Recently, the series arc fault detection uses the main line current as decision object, which is easy to be affected by the singularity of normal working current in nonlinear load and results in misjudgment. And the arc fault characteristic in the small power branch is easily ‘submerged’ by the main circuit current, which leads to missed judgment. In order to solve this problem, according to the electromagnetic coupling mechanism of high frequency arc current, a detection method based on asymmetrical distribution of LN lines and highorder cumulant identification is presented in this paper. Through analyzing the coupling signal of high frequency residual flux during the process of arcing extinction and reignition, the kurtosis of the coupling signal is calculated by means of the highorder cumulant statistical tool. In this paper, the arc faults in different conditions such as combined load main circuit arc fault and combined load branch circuit arc fault are analyzed and judged, and the unified kurtosis threshold is obtained. The results show that the method can be effectively used to detect and identify series arc faults.