The existing transient-state-based method strongly relies on the realization of specific centralized device, which means additional line selection device for the substation is required, thus hinders the flexibility in allocation of distribution network protection measures. In this paper, a transient wavelet power direction selection method based on the zero sequence current and voltage fault transient components of the present interval individually is proposed. The independence of the proposed method guarantees a convenient application in protection device. RTDS simulations along with in-field tests were conducted for the verification of the transient wavelet power direction method. Simultaneously, the effectiveness of the established algorithm of grounding line selection based on transient wavelet power direction using wavelet packet transformation is verified through the field application.