低气压下的直流电弧特性

Characteristic of DC Arc Under Low Air Pressure

低气压下绝缘子污闪放电过程中局部电弧存在飘离绝缘子表面形成空气间隙电弧的现象。为研究低气压下沿面电弧和空气间隙电弧特性并确定二者的差异,利用三角形玻璃平板和铜球电极在人工气候室分别测试了低气压沿面直流电弧和空气间隙直流电弧特性。结果表明：随着气压降低,沿面直流电弧和空气间隙直流电弧的E-I特性明显下降;同等条件下,单位长度沿面直流电弧电压高于单位长度空气间隙直流电弧电压;泄漏电流为0.1-0.5A时,空气间隙直流电弧和沿面直流电弧的E-I特性均可按幂指数或线性表示;空气间隙直流电弧特性受气压的影响程度较沿面直流电弧特性大。研究结果为进一步揭示低气压下绝缘子串直流污闪放电机理打下了基础。

The partial are may derive from the surface of polluted insulator string and form the air gap arc during the pollution flashover process at low air pressure. Using the triangle glass plate and copper sphere electrode separately, the air gap dc arc characteristic and surface dc arc performance under low air pressure were tested in the artificial climate chamber to confirm the difference between them. The experimental results show that： the curve of E-I characteristic, of air gap dc arc and surface dc arc may turn down under lower air pressure, the voltage of surface dc arc per length is higher than that of air gap dc arc per length at the same conditions, the E-I characteristic of air gap dc arc and surface dc arc can be described as power function or linear function when the leakage current is in the range of 0.1-0.5 A, and the influence of air pressure on air gap de arc characteristic is more obvious than that of surface de arc. These results can offer a theoretical basis for deeply investigating dc pollution flashover mechanism of insulator string under low air pressure.