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 t.sub.0 to a time t.sub.1 so that the rotation frequency of the rotor of the synchronous generator is, at time t.sub.1 equal to the frequency of the grid, and closing the circuit breaker at time t.sub.1. 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.

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 t.sub.0 to a time t.sub.1 so that the rotation frequency of the rotor of the synchronous generator is, at time t.sub.1 equal to the frequency of the grid, and closing the circuit breaker at time t.sub.1. 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.

An underground hydraulic system is disclosed, the system comprising an intake tunnel (2) connected to a body of water (1), a control unit (3) arranged to control flow of water from the body of water (1) into the intake tunnel (2), a distribution tunnel (5) connected to the intake tunnel (2), and at least one riser tunnel (6) connected at a lower end to the distribution tunnel (5), and arranged for receiving water from the distribution tunnel (5).

A hydroelectric apparatus includes multiple propellers to be driven by a hydraulic current, a generating module and a transmission arranged between the propellors and the generating module. Thus, the rotation of the propellors is convertible into electricity. The transmission is used to change a rotational speed of the set of propellers. The propellors are able to float on water in a canal without affecting the performance of the canal. The number of the propellors is large to produce a large torque to increase the power of the hydroelectric apparatus so that the electricity can be supplied to the public. Moreover, the small size of the hydroelectric apparatus renders the hydroelectric apparatus inexpensive and environmentally friendly.

A hydroelectric apparatus includes multiple propellers to be driven by a hydraulic current, a generating module and a transmission arranged between the propellors and the generating module. Thus, the rotation of the propellors is convertible into electricity. The transmission is used to change a rotational speed of the set of propellers. The propellors are able to float on water in a canal without affecting the performance of the canal. The number of the propellors is large to produce a large torque to increase the power of the hydroelectric apparatus so that the electricity can be supplied to the public. Moreover, the small size of the hydroelectric apparatus renders the hydroelectric apparatus inexpensive and environmentally friendly.

The invention relates to a drill fire extinguishing device (1) having: a tool holder (13) to hold or be connected to a tool; a fluid connection to supply a fluid; a turbine with an impeller that has at least one stage with a plurality of runner blades connected to the tool holder (13) to drive it in a rotary and/or percussive fashion using drive fluid via the fluid connection.

The drill fire extinguishing device (1) also has: at least one discharge opening (20) in a stationary wall (4) of the drill fire extinguishing device (1) communicating with a fluid chamber and/or a nozzle assembly (12) with one or more nozzles (18) in a stationary wall (4) of the drill fire extinguishing device (1) for dispensing the fluid and communicating with the fluid chamber.

The invention also relates to a drill fire extinguishing system and a drill bit.

A hydroelectric power generation system includes a water turbine, a generator connected to the water turbine, and a controller. The water turbine is arranged in a flow path through which a fluid flows. The controller performs a pressure control by controlling the generator to regulate a pressure of the fluid downstream of the water turbine. The pressure control includes a first control regulating the pressure in parallel with a regenerative operation of the generator, and a second control regulating the pressure in parallel with a power running operation of the generator.

An apparatus, system, and method to capture water power from head or pressure is provided utilizing pipes, inlets, and outlets. The apparatus comprises a central bore having an internal diameter suitable for a fluid flow, the fluid flow moves inside the central bore through the apparatus, and at least one outlet, the fluid flow exits the apparatus through the at least one outlet, optionally, a plurality of inlets for flowing additional fluid to the central bore mix the fluid flow with the additional fluid from the plurality of inlets. The apparatus can further mix the fluid through additional mixing devices and additional devices can be used to recapture energy such as hydroelectric power from the fluid flow. The system and method can capture water energy from the fluid flow.

An apparatus, system, and method to capture water power from head or pressure is provided utilizing pipes, inlets, and outlets. The apparatus comprises a central bore having an internal diameter suitable for a fluid flow, the fluid flow moves inside the central bore through the apparatus, and at least one outlet, the fluid flow exits the apparatus through the at least one outlet, optionally, a plurality of inlets for flowing additional fluid to the central bore mix the fluid flow with the additional fluid from the plurality of inlets. The apparatus can further mix the fluid through additional mixing devices and additional devices can be used to recapture energy such as hydroelectric power from the fluid flow. The system and method can capture water energy from the fluid flow.

An aquifer storage and recovery system can include a pump, an electric motor coupled to the pump, a drive unit configured to control operation of the electric motor, and a controller. The controller can be configured to flow water into a well bore from a source reservoir through the pump such that the pump rotates in a reverse direction and drives the electric motor coupled to the pump in the reverse direction to operate as a generator, determine a power output of the electric motor, determine a difference between the power output of the electric motor and a power output set point, and operate the drive unit to control a rotational speed of the electric motor based at least in part on the difference between the power output of the electric motor and the power output set point.