Numerical Study on Arc Plasma Behavior During Arc Commutation Process in Direct Current Circuit Breaker

This paper focuses on the numerical investigation of arc plasma behavior during arc commutation process in a medium-voltage direct current circuit breaker(DCCB) contact system.A three-dimensional magneto-hydrodynamic(MHD) model of air arc plasma in the contact system of a DCCB is developed,based on commercial software FLUENT.Coupled electromagnetic and gas dynamic interactions are considered as usual,and a thin layer of nonlinear electrical resistance elements is used to represent the voltage drop of plasma sheath and the formation of new arc root.The distributions of pressure,temperature,gas flow and current density of arc plasma in arc region are calculated.The simulation results indicate that the pressure distribution related to the contact system has a strong effect on the arc commutation process,arising from the change of electrical conductivity in the arc root region.In DCCB contact system,the pressure of arc root region will be concentrated and higher if the space above the moving contact is enclosed,which is not good for arc root commutation.However,when the region is opened,the pressure distribution would be lower and more evenly,which is favorable for the arc root commutation.     

高气压电弧状态转换规律的蝴蝶型突变模型

阐明了高气压条件下(0.1MPa及以上)电器开断电路过程中触头间金属蒸汽电弧和气体电弧及其转换这一物理事实;根据金属蒸汽电弧向气体态电弧转换的规律和条件,应用基本突变理论,建立的反映电弧状态转换规律的蝴蝶型突变模型,使得预见和控制电弧转换成为可能.     

Numerical Simulation of Gas Flow During Arcing Process for 252 kV Puffer Circuit Breakers

A numerical simulation model for 252 kV puffer circuit breaker is constructed, by using a proven commercial computational fluid dynamics （CFD） package, PHOENICS...     

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。     

超高压GIS剩余寿命评估方法综述

探讨了目前国内外在GIS状态监测技术、剩余寿命评估方法等方面的研究现状,指出现有技术在GIS剩余寿命评估方面的缺陷,提出了超高压GIS剩余寿命评估方法的总体构想及发展趋势.     

非平衡态等离子体的仿真研究现状与新进展

非热力学平衡态等离子体技术既是现代工业的关键技术之一,也是未来高科技的重要发展方向。通过仿真研究深入揭示此类等离子体的微观机理,阐明等离子体的宏观特性变化规律,对于提高科学认知水平并促进产业发展具有重要意义。传统的仿真研究主要集中于低气压条件下的非热力学平衡态等离子体,在大气压及更高气压条件下开展较少。本文主要针对高气压非热力学平衡态等离子体,对国内外仿真模型进行了综述。非热力学平衡态等离子体一般包括局部化学平衡和非化学平衡两种状态,前者中的粒子组分可由宏观的热力学统计原理计算得到,后者必需考察微观的物理和化学过程。针对局部化学平衡态等离子体,介绍了双温度条件下微观粒子组分和宏观物理特性分布规律的计算模型,重点讨论了基于质量作用定律、吉布斯自由焓最小化原理与化学动力学方法的粒子组分计算方法;针对非化学平衡态等离子体,介绍了基于漂移-扩散原理的流体模型和化学动力学模型,提出了全局模型与流体模型的联合仿真新方法。     

The Influence of Medium on Low-Voltage Circuit Breaker Arcs

This paper mainly focuses on the influence of three kinds of media： air, air-10%PA （Nylon） and air-10% POM （polyoxymethylene） on low-voltage circuit breaker arcs. A threedimensional （3-D） model of arc motioa under the effect of external magnetic field is built based on magnetohydrodynamics （MHD） equations. By adopting the commercial computational fluid dynamics （CFD） package based on the control-volume method, the above MHD equations are solved. For the media of air-10%PA and air-10%POM, the distributions of stationary temperature and electrical potential and the transient motion processes are compared with those of air arc. The research shows that both air-10%PA and air -10% POM can cool the arc plasma and the former is more effective. Both of them can increase the stationary voltage as well. Moreover, the presence of the two mixtures can accelerate the arc motion toward the quenching area and ensures the arc quenched in time.     

电接触及电弧研究的新进展

1引言电接触与电弧现象受到关注,几乎与电工学同时起步。世界上最早关心电接触与电弧问题的是英国Johnson Matthey Company。19世纪50年代,由于在电信用途中继电器的使用,研究者选用金属铂用作     

基于振动信号的超程变化情况下断路器刚分刚合时刻识别方法研究

在断路器的长期使用过程中,由于触头磨损、螺丝松动等原因,超程将会发生改变,断路器刚分刚合时刻的确定具有较大难度。刚分刚合时刻的判断方法在超程变化情况下的准确性还未有人研究。文中以12 kV交流中压真空断路器为研究对象,搭建了断路器机械状态离线测试试验平台。在模拟多种超程量的条件下,对断路器分合闸过程中的触头换位信号与振动信号进行同步采集,采用短时能量法对振动信号进行处理,准确分析出断路器换位信号提取的分合闸时刻与振动信号提取的特征量间的对应关系。利用振动信号替代换位信号,通过对断路器分合闸过程振动信号的提取,准确判断刚分刚合时刻,获得分合闸时间。测试试验结果表明,该方法在超程改变情况下对分合闸时刻的判断误差在0.5 ms以内,提高了断路器在超程变化时机械数据的准确性,为断路器机械状态的在线监测提供了依据。