TWI700431B

Provided is a wind power generation system that has a sign diagnosis function capable of highly accurately diagnosing an abnormality by switching diagnosis reference data for each control mode. A wind power generation system 1 is provided with: a windmill controller 15 that controls a windmill 2; and a sign diagnosis device 16. The sign diagnosis device 16 is provided with: a diagnosis reference data generator 19 that receives a signal from a monitoring sensor 14 installed in the windmill 2 for at least sign diagnosis and an internal state variable which is a signal indicating a windmill control state from the windmill controller 15, and generates diagnosis reference data on the basis of the signal inputted from the monitoring sensor 14 for each internal state variable during a learning period of a sign diagnosis reference or analysis processing data necessary for executing sign diagnosis, and a diagnosis device 22 that executes diagnosis on the basis of the corresponding diagnosis reference data for each int