Wind turbine blade, monitoring apparatus for wind turbine blade and wind power generating apparatus, and monitoring method for wind turbine blade

A monitoring apparatus for a wind turbine blade that includes a blade body and a down conductor extending along a longitudinal direction of the blade body, comprising:

• at least a pair of magnetic field sensors disposed inside the blade body and in the wind turbine blade at opposite positions across the down conductor, the pair of magnetic field sensors being configured to detect a local magnetic field at each of the positions;
• and
• a lightning-struck position information acquisition part for acquiring information about a lightning-struck position of the wind turbine blade, based on a detection signal of each of at least the pair of magnetic field sensors, wherein
• at least the pair of magnetic field sensors comprises:
• a first sensor disposed on a first axis passing through an installation position of the down conductor in a cross section intersecting the longitudinal direction;
• and
• a second sensor disposed on a second axis passing through the installation position and being orthogonal to the first axis in the cross section.

A monitoring method for a wind turbine blade that comprises a blade body and a down conductor extending along a longitudinal direction of the blade body, comprising:

• a step of detecting, by using at least a pair of magnetic field sensors disposed inside the blade body and in the wind turbine blade at opposite positions across the down conductor, a local magnetic field at each of the positions;
• and
• a step of acquiring information about a lightning-struck position of the wind turbine blade, based on a detection signal of each of at least the pair of magnetic field sensors, wherein
• at least the pair of magnetic field sensors comprises:
• a first sensor disposed on a first axis passing through an installation position of the down conductor in a cross section intersecting the longitudinal direction;
• and
• a second sensor disposed on a second axis passing through the installation position and being orthogonal to the first axis in the cross section.