Abstract: A displacement system for a submersible electrical system such as a tidal turbine system, the displacement system comprising a base for the turbine or related electrical components, a vessel having a buoyant body and at least three rigid legs each displaceable relative to the body between a raised and a lowered position, and in which the base is adapted to be secured to and displaceable by the three legs in order to allow the base to be deployed or retrieved from the seabed using the legs, which legs can also be utilised to raise the body of the vessel out of the water to provide a stable work platform above the deployment site.

Abstract: The present invention provides an adaptive hydroelectric turbine system comprising a base for a hydroelectric turbine or other electrical component, the base having four ground contacting feet, at least one of which is displaceable relative to the remaining of the base such as to ensure that all four feet can contact the seabed to provide improved stability and load bearing capabilities.

Abstract: A method of controlling power provided by a generator to an end system in which power is diverted from the output of said generator to an auxiliary system during periods of excessive power output from the generator. The diverted power is stored in an energy store and, during periods of lower power output from the generator, is returned to the end system by discharging the energy store. The diversion and return of power is controlled to maintain the power delivered to the end system at a desired mean power level. Diversion of power from the generator also has the effect of preventing the generator from producing excessive voltage levels.

Abstract: A method of controlling power provided by a generator to an end system in which power is diverted from the output of said generator to an auxiliary system during periods of excessive power output from the generator. The diverted power is stored in an energy store and, during periods of lower power output from the generator, is returned to the end system by discharging the energy store. The diversion and return of power is controlled to maintain the power delivered to the end system at a desired mean power level. Diversion of power from the generator also has the effect of preventing the generator from producing excessive voltage levels.

Abstract: The present invention provides a hydroelectric turbine system comprising a base mounted turbine for location on the seabed or the like, in order to generate electricity from the tidal flow of water through the turbine, the system incorporating a load bank, for example in the form of an array of resistive windings, to which the turbine can be selectively electrically connected in order to dissipate the electrical power as heat into the passing water.

Abstract: A control system for controlling an operation of a hydroelectric turbine. The control system comprises a converter system to convert AC power, supplied by a generator connected to the turbine, and having a voltage and frequency that is a function of a rotational speed of the turbine, to AC power having a voltage and frequency of a transmission system for transmitting the AC power to a receiving station. The system further comprises a control unit that is arranged to co-operate with the converter system to adjust the AC voltage supplied by the generator in response to a water flow speed through the turbine to thereby control rotation of the turbine. The converter system comprises a first-stage converter and a second-stage converter, with a DC link provided between the first and second-stage converters. The first-stage converter is arranged to convert the AC power supplied by the generator to DC power.

Abstract: A hydroelectric turbine array system comprises an array of turbine systems and a supervisory controller. Each turbine system of the array comprises a hydroelectric turbine and a control system. The control system includes a converter system arranged to convert AC power, supplied by a generator connected to the hydroelectric turbine and having a voltage and frequency that is a function of a rotational speed of the hydroelectric turbine, to AC power having a voltage and frequency of a transmission system for transmitting the AC power to a receiving station and a control unit co-operable with the converter system to adjust the AC voltage supplied by the generator.

Abstract: The present invention provides a hydroelectric turbine for generating electricity by extracting power from the tidal flow of water through the turbine, the turbine comprising a shaftless rotor which results in the eccentric rotation of the rotor relative to the stator, which can result in uneven generation of power through differences in the spacing between rim mounted magnets and coils forming a generator of the turbine, the turbine thus employing groupings of equally spaced and serially connected coils.

Abstract: The present invention relates to a hydroelectric turbine recovery system, and in particular a system which significantly reduces the complexity of recovering a base mounted hydroelectric turbine from a deployment site on the seabed by providing a frame having an open mouth which can be advanced around the turbine before the frame is fully lowered into locking engagement with the base, thereby allowing the base, with the turbine thereon, to be recovered from the seabed.

Abstract: The present invention provides a hydroelectric turbine system comprising an array of turbines in series and a cabling system for use in connecting together adjacent turbines in the array, the cabling system being designed to allow the majority of the cabling connecting adjacent turbines to be laid substantially in line with the direction of tidal flow in order to reduce stress the cabling system when the turbines are deployed on the seabed at sites of high tidal flow.

Abstract: The present invention provides provided a hydroelectric turbine having a stator and a rotor, an array of magnets being fixed to rotor and a corresponding array of coils being fixed to the stator, the turbine further including means for cooling the coils during operation of the turbine, the cooling means preferably taking the form of one or more channels passing through the stator, in close proximity to the coils, in order to allow fluid flow through the channels to cool the coils.

Abstract: There is described a method for controlling the output of a tidal hydroelectric turbine generator from a remote location, with the need for control circuitry to be housed local to the generator. The rotational speed of the turbine, and consequently the output power level of the generator, is controlled by varying the transmission line voltage of the submarine power cable connecting the off-shore turbine with an on-shore substation.

Abstract: A method of installing an off-shore tidal hydroelectric turbine generator is described. The method provides for a number of safety features, ensuring that all components are safe to handle during the installation operation, and also ensuring that the turbine will not start spinning during the installation operation.

Abstract: The present invention provides a hydroelectric turbine support system, and in particular the combination of a base on which the turbine is supported on the seabed during use, and a vessel used to transport the turbine and base to a deployment site, and which are designed to allow, when the system is docked at a quayside or the like, the base to contact the seabed during periods of low tide and to support the vessel thereon during such periods, without damage to either the base or the vessel.

Abstract: The present invention provides a method of securing a hydroelectric turbine at a deployment site, for example on the seabed and in an area of significant tidal flow, which method enables the turbine to be located securely without risk of overturning or sliding out of position, but without requiring the use of piling or other complex fixing operations, by using the tidal flow to generate a downwardly acting force on one or more legs of a base on which the turbine is mounted.

Abstract: The present invention is concerned with a hydroelectric turbine system with aligning means which enables a hydroelectric turbine system, comprising a base and a turbine mounted thereon, to be lowered to the seabed in a running tide while effecting and maintaining stability and a desired orientation of the system.

Abstract: This present invention relates to a hydroelectric turbine having a stator and a rotor within the stator on at least one set of bearings, the turbine having a brake which becomes operational following a predetermined level of bearing wear in order to avoid damage to the turbine.