In order to study the arcing characteristics of the short-circuit arc in the air due to the single-phase grounding of the 66 kV Petersen-coil grounding system

an artificial single-phase grounding test simulation platform is set up in the substation. The grounding arc is tested at conditions of Petersen-coil compensation current of 92.8 A

97.9 A and 103.3 A

and the voltage and current waveform is recorded. The test results show that the frequency characteristics of the grounding arc does not change with the compensation degree of the Petersen-coil. The arc channel resistance at the initial time is related to the closing angle

the larger the closing angle is

the greater the arc channel resistance is. Under the stable arcing state

the voltage variation rate of half cycle does not change with the compensation degree of Peterson-coil

which is 120 kV/s

while the current variation rate increases with the compensation degree of Petersen-coil

which are 12 kA/s

14 kA/s and 16 kA/s respectively. In different periods after the stable arcing

the arc volt-ampere curves are inconsistent

but its development is the same. The voltage amplitude after stable arcing has nothing to do with the compensation degree of the Petersen-coil. The difference between the positive and negative amplitudes is 1 200 V. The greater the overcompensation degree of the Petersen-coil is

the higher the current amplitude is

and its amplitude can reach 80 A. The research results can provide a theoretical reference base for the parameter setting of the Petersen-coil.