电力系统继电保护技术的现状与发展趋势分析

近年来,随着我国电力行业产业结构调整优化升级,使得电力系统的传输运行需要更高的继电保护技术来支持和维护。然而,现阶段由于继电技术属于外来的舶来品,在我国应用和发展的时间并没有很长的时间,因此不论在技术上,还是在设备装置方面都还存在很多的问题。对此,本文首先从现阶段,继电保护技术对我国电力系统运行发展的重要性角度出发,其次分析继电保护技术在我国电力系统发展过程中具体应用现状,最后得出继电保护技术在未来我国电力运行系统中的主要发展趋势和方向,从而不断推动我国电力行业的可持续全面发展的战略目标。

First-principles study of intrinsic defects,dopants and dopant-defect complexes in LiBH_4

A first-principles study was reported based on density functional theory of hydrogen vacancy,metal dopants,metal dopant-vacancy complex in LiBH4,a promising material for hydrogen storage.The formation of H vacancy and metal doping in LiBH4 is difficult,and their concentrations are low.The presence of one kind of defect is helpful to the formation of other kind of defect.Based on the analysis of electronic structure,the improvement of the dehydrogenating kinetics of LiBH4 by metal catalysts is due to the weaker bonding of B—H and the new metal-like system,which makes H atom diffuse easily;H vacancy accounts for a trace amount of BH3 release during the decomposing process of LiBH4;metal dopant weakens the strength of B—H bonds,which reduces the dehydriding temperature of LiBH4.The roles of metal and vacancy in the metal dopant-vacancy complex can be added in LiBH4 system.

电力系统继电保护的现状与发展趋势

目前,我国只有确保电力系统运行的稳定性、安全性、经济性、可靠性和可持续性,才能满足社会各行业对电力资源的需求。就我国电力系统继电保护的现状进行了分析和总结,展望了电力系统继电保护的发展趋势,以期为我国各行业的发展以及人们的日常生活提供更加便利、安全的电力资源。

浅析电力系统继电保护的现状与发展趋势

从当前的阶段来看,我们只有确保了电力系统的稳定运行,才能够不断的满足生产生活的需求,才能不断的适应我们未来的发展,本文电力系统继电保护的现状与发展趋势,做了一系列的深入剖析,分析了其发展的未来走向,希望对电力系统的稳定运行起到一点建议。

Design rules of pseudocapacitive electrode materials:ion adsorption,diffusion,and electron transmission over prototype TiO_(2)

The development of a high-performing pseudocapacitor requires a comprehensive understanding of electrode materials from the aspects of electron transfer and electrolyte ion adsorption and diffusion.Herein,these factors are considered over the prototype TiO_(2),and a high pseudocapacitance is achieved via the introduction of various defects,i.e.,oxygen defect(V_(O))and co-doped defect(V_(O)+N_(O)).The study is based on joint explorations of first-principle calculations and the transfer matrix method.Relative to pristine TiO_(2)(300 F g^(-1)),defective TiO_(2) produces pseudocapacitance as high as 1700 F g^(-1).Moreover,defects induce small barriers for electron transmission caused by surface band bending.The climbing image nudged elastic band diffusion of H ions displays a much higher barrier in TiO_(2)-V_(O) than in TiO_(2)-V_(O)+N_(O).Such a result indicates easy H diffusion in the co-doped system.This work provides insights into the adsorption and diffusion of electrolyte ions and the influence of defects on electron transfer.The results are also significant for the design and optimization of electrode materials for the next generation of supercapacitors.

First-principles study of He point-defects in HCP rare-earth metals

He defect properties in Sc, Y, Gd, Tb, Dy, Ho, Er and Lu were studied using first-principles calculations based on density functional theory. The results indicate that the formation energy of an interstitial He atom is smaller than that of a substitutional He atom in all hcp rare-earth metals considered. Furthermore, the tetrahedral interstitial position is more favorable than an octahedral position for He defects. The results are compared with those from bcc and fcc metals.