Vestas

About: Vestas is a company organization based out in Aarhus, Denmark. It is known for research contribution in the topics: Turbine & Wind power. The organization has 1075 authors who have published 1519 publications receiving 23285 citations. The organization is also known as: Vestas Wind Systems & Vestas Wind Systems A/S.

Cooling system for a wind turbine

Abstract: A wind turbine having a cooling system, which wind turbine includes a nacelle in connection with which one or more wind turbine components are arranged, is disclosed. The cooling system includes at least one cooling circuit arranged to lead a heat transfer medium to and from one or more of the wind turbine components, at least one cooling device arranged to cool the heat transfer medium, at least one pump arranged in connection with the at least one cooling circuit to circulate the heat transfer medium in the cooling circuit, and at least one medium tank arranged in connection with the cooling circuit. The at least one medium tank is arranged inside the nacelle.

Test rig for testing blades for a wind turbine

Abstract: A test rig for testing blades for a wind turbine includes a fixing structure where a root end of a wind turbine blade can be fixed, a loading mass structure extending from the fixing structure, and an actuation structure which can apply a sinusoidal force to the loading mass structure so that a counterbalanced resonance is established between the loading mass structure and a blade which is fixed in the fixing structure. Due to the counterbalanced resonance, the force from the test rig onto the floor or other building components can be reduced relative to that known from the traditional rigs for blade testing.

Comparative Study of Al Metallization Degradation in Power Diodes Under Passive and Active Thermal Cycling

Abstract: Degradation of Al metallization on Si-based semiconductor chips under operation is a reliability problem known for many years, but the mechanisms of this phenomenon are not fully understood. To quantify contributions of different possible effects, a passive thermal cycling setup has been developed allowing for accelerated tests by varying the device temperature on a short-time scale without applying electrical power. The setup is also capable of testing devices in different atmospheres. The results obtained by the thermal tests of diode chips are compared to those from power cycled diodes with a focus on the degradation of the top metallization layer. The data on the structural and electrical characterization of the samples show that the passive thermal cycling induces metallization degradation very similar to that found for the power-cycled devices. Thus, it can be concluded that the thermal-induced stresses are the dominating mechanisms for the metallization fatigue and the following failure. The role of oxidation and corrosion effects is also studied in the experiments on passive thermal cycling using different environmental conditions. It is suggested that the formation of self-passivating aluminum oxide under ordinary atmospheric conditions can play a positive role in limiting the structural and electrical degradation of the metallization layers. The obtained results represent a considerable contribution to an understanding of major failure mechanisms related to metallization fatigue and reconstruction.

Method for controlling the operation of a wind turbine and a wind turbine

Abstract: A method for controlling the operation of a wind turbine includes determining a first measure of a mechanical input of a component of the wind turbine, and concurrently, determining a second measure of a mechanical output of the component, determining an operating frequency response function of the component from an analysis of the relation between the first measure and the second measure, comparing the operating frequency response function with a predetermined operating frequency response function and determining a possible deviation between the two, and controlling the operation of the wind turbine so as to alter the mechanical input to the component in response to the deviation. A wind turbine that implements such a method is also disclosed.

Detecting blade structure abnormalities

Abstract: To identify abnormal behavior in a turbine blade, a failure detection system generates a "fingerprint" for each blade on a turbine. The fingerprint may be a grouping a dynamic, physical characteristics of the blade such as its mass, strain ratio, damping ratio, and the like. While the turbine is operating, the failure detection system receives updated sensor information that is used to determine the current characteristics of the blade. If the current characteristics deviate from the characteristics in the blade's fingerprint, the failure detection system may compare the characteristics of the blade that deviates from the fingerprint to characteristics of another blade on the turbine. If the current characteristics of the blade are different from the characteristics of the other blade, the failure detection system may change the operational mode of the turbine such as disconnecting the turbine from the utility grid or stopping the rotor.