Fundamental investigation on the thermal transfer coefficient due to arc faults
Fundamental investigation on the thermal transfer coefficient due to arc faults
复制标题
DOI：
10.1109/tps.2006.874846
复制
发表时间：
2006-06
影响因子：
1.5
通讯作者：
Xiang Zhang;G. Pietsch;Jiaosuo Zhang;E. Gockenbach
中科院分区：
文献类型：
--
作者：
Xiang Zhang;G. Pietsch;Jiaosuo Zhang;E. Gockenbach
为了确定由于电气设备中的电弧故障引起的压力升高，必须知道加热故障电弧的周围气体的能量部分。这里采用能量部分与电能的比率，即传热系数，在文献中称为kp因子。本文提出了一种确定电气装置中压力升高的理论方法。它基于基本的水力和热力学守恒方程和气体状态方程，考虑到金属的熔化和蒸发以及与周围气体的化学反应。针对电弧能量与气体密度的关系，引入了故障电弧对能量平衡的辐射效应。在能量平衡中，考虑辐射的影响，采用更合理的电弧能量来估算气体温度和传热系数。为了方便地确定哪些因素对压力的发展有本质的影响，传热系数作为气体压力的替代变量进行了研究和评估。试验容器的结果表明，绝缘气体种类、电极材料种类、试验容器尺寸和气体密度等因素对传热系数和压力升高有很大影响
In order to determine the pressure rise due to arc faults in electrical installations, the portion of energy heating the surrounding gas of fault arcs has to be known. The ratio of the portion of energy to the electric energy, the thermal transfer coefficient, well known in literature as kp factor, is adopted here. This paper presents a theoretical approach for the determination of the pressure rise in electrical installations. It is based on the fundamental hydro- and thermodynamic conservation equations and the equation of gas state taking into account melting and evaporation of metals as well as chemical reactions with the surrounding gas. With respect to the dependence of the arc energy on gas density, the radiative effect of fault arcs on the energy balance is introduced. In consideration of the radiation, the more reasonable arc energy is applied for the estimation of the gas temperature and of the thermal transfer coefficient in the energy balance. In order to identify conveniently which factors essentially influence the development of pressure, the thermal transfer coefficient is studied and evaluated as an alternative variable of the gas pressure. The results for a test container show that factors such as the kind of insulating gases and of electrode materials, the size of test vessels, and the gas density considerably influence the thermal transfer coefficient and thus the pressure rise