LTD模块气体开关电极材料烧蚀性能实验

针对直线变压器驱动源(LTD)对开关的长寿命需求,基于前期研制的200kV低抖动多间隙气体开关电极几何参数以及开关通流水平,详细开展了不同电极材料(钼、黄铜、铜钨合金、高密度石墨、304和321不锈钢)的烧蚀性能实验。实验结果表明,在单次电荷转移量15.4mC,脉冲电流20kA条件下,体积烧蚀速率从大到小依次为:石墨、黄铜、铜钨合金、钼、不锈钢。电极烧蚀微观形貌分析表明,不锈钢是用于LTD开关相对较好的电极材料。根据不锈钢电极的体积烧蚀速率,可知理论上LTD开关的运行寿命可以超过1×106次,但前提是开关外壳需保持足够的绝缘强度。

Electrode erosion performance test of LTD stage gas spark switches

To extend the lifetime of gas switches used by linear transformer drivers (LTD), electrode erosion tests for different materials (molybdenum, brass, copper-tungsten alloy, high density graphite, stainless steel 304 and 321) were conducted. These electrodes were designed according to the geometry and switching ability of the 200 kV low jitter multi-gap switches made before. Measurements show that under the condition of 20 kA peak current and 15.4 mC transferring charge, volume erosion rates decrease following the order of high density graphite, brass, copper-tungsten alloy, molybdenum and stainless steel. This relation, together with the electrode surface morphology images, shows that stainless steel works better than the other materials as LTD switch electrodes. According to the obtained volume erosion rates, the theoretical lifetime of an LTD switch using stainless steel electrodes could exceed 1 million times, provided that the insulation strength of the switch shell doesnt fail.