A startup method of a Francis turbine according to an embodiment includes: a first rotation-speed increasing step in which a rotation speed of the runner is increased by opening the guide vane at a first opening; a second rotation-speed increasing step in which the increase in the rotation speed of the runner is accelerated by opening the guide vane at a second opening that is larger than the first opening after the first rotation-speed increasing step; and a rotation-speed regulating step in which the rotation speed of the runner is regulated to a rated rotation speed by opening the guide vane at a no-load opening after the second rotation-speed increasing step. The first opening is an opening that is half or less than the no-load opening.

Provided is a method for operating a wind turbine, an associated wind turbine and a wind park. The method comprises a) providing an indicator for the occurrence of a flow separation on a pressure side of a rotor blade of a rotor of the wind turbine, and b) changing an operational management of the wind turbine using the indicator, wherein the indicator comprises a pitch angle of the rotor blade. By using the pitch angle as an indicator, a flow separation on the pressure side of the rotor blade can be effectively prevented.

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 circular dam for generating, accumulating, storing, and releasing electrical energy comprises a wall defining a water reservoir built in an abundant body of water such as a sea or an ocean. Water inside the water reservoir is kept at a water level below the water level outside the wall so as to create a water level difference sufficient to operate one or more water turbines positioned across the wall of the water reservoir. Excess electrical energy from other renewable sources of electricity such as wind, solar power, or supplied by a local power grid is used to operate water turbines as water pumps to lower the water level inside the reservoir during times of peak supply of electricity. Water is drained from outside the wall back into the water reservoir to generate electrical energy by flowing over a plurality of water turbines. Generated electricity supplements electrical power for the local power grid during times of high demand.

The present invention relates to a self-powered remote control system for a smart valve, the system comprising: a smart valve for regulating the flow of a fluid in a pipe; a sensing module for sensing the flow rate, pressure, and temperature of the fluid in the pipe; a power generation module for generating power according to the flow of the fluid; a control module for controlling the lifting or lowering of the opening/closing plate of the smart valve according to the flow rate, pressure, or temperature state sensed by the sensing module; and an administrator terminal for transmitting and receiving control signals to and from the control module, wherein the power generation module comprises: a conical fluid guide member provided in a direction in which the fluid is supplied; and a rotating member rotated by the fluid guided through the fluid guide member, whereby the operation of the smart valve can be controlled by manipulating the administrator terminal at a remote location, so as to supply the fluid into the pipe or intercept the supply of the fluid into the pipe.

Disclosed is an apparatus that adapts the rate of its computational work to match the availability of energy harvested from a stochastic energy source; and, with respect to some types of energy harvesting, regulates the rate of energy capture, the rate of energy conversion, and the rate of consumption of stored potential energy, through its alteration, regulation, and/or adjustment, of that same computational work load.

A hydroelectric power generation system includes a water turbine disposed in a channel that carries a flow of a fluid, a generator driven by the water turbine, and a controller that performs a first control. The channel includes a first channel located on an inflow side of the water turbine. The controller controls, in the first control, a flow rate or a head of the water turbine so that any one of a pressure of the fluid in the first channel, a flow rate of the fluid in the first channel, and a liquid level of the fluid in a first reservoir from which the fluid flows out to the first channel approaches a first target value.

A startup method of a Francis turbine according to an embodiment includes: a first rotation-speed increasing step in which a rotation speed of the runner is increased by opening the guide vane at a first opening; a second rotation-speed increasing step in which the increase in the rotation speed of the runner is accelerated by opening the guide vane at a second opening that is larger than the first opening after the first rotation-speed increasing step; and a rotation-speed regulating step in which the rotation speed of the runner is regulated to a rated rotation speed by opening the guide vane at a no-load opening after the second rotation-speed increasing step. The first opening is an opening that is half or less than the no-load opening.

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.

An example system comprises an enclosure submerged in a body of water. The system also comprises an intake port disposed along a periphery of the enclosure to transport water into the enclosure. The system also includes a turbine generator disposed inside the enclosure and coupled to the intake port to receive the water entering the enclosure through the intake port. The system also comprises a water storage tank coupled to the turbine generator to receive the water flowing out of the turbine generator. The system also comprises a pump coupled to the water storage tank to pump the water out of the water storage tank. The system also comprises a controller to control flow of the water into the enclosure by operating the intake port and to control flow of the water out of the enclosure by operating the pump.