纳秒脉冲下几种液态介质绝缘性能的比对

利用自行研制的纳秒脉冲实验平台(输出脉冲前沿30 ns,半宽百纳秒)和标准介电强度测试仪,对变压器油、甘油、去离子水、Galden HT200四种液体绝缘介质在直流与纳秒脉冲下的击穿特性进行了实验研究与结果比对,结果表明:在直流与纳秒脉冲下,Galden HT200均具有最高的击穿场强,且两种情况下均比变压器油高出40%以上;纳秒脉冲下,Galden HT200与变压器油的击穿场强均提高6.5~7倍,Galden HT200击穿过程耗时最短(ns量级),其次是变压器油(20 ns),然后依次为甘油(45 ns)和去离子水(70 ns);多次放电后,粘度系数最大的甘油更易在电极间隙处聚集碳化放电产物,粘度系数较小的Galden HT200和去离子水则无明显痕迹,但二者放电过程会产生明显的冲击波,多次放电后易造成间隙电极松动。

Comparison of insulation properties of several liquid dielectrics under nanosecond pulses

Based on the self-developed nanosecond pulsed test platform with output voltage of 30 ns risetime and 100 ns half width, and the standard dielectric strength DC tester, the breakdown characteristics of four liquid dielectrics (transformer oil, glycerol, deionized water and Galden HT200) under DC and nanosecond pulses were experimentally studied and compared. The following conclusions were obtained: (1)Under both DC and nanosecond pulse, Galden HT200 has the highest breakdown field strength which is more than 40% higher than that of the transformer oil. (2) Under the nanosecond pulse, the breakdown field strength of Galden HT200 and transformer oil both increased by 6.5-7 times than those under DC. And it took the shortest time(nanosecond scale) for Galden HT200 to breakdown, followed by the transformer oil(20 ns), then glycerol(45 ns) and deionized water(70 ns). (3) After multiple breakdowns, a lot of carbonized discharge products were accumulated at the electrode gap in the glycerol which has the largest viscosity coefficient. However, there are no obvious breakdown traces in the Galden HT200 and deionized water, which both have the smaller viscosity coefficient. But obvious shock waves were observed in the Galden HT200 and deionized water, which make the gap electrodes  loose.