, (4) 30-34. Discusses the US Energy Policy Act of 1992 (EPAct) and the way it has affected how lighting engineers write specifications.
96/00459
Improved
estlmatlon
of
Induction
machlns
parameters Akbaba, M. et al., Elecrric Power Systems Res., Jul. 1995, 34, (I), 65-73. Induction machine parameters are often estimated from no-load and blocked-rotor tests. At different machine oueratinn noints. the narameter values may vary because of the nonlinearities caused mainly b; the skin effect and saturation. Some investigators have already published techniques to estimate the parameters more accurately. Their- techniques are either complicated or involve many simplified assumptions and are valid only at specific points. The paper proposes a less complicated yet accurate technique by making use of on-load machine performance measurements as input data. The proposed technique is formulated in an interative algorithm while making few assumptions. The results obtained clearly show the influence of the skin effect and saturation on the rotor resistance, magnetizing and leakage reactances.
Improvement of enthalpy sxtractlon over 30% uslng a disk MHD generator with Inlet swirl
96/00460
Harada, N. et al., Energy Convers. Mgmt., May 1995, 36, (S), 355-364. Performance of a disk-type CCMHD generator has been investigated. In the present power generation experiments, special attention has been devoted to the effect of inlet swirl on generator performance. In order to clarify this effect, one-dimensional numerical simulation has also been performed. The results showed that the enthalpy extraction ratio was successfully improved up to 32.5% by employing inlet swirl with the swirl ratio.
Influence of an applied magnetic field on shielding current paths In a high T, superconductor
96100461
96lOO453 Furnlshlng with the electric light Harris, J. B. Power Engng. J., Oct. 1995, 9, (S), 231-232. Discusses street lighting in the United Kingdom.
Takeda, N. et al., Cryogenics, Dec. 1995, 35, (12), 893-899. The influence of an annlied maenetic field on shieldine current oaths in a bulk high T, superco&ctor was investigated. This is& is very ‘important for the quantitative analysis of levitation force, since the distortion and localization of the current paths have been found to be a major source of discrepancy between computed and experimentals results.
Further developments of the equal-area criterion for multlmachlne Dower svstems
96100462
Haque, M. H. El&;ric Pow;; Systems Rex, Jun. 1995, 33: (3), 175-183. An efficient method for determining the transient stabtltty of a multimachine power system is presented.For a given disturbance, the method identifies the critical machine by observing the variation in accelerating power of the severely disturbed machines. The critical machine is considered to be the one which has a tendency to initiate the instability. The transient stability of the system is determined by checking the stability limit of only the critical machine through a modified equal-area criterion. The stability limit or critical situation is diagnosed from the simultaneous occurrence of zero accelerating power and speed of the critical machine in the postfault period.
Tang, Y. J. et al., Cryogenics, Dec. 1995, 35, (12), 861-866. The a.c. quench current level of a superconducting cable when formed into a coil is, in general, lower than that of a short sample. The current in the coil induces a self-magnetic field on the superconducting winding. It was found from the authors experiments that the transition from the superconducting state to the normal one in a superconducting coil originates in that part of the winding where the self-magnetic flux density is estimated to be the largest. It is concluded that degradation of the a.c. quench current level in the superconducting coil is mainly brought about by the influence of the self-magnetic field.
96lQO454
Influence of self-magnetic field on a.c. quench current level of superconductlng coils
Fuel and Energy Abstracts January 1996
27