- Email: [email protected]
02070 A passive fuel delivery system for portable direct methanol fuel cells
06 Electrical power supply and utilization (scientific, technical) event sequence information from the database. For this, the S A R D m e n u system provides a user-friendly interface for the user to explore the contents of the database and to obtain answers to various questions. The present database m a n a g e m e n t system is very useful in a n u m b e r of applications including the support of the Level 2 PSA, comparison of severe accident analysis results, training and understanding of the severe accident phenomenology, and assistance in severe accident m a n a g e m e n t .
05•02064 Purex co-processing of spent LWR fuels: comparative fuel cycle cost analyses Zabuno~lu, O. H. and Ozdemir, L. Annals of Nuclear Energy, 2005, 32, (2), 137 149. Nuclear fuel cycle costs for purex reprocessing and co-processing cycles are to be evaluated, by calculating unit costs of recovered, accordingly treated and fabricated products and then comparing those to the unit cost of fresh u r a n i u m fuel ready to be loaded into a typical L W R on the once-through cycle.
05•02065
Reliability analysis of shutdown system
Kumar, C. S. et al. Annals of Nuclear Energy, 2005, 32, (1), 63 87. This p a p e r presents the results of reliability analysis of Shutdown System (SDS) of Indian Prototype Fast Breeder Reactor. Reliability ana!ysis carried out using Fault Tree Analysis predicts a value of 3.5 x 10 Ude for failure of shutdown function in case of global faults and 4.4 x 10 ~/de for local faults. Based on 20 de/y, the frequency of shutdown function failure is 0.7 x 10 6/ry, which meets the reliability target, set by the Indian A t o m i c E n e r g y R e g u l a t o r y Board. The reliability is limited by C o m m o n Cause Failure (CCF) of actuation part of SDS and to a lesser extent CCF of electronic components. The failure frequency of individual systems is <1 x 10 3/ry, which also meets the safety criteria. U n c e r t a i n t y analysis indicates a m a x i m u m error factor of 5 for the top event unavailability.
05•02066 Technological change of nuclear fuel cycle in Korea: the case of dupic Lee, T. J. Progress in Nuclear Energy, 2004, 45, (1), 85 102. This paper describes how Korea has been successfully carrying out the D U P I C project for the d e v e l o p m e n t of the nuclear fuel cycle. To enhance energy security, the D U P I C is a response to the challenge faced by Korea's nuclear energy program. First of all, indigenous technological capabilities have played a significant role in finding an alternative technological trajectory for proliferation resistance as well as energy economics and in solving innovative and complex technological problems. While being s u p p o r t e d by a long-lasting national commitment, the i m p l e m e n t a t i o n of D U P I C has also d e p e n d e d upon the domestic techno-economic validity in association with energy security, m a r k e t condition and the industrial d e m a n d of spent fuel management.
ELECTRICAL POWER SUPPLY AND UTILIZATION
06
Scientific, technical 05•02067 cell
A miniature air breathing direct formic acid fuel
Ha, S. et al. Journal of Power Sources, 2004, 128, (2), 119 124. Small fuel cells are considered likely r e p l a c e m e n t s for batteries in portable power applications. In this paper, the performance of a 2 c m x 2 . 4 c m x l . 4 cm passive miniature air b r e a t h i n g direct formic acid fuel cell ( D F A F C ) at r o o m t e m p e r a t u r e is reported. The cell produced current density up to 250 m A / c m z and power density up to 33 m W / c m z at a m b i e n t conditions. The fuel cell runs successfully with formic acid concentration ranging from 1.8 and 10 M with little d e g r a d a t i o n in performance. These results show that passive fuel cells can compete with batteries in portable power applications.
05•02068 A new approach to locate the voltage sag source using real current component Hamzah, N. et al. Electric Power Systems Research, 2004, 72, (2), 113 123.
306
Fuel and Energy Abstracts
September 2005
Voltage sag can cause hours of downtime, substantial loss of product and also can attribute to malfunctions, instabilities and shorter lifetime of the load. Accurate voltage sag source location can help to minimize the loss and problems caused by voltage sag in a power distribution system. This p a p e r proposes a new m e t h o d to locate the source of voltage sag in a power distribution system. The proposed m e t h o d uses the polarity of the real current c o m p o n e n t to d e t e r m i n e the sag location relative to the m o n i t o r i n g point. The product of the R M S current and the power factor angle at the m o n i t o r i n g point is employed for the sag source location. A graph of this product against time is plotted. The voltage sag source location is d e t e r m i n e d by examining the polarity of the RMS current at the b e g i n n i n g of the sag. The proposed m e t h o d has been verified by simulations and the results are proven to be in a g r e e m e n t w h e n c o m p a r e d with the slope of system trajectory method.
05•02069 A non-interior point approach to optimum power flow solution Patra, S. and Goswami, S. K. Electric Power Systems Research, 2005, 74, (1), 17 26. A formulation of the o p t i m u m power flow problem using a smoothing variable based non-interior point m e t h o d is p r e s e n t e d in this paper. H e r e a combination of regular smoothing m e t h o d and Jacobian smoothing m e t h o d is used. The proposed m e t h o d makes use of the slack variables to handle the inequality constraints, Dual variables to form the L a g r a n g i a n function and employs the KKT optimality condition and Newton's m e t h o d to solve the resultant equations. But instead of the logarithmic barrier to handle the c o m p l e m e n t a r y condition, the proposed m e t h o d uses a smoothing function and thereby overcomes the limitation of the variables to be in the interior of the feasible space through all iterations. Also, the smoothing p a r a m e t e r is treated as a variable of the original problem thus avoiding the necessity of heuristics in u p d a t i n g the value of the s m o o t h i n g p a r a m e t e r , which approaches zero as the convergence is approached.
05•02070 A passive fuel delivery system for portable direct methanol fuel cells Guo, Z. and Cao, Y. Journal of Power Sources, 2004, 131, (1 2), 86 91. A passive device is utilized for transferring m e t h a n o l into water through a wick material. The wick material preferentially has a higher wicking capability with respect to m e t h a n o l than water, and operates in a siphon fashion with the intake end in contact with m e t h a n o l and the discharge end in contact with water. Due to the difference of wicking capabilities, a net a m o u n t of m e t h a n o l is p u m p e d into water. The device described above is used as a fuel delivery c o m p o n e n t for a liquid-feed fuel cell system, such as a direct m e t h a n o l fuel cell (DMFC), which directly utilizes a liquid fuel without an i n t e r m e d i a t e reforming process. In the present e x p e r i m e n t a l study, m e t h a n o l and water are stored separately in two containers and a wick is positioned between the containers as a siphon, with the aqueous m e t h a n o l solution c o m m u n i c a t i n g with the anode of the DMFC. M e t h a n o l is siphoned from the m e t h a n o l container to the water container in situ when the m e t h a n o l in the water is consumed during the operation of the fuel cell. Through a proper selection of the wick and the containers, the m e t h a n o l concentration near the anode of the D M F C was m a i n t a i n e d within a preferred range.
05•02071 A PMU based special protection scheme: a case study of Taiwan power system Wang, Y.-J. et al. hzternational Journal of Electrical Power & Energy Systems, 2005, 27, (3), 215 223. This paper proposes a special protection scheme to prevent power system blackout due to a sequence of relay trip events based on phasor m e a s u r e m e n t units (PMUs). In a control centre, P M U s are used to monitor the generators and the major E H V transmission lines of a power system, and apply an instability prediction algorithm for initiating a special protection schemes (SPS) to avoid a sequence of relay trip events w h e n e v e r necessary. W h e n a fault happens, we group the generators swinging coherently and reduce the system to OneMachine-Infinite-Bus ( O M I B ) system. The r e m e d i a l control actions consist of load shedding and generation tripping. The strategy for d e t e r m i n i n g the a m o u n t of r e m e d i a l control actions is a proposed relay setting limited equal-area criterion for OMIB. A case study of Taiwan power system assumed to be e q u i p p e d with proposed special protection scheme is conducted. E n c o u r a g i n g results are obtained.
05•02072 An actively controlled fuel cell/battery hybrid to meet pulsed power demands Gao, L. et al. Journal qfPower Sources, 2004, 130, (1 2), 202 207. This p a p e r presents the e x p e r i m e n t a l results of an actively controlled fuel cell/battery hybrid power source topology that can be widely used in many applications, such as portable electronic devices, communication equipment, spacecraft power systems, and electric vehicles, in which the power d e m a n d is impulsive rather than constant. A stepdown D C / D C power converter is incorporated to actively control the
05•02064 Purex co-processing of spent LWR fuels: comparative fuel cycle cost analyses Zabuno~lu, O. H. and Ozdemir, L. Annals of Nuclear Energy, 2005, 32, (2), 137 149. Nuclear fuel cycle costs for purex reprocessing and co-processing cycles are to be evaluated, by calculating unit costs of recovered, accordingly treated and fabricated products and then comparing those to the unit cost of fresh u r a n i u m fuel ready to be loaded into a typical L W R on the once-through cycle.
05•02065
Reliability analysis of shutdown system
Kumar, C. S. et al. Annals of Nuclear Energy, 2005, 32, (1), 63 87. This p a p e r presents the results of reliability analysis of Shutdown System (SDS) of Indian Prototype Fast Breeder Reactor. Reliability ana!ysis carried out using Fault Tree Analysis predicts a value of 3.5 x 10 Ude for failure of shutdown function in case of global faults and 4.4 x 10 ~/de for local faults. Based on 20 de/y, the frequency of shutdown function failure is 0.7 x 10 6/ry, which meets the reliability target, set by the Indian A t o m i c E n e r g y R e g u l a t o r y Board. The reliability is limited by C o m m o n Cause Failure (CCF) of actuation part of SDS and to a lesser extent CCF of electronic components. The failure frequency of individual systems is <1 x 10 3/ry, which also meets the safety criteria. U n c e r t a i n t y analysis indicates a m a x i m u m error factor of 5 for the top event unavailability.
05•02066 Technological change of nuclear fuel cycle in Korea: the case of dupic Lee, T. J. Progress in Nuclear Energy, 2004, 45, (1), 85 102. This paper describes how Korea has been successfully carrying out the D U P I C project for the d e v e l o p m e n t of the nuclear fuel cycle. To enhance energy security, the D U P I C is a response to the challenge faced by Korea's nuclear energy program. First of all, indigenous technological capabilities have played a significant role in finding an alternative technological trajectory for proliferation resistance as well as energy economics and in solving innovative and complex technological problems. While being s u p p o r t e d by a long-lasting national commitment, the i m p l e m e n t a t i o n of D U P I C has also d e p e n d e d upon the domestic techno-economic validity in association with energy security, m a r k e t condition and the industrial d e m a n d of spent fuel management.
ELECTRICAL POWER SUPPLY AND UTILIZATION
06
Scientific, technical 05•02067 cell
A miniature air breathing direct formic acid fuel
Ha, S. et al. Journal of Power Sources, 2004, 128, (2), 119 124. Small fuel cells are considered likely r e p l a c e m e n t s for batteries in portable power applications. In this paper, the performance of a 2 c m x 2 . 4 c m x l . 4 cm passive miniature air b r e a t h i n g direct formic acid fuel cell ( D F A F C ) at r o o m t e m p e r a t u r e is reported. The cell produced current density up to 250 m A / c m z and power density up to 33 m W / c m z at a m b i e n t conditions. The fuel cell runs successfully with formic acid concentration ranging from 1.8 and 10 M with little d e g r a d a t i o n in performance. These results show that passive fuel cells can compete with batteries in portable power applications.
05•02068 A new approach to locate the voltage sag source using real current component Hamzah, N. et al. Electric Power Systems Research, 2004, 72, (2), 113 123.
306
Fuel and Energy Abstracts
September 2005
Voltage sag can cause hours of downtime, substantial loss of product and also can attribute to malfunctions, instabilities and shorter lifetime of the load. Accurate voltage sag source location can help to minimize the loss and problems caused by voltage sag in a power distribution system. This p a p e r proposes a new m e t h o d to locate the source of voltage sag in a power distribution system. The proposed m e t h o d uses the polarity of the real current c o m p o n e n t to d e t e r m i n e the sag location relative to the m o n i t o r i n g point. The product of the R M S current and the power factor angle at the m o n i t o r i n g point is employed for the sag source location. A graph of this product against time is plotted. The voltage sag source location is d e t e r m i n e d by examining the polarity of the RMS current at the b e g i n n i n g of the sag. The proposed m e t h o d has been verified by simulations and the results are proven to be in a g r e e m e n t w h e n c o m p a r e d with the slope of system trajectory method.
05•02069 A non-interior point approach to optimum power flow solution Patra, S. and Goswami, S. K. Electric Power Systems Research, 2005, 74, (1), 17 26. A formulation of the o p t i m u m power flow problem using a smoothing variable based non-interior point m e t h o d is p r e s e n t e d in this paper. H e r e a combination of regular smoothing m e t h o d and Jacobian smoothing m e t h o d is used. The proposed m e t h o d makes use of the slack variables to handle the inequality constraints, Dual variables to form the L a g r a n g i a n function and employs the KKT optimality condition and Newton's m e t h o d to solve the resultant equations. But instead of the logarithmic barrier to handle the c o m p l e m e n t a r y condition, the proposed m e t h o d uses a smoothing function and thereby overcomes the limitation of the variables to be in the interior of the feasible space through all iterations. Also, the smoothing p a r a m e t e r is treated as a variable of the original problem thus avoiding the necessity of heuristics in u p d a t i n g the value of the s m o o t h i n g p a r a m e t e r , which approaches zero as the convergence is approached.
05•02070 A passive fuel delivery system for portable direct methanol fuel cells Guo, Z. and Cao, Y. Journal of Power Sources, 2004, 131, (1 2), 86 91. A passive device is utilized for transferring m e t h a n o l into water through a wick material. The wick material preferentially has a higher wicking capability with respect to m e t h a n o l than water, and operates in a siphon fashion with the intake end in contact with m e t h a n o l and the discharge end in contact with water. Due to the difference of wicking capabilities, a net a m o u n t of m e t h a n o l is p u m p e d into water. The device described above is used as a fuel delivery c o m p o n e n t for a liquid-feed fuel cell system, such as a direct m e t h a n o l fuel cell (DMFC), which directly utilizes a liquid fuel without an i n t e r m e d i a t e reforming process. In the present e x p e r i m e n t a l study, m e t h a n o l and water are stored separately in two containers and a wick is positioned between the containers as a siphon, with the aqueous m e t h a n o l solution c o m m u n i c a t i n g with the anode of the DMFC. M e t h a n o l is siphoned from the m e t h a n o l container to the water container in situ when the m e t h a n o l in the water is consumed during the operation of the fuel cell. Through a proper selection of the wick and the containers, the m e t h a n o l concentration near the anode of the D M F C was m a i n t a i n e d within a preferred range.
05•02071 A PMU based special protection scheme: a case study of Taiwan power system Wang, Y.-J. et al. hzternational Journal of Electrical Power & Energy Systems, 2005, 27, (3), 215 223. This paper proposes a special protection scheme to prevent power system blackout due to a sequence of relay trip events based on phasor m e a s u r e m e n t units (PMUs). In a control centre, P M U s are used to monitor the generators and the major E H V transmission lines of a power system, and apply an instability prediction algorithm for initiating a special protection schemes (SPS) to avoid a sequence of relay trip events w h e n e v e r necessary. W h e n a fault happens, we group the generators swinging coherently and reduce the system to OneMachine-Infinite-Bus ( O M I B ) system. The r e m e d i a l control actions consist of load shedding and generation tripping. The strategy for d e t e r m i n i n g the a m o u n t of r e m e d i a l control actions is a proposed relay setting limited equal-area criterion for OMIB. A case study of Taiwan power system assumed to be e q u i p p e d with proposed special protection scheme is conducted. E n c o u r a g i n g results are obtained.
05•02072 An actively controlled fuel cell/battery hybrid to meet pulsed power demands Gao, L. et al. Journal qfPower Sources, 2004, 130, (1 2), 202 207. This p a p e r presents the e x p e r i m e n t a l results of an actively controlled fuel cell/battery hybrid power source topology that can be widely used in many applications, such as portable electronic devices, communication equipment, spacecraft power systems, and electric vehicles, in which the power d e m a n d is impulsive rather than constant. A stepdown D C / D C power converter is incorporated to actively control the