特高压变电站主设备焊缝衍射时差法检测适应性分析

针对特高压变电站主设备GIS、变压器和电抗器的使用材料、工艺结构和加工特点，提出利用衍射时差（time of flight diffraction，TOFD）超声检测法，对主设备进行焊缝缺陷检测。首先从设备的材料、母材的厚度等方面深入分析TOFD超声检测法的适应性及检测参数选择原则，并对不同厚度的铝板、钢板进行试验验证。结果表明，TOFD法检验厚度为6 mm左右和10 mm及以上的合金铝、碳钢等材料的焊缝时，采用高频率探头，能够清晰而准确地判断缺陷大小、性质、自身高度。

Adaptability Analysis of TOFD Weld Detection for UHV Substation Primary Equipment

According to the GIS, materials, craft structures and processing characteristics of UHV primary equipment, ultrasonic testing method based on time of flight diffraction (TOFD) was presented for the weld detection of primary equipment. Firstly, the adaptability and parameters selection principle of TOFD ultrasonic testing method were analysed from aspects of equipment material, base metal thickness, etc. Then, two briquettes with different thickness: aluminium alloy and carbon steel, were used for experimental verification. The results show that the welds of aluminium alloy and carbon steel with thickness of about 6 mm and 10 mm above can be detected by high frequency probe with using TOFD method, which can clearly and accurately determine the size, nature, height of defect.