Thundercloud-Induced Spatial Ion Flow in the Neighborhood of Rotating Wind Turbine and Impact Mechanism on Corona Inception

Abstract

Lightning accidents seriously threaten safe operation of the wind turbines due to unclear initiation mechanism of the airborne lightning induced discharges on turbine blades, in which turbine rotation is one of the principal influencing factors. To study the impact mechanism of wind turbine rotation on corona discharge inception, a numerical model with dynamic meshing of charged ions in the neighboring space of large-scale rotating wind turbine during thunderstorm was established in this paper, and the validity of the model was verified by long gap discharge experiments on a scaled wind turbine. Based on the proposed model, the spatial and temporal distribution of charged particles in the neighboring area of the rotating wind turbine as well as the space charge-caused local electric field distortion scenario were obtained. The influence mechanism of blade rotation on corona discharge inception was further analyzed and elucidated accordingly. The results indicate that, the charged particles are unevenly distributed near the rotating blade tip, and the contours present a strip-like shape, the critical area of which may facilitate corona discharge inception. As the blade speed increases from 6rpm to 20rpm, the E-field extremum at the blade tip increases by 38%, causing the blade tip prone to initiate corona discharge. The critical rotating speeds corresponding to corona inception probability were calculated under different thunderclouds-determined field strengths and a safe boundary was defined, by which it is recommended that wind turbines operate at a reduced speed below 8rpm under thunderclouds conditions. Index Terms-Wind turbine, rotating blade, ion flow distribution, charge density descent vector, corona discharge I. INTRODUCTIONN recent years, wind power generation has developed on a large scale worldwide. According to the statistical data from Global Wind Energy Council (GWEC), the new installations surpassed 90GW in 2020, among which China's new wind power capacity accounted for 56%; at the end of 2020, the global cumulative wind power capacity was up to 707GW, and

Numerical Simulation of the Lightning Leader Development and Upward Leader Initiation for Rotating Wind Turbine

“…Without the influence of space charge, the E-field strength of the blade tip shows a periodic variation of rotation angle [18], as shown in Figure 7. The solid line in the figure shows the actual E-field of the blade tip after considering the shielding effect between the blades.…”

Numerical study on explosion characteristics of wind turbine blade under lightning induced arc

“…The coupled effects of heat, magnetic and airflow caused by the lightning arc may tear or break the blade, or even burn it, as shown in Fig. On the one hand, many studies have contributed to improving the lightning protection system of wind turbine blades [3]- [6]. On the other hand, the damage to blades by lightning strike can be reduced by strong mechanical structure design, which requires the study of mechanical explosion characteristics of blades under lightning induced arcs.…”