Influence of humidity on the breakdown mechanism of medium length rod-plane gaps stressed by positive impulse voltages

Positive switching impulse discharge performance of rod‐plane short air gap under rain conditions

“…When I, γ 20 and T a varies in 1 mm/min, 100 μS/cm and 1°C, respectively, the corresponding relative change of U 50 expressed as Δ (I ) , Δ (γ20) , and Δ (Ta) , respectively, can be derived as shown below, according to (8)…”

“…7-9. From (8) and Figs. 7-9, it can be seen that U 50 decreases, respectively, with the increase in I, γ 20 and T a , with the maximum relative change of discharge voltage resulting from these factors, respectively, being about 1.43%/(mm/min), 0.1%/(100 μS/cm) and 0.33%/°C, respectively, which implies that I is the most significant one, T a the next, whereas γ 20 is the minimum and trifling.…”

“…The researches in this field mainly focus on dry and wet conditions [1][2][3][4][5][6][7][8], and so far knowledge of the discharge characteristics under rain conditions are still limited [9][10][11]. Rizk [9,10] investigated the influence of rain on the switching impulse discharge voltage of rod-plane air gap and found that the positive discharge voltage is unaffected.…”

Positive Switching Impulse Discharge Performance and Voltage Correction of 1 meter Rod-plane Air Gap

“…In [15]- [18], it is found that a linear correlation exists when the 50% breakdown voltage U50 is linked with the corresponding values of absolute humidity. In contrast with IEC, the percentage correction factor k, for U50 per g/m3 of absolute humidity is found to display values different from 1.…”

“…With the increasing absolute humidity, discharge voltage of air gap increases [15]- [18]. Reference [19] points out that humidity has little influence on discharge voltage, just within 2%.…”