Expected utility theory of Von Neumann-Morgenstern assumes that a preference order is defined for all lotteries (c1, p; c2, 1 -p) (of with probability p, c2 with probability 1 - p) for all real p, 0≤p≤1. But when th...Expected utility theory of Von Neumann-Morgenstern assumes that a preference order is defined for all lotteries (c1, p; c2, 1 -p) (of with probability p, c2 with probability 1 - p) for all real p, 0≤p≤1. But when the probability p is irrational, it is hard to interpret the lottery intuitively. The utility theory of J. C. Shepherdson is introduced based on rational probabilities in this paper. And then, this paper studies the axioms proposed by J. C. Shepherdson, and puts forward a set of alternative axioms. At last, it is shown that both sets of axioms are equivalent.展开更多
Fault current magnitude in a microgrid depends upon its mode of operation,namely,grid-connected mode or islanded mode.Depending on the type of fault in a given mode,separate protection schemes are generally employed.W...Fault current magnitude in a microgrid depends upon its mode of operation,namely,grid-connected mode or islanded mode.Depending on the type of fault in a given mode,separate protection schemes are generally employed.With the change in microgrid operating mode,the protection scheme needs to be modified which is uneconomical and time inefficient.In this paper,a novel optimal protection coordination scheme is proposed,one which enables a common optimal relay setting which is valid in both operating modes of the microgrid.In this con-text,a common optimal protection scheme is introduced for dual setting directional overcurrent relays(DOCRs)using a combination of various standard relay characteristics.Along with the two variables,i.e.,time multiplier setting(TMS)and plug setting(PS)for conventional directional overcurrent relay,dual setting DOCRs are augmented with a third variable of relay characteristics identifier(RCI),which is responsible for selecting optimal relay characteristics from the standard relay characteristics according to the IEC-60255 standard.The relay coordination problem is formulated as a mixed-integer nonlinear programming(MINLP)problem,and the settings of relays are optimally determined using the genetic algorithm(GA)and the grey wolf optimization(GWO)algorithm.To validate the superiority of the pro-posed protection scheme,the distribution parts of the IEEE-14 and IEEE-30 bus benchmark systems are considered.展开更多
基金Supported by the National Natural Science Foundation of China(No.79870034).
文摘Expected utility theory of Von Neumann-Morgenstern assumes that a preference order is defined for all lotteries (c1, p; c2, 1 -p) (of with probability p, c2 with probability 1 - p) for all real p, 0≤p≤1. But when the probability p is irrational, it is hard to interpret the lottery intuitively. The utility theory of J. C. Shepherdson is introduced based on rational probabilities in this paper. And then, this paper studies the axioms proposed by J. C. Shepherdson, and puts forward a set of alternative axioms. At last, it is shown that both sets of axioms are equivalent.
文摘Fault current magnitude in a microgrid depends upon its mode of operation,namely,grid-connected mode or islanded mode.Depending on the type of fault in a given mode,separate protection schemes are generally employed.With the change in microgrid operating mode,the protection scheme needs to be modified which is uneconomical and time inefficient.In this paper,a novel optimal protection coordination scheme is proposed,one which enables a common optimal relay setting which is valid in both operating modes of the microgrid.In this con-text,a common optimal protection scheme is introduced for dual setting directional overcurrent relays(DOCRs)using a combination of various standard relay characteristics.Along with the two variables,i.e.,time multiplier setting(TMS)and plug setting(PS)for conventional directional overcurrent relay,dual setting DOCRs are augmented with a third variable of relay characteristics identifier(RCI),which is responsible for selecting optimal relay characteristics from the standard relay characteristics according to the IEC-60255 standard.The relay coordination problem is formulated as a mixed-integer nonlinear programming(MINLP)problem,and the settings of relays are optimally determined using the genetic algorithm(GA)and the grey wolf optimization(GWO)algorithm.To validate the superiority of the pro-posed protection scheme,the distribution parts of the IEEE-14 and IEEE-30 bus benchmark systems are considered.
