Inorganic insulating powder can potentially be used in nuclear power plant cables, fire-resistant cables, and so on due to its high heat resistance and radiation resistance. It is of great academic and engineering value to study the dielectric properties of inorganic insulating powder. In this paper, we aim to study the nonlinear dielectric properties via the measurement of the time-domain polarization current spectrum under the application of a DC electric field. Three kinds of silica powders are measured by a measurement system with adjustable pressure. The effects of powder shape, particle size, and packing pressure and temperature on the dependence of relaxation polarization and electrical conductivity on the applied electric field are studied. The experimental results show that the relationship between electrical conductivity and the electric field of inorganic insulating powder presents two different characteristics, i.e., field-induced enhancement and field-induced weakening. The relationship between conductance and temperature shows an increase with temperature. That is, the electrical conductivity increases or decreases with the increase in temperature. The inorganic powder insulation can be regarded as a composite, which is composed of inorganic powder particles and air gaps. The interface between the powder particles and air gaps contributes a lot to the polarization of inorganic insulating powder. The phenomena (including the field-induced weakening characteristic between relaxation polarization and electric field and the decrease characteristic of polarization with increasing temperature) can be explained by a simplified interface polarization mechanism.

我国高度重视高校思想政治教育工作,思政教育是新时代高校"立德树人、铸魂育人"的根本任务.电力电子技术作为电气工程专业的主要核心内容,其配套的实验课程不仅可以与理论知识相结合,提高学生动手能力,培养电气工程专业应用型人才,还是使学生树立正确的人生观和价值观,成为品德高尚、诚实守信、团结合作、热爱党和国家的创新型人才的重要教学改革媒介.为此,课程团队在结合了电气工程专业特色和课程特点的基础上,将思政元素有机地融入了电力电子实验的实验过程、实验内容和课外环节之中,让知识讲解、德育教育和"双创"培育紧密联系,使学生的思想政治素养得到提高.

The total current of dielectrics under DC voltage consists of relaxation current and conduction current, which contains the information about the relaxation polarization and conduction. The time-domain spectrum (TDS) is an effective method to study the dielectric properties of insulating dielectrics. In this paper, the TDS method is also used to study the dielectric properties of the compressed inorganic hexagonal boron nitride (BN) and magnesium oxide (MgO) insulating powders. It is interestingly found that these inorganic insulating powders shows an abnormal TDS, where the current decreases monotonically to a certain level at first and then increases with time while in normal TDS the current decreases monotonically with time and finally reaches a steady value which is conduction current. The experiments verify that the abnormal phenomenon is attributed to the moisture absorption of powders during the testing process, which causes an increase in conductivity and leads to the increasing current at the end of testing time. The insulating powder cannot be regarded as a time-invariant system during the measurement, and the time-varying characteristic is mainly manifested in conduction. A time-domain least squares fitting method is presented and is effective to eliminate the deviation from normal TDS. The results of this paper provide a reference for dealing with abnormal TDS.

通过对机关教职工思想状况进行调研,了解和掌握机关教职工的思想动态、身心健康、生涯规划等,进而把握机关教职工现状和需求,提出进一步开展工作的方向和着力点.

基于CDIO工程教育理念,针对电力工程基础理论课的教学进行改革.通过改革课程内容、教学方法、手段和资源,建立了"教—学—研"深度融合的载体,即"项目—竞赛—软件平台",形成了CDIO工程模式下的解题路线.教改实践表明,学生的成绩得到显著提高,竞赛技能得到增强,教师的教学能力得到提升,教改实践对提高学生能力和提升教师教学水平起到了双重催化作用.

文章以S5PV210微处理器为主控芯片,设计了一种基于QT语音技术控制电缆终端巡检的系统,并通过硬件组建与软件调试给予实现.研究表明,该巡检系统及装置可以对电缆工作外场环境的温度、湿度、可燃气体浓度、人体等多数据信息及图像信息进行实时采集与反馈;并且,控制者可以通过语音对检测系统装置进行远程可视化的快速控制.系统装置简化电缆终端检测操作程度,人机对话界面可操作性强,具有较好的扩展性和实用性.

柔性直流输电技术是目前全世界各国应用比较广泛的一种直流输电技术。本文主要向读者介绍有关柔性直流输电技术方面的知识，简单介绍了柔性直流输电的特点和发展现状，对现阶段柔性直流输电技术的几个应用进行较为详细的叙述，同时分析柔性直流输电技术的发展趋势，柔性直流输电技术的良好发展对未来电网的发展具有极其重要的促进作用。

电力电子技术是一门融合了电子技术、控制技术和电力技术于一体的综合性交叉学科,是使用电力电子器件、电路理论和控制技术对电能进行处理、控制和变换的技术.随着新型电力电子器件、新的电路拓扑结构和新的控制理论的发展,电力电子技术得到了飞速发展,并广泛的应用于交通、通信、电力新能源、家电等各个领域.尤其是新能源开发应用过程中如太阳能、风能、潮汐发电等更是离不开电力电子技术.因此该课程是电气工程及其自动化专业的必修基础课程,也是实用性、工程性和综合性很强的课程.

柔性直流输电是目前通用的一种新型直流输电技术,具有方便灵活,提高交流系统电压及功角稳定性,故障恢复速度快以及损耗较低等诸多优点,其中柔性直流输电系统的雷电控制保护是保证其性能和安全性的重要环节. 1.直流输电系统耐雷性分析 柔性直流输电属于直流输电系统的范畴,现对直流输电系统的耐雷性进行简要的分析.

近些年来,随着经济的发展以及科技的进步,电气传动领域的技术也得到了很大程度的革新.特别是交流异步电动机变频调速技术的不断发展以及完善,使得交流电动机调速系统的性能得到了很大的优化,并且被广泛的应用到了社会生产的各个领域.本文通过对交流异步电动机的变频调速技术原理以及方法的研究,在分析其发展现状的基础上介绍了变频调速技术的具体应用.

针对粒子群算法存在局部最优,易陷入局部最小值的问题,提出了一种基于早熟收敛程度的惯性权重的评价方法,来动态调整惯性权重的自适应粒子群优化算法DAPSO(Dynamic Adaptive Particle Swarm Optimization),通过仿真并于其它算法相比较,验证了算法的有效性。

Moral education is an important part of higher education.Political instructors form a backbone of the moral education among university students.With the development of multi-campus universities,the development of staff faces such problems as the imbalance of resources allocation and the imperfect mechanism of management.Through a scientific and professional construction,it is possible to cultivate vigorous staff who do have general and professional knowledge and skills. The professional mechanism and promotion standards should be clearly defined.It is also necessary to train political instructors before and during their service so as to set up a system of training professional talents,to reinforce the disciplinary construction,to provide a scientific platform for professional training political instructors.

Electron traps in polyimide (PI) film were investigated by analyses of thermally stimulated depolarization current (TSDC). A broad a peak of TDSC was observed around 459K in PI which was ascribed to the release of space charge. Then we estimated electron tr ap levels in polyimide based on the theory of Simmons and found their distributed by Gaussian distribution in the range of 0.45~0.90eV. And compare the trap distributions of PI-SiO 2 and PI-Al 2 O 3 nano-composite films, give a picture of nano-particle effected on the properties of polymeric dielectric.