A power generating apparatus of renewable energy type which generates power using renewable energy, comprising: a blade; a rotating shaft which is rotated by the renewable energy received via the blade; a hydraulic transmission which comprises a hydraulic pump driven by the rotating shaft and a hydraulic motor driven by pressurized oil supplied from the hydraulic pump; a synchronous generator which is driven by the hydraulic motor to generate power and coupled to a grid without an intervening frequency-conversion circuit, the generated power being supplied to the grid; a transmission controller which controls the hydraulic transmission in a normal operation mode to adjust displacement of each of the hydraulic pump and the hydraulic motor such that the rotating shaft rotates at a rotational speed that is variable with respect to flow speed of the renewable energy while keeping a rotational speed of the synchronous generator at a synchronous speed based on frequency of the grid during normal operation of the power generating apparatus, a high pressure oil line connecting an outlet of the hydraulic pump to an inlet of the hydraulic motor, and an accumulator connected to the high pressure oil line, characterized in that said transmission controller controls the hydraulic transmission in a fault event response mode to adjust the displacement of the hydraulic motor such that a difference between a load torque of the synchronous generator and a torque input to the synchronous generator by the hydraulic motor decreases, and the displacement of the hydraulic pump becomes excessive with respect to the displacement of the hydraulic motor, when a terminal voltage of the synchronous generator decreases due to the fault event at a transmission line from the grid to the synchronous generator or the grid, and in that the displacement of the hydraulic pump which is excessive with respect to the displacement of the hydraulic motor is accumulated in the accumulator when the fault event occurs at the grid or the transmission line. a blade; a rotating shaft which is rotated by the renewable energy received via the blade; a hydraulic transmission which comprises a hydraulic pump driven by the rotating shaft and a hydraulic motor driven by pressurized oil supplied from the hydraulic pump; a synchronous generator which is driven by the hydraulic motor to generate power and coupled to a grid without an intervening frequency-conversion circuit, the generated power being supplied to the grid; a transmission controller which controls the hydraulic transmission in a normal operation mode to adjust displacement of each of the hydraulic pump and the hydraulic motor such that the rotating shaft rotates at a rotational speed that is variable with respect to flow speed of the renewable energy while keeping a rotational speed of the synchronous generator at a synchronous speed based on frequency of the grid during normal operation of the power generating apparatus, a high pressure oil line connecting an outlet of the hydraulic pump to an inlet of the hydraulic motor, and an accumulator connected to the high pressure oil line, characterized in that said transmission controller controls the hydraulic transmission in a fault event response mode to adjust the displacement of the hydraulic motor such that a difference between a load torque of the synchronous generator and a torque input to the synchronous generator by the hydraulic motor decreases, and the displacement of the hydraulic pump becomes excessive with respect to the displacement of the hydraulic motor, when a terminal voltage of the synchronous generator decreases due to the fault event at a transmission line from the grid to the synchronous generator or the grid, and in that the displacement of the hydraulic pump which is excessive with respect to the displacement of the hydraulic motor is accumulated in the accumulator when the fault event occurs at the grid or the transmission line.