A review of offshore wind turbine nacelle: Technical challenges, and research and developmental trends

Abstract

The turbine nacelle with traditional wind power generation system is heavy, especially in offshore applications due to the large mass of the power frequency step-up transformer operated at 50 or 60 Hz, and copper conductor generator. For example, the weight and volume of a 0.69/33 kV 2.6 MVA transformer are typically in the range of 6-8 t and 5-9 m 3 , respectively. The weight for a 10 MW direct drive permanent magnet generator is about 300 t. These penalties significantly increase the tower construction, and turbine installation and maintenance costs. The tower cost represents 26% of the total component cost of the turbine and on average about 20% of the capital costs are associated with installation. Typical maintenance cost of an offshore wind turbine is about 2.3 cents/kWh, which is 20% higher than that of an onshore based turbine. As alternative approaches to achieve a compact and lightweight offshore wind turbine nacelle, different concepts have been proposed in recent years, such as step-up-transformer-less system, medium-frequency (in the range of a few kHz to MHz) power transformer-based system, multilevel and modular matrix converter-based system and superconducting generator-based system. This paper aims to review the challenges, current research and development trends, possible future directions of the research to reduce the weight and volume of the nacelle. In addition, a comprehensive review of traditional wind power generation technologies is conducted in this article as well. Keywords:Offshore wind farm, power generation, research and development, compact and lightweight nacelle 2

One style to build them all: Corporate culture and innovation in the offshore wind industry

“…They were also the first to deploy their own fleet of tailor-made ships for installation of offshore wind turbines, reducing installation times. They are, lastly, in the process of developing their own proprietary voltage source converter based HVDC technology (Islam et al, 2014). One study called Siemens "an exemplar of integration of knowledge management and innovation management" (Goh, 2005) and concluded that "for several decades, Siemens has enjoyed an internationally enviable reputation in world-class innovations."…”

“…Like Vestas, Siemens has shown a proclivity to partnering with a diverse group of corporate and even non-profit entities. In 2005, SWP entered into a research partnership with the American Superconductor Corporation, U.S. Navy, and Northrop Grumman to develop rotors using superconducting field windings (Islam et al, 2014). In 2009, the company also prototyped the world's first ever floating platform, called Hywind, developed jointly with the Norwegian oil and gas company Statoil and built near Karmø (Perveen , 2014).…”

“…Rather than presume, like Vestas and other major companies, that permanent magnet synchronous generators were the preferred way of generating electricity, Siemens offers them but also has experimented with squirrel cage induction generators and advanced direct drive turbines (Islam et al, 2014). SWP has also attempted to innovate in areas where they considered their competitors weak, such as in the use and development of offshore electro-hydraulic cranes, remotely operated vehicles for laying cables, and jack-up sea barges that can install foundations and towers for wind turbines up to 5 MW (Marsh, 2010).…”

Rotor Speed Control of a Direct-Driven Permanent Magnet Synchronous Generator-Based Wind Turbine Using Phase-Lag Compensators to Optimize Wind Power Extraction

“…Although the DFIGs are well developed and have previously been widely applied in WECS due to their ability to achieve variable speed control with the reduced cost of converter requirements, the use of slip rings and the protection issues in the event of grid faults are the major drawbacks [8]. As a result, the PMSGbased WECSs have gained more popularity and preference over DFIG-based WECSs owing to their advantages such as high energy density, simple control methodology, high reliability, low maintenance cost, and the self-excitation system [1,13,14]. Moreover, direct-driven multipole PMSGs have been adopted to exclude the gearbox, which improves the efficiency of the WT and cuts down the weight of the nacelle Figure 1: The direct-driven PMSG-based WECS [1].…”

“…Moreover, direct-driven multipole PMSGs have been adopted to exclude the gearbox, which improves the efficiency of the WT and cuts down the weight of the nacelle Figure 1: The direct-driven PMSG-based WECS [1]. and the operation and maintenance cost of the WT system [3,13,15]. The major challenge associated with WECS in general is the intermittent nature of the wind resource leading to an inconsistent wind power output.…”