Condition monitoring system and wind power generation system using the same

1. A condition monitoring system for monitoring a condition of equipment configuring a wind turbine, the wind turbine including a nacelle rotatably supported on

a top of a tower, the condition monitoring system comprising:

a first detector configured to detect the condition of the equipment;

a monitor device configured to generate a diagnosis parameter based on a detection result of the first detector;

a controller configured to diagnose a failure of the equipment based on the diagnosis parameter; and

a second detector configured to detect a rotation speed of the nacelle,

the controller being configured to diagnose whether the equipment has a failure by correcting the diagnosis parameter using a relationship between a dimensionless diagnosis parameter, which is obtained by dividing the diagnosis parameter by a diagnosis parameter obtained during non-rotation of the nacelle, and a dimensionless rotation speed of the nacelle, which is obtained by dividing the rotation speed of the nacelle calculated based on a detection result of the second detector by a maximum speed thereof, and comparing the corrected diagnosis parameter with a predetermined threshold value.

2. The condition monitoring system according to claim 1 , wherein:

the controller is configured to correct the diagnosis parameter by using a correction function with the dimensionless rotation speed of the nacelle used as a variable; and

the correction function is a function which corrects the diagnosis parameter so that as the nacelle has a higher rotation speed, a ratio of the diagnosis parameter after the correction to the diagnosis parameter before the correction becomes smaller.

3. The condition monitoring system according to claim 2 , wherein the controller is configured to calculate an average value of the rotation speed of the nacelle in a predetermined period before the diagnosis, and correct the diagnosis parameter using the correction function based on the average value.

4. The condition monitoring system according to claim 1 , wherein:

the monitor device is configured to transmit the diagnosis parameter and a detection result of the second detector in a first period before the diagnosis to the controller;

the controller is configured to (i) store data received from the monitor device, (ii) when the first period ends, correct the diagnosis parameter of the first period based on the detection result of the second detector and (iii) generate the threshold value based on the corrected diagnosis parameter;

the monitor device is configured to transmit to the controller the diagnosis parameter obtained in a second period after the first period elapses; and

the controller is configured to correct the diagnosis parameter of the second period based on a detection result of the second detector in the second period, and diagnose whether the equipment has a failure by comparing the corrected diagnosis parameter with the threshold value.

5. The condition monitoring system according to claim 1 , wherein the controller is configured to correct the diagnosis parameter based on the rotation speed of the nacelle obtained from information from SCADA (Supervisory Control and Data Acquisition) separately monitoring the wind turbine.

6. The condition monitoring system according to claim 1 , wherein the second detector includes at least one of a direction sensor, a gyro sensor, and a GPS (Global Positioning System).

7. The condition monitoring system according to claim 1 , wherein the second detector includes a detector to detect at least one of a driving current and a driving voltage of a drive device driving the nacelle.

8. A wind power generation system comprising:

the wind turbine; and

the condition monitoring system according to claim 1 .