Patent ID: 8840368

Claim:
An abnormal vibration detection unit for detecting an abnormal vibration of a wind turbine generator, comprising: first and second acceleration detectors each of which detects an acceleration of the wind turbine generator at a specified position of the wind turbine generator; a calculation device which receives a first analog output signal that is outputted from the first acceleration detector; a filtering relay which receives a second analog output signal that is outputted from the second acceleration detector; and a safety system which performs an emergency stop of the wind turbine generator depending on whether an output terminal of the filtering relay is open or closed, wherein the filtering relay comprises: a filter circuit part equipped with an analog circuit that performs a filtering process to extract a predetermined frequency component from the second analog output signal; an output circuit part for opening and closing the output terminal of the filtering relay in response to an output signal of the filter circuit part; and a monitor output terminal extracting the output signal of the filter circuit part to outside of the filtering relay, and wherein the calculation device receives the output signal of the filter circuit part from the monitor output terminal, generates a predicted value of the output signal of the filter circuit part by performing a digital calculation in which an operation of the filter circuit part is simulated for a value obtained from analog-digital conversion of the first analog output signal, and detects a failure of the first acceleration detector, the second acceleration detector or the filter circuit part by comparing the predicted value of the output signal of the filter circuit part with a measured value of the output signal of the filter circuit part received from the monitor output terminal.