The Franklin lightning conductor: conditions necessary for the initiation of a connecting leader

Physical mechanism and numerical simulation of the inception of the lightning upward leader

“…When a lightning downward leader propagates gradually from the thunderclouds to the ground, a stable upward leader may emerge from elevated objects and experience three typical stages: 13 (1) The streamer discharge is incepted at the tip of the ground object with the initial corona inception; (2) the transition from streamer to leader occurs, which means an unstable upward leader inception; (3) the leader starts its continuous propagation across the air gap, representing a stable upward leader inception. As the downward leader propagates, the electric field intensity around the surface of the ground object increases gradually while the air is heated and ionized.…”

“…(13). Also, because the actual conductors used in transmission lines are not ideally smooth, we add a roughness coefficient of the conductor surface for modeling with the Peek formula of Eq.…”

Lightning protection of wind turbines — A comparison of real lightning strike data and finite element lightning attachment analysis

“…These are as follows and have been used in other papers relating to upward / downward lightning (even though these conditions have been derived from laboratory experiments for the streamer inception from Frankin rods) [19]: Equation (1) is used in determining the required background field necessary for the propagation of the leader. According to [16] (a simplified theory of Lalande's theory), for stable propagation of the leader, the atmospheric electric field E atm must be greater than the minimum value required for stable propagation of the leader E stab which is given by the following:…”

Attachment of lightning flashes to grounded structures

“…It assumes that a positive upward leader can successfully develop when the streamers from the structure ex-tend beyond a critical length equal to 0.7 m. The electric field over the streamer zone must exceed a value equal to 500 kV m -1 . A similar approach was followed by Akyuz and Cooray [97] but considering a critical streamer length of 2 m. The field intensification model was extended in [98] by assuming that the stable propagation of the incepted leader is reached if the rate of change of the potential induced by the downward leader at the tip of the rod is larger than 6 kV Ps í1 .…”