A startup method of a Francis turbine according to an embodiment includes: a bypass-valve opening step of opening the bypass valve with the inlet valve closed; an inlet-valve opening step of opening the inlet valve after the bypass-valve opening step; and a first rotation-speed increasing step of increasing a rotation speed of the runner by opening the guide vane at an opening that is 50% or more of a maximum opening before a flow velocity of a swirling flow flowing around the runner reaches 90 m/sec.

A method for stabilizing the rotation speed of a machine with S-characteristics is provided. The method includes calculating a target net head and a target opening to affect guide vanes of the machine, the target net head and the target opening being calculated so that the torque exerted by water flow on the turbine is null and that the machine rotates at a target rotation speed; determining a real net head to which the machine is subjected; comparing the target net head with the real net head; and adjusting the opening of the guide vanes so as to converge towards the target opening and reduce a height difference between the target net head and the real net head.

A hydraulic machine has a runner, a guide apparatus, a draft tube, and an apparatus for measuring the water level in the region of the draft tube. The apparatus includes a first pressure measuring device, a second pressure measuring device, and a unit for generating differential pressure values. The pressure measuring devices are arranged in such a way that they may detect the pressures applied inside the draft tube and are respectively connected to the unit. The first pressure measuring device is located above the second pressure measuring device, and the unit is configured to generate the difference between the pressures that the pressure measuring devices detect. There is also described a method for dewatering the runner of such a hydraulic machine.

The invention concerns a method for starting a hydroelectric turbine (10) provided with a runner (6) mechanically coupled to a shaft line (8), a distributor (4) comprising leak tight guide vanes to control a flow of water to said runner, a spiral case (12) for supplying water to said runner, said spiral case comprising a duct connected to a main inlet valve (14), the method comprising: a) a step of balancing pressures on both sides of said main inlet valve (14), and of at least partially opening said main inlet valve (14), while the leak-tight guide vanes of the distributor (4) are closed, water pressurized at an upstream level being present in said spiral case and at said distributor (4); b) then a step of opening the leak-tight guide vanes of the distributor (4).

A hydropower plant for regulating the frequency of an electric grid has an upper water reservoir; a lower water reservoir; a waterway that connects the upper water reservoir with the lower water reservoir. A turbine that is arranged in the waterway includes a runner, a guide vane apparatus and a device for blowing out the runner space. An electric synchronous machine is mechanically connected to the turbine and a frequency converter is electrically connected to the synchronous machine. A mains transformer is electrically connected to the frequency converter and the mains grid. A resistor is connected in a DC intermediate circuit of the frequency converter in such a way that it may connect the line sections of the DC intermediate circuit to one another. The assembly also includes a device for cooling the resistor.

The invention concerns a method for starting a hydroelectric turbine (10) in a pumping mode, said turbine being provided with a runner (6) mechanically coupled to a shaft line (8) and a variable speed electric motor connected to a grid, a distributor (4) comprising guide vanes to control a flow of water to said runner, the method comprising: a) a step of operating the variable speed motor at least partly at fixed speed, said guide vanes being only partially opened, and of defining or calculating: data of a plurality of hydraulic characteristics (C.sub.1, C.sub.2, C.sub.i) of the turbine for an operation without cavitation; data of an operation range of the electric motor, giving the speed of the motor as a function of its power; b) then a step of operating the turbine in a power control mode.

The present invention provides a hydraulic drive train including a check valve provided in a return oil passage disposed between a branching position of a first branching oil passage and a branching position of a second branching oil passage, wherein at the time of starting of startup of the hydraulic drive train, the switching valve is closed, the opening degree of the flow rate adjusting valve is set to the initial opening degree, the on-off valve is opened, the boost pump is driven by the drive motor, and the hydraulic oil is supplied to the hydraulic pump, thereby assisting the rotational speed of the vanes by the hydraulic oil.

A hydrokinetic turbine system with dynamic tuning capabilities is disclosed. Individual hydrokinetic turbine units are dynamically tuned to accommodate changes in height and flow velocity corresponding to water in a waterway. Dynamically tuning the turbine units to accommodate waterway changes optimizes power generation output. Dynamically tuning a turbine system includes raising or lowering turbine blade height, extending or retracting turbine blade length, and narrowing or widening a turbine mouth, channel, and exit through which water flows. The hydrokinetic turbines may be arranged in an array along a waterway, and each hydrokinetic turbine in the array is connected over a controls system configured to adjust turbine characteristics at each turbine unit in the array for optimizing power generation output for the waterway in which the turbine array is installed.

A gentle start-up device includes: a rotational type hollow pipe body, including an inlet and an outlet, and having an inner wall provided with a plurality of bar-shaped fins; a transmission unit, physically connected to the rotational type hollow pipe body; and a driving unit, physically connected to the transmission unit for driving the transmission unit to rotate the rotational type hollow pipe body in a rotational direction and to achieve a predetermined rotational speed according to a water supply flow value of a water turbine of a hydraulic generator set, whereby water flow which passes through the rotational type hollow pipe body generates rotational flow.

A hydraulic machine has a runner, a guide apparatus, a draft tube, and an apparatus for measuring the water level in the region of the draft tube. The apparatus includes a first pressure measuring device, a second pressure measuring device, and a unit for generating differential pressure values. The pressure measuring devices are arranged in such a way that they may detect the pressures applied inside the draft tube and are respectively connected to the unit. The first pressure measuring device is located above the second pressure measuring device, and the unit is configured to generate the difference between the pressures that the pressure measuring devices detect. There is also described a method for dewatering the runner of such a hydraulic machine.