纳秒脉冲下变压器油中闪络光信号特性

 对变压器油中闪络过程的光信号特性进行了分析。在预闪络阶段，光信号呈现出脉宽为2~4 ns，幅值为30~50 mV的不规则脉冲;临近闪络阶段，光信号频率更高，脉宽为1/2~1/3 ns，最高幅值也增长到约70 mV；在闪络阶段，光信号波形呈现出1个波峰或者2个波峰的形状，幅值差异显著。光信号的形状预示了闪络中流注通道的发展过程及流注通道中粒子的变化。分析表明：光电离是纳秒脉冲下变压器油中闪络的重要因素。

Optical characteristics of flashover in transformer oil under nanosecond pulses

Studying optical characteristics in the course of flashover in transformer oil is an effective way to explore breakdown mechanism of transformer oil. Optical signals were irregular pulses of 2~4 ns pulse-width and 30~50 mV amplitude at the pre-flashover stage. When approaching to flashover, the signals were turned into higher frequency one with pulse-widths of 1/2~1/3 ns and maximal amplitudes of about 70 mV, and these optical signals were immediately transformed into only one or two wave peaks having observably different amplitudes at the flashover stage. The optical signals reflected the development of streamer channels and changes of particles in channels in flashover. It is confirmed that photoionization is an important factor of flashover in transformer oil under nanosecond pulses.