Influence of blade rotation on the lightning stroke characteristic of a wind turbine

Abstract

The blades of a wind turbine rotate during normal operation. To investigate the influence of blade rotation on the lightning‐attracting ability of a wind turbine, a discharge test platform is designed for scaled wind turbines. The 50% impulse voltages and flash probabilities of the scaled wind turbines with gap distances of 1 to 8 m in the static and rotary conditions are determined by using the discharge test and selective discharge test. The discharge test for a single wind turbine with a gap of 1 to 2 m indicates that the breakdown voltages of the gap between the scaled turbine and electrodes increases with an increase in the blade rotation speed. However, the discharge test with a gap distance of 4 to 8 m indicates that the breakdown voltage of the fan decreases with an increase in the blade rotation speed. The test results of the scaled dual wind turbines experiment have the same rules. To explain this phenomenon, the influence of wind speed on the space‐charge distribution and electrical field intensity of corona discharge is simulated in the background of a target thundercloud. The rotation of the fan reduces the space‐charge density near the area of the blade tip, which leads to an increase in the field strength near the blade tip of the wind turbine and a decrease in the field strength away from the blade tip. This influence varies in short and long air gap, resulting in opposite relationships between discharge voltage and distance from the tip of the turbine. The results can provide a reference for the lightning protection of wind turbines.

Discharge path observation and the statistical characteristics of discharge paths for long–air gap discharge for in‐operation wind turbines

“…The distance from the tip of the blade to the high‐voltage electrode must be constant when the blade is rotating so that the movement condition of the wind turbine (static or in motion) is the only variable analyzed in the test. Therefore, circular‐arc high‐voltage electrodes suitable for gap distances of 1, 2, 4, 6, and 8 m are designed and manufactured separately . The dimensions of the arc‐shaped high‐voltage electrodes with a blade length of 1.25 m are presented in Table .…”

“…Consequently, a wind turbine should be rated at the time of thunderstorm occurrence in the wind farm region. Wang et al of Wuhan University conducted a test study based on the aforementioned test and using gap distances of 1 to 8 m. When the gap distance was less than 4 m, the test results were similar to the aforementioned results by Radičević B M et al When the gap distance was 4 to 6 m, the gap breakdown voltage decreased with an increase in the blade rotation speed, which was consistent with the natural observation results. Qingmin et al performed experimental analysis on the discharge of a scaled wind turbine under positive and negative operating voltages and discovered that rotation affects the distribution of the blade flash point and the discharge channel after the flashing process.…”

Observation and Simulation of Lightning Strikes in an Offshore Wind Turbine Cluster

“…WTs have unique structures, and their lightning strike characteristics are more complex. In particular, the rotating blades of WTs are more vulnerable to lightning strikes than stationary tall buildings (Montanyà et al., 2014; D. Wang & Takagi, 2012; D. Wang et al., 2008; Y. Wang et al., 2019). Wilson et al.…”

Effects of Onshore and Offshore Environmental Parameters on the Leading Edge Erosion of Wind Turbine Blades: A Comparative Study

“…For instance, less turbulent winds are present in the offshore environment together with rainfall having varying statistical characteristics at onshore and offshore locations [25]. In addition, there are wave loads present Figure 2: Different input variables related to onshore and offshore wind turbines (Modified figure from [24]) and definition of impact angle α in the offshore environment (Figure 2) that can cause additional dynamic responses in the WT and can affect the overall erosion damage rate of WTBs. Thus, the present paper tries to provide guidelines for erosion modelling and investigates whether there are differences in erosion of blades due to (1) varying rainfall conditions modelled using different droplet size distributions for onshore and offshore locations in combination with (2) winds of varying turbulence intensities and (3) wave-induced loads.…”