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

Abstract

The upward leader is a key physical process of the leader progression model of lightning shielding. The inception mechanism and criterion of the upward leader need further understanding and clarification. Based on leader discharge theory, this paper proposes the critical electric field intensity of the stable upward leader (CEFISUL) and characterizes it by the valve electric field intensity on the conductor surface, E L , which is the basis of a new inception criterion for the upward leader. Through numerical simulation under various physical conditions, we verified that E L is mainly related to the conductor radius, and data fitting yields the mathematical expression of E L . We further establish a computational model for lightning shielding performance of the transmission lines based on the proposed CEFISUL criterion, which reproduces the shielding failure rate of typical UHV transmission lines. The model-based calculation results agree well with the statistical data from on-site operations, which show the effectiveness and validity of the CEFISUL criterion. V C 2012 American Institute of Physics. [http://dx.

Analysis of the lightning‐attractive radius for wind turbines considering the developing process of positive attachment leader

“…Li et al . [] has established a computational model for lightning, shielding performance of power transmission lines; however, it is assumed that the lightning strike could take place successfully when the inception condition of upward leader is satisfied. Sima et al .…”

“…Many researchers have contributed to improve this model for many years. Li et al [2012] has established a computational model for lightning, shielding performance of power transmission lines; however, it is assumed that the lightning strike could take place successfully when the inception condition of upward leader is satisfied. Sima et al [2014] has also presented an analytical method for predicting the lightning strike to transmission lines, the Rizk criterion was employed as inception criterion of positive attachment leader, and the speed ratio λ of downward/upward leader was assumed to be equal to 2.5 in their model which varies from 4 to 1 [Dellera and Garbagnati, 1990a].…”

Experimental Study on Lightning Attachment Manner to Wind Turbine Blades With Lightning Protection System

“…12(e), one upward leader incepts from the creeping discharge channel and one may incept from the edge of the receptor inside the blade and get out of the blade surface from the pinhole. Preliminary numerical simulation is done based on unstable leader inception physical model [17][18][19]. The time-dependent background electric field near the blade specimen and the charge in corona zone are calculated to evaluate whether the unstable leader will incept.…”

Transmission line vulnerability to lightning over areas of dense rainforests and large rivers in the Amazon region

“…This technique is in contrast to the use of data obtained from discharge studies in high voltage laboratories, used for generating empirical formulas, and/or numerical models [2,3,11]. For the energized overhead conductors, the electric field is evaluated with the help of formulas derived from the Combined Charge Simulation Method (CSM) [12] depending upon the voltage in kV, remembering that this field changes polarity with the transmitting frequency of the transmission line.…”

“…While normally electrical transient simulations are achieved by software based on electromagnetic models, the Monte Carlo method and others, for determining the possibility of flashover and the maximum voltages appearing on important electric devices [1], one finds in literature works that make use of different models like the LPM type (Leader Progression Model) for evaluating lightning induced flashover in transmission lines [2][3][4], a simplified approach to model construction. This paper assesses the vulnerability level of the TucuruiOriximina-Manaus 500 kV transmission line with a length of approximately 1500 km, under lightning conditions, calculating the protection levels and expected lightning flashover rates (LFR) (estimated overvoltage's due to lightning that may collapse the basic insulation level-BIL, or the insulator Critical Flashover Voltage -CFO), using an LPM model that we call ModSalto, abstracting the influence of discharges on the transmission line project and operation, by modeling the phenomenon of lightning attachment, when the discharge is irreversible, in the boundary between the atmosphere and the architecture of conductors, shield wires and support structures, for the analyzed transmission line.…”