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06095 Hydroxyl as a defect of the manganese dioxide lattice and its applications to the dry cell battery
06 Design of load shedding scheme for a cogeneratlon facility: A case study Tzeng, Y. M. et al., Electrical Power & Energy Systems, Oct. 1996, 18, (7), 431-436. 96106064
The paper develops the coordination of a load shedding scheme for a large integrated steelmaking cogeneration facility. A detailed description of each design procedure is given. The loads are tripped by the underfrequency relays to revent the power system from collapsing when the plant beomes isolated 8 ue to utility service outage. Suitable models of generators, exciters, governors and loads are included in the transient stability program to derive the proper formulation of the load shedding scheme.
WO6066
Diffusion-llmlted self-discharge reaction in the Hubble space telescope battery
Fe!:;;
J. P. and Sandhu,
S. S.
J. @Power Sources, Jan. 1996, 58, (l),
The self-discharge rate of aeros ace flight-quality nickel-hydrogen batteries is limited by hydrogen dt? fusion within the nickel electrode active material. A diffusion-limited reaction model is developed which accounts for the observed self-discharge behaviour. Effective hydrogen diffusion coefficients were calculated from the o en-circuit self-discharge data on Hubble s ace technology flight-juahfte’’inickel-h$dro%en cells and ranged from 1.1 $ X lo”’ cm*/sec at 25 C to 7.45 X lo‘ cm /set at 0°C.
96106066
Digital computer computation and analysis of gas insulated substation overvoltages
Hamza, A. S. and Abdel-Gawad, N. M. Energy Convers. Mgmf., Nov. 1996. 37. (11). 1.589-1599. A gas- insulated substation can be subjected to a high amplitude of overvoltages as a result of lightning strokes striking the substation. This can cause-a back flashover faTlure, which will damage the equipment and devices in the substation if these overvoltages are allowed to exceed those that the devices can withstand. In this study, an investigation of the overvoltages in a gas insulated substation as a result of a back flashover, with the variation of some different parameters, is conducted using a digital computer so that the substation performance can be determined under these conditions. This is very useful for determining the protection level and method of the gas insulated substation.
96lO6007
Dynamic analysis of small signal voltage instability decoupled from angle instability
Padiyar, K. R. and Rao, S. S. Electrical Power & Energy Systems, Oct. 1996, 18, (7), 445-452. The paper presents a methodology for dynamic analysis of short term small sierra1 voltane instabilitv in a multi-machine Dower svstem. The formulat&t of the Eroblem is hone by decou ling the angle’instability from the voltage instability. The method is base x on the incremental reactive current flow network, where the incremental reactive current injection of each bus is related to the incremental voltage magnitude at all the buses. Small signal stability using the eigenvalue analysis is illustrated utilizing a singlemachine load bus and a three-machine system examples. The role of a static var compensator at the load bus is also examined.
96/06086
Effect of cobalt addition to nickel hydroxide as a posltlve materlal for rechargeable alkaline batteries
Watanabe, K. er al., J. of PowerSources, Jan. 1996, 58, (l), 23-28. Nickel hydroxide powder is used widely as an active material in pastedtype nickel electrodes. The effect on the electrochemical behaviour of cobalt addition to the nickel hydroxide powder is investigated.
Electric power generation and utilisation(scientific, t8chnical)
96109091 legialatlon
Effects of prioritizlng demand on optimal load shedding policy
Mostafa, M. A. er al., Electrical Power & Energy Systems, Oct. 1996, 18, f7). 415-424. Demand priorities in the power system optimal load shedding policy are major decision variables used to regulate the amount of load shedding at specific buses during contingencies: Previous work on optimal load shedding does not explicitly consider demand priorities. The paper investigates the effects of demand priorities on the performance of the power system during emergencies. A nonlinear programming approach is used to determine the optimal values of demand priorities for two test systems. Optimizing demand priorities is shown to enhance overall system performance measured by total supplied load, bus voltages and system losses during the contingency. Results are offered demonstrating additional enhancements by optimizing the demand priority at the bus with the second largest load.
96/06090
Electrochemical behavlour of addition agents Impregnated In cadmium hydroxide electrodes for alkaline batteries
Kalaianan. G. P. er al.. J. of PowerSources, Jan. 1996, 58, (l), 29-34. Discusses the development of electrode additives for the cadmium electrode of the nickel/cadmium battery which is aimed mainly at increasing the discharge capacity and minimizing self-discharge.
of electromagnetic
compatibility
Ridley, P. Environ. Engng., Jun. 1996, 9, (2), 32-36. The Electromagnetic Compatibility (EMC Directive) became fully implemented on 1st January 1996 by the UK’s EMC Regulations, S.I., 1992, 2372. Discusses the uncertainty among suppliers and users in the UK process and energy industry regarding the attitude of the Weights and Measures Authorities and the Health and Safety Executive in relation to the legislation.
Enhancement of power system stability by using 96106092 controlled series compensation Chen. X. R. et al... Electrical Power & Enerw (7). “,, Svsfems. Oct. 1996. lg. ,\,,
475-481. ’ The paper studies the application
of controlled series compensator to damp power swings m multimachine power systems.
(CSC)
Evaluation of methods for discrimination of energlzed underground power cables
96106093
Short, S. X. ef al., Electric Power Systems Research, Apr. 1996, 37, (l), 29-38. The maintenance and repair of underground cable power networks often requires the discrimination of energized cables among a group of unenergized ones. Presently, an invasive detection method is performed which requires utility personnel to puncture the protective cable shielding, creating a ootentiallv hazardous situation. The oaoer presents a noninvasive approach for energized cable detection based ‘on the electrically induced acoustic waves inside of the cable.
Flnlte element software for 3-D field calculations in electrical engineering
96106094
Ostovic, V. and Soyk, K. H. ABB Review, 1996, (6), 29-36. Finite element modellmg (FE) allows fast, precise analysis of the electrical, magnetic and thermal fields in electrotechnical components while the parts are still at the design stage. Costly prototypes are often not needed when FE is used, while weak points in finished products are easier to identify and potential design improvements can be checked in a more cost-effective way.
Hydro I as a defect of the manganese dioxide lat96106095 tice and its applicat r ona to the dry cell battery ?I$?, H. and Nasser, S. A. J. of Power Sources, Jan. 1996, 58, (l), Manganese dioxide polymorphs with different OH contents were prepared under various reaction conditions. X-ray diffraction measurements showed the presence of orthorhombic, tetragonal and hexagonal forms of MnO, Infrared absorption spectra in frequency range 200-4CKKl cm.’ of the different modifications were studied.
Interval predlction of annual maximum demand using grey dynamic model
96106096
Morita, H. et a/., Electrical Power & Energy Systems, Oct. 1996, 18, (7), 409-413. The paper proposes an interval prediction of the u per and lower bound values of load demand using the grey dynamic mo Bel in grey system theory. Su ply and demand in power system planning and operation are requtre ,8 to be balanced. A marginal supply capability against accidental demands or faults is also required. The confidence interval can become an index for determining the marginal supply capability. The interval prediction using the grey dynamic model is illustrated using an example. The results are compared with the actual demands and with those obtained from a linear single regression model. 96106097
96106089
Enforcement
Investigations of awltchlng operations on compos-
ite feeders Hamza, A. S. Energy Convers. Mgmr., Nov. 1996, 37, (ll), 1575-1587. Describes switchinn ooerations and the accomoanvine overvoltanes uroduced on compositcfeiders when a circuit breaker c’lo& at the peik of the applied voltage. Transformer and line-cable feeders are considered. The means of reducing such overvoltages are also included, and the effect of system parameters and factors on ihe initial voltage applied and accompanying overvoltages are covered.
Leady oxide for lead/acid battery positive plates: 96/06098 scope for improvement? Mayer,M. G. andRand, D. A. J. of Power Sources, Mar.-Apr. 1996, 59, (1); 17-24. Among the many factors that determine the influence the performance of lead/acid batteries, one of the most important, and as yet not fully developed, is how to make the positive active mass more electrochemically reactive. The inherent characteristics of this active mass are the cumulative result of the four precursor stages of its production, namely, the leady oxide, paste mixing, curing and formation procedures. There is evidence to suggest that the method of pasting itself is also influential. Many recent studies have reported progress on techniques to increase active-material utilization, to improve plate conditioning, and to solve the vexagious problem of premature capacity. The purpose-of this discussion is to focus attention on the role and the importance of leady oxide on battery design and performance.
Fuel and Energy Abstracts November 1996 431
The paper develops the coordination of a load shedding scheme for a large integrated steelmaking cogeneration facility. A detailed description of each design procedure is given. The loads are tripped by the underfrequency relays to revent the power system from collapsing when the plant beomes isolated 8 ue to utility service outage. Suitable models of generators, exciters, governors and loads are included in the transient stability program to derive the proper formulation of the load shedding scheme.
WO6066
Diffusion-llmlted self-discharge reaction in the Hubble space telescope battery
Fe!:;;
J. P. and Sandhu,
S. S.
J. @Power Sources, Jan. 1996, 58, (l),
The self-discharge rate of aeros ace flight-quality nickel-hydrogen batteries is limited by hydrogen dt? fusion within the nickel electrode active material. A diffusion-limited reaction model is developed which accounts for the observed self-discharge behaviour. Effective hydrogen diffusion coefficients were calculated from the o en-circuit self-discharge data on Hubble s ace technology flight-juahfte’’inickel-h$dro%en cells and ranged from 1.1 $ X lo”’ cm*/sec at 25 C to 7.45 X lo‘ cm /set at 0°C.
96106066
Digital computer computation and analysis of gas insulated substation overvoltages
Hamza, A. S. and Abdel-Gawad, N. M. Energy Convers. Mgmf., Nov. 1996. 37. (11). 1.589-1599. A gas- insulated substation can be subjected to a high amplitude of overvoltages as a result of lightning strokes striking the substation. This can cause-a back flashover faTlure, which will damage the equipment and devices in the substation if these overvoltages are allowed to exceed those that the devices can withstand. In this study, an investigation of the overvoltages in a gas insulated substation as a result of a back flashover, with the variation of some different parameters, is conducted using a digital computer so that the substation performance can be determined under these conditions. This is very useful for determining the protection level and method of the gas insulated substation.
96lO6007
Dynamic analysis of small signal voltage instability decoupled from angle instability
Padiyar, K. R. and Rao, S. S. Electrical Power & Energy Systems, Oct. 1996, 18, (7), 445-452. The paper presents a methodology for dynamic analysis of short term small sierra1 voltane instabilitv in a multi-machine Dower svstem. The formulat&t of the Eroblem is hone by decou ling the angle’instability from the voltage instability. The method is base x on the incremental reactive current flow network, where the incremental reactive current injection of each bus is related to the incremental voltage magnitude at all the buses. Small signal stability using the eigenvalue analysis is illustrated utilizing a singlemachine load bus and a three-machine system examples. The role of a static var compensator at the load bus is also examined.
96/06086
Effect of cobalt addition to nickel hydroxide as a posltlve materlal for rechargeable alkaline batteries
Watanabe, K. er al., J. of PowerSources, Jan. 1996, 58, (l), 23-28. Nickel hydroxide powder is used widely as an active material in pastedtype nickel electrodes. The effect on the electrochemical behaviour of cobalt addition to the nickel hydroxide powder is investigated.
Electric power generation and utilisation(scientific, t8chnical)
96109091 legialatlon
Effects of prioritizlng demand on optimal load shedding policy
Mostafa, M. A. er al., Electrical Power & Energy Systems, Oct. 1996, 18, f7). 415-424. Demand priorities in the power system optimal load shedding policy are major decision variables used to regulate the amount of load shedding at specific buses during contingencies: Previous work on optimal load shedding does not explicitly consider demand priorities. The paper investigates the effects of demand priorities on the performance of the power system during emergencies. A nonlinear programming approach is used to determine the optimal values of demand priorities for two test systems. Optimizing demand priorities is shown to enhance overall system performance measured by total supplied load, bus voltages and system losses during the contingency. Results are offered demonstrating additional enhancements by optimizing the demand priority at the bus with the second largest load.
96/06090
Electrochemical behavlour of addition agents Impregnated In cadmium hydroxide electrodes for alkaline batteries
Kalaianan. G. P. er al.. J. of PowerSources, Jan. 1996, 58, (l), 29-34. Discusses the development of electrode additives for the cadmium electrode of the nickel/cadmium battery which is aimed mainly at increasing the discharge capacity and minimizing self-discharge.
of electromagnetic
compatibility
Ridley, P. Environ. Engng., Jun. 1996, 9, (2), 32-36. The Electromagnetic Compatibility (EMC Directive) became fully implemented on 1st January 1996 by the UK’s EMC Regulations, S.I., 1992, 2372. Discusses the uncertainty among suppliers and users in the UK process and energy industry regarding the attitude of the Weights and Measures Authorities and the Health and Safety Executive in relation to the legislation.
Enhancement of power system stability by using 96106092 controlled series compensation Chen. X. R. et al... Electrical Power & Enerw (7). “,, Svsfems. Oct. 1996. lg. ,\,,
475-481. ’ The paper studies the application
of controlled series compensator to damp power swings m multimachine power systems.
(CSC)
Evaluation of methods for discrimination of energlzed underground power cables
96106093
Short, S. X. ef al., Electric Power Systems Research, Apr. 1996, 37, (l), 29-38. The maintenance and repair of underground cable power networks often requires the discrimination of energized cables among a group of unenergized ones. Presently, an invasive detection method is performed which requires utility personnel to puncture the protective cable shielding, creating a ootentiallv hazardous situation. The oaoer presents a noninvasive approach for energized cable detection based ‘on the electrically induced acoustic waves inside of the cable.
Flnlte element software for 3-D field calculations in electrical engineering
96106094
Ostovic, V. and Soyk, K. H. ABB Review, 1996, (6), 29-36. Finite element modellmg (FE) allows fast, precise analysis of the electrical, magnetic and thermal fields in electrotechnical components while the parts are still at the design stage. Costly prototypes are often not needed when FE is used, while weak points in finished products are easier to identify and potential design improvements can be checked in a more cost-effective way.
Hydro I as a defect of the manganese dioxide lat96106095 tice and its applicat r ona to the dry cell battery ?I$?, H. and Nasser, S. A. J. of Power Sources, Jan. 1996, 58, (l), Manganese dioxide polymorphs with different OH contents were prepared under various reaction conditions. X-ray diffraction measurements showed the presence of orthorhombic, tetragonal and hexagonal forms of MnO, Infrared absorption spectra in frequency range 200-4CKKl cm.’ of the different modifications were studied.
Interval predlction of annual maximum demand using grey dynamic model
96106096
Morita, H. et a/., Electrical Power & Energy Systems, Oct. 1996, 18, (7), 409-413. The paper proposes an interval prediction of the u per and lower bound values of load demand using the grey dynamic mo Bel in grey system theory. Su ply and demand in power system planning and operation are requtre ,8 to be balanced. A marginal supply capability against accidental demands or faults is also required. The confidence interval can become an index for determining the marginal supply capability. The interval prediction using the grey dynamic model is illustrated using an example. The results are compared with the actual demands and with those obtained from a linear single regression model. 96106097
96106089
Enforcement
Investigations of awltchlng operations on compos-
ite feeders Hamza, A. S. Energy Convers. Mgmr., Nov. 1996, 37, (ll), 1575-1587. Describes switchinn ooerations and the accomoanvine overvoltanes uroduced on compositcfeiders when a circuit breaker c’lo& at the peik of the applied voltage. Transformer and line-cable feeders are considered. The means of reducing such overvoltages are also included, and the effect of system parameters and factors on ihe initial voltage applied and accompanying overvoltages are covered.
Leady oxide for lead/acid battery positive plates: 96/06098 scope for improvement? Mayer,M. G. andRand, D. A. J. of Power Sources, Mar.-Apr. 1996, 59, (1); 17-24. Among the many factors that determine the influence the performance of lead/acid batteries, one of the most important, and as yet not fully developed, is how to make the positive active mass more electrochemically reactive. The inherent characteristics of this active mass are the cumulative result of the four precursor stages of its production, namely, the leady oxide, paste mixing, curing and formation procedures. There is evidence to suggest that the method of pasting itself is also influential. Many recent studies have reported progress on techniques to increase active-material utilization, to improve plate conditioning, and to solve the vexagious problem of premature capacity. The purpose-of this discussion is to focus attention on the role and the importance of leady oxide on battery design and performance.
Fuel and Energy Abstracts November 1996 431