In order to study the energy coupling characteristics from lightning to wind turbines

tests were designed and carried out in Guangzhou Field Experiment Base for Lightning Research and Testing of China Meteorological Administration.The trigger lightning current

induced voltage

and current inside the wind turbine tower were measured during an artificially triggered lightning experiment on July 30

2011. The trigger lightning current measured in the experiment belongs to precursor pulse current with damped oscillation waves. The analyses show that the pulse amplitude of the precursor pulse current can reach 850～1162.5 A; the spectrum is a sin

gle peak curve; the amplitude monotonically rises rapidly and reaches the peak value at the point of 351.875 kHz; then

the amplitude attenuates monotonically and rapidly; the energy of precursor pulse current mainly concentrates on the low frequency range of 0～800 kHz. The peak value of induced voltage in phase line L

2

of generator inside the wind turbine tower reaches-8.876 kV; the peak value of induced voltage in controlling line reaches 2.39 kV; the peak value of induced current in generator’s phase L

1

—L

3

circuit is 1.118 kA; the peak value of induced current in twisted pair laying circuit is only-60.55 A. The induced voltage and current in electronic and electrical circuits inside the wind turbine towers may exceed the insulation level of terminal equipment and cause damage when lightning occurs. High-permeability material can be used to shield the low frequency magnetic field caused by lightning. Energy coupling from lightning to signal lines can be reduced to the lowest level through the twisted pair wiring mode.