极不均匀电场中负直流电晕放电紫外特性

Ultraviolet Characteristics of Negative DC Corona Discharge in Extremely Non-uniform Electric Field

为了对极不均匀电场中负直流电晕放电强弱进行评估,必须对电晕放电产生的紫外光子计数进行定量分析。通过棒-板电极中负直流电晕放电进行了Trichel脉冲频率、电晕电流及紫外光子计数的测量,得到了试验电压、Trichel脉冲频率、电晕离子电流与紫外光子计数之间的相互关系。试验结果表明,在距离放电点相同距离、相同增益时,Trichel脉冲频率与试验电压近似呈线性关系,且在不同棒-板距离时,试验电压对脉冲频率的影响梯度基本相同,在3.6～4.2之间;紫外光子计数与试验电压及Trichel脉冲频率均近似呈2次方关系,而且紫外光子计数与频率在一定电极距离范围内存在固定函数关系。这一结论为紫外仪在电晕缺陷检测方面奠定了基础。

The quantitative analysis of ultraviolet photon number is fundamental to the strength assessment of corona discharges in extremely non-uniform electric fields. Hence, using a rod-plane gap, we measured the photon number and the frequency and amplitude of Trichel pulses of negative DC corona discharges. The relationship between these factors was consequently acquired. When the gain of an ultraviolet（UV） imager and its distance remained the same, the Trichel pulses＇ frequency was approximately proportional to the applied voltage. The proportional relationship had the gradient within 3.6～4.2, which was basically the same in despite of varying length of the rod-plane gap. Approximately, the photon number had a quadratic relationship to both the applied voltage and the Trichel pulses frequency, and within a specific range of the gap length, the quadratic relationship between the photon number and the frequency was constant. The conclusion lays a foundation for applying UV imager in the defect inspection with the corona occurrence.