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01369 Developing a computer package for designing an electric power station
06 Electrical power generation
and utilization (scientific, technical)
00/01363 Applying network window schema and a simulated annealino technique to optimal VAR planning in large-scale power systems _ Hsiao, Y.-T. and Chiang, H.-D. EIecfriccrl Poirrr & .&erg!, S~slems. 2000, 22, (I), 1-8. This paper combines network window schema with a simulated annealing (SA) technique and applies them to reactive volt-ampere (VAR) planning in laree-scale Dower svstems. The network window schema alleviates the comp;tationalburden ;n large-scale systems, while the simulated annealing technique finds global optimal solutions for combinatorial complex problems. The solution algorithm based on this technique consists of two stages. The first stage introduces a moving window schema that partitions a large system into several small subsystems; an equivalent method then builds a reduced system for every subsystem. The results from the first stage are mapped into the original system and serve as the initial conditions for the second stage. The second stage compensates for the effect of system partitioning on the quality and feasibility of solutions. According to simulation results, the proposed approach significantly reduces the run time of the SA, and also improves the quality of the solution. For a 358-bus test system, loss reduction was improved by 17.6%, along with a saving in CPU time of approximately 50%.
Bipolar lead/acid batteries: effect of membrane conductivity on performance Coux,M. e, crl. J. Poirer SOI~~(.ES,1999, 78, (l-2). 115-122.
00101364
Bipolar lead-acid batteries offer the possibility of increased energy and power density. This paper presents the results of a theoretical and experimental study into the performance of a bipolar construction. A model that calculates the ohmic losses in a bipolar lead acid battery has been used to predict the cell voltage during discharge. The calculated discharge curves are in good agreement with experimental results obtained with a 6 V lead membrane bipolar prototype. In a second part the conductivity of the bipolar plates have been adjusted in the programme to estimate its influence on battery performance.
Calculation of phase equilibria and physicochemical properties of gas hydrates in electric field
00/01366
Nazmutdinov, F. F. and Sayakhov, F. L. Elektron. Ohrob. Mater., 1996, I. 26-29. (In Russian) Shtiintsa. Expressions were derived for the chemical potential of gas hydrate exchange in electric fields, taking into consideration the filling of small and large cavities described by the Langmuir isotherm. The methane hydrate data is presented.
00/01366 Characteristics of platinum-based electrocatalysts for mobile PEMFC applications Starz, K. A. 1. qf Powr Sources. 1999. 84. (2), 167-172. Platinum-based electrocatalysts play an important role in the development of high performance PEMFC stacks for mobile applications. This paper reviews objectives, development work, and results of a Research and Develooment Proeram funded bv the German Ministrv of Education. Science, Research ind Technology’(BMBF) to develop thebasic technology as well as components for mobile PEMFC applications. In the framework of this program, Degussa-Htils developed precious metal-based electrocatalvsts for ooeration under practical reformate / air PEMFC conditions which yield high’power densitiesup to 0.5 Wi cm’ at low total platinum loadings of less than 0.5 mg Pticm’. A CO-tolerant anode electrocatalyst, exhibiting a CO-tolerance of 100 ppm CO, was developed and characterized. The features of the new electrocatalyst materials were verified by DaimlerChrysler in a 2.7 kW PEMFC stack at the end of the program.
00101367 Coordination of TCSC and SVC for improvement of power system performance with NN-based parameter adaptation Tso, S. K. er al. Electtkwl Power & l3terg.r SJ‘.rtms. 1999, 21, (4), A non-linear design technique, DFL (direct feedback linearizing), is used to deduce the control law for the TCSC (thyristor controlled series compensator) and SVC (static VAR compensator). The co-ordination between the two pieces of equipment is also designed in the paper with the SVC treated as the supplement of the TCSC. When operation of the TCSC is constrained by the inherent limitation of equipment, the adjustable SVC can supply the auxiliary support to improve the overall performance. In order to adapt to the changes of the operating mode and active power of generators, a neural network (NN) is applied to determine the control parameters of the equipment. Analysis and simulation of a case study have proved the effectiveness of the non-linear control strategy.
00101366 Design and synthesis of inorganic-organic hybrid microstructures Harreld, J. H. et nl. Int. J. Imrg. Matcricrls. 1999. I, (2). 1355146. Vanadium oxide-polypyrrole (VjOs-PPy) hybrid aerogels were prepared using three different strategies. These approaches were focused on either sequential or consecutive polymerization of the inorganic and organic networks. The hybrid microstructure differed greatly depending on which synthesis approach was used. Microcomposite aerogels were synthesized by encapsulating a dispersion of preformed PPy in a VzOs gel. In the second approach, pyrrole was polymerized and doped within the pore volume of a preformed VzOs gel. The hybrid microstructure of these materials was nanometre scaled but inhomogeneous. When the inorganic and organic precursors were allowed to polymerize simultaneously, the resulting gels
164
Fuel and Energy Abstracts
May 2000
exhibited a nanometre-scaled microstructure with a homogeneous distribution of the PPy and the VzOs. Through this route, a suitable microstructure and composition for a lithium secondary battery cathode were obtained. Undoped material with a composition of lPPylO.8 VzOc exhibited a lithium mtercalation capacity comparable to -that’ of Vi05 aerogel. For the full benefit of the PPy phase to be achieved, a suitable doping procedure is still required to oxidize the PPy into its high conductivity state while preserving the inorganic structure.
00101369 Developing a computer package for designing an electric power station Qamber, I. S. and Al-Butti. Y. App/~& E/irrg~,. 1999. 64. t I-4). 35?--367. In order to find the transient orobahilities that reflect the behaviour of a large electrical-power system or any other system, a suitahlc technique is needed. Before calculating the transient probabilities for the overall electrical power-system, which consists of a number of sub-systems (such as generators), the failure and repair rates of each generator are needed. These two coefficients can form a transition rate matrix, which represent each sub-system. In the present study, the Kronecker technique is used to form the overall system: this is the first part of the current study. The second part is to find the transient probabilities following the fourth-order Runge-Kutta method. A number of examples related to the State of Bahrain are considered. In addition, by applying the new technique under investigation, we describe the behaviours of electric-power stations.
00/01370 Development of solid oxide fuel cells for power generation Takatsuka, H. Mit.svbishi Juko Giho. 1999. 36, (I). 34-37. (In Japanese) Mitsubishi Jukogyo K. K. Heavy Mitsubishi Heavy Industries Ltd. has recently developed solid oxide fuel cells (SOFCs). The fuel cells have been designed with the intention of providing high plant efficiency for power stations (~65% for liquefied natural gas fired SOFC combined plants and ~55% for coal gasification SOFC combined plants). Since March 1998 a pressurized IO kW class tubular type SOFC has been operating at the maximum output of 21.0 kW. with a continuous run of >7000 h exuected. Moreover. a monoblock laver built type SOFC was operated at the maximum output of 5.1 kW in 1996 and under a continuous run of 1500 h in 1998. Developments are now underway for the next 10 kW class module
00/01371 Direct torque control of induction motors for electric propulsion systems Faiz, J. et alElectric Poit’er Sr.s~erns Reseurch, 1999. 51, (2). 95-102. This paper describes an induction motor drive for use in electric propulsion. The specifics of the application (electric vehicle) require fast response and high efficiency for the drive. Direct torque control (DTC) is used to control the motor. In this control strategy, efficiency is optimized by adjusting the magnetic flux of the motor. The sensitivity of the DTC to temperature variations, leading to stator resistance changes, is eliminated by online estimation of stator resistance. 00/01372 Discussion on some voltage collapse indices Zambroni de Souza, A. C. Electric POIIYV S~~.s~emsRe.tecw~~/~.2000. 53. (I ). 53-58. This paper discusses some voltage collapse indices with the help of bifurcation theory. Two main topics are presented: first, the identification of a well-behaved eizenvalue as a function of load increase: second a theoretical interpretayion of the results. For this purpose, the centre manifold theorem is employed. The tests are carried out using the IEEE300 Bus test system. The.results show that under certain considerations, the voltage collapse indices analysed produce identical results.
00101373 Effect of a special additive on the performance of standby valve-regulated lead acid batteries Torcheux, L. J. Power Sowces. 1999. 78. (l-2). 147-l 55. This paper is devoted to the effect of FORAFAC l033D (polyfluoroalkyl sulfonic acid) as electrolyte additive on the performance of standhy VRLA AGM batteries. This additive has a surfactant character and its stability is increased by substitution of some hydrogen atoms by fluoride atoms in the molecule. With the use of FORAFAC, the objective is to improve the life of VRLA lead acid batteries for standby applications. Comparative accelerated floating tests with and without FORAFAC have been carried out on standard AGM batteries. Batteries containing FORAFAC in acid at low concentration (0.1%) show a remarkable electrical behaviour during the test. A good influence of FORAFAC on water consumption and on selfdischarge is also observed. Results indicate that the life duration of standby VRLA lead acid batteries could be improved by a factor 1.5 to 2 with the use of FORAFAC. The mechanism of the FORAFAC action has been investigated and is discussed in this paper. The use of the FORAFAC method appears to be a very promising solution in order to improve the behaviour of batteries for standby applications. For example, it could be useful for applications at higher temperatures or to increase the specific energy of batteries by the utilization of thinner grid collectors and plates.
00101374 Effect of demand prioritization and load curtailment policy on minimum emlssion dispatch Mbamalu,
G. A. N. Electric
Power S~~stcvns Resec~d~. 2000. 53. (I ). I-S.
and utilization (scientific, technical)
00/01363 Applying network window schema and a simulated annealino technique to optimal VAR planning in large-scale power systems _ Hsiao, Y.-T. and Chiang, H.-D. EIecfriccrl Poirrr & .&erg!, S~slems. 2000, 22, (I), 1-8. This paper combines network window schema with a simulated annealing (SA) technique and applies them to reactive volt-ampere (VAR) planning in laree-scale Dower svstems. The network window schema alleviates the comp;tationalburden ;n large-scale systems, while the simulated annealing technique finds global optimal solutions for combinatorial complex problems. The solution algorithm based on this technique consists of two stages. The first stage introduces a moving window schema that partitions a large system into several small subsystems; an equivalent method then builds a reduced system for every subsystem. The results from the first stage are mapped into the original system and serve as the initial conditions for the second stage. The second stage compensates for the effect of system partitioning on the quality and feasibility of solutions. According to simulation results, the proposed approach significantly reduces the run time of the SA, and also improves the quality of the solution. For a 358-bus test system, loss reduction was improved by 17.6%, along with a saving in CPU time of approximately 50%.
Bipolar lead/acid batteries: effect of membrane conductivity on performance Coux,M. e, crl. J. Poirer SOI~~(.ES,1999, 78, (l-2). 115-122.
00101364
Bipolar lead-acid batteries offer the possibility of increased energy and power density. This paper presents the results of a theoretical and experimental study into the performance of a bipolar construction. A model that calculates the ohmic losses in a bipolar lead acid battery has been used to predict the cell voltage during discharge. The calculated discharge curves are in good agreement with experimental results obtained with a 6 V lead membrane bipolar prototype. In a second part the conductivity of the bipolar plates have been adjusted in the programme to estimate its influence on battery performance.
Calculation of phase equilibria and physicochemical properties of gas hydrates in electric field
00/01366
Nazmutdinov, F. F. and Sayakhov, F. L. Elektron. Ohrob. Mater., 1996, I. 26-29. (In Russian) Shtiintsa. Expressions were derived for the chemical potential of gas hydrate exchange in electric fields, taking into consideration the filling of small and large cavities described by the Langmuir isotherm. The methane hydrate data is presented.
00/01366 Characteristics of platinum-based electrocatalysts for mobile PEMFC applications Starz, K. A. 1. qf Powr Sources. 1999. 84. (2), 167-172. Platinum-based electrocatalysts play an important role in the development of high performance PEMFC stacks for mobile applications. This paper reviews objectives, development work, and results of a Research and Develooment Proeram funded bv the German Ministrv of Education. Science, Research ind Technology’(BMBF) to develop thebasic technology as well as components for mobile PEMFC applications. In the framework of this program, Degussa-Htils developed precious metal-based electrocatalvsts for ooeration under practical reformate / air PEMFC conditions which yield high’power densitiesup to 0.5 Wi cm’ at low total platinum loadings of less than 0.5 mg Pticm’. A CO-tolerant anode electrocatalyst, exhibiting a CO-tolerance of 100 ppm CO, was developed and characterized. The features of the new electrocatalyst materials were verified by DaimlerChrysler in a 2.7 kW PEMFC stack at the end of the program.
00101367 Coordination of TCSC and SVC for improvement of power system performance with NN-based parameter adaptation Tso, S. K. er al. Electtkwl Power & l3terg.r SJ‘.rtms. 1999, 21, (4), A non-linear design technique, DFL (direct feedback linearizing), is used to deduce the control law for the TCSC (thyristor controlled series compensator) and SVC (static VAR compensator). The co-ordination between the two pieces of equipment is also designed in the paper with the SVC treated as the supplement of the TCSC. When operation of the TCSC is constrained by the inherent limitation of equipment, the adjustable SVC can supply the auxiliary support to improve the overall performance. In order to adapt to the changes of the operating mode and active power of generators, a neural network (NN) is applied to determine the control parameters of the equipment. Analysis and simulation of a case study have proved the effectiveness of the non-linear control strategy.
00101366 Design and synthesis of inorganic-organic hybrid microstructures Harreld, J. H. et nl. Int. J. Imrg. Matcricrls. 1999. I, (2). 1355146. Vanadium oxide-polypyrrole (VjOs-PPy) hybrid aerogels were prepared using three different strategies. These approaches were focused on either sequential or consecutive polymerization of the inorganic and organic networks. The hybrid microstructure differed greatly depending on which synthesis approach was used. Microcomposite aerogels were synthesized by encapsulating a dispersion of preformed PPy in a VzOs gel. In the second approach, pyrrole was polymerized and doped within the pore volume of a preformed VzOs gel. The hybrid microstructure of these materials was nanometre scaled but inhomogeneous. When the inorganic and organic precursors were allowed to polymerize simultaneously, the resulting gels
164
Fuel and Energy Abstracts
May 2000
exhibited a nanometre-scaled microstructure with a homogeneous distribution of the PPy and the VzOs. Through this route, a suitable microstructure and composition for a lithium secondary battery cathode were obtained. Undoped material with a composition of lPPylO.8 VzOc exhibited a lithium mtercalation capacity comparable to -that’ of Vi05 aerogel. For the full benefit of the PPy phase to be achieved, a suitable doping procedure is still required to oxidize the PPy into its high conductivity state while preserving the inorganic structure.
00101369 Developing a computer package for designing an electric power station Qamber, I. S. and Al-Butti. Y. App/~& E/irrg~,. 1999. 64. t I-4). 35?--367. In order to find the transient orobahilities that reflect the behaviour of a large electrical-power system or any other system, a suitahlc technique is needed. Before calculating the transient probabilities for the overall electrical power-system, which consists of a number of sub-systems (such as generators), the failure and repair rates of each generator are needed. These two coefficients can form a transition rate matrix, which represent each sub-system. In the present study, the Kronecker technique is used to form the overall system: this is the first part of the current study. The second part is to find the transient probabilities following the fourth-order Runge-Kutta method. A number of examples related to the State of Bahrain are considered. In addition, by applying the new technique under investigation, we describe the behaviours of electric-power stations.
00/01370 Development of solid oxide fuel cells for power generation Takatsuka, H. Mit.svbishi Juko Giho. 1999. 36, (I). 34-37. (In Japanese) Mitsubishi Jukogyo K. K. Heavy Mitsubishi Heavy Industries Ltd. has recently developed solid oxide fuel cells (SOFCs). The fuel cells have been designed with the intention of providing high plant efficiency for power stations (~65% for liquefied natural gas fired SOFC combined plants and ~55% for coal gasification SOFC combined plants). Since March 1998 a pressurized IO kW class tubular type SOFC has been operating at the maximum output of 21.0 kW. with a continuous run of >7000 h exuected. Moreover. a monoblock laver built type SOFC was operated at the maximum output of 5.1 kW in 1996 and under a continuous run of 1500 h in 1998. Developments are now underway for the next 10 kW class module
00/01371 Direct torque control of induction motors for electric propulsion systems Faiz, J. et alElectric Poit’er Sr.s~erns Reseurch, 1999. 51, (2). 95-102. This paper describes an induction motor drive for use in electric propulsion. The specifics of the application (electric vehicle) require fast response and high efficiency for the drive. Direct torque control (DTC) is used to control the motor. In this control strategy, efficiency is optimized by adjusting the magnetic flux of the motor. The sensitivity of the DTC to temperature variations, leading to stator resistance changes, is eliminated by online estimation of stator resistance. 00/01372 Discussion on some voltage collapse indices Zambroni de Souza, A. C. Electric POIIYV S~~.s~emsRe.tecw~~/~.2000. 53. (I ). 53-58. This paper discusses some voltage collapse indices with the help of bifurcation theory. Two main topics are presented: first, the identification of a well-behaved eizenvalue as a function of load increase: second a theoretical interpretayion of the results. For this purpose, the centre manifold theorem is employed. The tests are carried out using the IEEE300 Bus test system. The.results show that under certain considerations, the voltage collapse indices analysed produce identical results.
00101373 Effect of a special additive on the performance of standby valve-regulated lead acid batteries Torcheux, L. J. Power Sowces. 1999. 78. (l-2). 147-l 55. This paper is devoted to the effect of FORAFAC l033D (polyfluoroalkyl sulfonic acid) as electrolyte additive on the performance of standhy VRLA AGM batteries. This additive has a surfactant character and its stability is increased by substitution of some hydrogen atoms by fluoride atoms in the molecule. With the use of FORAFAC, the objective is to improve the life of VRLA lead acid batteries for standby applications. Comparative accelerated floating tests with and without FORAFAC have been carried out on standard AGM batteries. Batteries containing FORAFAC in acid at low concentration (0.1%) show a remarkable electrical behaviour during the test. A good influence of FORAFAC on water consumption and on selfdischarge is also observed. Results indicate that the life duration of standby VRLA lead acid batteries could be improved by a factor 1.5 to 2 with the use of FORAFAC. The mechanism of the FORAFAC action has been investigated and is discussed in this paper. The use of the FORAFAC method appears to be a very promising solution in order to improve the behaviour of batteries for standby applications. For example, it could be useful for applications at higher temperatures or to increase the specific energy of batteries by the utilization of thinner grid collectors and plates.
00101374 Effect of demand prioritization and load curtailment policy on minimum emlssion dispatch Mbamalu,
G. A. N. Electric
Power S~~stcvns Resec~d~. 2000. 53. (I ). I-S.