Study on Power Frequency Follow Current Interruption Test of Self Arc-extinguishing Lightning Protection Gap in 35 kV Distribution Lines

In order to verify arc-extinguishing effectiveness of self arc-extinguishing lightning protection gap in 35 kV lines before relay protection action, its power frequency current interruption capability was studied. The performance of its multi-fracture structure was determined by analyzing the arc- extinguishing mechanism of self arc-extinguishing lightning protection gap. The test was carried out in accordance with the regulation of lightning impulse discharge test and air gap distance in Chinese national standards, i.e. breakdown discharge voltage greater than 325.1 kV, air gap distance approximately 376 mm, and rated voltage 40.5 kV. According to IEC standards, a test platform of power frequency follow current interruption is built. The test platform could generate 1.2/50 μs standard lightning impulse voltage and 10 full-cycle power frequency voltage of approximately 50 Hz, and had phase selection trigger ability. The results of the power frequency follow current interruption test showed that the airflow produced by 35 kV self arc-extinguishing lightning protection gap acted most strongly on the arc at approximately 1.5 ms, and the power frequency follow current with 1.289 kA peak value was extinguished in approximately 3 ms without arc reignition phenomenon. © 2021, Power System Technology Press. All right reserved.