Calculation and characteristic analysis on synergistic effect of CF3I gas mixtures

CF_3I is a potential SF_6 alternative gas.In order to study the insulation properties and synergistic effects of CF_3I/N_2 and CF_3I/CO_2 gas mixtures,two-term approximate Boltzmann equations were used to obtain the ionization coefficient α,attachment coefficient η and the critical equivalent electrical field strength(E/N)_(cr).The results show that the(E/N)_(cr)of CF_3I gas at 300 K is 1.2 times that of SF_6 gas,and CF_3I/N_2 and CF_3I/CO_2 gas mixtures both have synergistic effect occurred.The synergistic effect coefficient of CF_3I/CO_2 gas mixture was higher than that of CF_3I/N_2 gas mixture.But the(E/N)_(cr)of CF_3I/N_2 is higher than that of CF_3I/CO_2 under the same conditions.When the content of CF_3I exceeds 20%,the (E/N)_(cr) of CF_3I/N_2 and CF_3I/CO_2 gas mixture increase linearly with the increasing of CF_3I gas content.The breakdown voltage of CF_3I/N_2 gas mixture is also higher than that of CF_3I/CO_2 gas mixture in slightly non-uniform electrical field under power frequency voltage,but the synergistic effect coefficients of the two gas mixtures are basically the same.     

基于频率监测网中广域电压相角的区域间振荡分析

区域间振荡会严重影响系统的正常运行,一旦线路发生连锁故障,将引发更大的系统扰动。通过频率监测网捕捉到了美国东部互联电力网发生的6例典型的区域间振荡现象并使用矩阵束方法对电压相角相对值多路数据进行了模态分析,计算了相应的振型参数,提出了每一个振荡现象案例的主模的振型,分析其结果并给出了东部互联电网的区域间振型的分布情况。     

基于电磁斥力机构的快速接地开关的仿真与设计

快速接地开关通过装置的快速动作形成的金属性短路熄灭故障电弧,从而保障设备以及人身安全。通过理论分析以及有限元仿真软件（ansoft）研究了快速接地开关最重要的两部分：电磁斥力机构以及永磁保持机构。通过改变电磁斥力机构的结构和电气参数获得了这些参数之间的关系并且设计了新型快速接地开关。仿真结果表明,样机的反应以及合闸时间都与设计相符,达到了快速接地开关的设计要求。     

新型弧光保护装置的设计

随着配电电网的发展,成套开关柜大量应用在中低压系统中。由于设备自身原因、运行环境等各种因素影响中低压母线弧光短路故障频发,对电网的供电可靠性以及操作人员的人身安全造成了极大的威胁。本文在分析中低压领域内部弧光故障产生机理的基础上设计了一种新型弧光保护系统,其组成包括超声检测模块、过电流检测模块、电弧光检测模块、逻辑处理模块及快速接地单元等。该装置不但能够实现在电弧故障发生之前发出警报信号提醒运行维护人员前来检修,还能够能在极短的时间(5ms)内将电弧故障转换为金属性短路从而熄灭故障电弧,最终再由上游断路器清除故障电流,极大地提高了中低压开关设备的可靠性。     

频率扰动录波器的设计与发展

频率是决定电力系统性能最重要的参数之一。为了加深对电网频率扰动的认识,提高电力系统在线监测水平,本课题组在2000年左右提出了建立电力系统频率监测网(Frequency Monitoring Network,FNET)的设想,经过一段时间的努力,目前已在北美地区建立了全面覆盖的频率监测信息系统。FNET系统由许多高精密的频率扰动录波器组成,这些频率扰动录波器(Frequency Disturbance recorder,FDR)可以便携地接入到110 V/220 V的电源插座上,实时获取动态的电网频率数据,并通过网络远距离传送所测得的频率数据至信息处理中心,从而实现对电网安全稳定性的实时动态监视。目前已经有超过40台频率扰动录波器部署于美国境内用来监测整个电力网络。文中总结了一些FDR已实现的设计思路并且讨论了FNET在硬件方面的研究进展。     

CF3I-N2混合气体作为SF6替代气体用于GIS/C-GIS的绝缘性能分析（英文）

CF3I has been widely considered as a potential alternative for SF6,because it has low global warming potential(GWP)but an insulation capability that is 1.2 times greater than that of SF6.In this paper,the electron swarm parameters of CF3I and its gas mixture with N2,including the effective ionization coefficient and electron drift velocity,are examined theoretically through the Boltzmann equation method in the condition of steady-state Townsend(SST)experiments.Based on the derived data of the limiting field strength of CF3I-N2gas mixture,taking into consideration of environmental aspects such as GWP,ozone depletion potential(ODP),liquefaction temperature and toxicity,we studied the possibility of applying the gas mixture as the insulation medium in gas-insulated switchgears(GIS)or cubic type gas-insulated switchgears(C-GIS).It is found that CF3I-N2gas mixtures contained 30%～70%CF3I perform comprehensively better than pure SF6and compressed N2,and especially in medium and low voltage environments,the boiling point of CF3I-N2gas mixture meets the domestic and global requirements in mid-low latitude regions.Therefore we conclude that the gas mixture is acceptable for replacing SF6as the insulation medium in C-GISs.     

挠性印制电路在高弯曲应力应用中的机械设计

从材料工艺以及应用的角度对高弯曲性能的应力分析,提出其模型的建立,实验验证以及措施。     

SF_6替代气体中绝缘子沿面闪络特性研究现状

阐述了目前国内外对SF_6替代气体中绝缘子沿面闪络特性的研究现状,介绍了气体中影响绝缘子沿面闪络的因素,指出气体的绝缘子闪络性能受气压和SF_6含量的影响最大,闪络电压通常随气压增大而增大,并呈线性关系;绝缘子形状、接触情况、湿度、温度、表面粒子的长度、粗糙度等因素对闪络性能也有一定影响。     

汤逊脉冲实验中的电磁兼容措施

分析了在汤逊脉冲实验中,测量系统和激光器的电磁兼容问题,并提出了屏蔽和接地的措施。