配电开关柜温升特性的多物理场仿真和实验

Multi-physical Field Simulation and Experiment of Temperature-rise Characteristics of Switchgear Compartment

配电开关柜散热效率不高,其内部安装的断路器等设备经常需要降容运行以满足国标允许的温升要求。为此研究了配电开关柜内生热与散热过程,探究强迫对流条件下开关柜散热能力的提升。首先利用Ansys E-mag与CFX软件模块,分别建立自然对流和强迫对流条件下的开关柜电-磁-热-流耦合仿真模型,获得开关柜内生热功率、气流速度、温度等分布;并利用温升实验平台测量开关柜关键部位的温升,与仿真结果进行对比与验证;最后,利用搭建的仿真模型,探究安装散热风扇降低开关柜温升的效果。研究结果表明:在额定电流下,开关柜进线断路器的上接线端子温升超标严重,出气口附近有较明显的回流现象,不利于热空气排出;出气口安装风扇后,散热效率明显加强,风扇风速达到3 m/s和6 m/s时,进线断路器上接线端子平均温升分别下降28.6%和42.1%。

The compartments usually operate at the reduced-current mode due to the limitation of the temperature rise. We investigated the heat generation and dissipation mechanism of a compartment, and tried to improve the heat dissipation capacity by installing fans. Firstly, Ansys E-mag and CFX were used to develop the electro-magnetic-heat-flow coupled model for the compartment with and without fans. The distributions of heat generation, air velocity, and temperature-rise were obtained. Then the calculated results were validated by the relevant tests. Finally, based on the calculation model,the thermal performance of the compartment with fans were investigated. It is found that the upper terminals of the incoming circuit breaker are beyond the limitation of the temperature-rise in the absence of fans. The recirculation can be clearly observed near outlets, which has negative effects on the elimination of the heat gas. The thermal performance of the compartment can be improved by installing fans at the outlets. The average temperature rise of the upper terminals will be decreased by 28.6% and 42.1%, when the air velocity of fans is 3 m/s and 6 m/s, respectively.