This paper introduces the concepts of platformless DC connections of offshore wind turbines. First, the paper describes the possible and preferred wind turbine drivetrain arrangements capable of producing sufficiently high DC voltage. Then, the electrical system designs appropriate for the platformless DC architectures are discussed. After that, the potential economic benefits of direct DC conn...

With the wind turbines being produced toward to large scale and light weight, the flexibility of blade, drive mechanism and tower increase apparently. Loads suffered by wind turbines during operation become increasingly intricate. Some control approaches could be used to cut down these loads in orde to expand life cycle of generating sets. Aiming at the full load operation zone above rated wind...

Three models for detecting abnormalities of wind turbine vibrations reflected in time domain are discussed. The models were derived from the supervisory control and data acquisition (SCADA) data collected at various wind turbines. The vibration of a wind turbine is characterized by two parameters, i.e., drivetrain and tower acceleration. An unsupervised data-mining algorithm, the k-means cluste...

In order to meet the demands of turbine integration into the wind park grids, advanced power converter technologies have successfully been developed by ABB. Along with the ongoing move from onshore to offshore wind installations, the system reliability, maintenance costs and product quality have come into focus to a far greater extent. Even the smallest service for offshore installations immedi...

A disturbance accommodating controller (DAC) to reject wind speed perturbations is applied on a 5MW wind turbine mounted on a tension leg platform (TLP). Multi-blade coordinate (MBC) transformation is used to address the periodicity of the floating wind turbine system. A method to apply DAC after applying MBC transformation is developed and several implementation options are presented. Simulati...

Current lidar technology is offering a promising opportunity to take a fresh look at wind turbine control. This work evaluates a flatness-based feedforward approach, that allows to calculate the control action based on trajectories of the rotor speed and tower motion using wind measurements. The trajectories are planned online considering actuator constrains to regulate the rotor speed and mini...

Floating platform concepts offer the prospect of harvesting offshore wind energy at deep water locations for countries with a limited number of suitable shallow water locations for bottom-mounted offshore wind turbines. The floating spar-buoy concept has shown promising experimental and theoretical results. Although various codes for a detailed simulation exist the purpose of this work is to el...

The demand for energy world wide is increasing every day. And in these "green times" renewable energy is a hot topic all over the world. Wind energy is currently one of the most popular energy sectors. The growth in the wind power industry has been tremendous over the last decade, its been increasing every year and it is nowadays one of the most promising sources for renewable energy. Since the...

The IEA Wind Task 30 OC4 (Offshore Code Comparison Collaboration Continuation) project was a continuation of the OC3 project of IEA Wind Task 23 Subtask 2, and was initiated due to the strong interest in continuing the work of OC3. The purpose of the project was to perform a benchmarking exercise of offshore wind turbine dynamics codes. OC4 consisted of two phases that were not considered in OC...

The dynamic stability of a coupled tower-blade wind turbine system is investigated analytically and experimentally. Coupled equations of motion and associated boundary conditions for the wind tower and a rotating blade are derived by considering the lateral acceleration of the nacelle at the tip of the tower, which is the base of the flexible blade. The coupled eigenvalues are computed for vari...