阀厅金具大电流温升试验及仿真计算

High Current Temperature-Rise Test and Simulation Calculation of Valve Hall Fittings

随着直流输电容量的不断提升,对阀厅金具通流容量,载流的可靠性、耐热性提出了更高的要求。在直流输电工程中,阀厅金具承担着电力设备的电气连接、机械固定及均压屏蔽的作用。其运行电流大、工作电压高、散热条件较差,因此研究容量提升后现有阀厅金具的运行可靠性十分必要。以2种阀厅典型金具为研究对象,应用等效圆柱体模拟接触电阻,以及电-热耦合方法对金具温度场进行了有限元仿真计算,同时进行了大电流温升试验,使用红外热像仪等设备测量分析了铝排、绞线的分流不均现象,以及焊接、螺栓连接处的局部过热现象。大电流温升试验及仿真分析表明:在电流为5.62 k A时,试品金具存在局部过热及分流不均的现象,仿真结果与试验吻合。

The improvement of DC transmission capacity proposes a higher request on the discharge current capacity, current-carrying reliability and heat resistance of valve hall fittings. In DC transmission project, valve hall fittings undertake the function of power equipment＇s electrical connection, mechanical fixation and shielding. As the fittings operate with large current, high working voltage and poor heat dissipation, it is essential to study the reliability of existing fitting after capacity enhanced. Taking two typical valve hall fittings as research objects, equivalent cylinder was modeled as equivalent contact resistance, and thermal-electric coupled field was used for the finite element simulation. The temperature-rise test with high current was also carried out on the fittings, and the unbalanced current distribution of aluminium strip and stranded wire was surveyed and analyzed with using infrared thermal imager, as well as the local overheating phenomenon at the connection of welding and bolt. The test results and simulation analysis show that the local overheating and uneven current distribution of the fittings exist under 5620A excitation current. The simulation result agrees with temperature-rise test.