Abstract: The invention relates to a device for inspecting a damage or a crack of part of a hydro turbine, comprising at least one underwater remote operated vehicle (20) or autonomous underwater vehicle, at least one floatable or buoyant probe (26) or at least one probe (26) and means to make said at least one probe floatable, said probe comprising at least one imaging device (32) and/or laser scaler, and means for transmitting data from said probe to said vehicle or to a ground station when it is distant from said vehicle.

Abstract: The invention relates to a device (1) for inspecting a cavitation damage or a crack of a runner (7) of a hydro turbine, comprising a remote operated vehicle (20) or an autonomous underwater vehicle, comprising at least one camera and/or scanner, and means (24) for processing images from said camera and/or scanner to generate at least one 3D view and/or IR thermal view of at least a part of a surface, or of a subsurface, of said runner comprising said cavitation damage or crack, said device further comprising means to reconstruct a 3D view by photogrammetry and/or means for locally heating, for example by induction or by a laser or by a heated water jet, said at least one part of a surface of said runner comprising said cavitation or crack.

Abstract: The invention concerns a method for coupling to the grid a hydraulic unit having a synchronous generator, a runner, and wicket gates. The method includes a step of increasing the flow of water into the runner from a time t0 to a time t1 so that the rotation frequency of the rotor of the synchronous generator is, at time t1 equal to the frequency of the grid, and closing the circuit breaker at time t1. A sub-interval from a time t2 to time t1 is defined, with t0<=t2<t3<=t1, wherein a sub-step is executed to apply an adjustment torque to the shaft line via a first actuator that controls the flow of water into the runner and a second actuator coupled to a stator of the synchronous generator.

Abstract: The invention concerns a method for coupling to the grid a hydraulic unit having a synchronous generator, a runner, and wicket gates. The method includes a step of increasing the flow of water into the runner from a time t0 to a time t1 so that the rotation frequency of the rotor of the synchronous generator is, at time t1 equal to the frequency of the grid, and closing the circuit breaker at time t1. A sub-interval from a time t2 to time t1 is defined, with t0<=t2<t3<=t1, wherein a sub-step is executed to apply an adjustment torque to the shaft line via a first actuator that controls the flow of water into the runner and a second actuator coupled to a stator of the synchronous generator.

Abstract: The invention concerns a method for coupling to the grid a hydraulic unit having a synchronous generator, a runner, and wicket gates, the method comprises: a) a step of increasing the flow of water into the runner from a time t0 to a time t1 so that the rotation frequency of the rotor of the synchronous generator is, at time t1 equal to the frequency of the grid; b) a step of closing the circuit breaker at time t1, step a) further comprises a sub-step a1) executed from a time t2 to time t1, wherein the flow of water is adjusted so that, at time t1, the phase of the synchronous generator is aligned with the grid phase.

Abstract: The invention concerns a method for coupling to the grid a hydraulic unit having a synchronous generator, a runner, and wicket gates, the method comprises: a) a step of increasing the flow of water into the runner from a time t0 to a time t1 so that the rotation frequency of the rotor of the synchronous generator is, at time t1 equal to the frequency of the grid; b) a step of closing the circuit breaker at time t1, step a) further comprises a sub-step a1) executed from a time t2 to time t1, wherein the flow of water is adjusted so that, at time t1, the phase of the synchronous generator is aligned with the grid phase.