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06117 A new 0–1 integer programming method of feeder reconfiguration for loss minimization in distribution systems
06
Micrdur-Plus - A New lnrulatlon system for the rtator windings of rlectrlcal mechlnes Stephan, C. E. et al., ABE Review, 1995, (8), 26-34. Recent years have witnessed a distmct trend towards electrical machines with indirectly cooled stator windings. In the case of turbogenerators, this simple and economic method of cooling has allowed an increase in unit ratings which, among other things, has imposed new and more rigorous demands on the stator winding insulation. Micadur-Pius is an improved insulation system -based on the well-known Micadur technology deveioped by ABB - that features considerably higher thermal conductivity as well as favourabie short- and long-term characteristics. 95/05115
95106116 A neural network operator oriented short-term and online load forecasting rnvlronment Sfoma, M. and Proverbio, F. Electric Power Systems Re*, May 1995,33, (2), 139-149. The paper owes its origins to a project, still in progress at ENEUARC, which aims to investigate the appiicatlon of artificial intelligence techniques and eventually to check their positive contribution in the field of short-term load forecasting. In particular, this article focuses on the construction problems of an integrated tool specifically designed to meet the needs of utility forecasters and power system operators. Even if the use of artificial neural networks for short-term forecasting had already been stressed in the past and no longer represents an innovative solution, the authors believe that their use for online forecasting in an adaptive and reliable calculation structure still represents a new subject of interest. 95106117 A new O-l integer programming method of feeder reconflauratlon for loss mlnimlzatlon In dlstrlbution svstems Sarma, R. D. and Prakasa Rao, K. S. Electric Power Systems-Res., May 1995, 33, (2). 125-131. Oneof the features provided by distribution automation which can result in substantial savings for the utilitv is feeder reconfieuration for loss minimization. Since the-composition df loads for various feeders is diffeent, and their loading patterns vary with time, there is a need for feeder reconfiguration to be carried out whenever there is a change in the loads. In this paper a new O-l integer programming method of feeder reconfiguration for loss minimization in distribution systems is proposed. The proposed method is illustrated with an example. 95106116 Nonaqueous electrolyte secondary lithium batteries Sugimoto, T. et al., (Assigned to Marsushira Electric Ind. Co.Ltd., JAP. Pat. JP.O7,37,618, Feb. 1995. (In Flemish) The batteries comprise Li-containing mixed oxide cathodes, nonaqueous
elecroiytes, rechareabie cathodes of composite carbon materials consisting of spherical graphite particles having optically anisotropic single phase, and other graphite fine particles with an average diameter smaller than that of another graphite particle. The spherical graphite particles may be manufactured by graphitization of mesocarbon microbeads from mesophase small spheres formed at carbonization of pitch. The composite carbon materials may contain 20% of the graphite fine particles to the spherical graphite particles. The graphite fine particles may be natural or synthetic graphite from petroleum or coal pitch. Power system stabilizer design vla structurally 95106119 constrained optimal control Simoes, A. 1. et al., Electric Power Systems Res.,’ Apr. 1995, 33, (l), 33-40. The paper proposes an integrated method for power system stabilizer design applicable to multimachine systems. The oarametem of all stabilizers are jdintiy determined, so that-the dynamii interactions among the system machines are properly taken into account during the design procedure. By imposing output feedback and decentralization as structural constraints on the control problem, the method provides results which are in full agreement with PSS topologies usually employed in practice. Also, it allows the design of stabilizers derived from speed, electric power, AC bus frequency, etc., or dynamical combinations of these signals. To assess the performance of the proposed method, both numerical and simulation results of its application to two distinct power systems are presented. 95106120 Probablllstlc productlon costing slmulatlon of a thermal system with a pumped-storage power pl nt Hoffer, J. Electrical Power & Energy Systems, 1995, I! , (4). 251-256. The paper presents a model and two algorithms for the cai&iation of the additional pumping generation of thermal power plants and the discharging energy of a pumped-storage power plant in a thermal system. Both aigorithms lead to the solution of a univariate global optimization problem. One of these problems provides an optimal result. The other suboptimal, as it is based on a lower estimation for the absolute value of the derivative of the equivalent load duration curve. The proposed algorithms can be applied within any load duration curve based probabilistic method, and the practical solution of any of these problems depends on the type of convolution method used. The pitfalls of using load duration curves is well known from the literature, therefore the proposed methods can be used only for medium- and long-term piannmg purposes.
Electric power generation
and utilisation
(scientific
technical)
95106121 Probability measure of adequacy arsessment using a fuzzy approach Ling, J. M. et al., EJecrric Power Systems Res., Apr. 1995, 33, (l), 7-15. An approach bvd on fuzzy set theory is developed for defiing the failure levels m assessmg the adequacy of facilitiw during the stages of operational and long-term pianmng In a power system. After analyzing the stochastic uncertainties of load variation and generation nonavailability by the probability load flow algorithm, the ‘probability measure of fuzzy events’ is proposed to combined these uncertainties and the linguistic failure inexactness to evaluate the adequacy indices of both transfer capacity and spinning reserve. The impact of load uncertainty on the adequacy assessment is investigated in nine different cases, and the resulting adequacy indices of an acutai system. Results show that the proposed fuzzy adequacy indices provide more information and a better realization than the deterministic adequacy index. 95106122 Quality control for vacuum clrcult-breakers through resldual-gas analyslr Fink, H. et al., ABE Review, 1995, (6), 39-46. No other kind of circuit-breaker is more reliable, can be more wideiv used. requires less maintenance or is environmentally kinder than the &cm& circuit-breaker. This reputation rests in large part on the high-grade materials and advanced technologies employed in the manufacture of its vacuum interrupters. Another factor is quality control, which should combine a scientific approach with state-of-the-art methods. This is because the amperages that have to be carried and interrupted - up to 50 kA at rated voltages as high a 52 kV - make excessive demands on the vacuum interrupter design. The primary goal is to maintain an ultra-high vacuum for the interrupter throughout its lifetime, i.e. at least 30 years. 95106123 Real-time simulation methpds for a six-pulse converter Haskew, T. _: A and Jackson, D. J. Electric Power Systems Res., Apr. 1995, __ ,_. __ 33, (11,W-73. The paper demonstrates the simulation of a six-pulse converter within stringent real-time constraints. A clamped-input technique was employed to reduce the computational burden at each time step and to relax the time step constraints associated with other system components which may be interacting in a system-level simulation. Additionally, unique architectural aspects of the computing platform were exploited to enhance the simuiation performance. The results and methodologies employed to obtain reaitime processing on the IBM RISC System -6000 that -are presented are intended to provide guidelines for various problems of a similar nature. 95106124 A rellablllty approach to transmlsslon expanslon planning using mlnlmal cut theory Chanda, R. S. and Bhattacharjee, P. K. Electric Power Systems Res., May 1995, 33, (2), 111-117. The paper presents a minimal cut set based a preach for the reliability evaluation of an optimally planned transmission %ystem (Part I) and obtains a configuration of transmission lines to achieve a desired failure rate set by the planner (Part II). In Part 1 an algorithm is developed to find minimal cuts which contain the system components. Overall system reliability indices are then calculated by considering that any bus failure causes system failure. In Part II the system failure rate and other reliability indices are calculated using system- first-order minimal cuts based on thd criteria that (a) the system f&h if overload occurs in a line or the bus voltage variation is greater than +/- 11% and (b) the system fails if overload in a line and bus voltage variation greater than +/- 11% occur simultaneously. 95106125 Rellablllty of supply to consumers as a function of the Installed generation reserve margln Kottick, D. et al., Electric Power Systems Res., Apr. 1995,33, (l), 63-67. The paper deals with the relation between a reliability criterion for iongrange generation system planning and the actual power not supplied to consumers in terms of unsupplied equivalent minutes. A high-reliability criterion for long-range generation system planning is reflected in a relatively high installed generation reserve margin. As a consequence, the reliability of supply to the consumers is expected to be high. A method to correlate the generation reserve margin v&h the reliability of supply to consumers has been developed. The proposed method was tested using operation data from the Israel Electric Corporation for a eriod of eight years (1986 -1993). The method could be used to predict tRe reliability of supply to consumers in the future. 95106126 The reliability of transmlsslon and dlatrlbutlon equlpment Rails, K. J. Power Engineering J., Jun. 1995, 9, (3), 109-112. An extended Editorial of the text of Keith Rails opening address at the IEE’s 2nd International Conference on The Reliability pf Transmission and Distribution Equipment, held at the University of Warwick in March 1995. 95106127 RTDE ‘95 - The Importance of equlpment rellabllity Steed, J. C. Power Ennineerinn J.. Jun. 1995. 9. 131. 142-144. A report on The Reliabaity of Transmission and’di&ibution Equipment (RTDE ‘95) conference held at the University of Warwick, UK.
Fuel and Energy Abstracts November 1995 433
Micrdur-Plus - A New lnrulatlon system for the rtator windings of rlectrlcal mechlnes Stephan, C. E. et al., ABE Review, 1995, (8), 26-34. Recent years have witnessed a distmct trend towards electrical machines with indirectly cooled stator windings. In the case of turbogenerators, this simple and economic method of cooling has allowed an increase in unit ratings which, among other things, has imposed new and more rigorous demands on the stator winding insulation. Micadur-Pius is an improved insulation system -based on the well-known Micadur technology deveioped by ABB - that features considerably higher thermal conductivity as well as favourabie short- and long-term characteristics. 95/05115
95106116 A neural network operator oriented short-term and online load forecasting rnvlronment Sfoma, M. and Proverbio, F. Electric Power Systems Re*, May 1995,33, (2), 139-149. The paper owes its origins to a project, still in progress at ENEUARC, which aims to investigate the appiicatlon of artificial intelligence techniques and eventually to check their positive contribution in the field of short-term load forecasting. In particular, this article focuses on the construction problems of an integrated tool specifically designed to meet the needs of utility forecasters and power system operators. Even if the use of artificial neural networks for short-term forecasting had already been stressed in the past and no longer represents an innovative solution, the authors believe that their use for online forecasting in an adaptive and reliable calculation structure still represents a new subject of interest. 95106117 A new O-l integer programming method of feeder reconflauratlon for loss mlnimlzatlon In dlstrlbution svstems Sarma, R. D. and Prakasa Rao, K. S. Electric Power Systems-Res., May 1995, 33, (2). 125-131. Oneof the features provided by distribution automation which can result in substantial savings for the utilitv is feeder reconfieuration for loss minimization. Since the-composition df loads for various feeders is diffeent, and their loading patterns vary with time, there is a need for feeder reconfiguration to be carried out whenever there is a change in the loads. In this paper a new O-l integer programming method of feeder reconfiguration for loss minimization in distribution systems is proposed. The proposed method is illustrated with an example. 95106116 Nonaqueous electrolyte secondary lithium batteries Sugimoto, T. et al., (Assigned to Marsushira Electric Ind. Co.Ltd., JAP. Pat. JP.O7,37,618, Feb. 1995. (In Flemish) The batteries comprise Li-containing mixed oxide cathodes, nonaqueous
elecroiytes, rechareabie cathodes of composite carbon materials consisting of spherical graphite particles having optically anisotropic single phase, and other graphite fine particles with an average diameter smaller than that of another graphite particle. The spherical graphite particles may be manufactured by graphitization of mesocarbon microbeads from mesophase small spheres formed at carbonization of pitch. The composite carbon materials may contain 20% of the graphite fine particles to the spherical graphite particles. The graphite fine particles may be natural or synthetic graphite from petroleum or coal pitch. Power system stabilizer design vla structurally 95106119 constrained optimal control Simoes, A. 1. et al., Electric Power Systems Res.,’ Apr. 1995, 33, (l), 33-40. The paper proposes an integrated method for power system stabilizer design applicable to multimachine systems. The oarametem of all stabilizers are jdintiy determined, so that-the dynamii interactions among the system machines are properly taken into account during the design procedure. By imposing output feedback and decentralization as structural constraints on the control problem, the method provides results which are in full agreement with PSS topologies usually employed in practice. Also, it allows the design of stabilizers derived from speed, electric power, AC bus frequency, etc., or dynamical combinations of these signals. To assess the performance of the proposed method, both numerical and simulation results of its application to two distinct power systems are presented. 95106120 Probablllstlc productlon costing slmulatlon of a thermal system with a pumped-storage power pl nt Hoffer, J. Electrical Power & Energy Systems, 1995, I! , (4). 251-256. The paper presents a model and two algorithms for the cai&iation of the additional pumping generation of thermal power plants and the discharging energy of a pumped-storage power plant in a thermal system. Both aigorithms lead to the solution of a univariate global optimization problem. One of these problems provides an optimal result. The other suboptimal, as it is based on a lower estimation for the absolute value of the derivative of the equivalent load duration curve. The proposed algorithms can be applied within any load duration curve based probabilistic method, and the practical solution of any of these problems depends on the type of convolution method used. The pitfalls of using load duration curves is well known from the literature, therefore the proposed methods can be used only for medium- and long-term piannmg purposes.
Electric power generation
and utilisation
(scientific
technical)
95106121 Probability measure of adequacy arsessment using a fuzzy approach Ling, J. M. et al., EJecrric Power Systems Res., Apr. 1995, 33, (l), 7-15. An approach bvd on fuzzy set theory is developed for defiing the failure levels m assessmg the adequacy of facilitiw during the stages of operational and long-term pianmng In a power system. After analyzing the stochastic uncertainties of load variation and generation nonavailability by the probability load flow algorithm, the ‘probability measure of fuzzy events’ is proposed to combined these uncertainties and the linguistic failure inexactness to evaluate the adequacy indices of both transfer capacity and spinning reserve. The impact of load uncertainty on the adequacy assessment is investigated in nine different cases, and the resulting adequacy indices of an acutai system. Results show that the proposed fuzzy adequacy indices provide more information and a better realization than the deterministic adequacy index. 95106122 Quality control for vacuum clrcult-breakers through resldual-gas analyslr Fink, H. et al., ABE Review, 1995, (6), 39-46. No other kind of circuit-breaker is more reliable, can be more wideiv used. requires less maintenance or is environmentally kinder than the &cm& circuit-breaker. This reputation rests in large part on the high-grade materials and advanced technologies employed in the manufacture of its vacuum interrupters. Another factor is quality control, which should combine a scientific approach with state-of-the-art methods. This is because the amperages that have to be carried and interrupted - up to 50 kA at rated voltages as high a 52 kV - make excessive demands on the vacuum interrupter design. The primary goal is to maintain an ultra-high vacuum for the interrupter throughout its lifetime, i.e. at least 30 years. 95106123 Real-time simulation methpds for a six-pulse converter Haskew, T. _: A and Jackson, D. J. Electric Power Systems Res., Apr. 1995, __ ,_. __ 33, (11,W-73. The paper demonstrates the simulation of a six-pulse converter within stringent real-time constraints. A clamped-input technique was employed to reduce the computational burden at each time step and to relax the time step constraints associated with other system components which may be interacting in a system-level simulation. Additionally, unique architectural aspects of the computing platform were exploited to enhance the simuiation performance. The results and methodologies employed to obtain reaitime processing on the IBM RISC System -6000 that -are presented are intended to provide guidelines for various problems of a similar nature. 95106124 A rellablllty approach to transmlsslon expanslon planning using mlnlmal cut theory Chanda, R. S. and Bhattacharjee, P. K. Electric Power Systems Res., May 1995, 33, (2), 111-117. The paper presents a minimal cut set based a preach for the reliability evaluation of an optimally planned transmission %ystem (Part I) and obtains a configuration of transmission lines to achieve a desired failure rate set by the planner (Part II). In Part 1 an algorithm is developed to find minimal cuts which contain the system components. Overall system reliability indices are then calculated by considering that any bus failure causes system failure. In Part II the system failure rate and other reliability indices are calculated using system- first-order minimal cuts based on thd criteria that (a) the system f&h if overload occurs in a line or the bus voltage variation is greater than +/- 11% and (b) the system fails if overload in a line and bus voltage variation greater than +/- 11% occur simultaneously. 95106125 Rellablllty of supply to consumers as a function of the Installed generation reserve margln Kottick, D. et al., Electric Power Systems Res., Apr. 1995,33, (l), 63-67. The paper deals with the relation between a reliability criterion for iongrange generation system planning and the actual power not supplied to consumers in terms of unsupplied equivalent minutes. A high-reliability criterion for long-range generation system planning is reflected in a relatively high installed generation reserve margin. As a consequence, the reliability of supply to the consumers is expected to be high. A method to correlate the generation reserve margin v&h the reliability of supply to consumers has been developed. The proposed method was tested using operation data from the Israel Electric Corporation for a eriod of eight years (1986 -1993). The method could be used to predict tRe reliability of supply to consumers in the future. 95106126 The reliability of transmlsslon and dlatrlbutlon equlpment Rails, K. J. Power Engineering J., Jun. 1995, 9, (3), 109-112. An extended Editorial of the text of Keith Rails opening address at the IEE’s 2nd International Conference on The Reliability pf Transmission and Distribution Equipment, held at the University of Warwick in March 1995. 95106127 RTDE ‘95 - The Importance of equlpment rellabllity Steed, J. C. Power Ennineerinn J.. Jun. 1995. 9. 131. 142-144. A report on The Reliabaity of Transmission and’di&ibution Equipment (RTDE ‘95) conference held at the University of Warwick, UK.
Fuel and Energy Abstracts November 1995 433