基于振动信号小波包提取和短时能量分析的高压断路器合闸同期性的研究

该文提出了一种分析高压断路器合闸同期性的新方法将小波包提取算法和短时能量分析方法相结合，利用小波包分解与重构原理将断路器合闸振动信号分解到不同频段中，并对代表高频冲击信号的分解系数进行重构，然后运用短时能量分析方法对重构后的信号进行分析，辨识出合闸变位点。通过对三相合闸过程的分析，得出三相同期性。通过MATLAB仿真分析和实验结果验证了该方法的有效性。     

断路器综合在线监测系统研制

开发了一套断路器运行状态在线监测系统,能实现包括机械、绝缘、温升等多种断路器运行特性的综合监测。该系统采用上、下位机结构,下位机是一个基于96单片机的数据采集系统,并拥有简单的人机接口,硬件设计中采用了PSD器件,大大提高了软件维护的灵活性。基于任务调度的下位机软件结构,保证了系统的稳定性和实时性。上位机实现数据的存储、状态量的显示和波形的显示;上下位机之间采用485串行通讯总线进行通讯。     

Influence of Jet Angle and Ion Density of Cathode Side on Low Current Vacuum Arc Characteristics

In this study, the influence of the initial jet angles （IJAs） and ion number densities （INDs） at the cathode side on the low current vacuum arc （LCVA） characteristics is simulated and analysed. The results show that the ion temperature, electron temperature, ion number density, axial current density and plasma pressure all decrease with the increase of the cathode IJAs. It is also shown that LCVA can cause a current constriction for lower cathode IND, and the anode sheath potential is more nonuniform, which is mainly related to the nonuniform distribution of the axial current density at the anode side.     

纳米金属粉在火炸药中应用进展

高活性、高热值纳米金属粉的应用是提高火炸药产品性能的重要途径.综述了纳米金属粉对推进剂、凝聚相炸药、云爆炸药、铝热剂的性能提高作用,总结了纳米金属粉的几种改性方法,如纳米金属/聚合物复合、纳米金属/炭复合、小分子助剂表面包覆、高分子聚合物表面接枝、气相沉积、颗粒微观整形等,指出了纳米金属粉应用研究的重点方向:纳米硼粉、...     

The Plasma Channel Evolution Characteristics of Pulsed Flashlamps Working in an Array

This work is devoted to the study of plasma channel evolution characteristics in pulsed xenon flashlamps working in an array. Influencing factors on the plasma channel evolution process are studied, including pre-ionization pulse and neighbor flashlamps. It has been found that neighbor flashlamps affect the plasma channel by shaping the electric potential distribution, rather than by Lorentz force. Branching is observed in the plasma channels of the flashlamps in the middle of the array. Inconsistency also exists in the plasma channels of these flashlamps in different tests. The branching and inconsistency are both caused by the unique electric field distribution in these flashlamps. Besides, the pre-ionization pulse can help the main pulse plasma channel to develop more smoothly and faster, which will weaken the shock wave and benefit the mechanical strength of the flashlamp.     

电弧电流以及纵向磁场对小电流真空电弧特性影响的数值仿真

建立了小电流真空电弧的双温度磁流体动力学模型,根据该模型首先对小电流真空电弧的基本特性进行了仿真研究,分析了不同电弧电流和不同纵向磁场强度对小电流真空电弧特性的影响。仿真结果表明,电弧电流和纵向磁场对小电流真空电弧特性的影响是明显的,仿真结果与实验结果基本吻合,尤其是离子温度的仿真结果与实验更加接近。另外,仿真结果还表明,对于小电流真空电弧而言,随着纵向磁场的增大,电子温度逐渐增大,变化趋势与实验结果一致。     

真空开断型环保GIS发展现状及趋势北大核心CSCD

文中对于真空开断型环保GIS的现状、趋势及关键技术进行了综述。针对深度低碳电力系统的需求,总结对比了SF_(6)混合气体、SF_(6)替代气体和真空开断+环保绝缘气体3种主流SF_(6)替代技术路线,分别介绍了SF_(6)/N_(2)混合气体、SF_(6)/CO_(2)混合气体、CF_(3)I、c-C_(4)F_(8)、C_(5)F_(10)O、C_(4)F_(7)N、HFO气体及真空开断+环保绝缘气体的技术特点与现有产品,经过对比分析认为真空开断+环保绝缘气体是一种非常有前景的SF_(6)替代手段。在此基础上,对于高电压真空灭弧室和真空开断型环保GIS的技术及产品现状进行了对比分析,总结了真空开断型环保GIS未来的发展趋势,最后讨论分析了真空开断型环保GIS在向更高电压等级发展过程中可能会面临的相关技术难点,以期为未来真空开断型环保GIS的开发和技术进步提供有益的参考。     

高密封性等离子体发生器一致性实验研究

毛细管放电等离子体发生器是电热化学炮中的关键部件,其工作特性直接影响着等离子体的点火效果。发生器工作的一致性则是实现发生器输出优化的基础,也是实现电热化学炮优势的重要保障。为验证并优化发生器的工作一致性,以放电中的电参数与射流压强作为表征参数,对一种典型的等离子体发生器设计结构开展了相同条件下的重复性实验。结果显示发生器不同次实验的输出特性一致性较差,且实验后的发生器中可见明显的烧蚀痕迹与大量炭黑。实验结果表明发生器内部密封性不足是造成输出不一致性的最主要原因。针对这一问题,设计了一种特殊截面的电极结构以增强发生器的密封性,验证性实验结果显示改进的发生器方案可明显改善发生器的内部密封性与工作一致性。     

Analysis of the Carbon Nano-Structures Formation in Liquid Arcing

Graphite electrodes were used for the direct current （DC） arc discharge in water. And high-resolution transmission electron microscopy （HRTEM） was used to investigate the products. Based on the experimental phenomena and nano-structure products, arc plasma characteristics in water were analyzed theoretically. Two growth regions and relevant growth modes were proposed to interpret the formation mechanisms of nano-structures by arc discharge in water. Furthermore, liquid nitrogen and cross magnetic field was applied to change the arcing state respectively, and new carbon nano-structures were obtained. Their formation mechanisms were also analyzed correspondingly.     

非均匀分布纵磁控制真空电弧分布的初步研究

与传统的纵向磁场与真空电弧作用的认识不同,提出了在真空灭弧室的触头间加入非均匀分布纵向磁场来抑制真空电弧在大电流下的收缩,从而提高其开断能力这一思路.设计了一种相应的电极结构,并通过计算和实验分析了它的纵向磁场分布及参数的影响.