METHOD FOR COUPLING A HYDROELECTRIC POWER PLANT TO THE GRID COMPRISING AT LEAST TWO HYDROELECTRIC UNITS

The invention concerns a method for coupling a hydroelectric power plant in a turbine mode to a grid, in order to generate power for a grid, said hydroelectric power plant comprising at least a first hydroelectric unit (10) and a second hydroelectric unit (100), each provided with a runner (6) mechanically coupled to a shaft line (8) and to a generator, a distributor (4) comprising guide vanes to control a flow of water to said runner, said hydroelectric power plant further comprising a variable frequency drive (20), the method comprising: a) starting the rotation of at least said first hydroelectric unit (10) and said second hydroelectric unit (100); b) connecting the variable frequency drive (20) to the generator of the first hydroelectric unit (10) and to the grid and stabilizing the speed of the first hydroelectric unit c) connecting the first hydroelectric unit (10) to the grid and disconnecting the generator of the first hydroelectric unit from the variable frequency drive (20); d) connecting said variable frequency drive (20) to the generator of the second hydroelectric unit (100) and to the grid and stabilizing the speed of the second hydroelectric unit; e) connecting the second hydroelectric unit (100) to the grid and disconnecting the generator of the second hydroelectric unit from said variable frequency drive (20).