Embodiments herein describe operating a first wind turbine using an auxiliary control system when a high-voltage link coupling a wind park to a grid is not functioning. When using the auxiliary control system, the first wind turbine provides power to a local AC grid which can be used to power auxiliary system in a second wind turbine while the second wind turbine is shutdown. However, when the high-voltage link is functional, the first and second wind turbines provide power to the high-voltage link using a primary control system.

A method of performing a black start in a wind farm is provided, the wind farm including a primary black start enabled wind turbine, at least one secondary black start enabled wind turbine, and a wind farm grid interconnecting at least a part of the wind turbines in the wind farm, the method including (a) starting the primary black start enabled wind turbine in black start mode in order to supply voltage to the wind farm grid, (b) monitoring, at the at least one secondary black start enabled wind turbine, an electric parameter value in the wind farm grid, and (c) starting the at least one secondary black start enabled wind turbine in black start mode in order to supply voltage to the wind farm grid when the monitored electric parameter value meets a predetermined condition. A corresponding wind farm is also provided.

An electric air pump includes an impeller and a blower motor coupled to the impeller and configured to drive the impeller to rotate and generate air pressure. The electric air pump also includes a power interface in electrical communication with the blower motor and configured to supply alternating current to power the blower motor. The electric air pump further includes an adjustable speed motor drive electrically coupled to the power interface and the blower motor to steplessly regulate the air pressure generated by the impeller via the blower motor.

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 method for operating a plurality of wind energy installations configured for supplying electric power to an electrical supply system, that each have an aerodynamic rotor with rotor blades and an electrical generator and also operating equipment, is disclosed. The wind energy installations are operated while they are not connected to the electrical supply system, where at least one of the wind energy installations produces electric power and inputs the electric power into a local DC voltage system that connects the wind energy installations if the at least one of the wind energy installations currently produces more power than needed for supplying its own operating equipment. Additionally or alternatively, the operating equipment is supplied totally or in part with power from the local DC voltage system if the at least one of the wind energy installations currently produces less power than needed for supplying its operating equipment.

A wind turbine device including: a blade rotation speed calculator to calculate a blade rotation speed of blades of a wind turbine, the blades crossing laser light emitted by a wind measurement lidar device installed on a wind turbine nacelle of the wind turbine; a coming wind velocity calculator to calculate a coming wind velocity on a basis of a wind velocity in line-of-sight direction of the laser light, the wind velocity being obtained from the wind measurement lidar device; and a start assist controller to control a start assist for starting rotation of the blades on a basis of the blade rotation speed calculated by the blade rotation speed calculator and the coming wind velocity calculated by the coming wind velocity calculator.

There is presented a wind turbine system, wherein the wind turbine system is comprising a support structure, a plurality of wind turbine modules mounted to the support structure wherein each of the plurality of wind turbine modules comprises a rotor, and wherein the wind turbine system further comprises a control system, wherein the control is arranged to execute a wind turbine system transition from a first system operational state of the wind turbine system to a second system operational state of the wind turbine system, and wherein the wind turbine system transition is performed by executing a plurality of wind turbine module transitions from a first module operational state of a wind turbine module to a second module operational state of the wind turbine module wherein the plurality of wind turbine module transitions are distributed in time with respect to each other.

A system for starting the flight of power wing airfoils, in particular for a wind generator, comprising at least one wing profile, operatively connected through control tie-rods, to winches or other control mechanisms of a flight of such wing profile, and at least one autonomous transporting flying vector adapted to be connected through disengageable connecting means to at least one wing profile and to transport in flight such wing profile. A process is further described, for starting the flight of such power wing airfoils through such system.

A start control method for wind turbines (102), comprising: a master control determines whether its real-time wind speed reaches a preset start wind speed when a wind speed of at least one wind turbine (102) or anemometer tower in a wind farm reaches or exceeds the preset start wind speed; the master controller updates a corresponding number simulative start times when determining that its real-time wind speed reaches or exceeds the preset start wind speed, and starts the wind turbine (102) when the number of simulative start times reaches a preset count value. The present invention also relates to a master controller, a system, and a central controller for wind turbines (102).

A method for detecting an electrical fault in the stator of an electric machine is provided, wherein the stator includes multiple groups of windings, wherein the windings of each group are assigned to a respective phase of the electric machine, including the steps of: determining a respective current firstly between a subgroup of one of the groups of windings and a distinct further subgroup of the same group of windings and/or secondly between a subgroup of one of the groups of windings and a neutral point, and/or thirdly between a neutral point and either a further neutral point or to a common neutral point connected to at least the neutral point and the further neutral point, evaluating a fault condition, wherein the fulfilment of the fault condition depends on the respective determined current, and outputting a fault signal to personal and/or a device when the fault condition is fulfilled.