The Research Of Inhibiting Arc Overvoltage Caused By Lightning With Air-Blast Interruption

When lightning strike cause transmission line insulator to flash, if single-phase grounding power frequency arc can not burn stably, sometimes burning or going out, it will cause arc overvoltage throughout the whole system and affect the safe operation of the system. This paper presents the application of air-blast interruption, it can let lightning current into the earth quickly and its high speed explosive airflow quench power frequency arc current rapidly at the same time, prevent to form the intermittent arc and inhibit arc overvoltage.The second chapter of the paper introduces arc grounding overvoltage formative and developing process based on frequency arc extinguish theory, and calculates the air gap length of the air-blast interruption to meet the insulation coordination. On the basis of the chain current model in the third chapter, the paper establishes the arc motion model under the jet airflow through magnetic force calculation、air friction computation and wind load calculation of air-blast parallel gap, simulate and analyze the motion state and time extinguishing characteristic of power frequency AC arc at the air-blast interruption under different jet airflow speed. Based on mayr arc model of matlab the fourth chapter builds the air-blast interruption model and35kV small current grounding system, and simulate single-phase short circuit fault arc overvoltage caused by lightning and arc extinguishing effect about neutral point grouding by arc suppression coil, small resistance and installing air-blast interruption gap. Arc test of air-blast interruption gap device is experimentized in the high voltage laboratory; the whole arc quenching process is to shoot using high speed camera, electrical signal of the device and arc extinction test waveforms are got by the digital oscilloscope.the simulation and the experiment in high voltage laboratory shows that the air-blast interruption gap can extinguish the grounding power frequency arc current quickly, and quench arc overvoltage.