unit dcu is positioned in the wind turbine hub wth whereas the sensor arrangement sea is positioned in the root of a wind turbine blade wtb now referring to fig8 a block diagram illustrating a lightning measuring system lms installed in a wind turbine wt according to an embodiment of the invention the lightning measuring system lms comprises a data collection unit dcu and a first second and third sensor arrangement sea 1 sea 2 sea 3 each sensor arrangement sea 1 sea 2 sea 3 is connected to the data collection unit dcu by a connection arrangement ca 1 ca 2 ca 3 each of the sensor arrangements sea 1 sea 2 sea 3 are arranged to measure on a down conductor dc of a separate blade of the wind turbine wt the lightning measuring system lms may furthermore optionally comprise an external communication arrangement exc for communicating data such as raw data analyzed data or parameters established based on analyzed data to an external receiver such as a scada surveillance system or similar furthermore the data collection unit dcu may typically also comprise one or more power supplies such as a 24 v dc external power supply a 230 v ac external power supply or other available voltages referring now to fig9 a lightning measuring system lms according to an embodiment of the invention.