高压开关柜电缆室温湿度场数值计算分析

Numerical Calculation of Temperature and Humidity Fields in Cable Room of High-voltage Switchgearr

由凝露引起的开关柜事故屡见不鲜,而温度和湿度是引起凝露现象的主要因素。基于能量、动量、质量以及组分守恒定律,构建了高压开关柜电缆室热传导、空气对流以及水蒸气扩散影响下的温湿度场数学模型,并利用有限元软件Comsol进行数值计算分析,研究其温度、湿度分布规律以及凝露与温度、湿度的关系。结果表明:由于自身发热,电缆处的温度最高,同时,电缆室空气温度在热传导、对流换热作用下也逐渐升高;而湿度的分布受水蒸气的扩散和温度的综合影响,呈现先增大后减小的趋势,与温度的分布大致相反;且温度差越大,相对湿度越高,凝露越容易产生。最后,基于仿真结果提出可用于实际工程的防凝露措施,为设备防凝露提供一定的理论基础。

Dew condensation may cause switchgear accidents, and temperature and humidity are both the main factors causing dew condensation. In this paper, following the conservation laws of energy, momentum, mass and component, a mathematical model of the temperature and humidity fields in cable room of a high-voltage switchgear is established with consideration of heat conduction, air convection and water vapor diffusion. The finite element software Comsol is used to conduct numerical calculation in order to reveal the distributions of temperature and humidity as well as the relationship of dew condensation with temperature and humidity. Results show that： ①cable has the highest temperature owing to its self-heating, and air temperature in cable room gradually increases under the effects of heat conduction and convection; ② humidity distribution is influenced by both water vapor diffusion and temperature;③the humidity increases at first, then decreases, in contrast with the temperature; ④the greater the temperature difference or the higher the relative humidity is, the more possibly the dew condensation produces. Finally, according to the simulation results, some countermeasures against dew condensation are offered for engineering.