Abstract: In a first aspect of the invention there is provided a method of manufacturing a wind turbine blade. The method comprises providing a mould for a shell of the wind turbine blade, the mould extending in a longitudinal direction from a root end to a tip end; providing a plurality of elongated root inserts; providing a root plate with a plurality of arcuately arranged connection points; at the connection points, connecting the root inserts to the root plate, such that the connected root inserts jointly form a contour of a portion of a root section of the wind turbine blade; and positioning the root plate relative to the mould in order to place the contour formed by the root inserts at least partially into the mould. The method further comprises providing a spacer having a decreasing thickness, and the connecting of the root inserts to the root plate comprises providing the spacer between the root inserts and the root plate.

Abstract: Aspects of the present invention relate to a method for controlling a renewable power plant connected to a power network to reduce deviation of a measured frequency of the power network from a target frequency. The method comprises determining a forecasted power gradient over a forecast interval defined between a first time point and a second time point, and, at a third time point during the forecast interval, controlling the power plant to output active power according to a minimum active power level if the measured frequency at the third time point is below the target frequency, controlling the power plant to output active power according to a maximum active power level if the measured frequency at the third time point is above the target frequency. The maximum and minimum active power levels are based on the forecasted power gradient.

Abstract: A wind turbine blade comprising a lightning protection system, which is at least partly disposed in an inboard portion of the blade. The lightning protection system comprises a plurality of inboard down conductor cables and a diverging electrical junction. The lightning protection system may comprise a down conductor cable having root and tip portions having insulation with different electrical breakdown voltages and/or a down conductor cable portion and a supporting component to hold the cable portion in free space in a position near or on a camber line of the blade aerofoil section, so that the cable portion is spaced apart from at least one electrically conductive structural component.

Abstract: An arrangement including a transmission, a feedthrough tube, and a fixing means is disclosed. A fixing means is disclosed whereby the feedthrough tube is fixed in the transmission. The fixing means includes an electrical non-conductor. Arrangements are disclosed in which the feedthrough tube is fixed axially and immovably in the fixing means.

Abstract: A wind turbine blade comprising a lightning protection system, which is at least partly disposed in an inboard portion of the blade. The lightning protection system comprises a down conductor cable portion and a supporting component to hold the cable portion in free space in a position near or on a camber line of the blade aerofoil section, so that the cable portion is spaced apart from at least one electrically conductive structural component. The lightning protection system may comprise a plurality of inboard down conductor cables and a diverging electrical junction; and/or a down conductor cable having root and tip portions having insulation with different electrical breakdown voltages.

Abstract: A method of preparing a wind turbine blade, comprising: removing at least a portion of a layer of material covering a region of a metallic part of the wind turbine blade from the wind turbine blade, applying a metal salt to the metallic part, the metal salt being arranged to oxidise a metal of the metallic part, such that the metal salt and the metal of the metallic part react and a new compound is formed on the metallic part.

Abstract: The disclosure relates to a method of operating a wind power plant, and related power plant controller and wind power plant. The method comprises determining a first active power at a first operating point and applying a first limit value for a reactive power limit. The method further comprises determining a second active power at a second operating point. The method further comprises, responsive to determining that the second active power meets one or more active power conditions referenced to the first active power, applying a second limit value for the reactive power limit. Applying the second limit value comprises limiting a ramp rate of the reactive power limit. The method further comprises generating control signals for one or more wind turbines to control a collective reactive power output of the wind power plant in accordance with the reactive power limit.

Abstract: The invention relates to a method for controlling a wind turbine system, more particular for a controlled sliding strategy to lower loads on the yaw system by controlling mechanical brakes and motor brakes in the yaw drive actuators. When the yaw system being in the non-yawing operational state, and the mechanical brake(s) being in an engaged state, and the yaw controller determines or receives a signal indicative of a yaw moment, and if the signal indicative of a yaw moment is above a signal threshold, then the yaw controller sends a braking signal to the yaw drive actuators to enter the motors into the brake state to apply a braking torque.

Abstract: Operating a renewable energy generator forming part of a renewable energy power plant. During a fault experienced by a power network: determining an active current set point to enable a reactive current supply boost at the point of connection between the plant and the network, the active current set point being based on a voltage level associated with the generator and on operational characteristics of the generator, plant, power network and/or connecting network; calculating a time period for the reactive current boost, the time period being the maximum time that the active current set point can be maintained for; and controlling the generator during the calculated time period to alter active current output to the determined active current set point, thereby providing the reactive current supply boost at the point of connection.

Abstract: The present disclosure relates to controlling an operation of a wind turbine. A first plurality of extreme load measures indicative of extreme loads experienced by at least part of the wind turbine during the first period of time are determined and a load probability characteristic is then determined based on a statistical analysis of the distribution of the first plurality of extreme load measures. A control strategy for controlling the operation of the wind turbine is then modified based at least in part on a comparison of the load probability characteristic and a design load limit and the wind turbine is then subsequently controlled in accordance with the modified control strategy for a second period of time.

Abstract: The invention provides a method for determining a wind turbine layout in a wind power plant comprising a plurality of wind turbines. The method comprises the steps of generating a plurality of random layout candidates fulfilling a set of basic requirements, and then performing a pre screening process on each of the plurality of random layout candidates. Based on the pre-screening process, a subset of layout candidates is selected and detailed optimization is performed on the layout candidates of the selected subset of layout candidates. Based on the detailed optimization, an optimized layout for the wind power plant is selected among the optimized layout candidates of the subset of layout candidates.

Abstract: The invention relates to a method for controlling power generation of a VSM wind turbine. The wind turbine comprises a machine side converter, a line side converter, a DC link, and an electric storage device electrically connected to the DC link. The method comprises determining a first power control signal to the machine side converter, determining a second power control signal for controlling a desired output power of the line side converter based on a storage device voltage error, and a power production reference, and determining a charging current reference for controlling charging and discharging of the electric storage device based on a DC-link voltage error.

Abstract: A method of assembling or disassembling a gear assembly (20) of a wind turbine (10), the gear assembly (20) comprising a first helical gear (28) and a second helical gear (24) configured for rotatable engagement with the first helical gear (28), the method comprising transmitting a control signal to cause: axial movement of the first helical gear (28) at an axial speed relative to the second helical gear (24) along a rotational axis of the first helical gear (28): and, rotational movement of the first helical gear (28) at a first rotation speed relative to the second helical gear (24) about the rotational axis of the first helical gear (28), wherein one of the axial speed and the first rotation speed is a predetermined speed, and the other of the axial speed and first rotation speed is determined in dependence on the predetermined speed, and wherein the control signal causes the axial and rotational movement of the first helical gear (28) to occur simultaneously to engage or disengage the first and second hel

Abstract: Systems, methods, and computer program products for virtual machine testing of an electric machine. A test signature including parameter values measured during one or more static tests of the electric machine is compared to a reference signature generated by performing a similar series of static tests on a reference machine. The reference machine is then validated by subjecting the reference machine to full-load dynamic testing. The test and reference signatures may include a plurality of parameters each characterizing a physical property of the respective machines in one or more physical domains. The parameters are selected so that the electric machine can be qualified for operation in the field by comparing the test signature to the reference signature, thereby avoiding the need for full-load dynamic testing of the electric machine.

Abstract: A method of forming a structural web for a wind turbine blade comprises providing a web member having a web portion and a flange portion extending away from each other, where 5 a heel of substantially curvilinear form is located between the web portion and the flange portion. A planar flange extender comprising a cured composite material is arranged together with the web member with the flange extender positioned adjacent to the flange portion so that a portion of the flange extender projects past the heel and away from the web portion. The flange extender is integrated with the web member in a resin matrix, or 10 with an adhesive, to form the structural web. A structural web and a wind turbine blade comprising the web is disclosed.

Abstract: Aspects of the present invention relate to a nacelle (14) for a wind turbine generator (10), and a method for transferring components into and out of a wind turbine generator (10). The nacelle (14) comprises a housing (26) surrounding an internal volume (24) of the nacelle (14). The housing (26) has a maintenance opening (50). The nacelle comprises a carriage (54) configured to hold a component (48), the carriage (54) being movable between a first position and a second position to transfer the component (48) through the maintenance opening (50). When the carriage (54) is in the first position, the component (48) is held within the internal volume (24). When the carriage (54) is in the second position, the component (48) is held such that at least a portion of the component (48) is outside the housing (26).

Abstract: According to an aspect of the invention there is provided a method of controlling an energy storage system to provide a frequency regulation service for a power network, to which the energy storage system is connected. The energy storage system is controlled according to one or more regulations of the power network to counteract frequency deviations within a frequency contingency deadband of the power network to provide the frequency regulation service for a service period. The energy storage system is one of a plurality of energy storage systems connected to the power network, each energy storage system being operated to counteract the frequency deviations according to the one or more regulations of the power network.

Abstract: There is provided a method for operating a renewable energy power plant comprising a plurality of renewable energy generators, the method comprising: calculating a rate of change of reactive power reference level for transitioning between a present reactive power reference level, output by a reactive power controller, and a target reactive power reference level, the target reference level being suitable for normal operation of the renewable energy power plant; and, following a fault on a power network to which the renewable energy power plant is connected, dispatching a control signal for controlling the renewable energy power plant to generate or consume reactive power at the calculated rate of change to transition the reactive power level of the renewable energy power plant to the target reactive power reference level.

Abstract: The present invention provides a method of repairing a bearing bore defined by an inner surface of a bearing housing, for instance a bearing housing that is part of a wind turbine. The method includes applying a liquid resin to at least part of the inner surface of the bearing housing. The method includes mounting a bore insert in the bearing bore, where the bore insert includes an arcuate portion having an edge positioned along a line of required radius of the bearing bore, so that the liquid resin fills a gap between the inner surface of the bearing housing and the edge of the arcuate portion of the bore insert. The method includes removing the bore insert from the bearing bore after the liquid resin has solidified to repair the bearing bore to the required radius.

Abstract: A main bearing housing for a wind turbine comprising a bearing arrangement having a sump located in a floor region of the main bearing housing. The sump comprises a floor pan surrounded by a side wall and includes an overflow arrangement configured to permit fluid to spill from the sump. The overflow arrangement comprises a spill passage configured with a spill inlet at or near the floor pan of the sump and a spill outlet located in a position between the spill inlet and an upper edge of the sump side wall. An advantage of the invention is that since the spill passage is fed with oil from a position that is close to the bottom of the sump, debris and sediment at the bottom of the sump tends to be entrained with the flow of oil and so tends not to collect at the bottom of the sump. The lubrication system therefore is able to clean the oil more effectively because the debris and sediment is encouraged to circulate around the lubrication system.