Method for controlling, advantageously coupling to the grid, a hydraulic unit having a synchronous generator intended to be connected to a grid via a circuit breaker, a hydraulic turbine provided with a runner mechanically coupled to the rotor of the synchronous generator via a shaft line to drive the synchronous generator, and means for adjusting a torque to the shaft line, the method comprises: a) a step of adjusting, advantageously increasing, the flow of water into the runner from a time t 0 to a time t 1, t 1 being a time for which the frequency of the rotor of the synchronous generator, called generator frequency, is equal to the frequency of the grid within a first tolerance interval and the grid phase and the synchronous generator phase are aligned within a second tolerance interval, the time interval from t 0 to time t 1 comprising a sub-interval from t 2 to a time t 3, with t 0 ≤ t 2 < t 3 ≤ t 1, step a) comprising a sub-step a1) executed from a time t 2 to time t 1, wherein an adjustment torque, calculated with a controller called adjustment controller, is applied to the shaft line so that, at a time t 3, for which the generator frequency enters for the first time within the first tolerance interval, the difference between the synchronous generator phase and the grid phase, is equal to a predetermined value A within a third tolerance interval, time t 1 being the nearest time with respect to time t 3 for which the grid phase and the synchronous generator phase are aligned within the second tolerance interval, wherein the torque is adjusted via a first actuator and a second actuator, both controlled by the adjustment controller, the torque adjustment comprising: - an adjustment of the flow of water running into the runner via said first actuator; - applying an electrical torque on the rotor of the synchronous generator via said second actuator; b) a step of closing the circuit breaker at time t 1. a) a step of adjusting, advantageously increasing, the flow of water into the runner from a time t 0 to a time t 1, t 1 being a time for which the frequency of the rotor of the synchronous generator, called generator frequency, is equal to the frequency of the grid within a first tolerance interval and the grid phase and the synchronous generator phase are aligned within a second tolerance interval, the time interval from t 0 to time t 1 comprising a sub-interval from t 2 to a time t 3, with t 0 ≤ t 2 < t 3 ≤ t 1, step a) comprising a sub-step a1) executed from a time t 2 to time t 1, wherein an adjustment torque, calculated with a controller called adjustment controller, is applied to the shaft line so that, at a time t 3, for which the generator frequency enters for the first time within the first tolerance interval, the difference between the synchronous generator phase and the grid phase, is equal to a predetermined value A within a third tolerance interval, time t 1 being the nearest time with respect to time t 3 for which the grid phase and the synchronous generator phase are aligned within the second tolerance interval, wherein the torque is adjusted via a first actuator and a second actuator, both controlled by the adjustment controller, the torque adjustment comprising: - an adjustment of the flow of water running into the runner via said first actuator; - applying an electrical torque on the rotor of the synchronous generator via said second actuator; - an adjustment of the flow of water running into the runner via said first actuator; - applying an electrical torque on the rotor of the synchronous generator via said second actuator; b) a step of closing the circuit breaker at time t 1.