scholarly journals Variable-Speed Engines on Wind Farm Support Vessels

2020 ◽  
Vol 8 (3) ◽  
pp. 229 ◽  
Author(s):  
Kristian Eikeland Holmefjord ◽  
Lars Husdal ◽  
Martijn de Jongh ◽  
Sverre Torben
Keyword(s):  
Direct Current ◽  
Diesel Engines ◽  
Wind Farm ◽  
East Coast ◽  
Frequency Converter ◽  
Real Life ◽  
Alternating Current ◽  
Variable Speed ◽  
Fixed Frequency ◽  
Fuel Savings

We examine the fuel savings of Edda Passat, a newly constructed wind farm support vessel that utilizes a common direct current (DC) grid. This enables its diesel engines to operate at variable speeds by using frequency converter technology. A detailed investigation of these benefits has been performed based on real-life measurements from three months of operations in the Race Bank wind farm off the east coast of England. The calculated fuel savings of Edda Passat achieved via its variable-speed engines are 21% lower compared to using a conventional alternating current (AC) grid with a fixed frequency. This paper will explain the technology, measurements, and results in detail.

Adjustment of Hydro-Governor Characteristics Using Separate Drive for the Speed-Sensing Element

1965 ◽  
Vol 87 (1) ◽  
pp. 13-17 ◽  
Author(s):  
L. M. Hovey
Keyword(s):  
Direct Current ◽  
Low Frequency ◽  
Alternating Current ◽  
Variable Speed ◽  
Sensing Element ◽  
Variable Speed Drive ◽  
Precise Control ◽  
Speed Change ◽  
Method Of Adjustment

This paper describes the application of a variable-speed drive for the speed-sensing element of a conventional hydro-governor which makes it possible to measure accurately the deflection of the speeder rod for a given speed change from normal. When this characteristic is determined in the field, changes can be made to the control springs if necessary, to make all machines consistent. The device may also be applied to measure directly both the permanent and temporary speed droops of the governor and allow these quantities to be readjusted to the desired values. The advantage of this method of adjustment is that it permits all the work to be carried out with the main machine shutdown. The variable-speed drive consists of a small motor-generator set which supplies direct-current power to a rotary converter, which in turn delivers low-frequency alternating-current power to the speed-sensing motor on the governor. The rotary converter and the motor-generator set are controlled by a system which gives precise control over the speed which is measured by an accurate tachometer.

Comparison of alternating current with direct current electroshock across the closed chest

1962 ◽  
Vol 10 (2) ◽  
pp. 223-233 ◽  
Author(s):  
Bernard Lown ◽  
Jose Neuman ◽  
Raghavan Amarasingham ◽  
Barouh V. Berkovits
Keyword(s):  
Direct Current ◽  
Alternating Current ◽  
Closed Chest

A Study on the New Grid Integration Solutions of Offshore Wind Farms

2011 ◽  
Vol 383-390 ◽  
pp. 3610-3616 ◽  
Author(s):  
Xin Yin Zhang ◽  
Zai Jun Wu ◽  
Si Peng Hao ◽  
Ke Xu
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Offshore Wind ◽  
Grid Integration ◽  
Variable Speed ◽  
Reliable Operation ◽  
Offshore Wind Farms ◽  
Electrical Interconnection ◽  
Investment Cost ◽  
And Performance

Offshore wind farm is developed in the ascendant currently. The reliable operation, power loss, investment cost and performance of wind farms were effect by the integration solutions of electrical interconnection system directly. Several new integration configurations based on VSC-HVDC were comparative analyzed. For the new HVDC topology applied the wind farm internal DC bus, the Variable Speed DC (VSDC) system that is suitable for those topologies was proposed. The structure of VSDC was discussed and maximum wind power tracking was simulated on the minimal system. It is clear that new integration configurations based on VSC-HVDC has good prospects.

CONCEPTS OF ELECTRONICALLY-CONTROLLED ELECTROMECHANICAL/MECHANOELECTRICAL STEER-, AUTODRIVE- AND AUTOABSORBABLE WHEELS FOR ENVIRONMENTALLY-FRIENDLY TRI-MODE SUPERCARS

1994 ◽  
Vol 04 (04) ◽  
pp. 501-516 ◽  
Author(s):  
BOGDAN T. FIJALKOWSKI ◽  
JAN W. KROSNICKI
Keyword(s):  
Direct Current ◽  
Integrated Circuit ◽  
Environmentally Friendly ◽  
Alternating Current ◽  
Switching Frequency ◽  
Neuro Fuzzy ◽  
Interior Permanent Magnet ◽  
Application Specific Integrated Circuit ◽  
Computer Processor ◽  
Application Specific

Concepts of the electronically-controlled electromechanical/mechanoelectrical Steer-, Autodrive- and Autoabsorbable Wheels (SA2W) with their brushless Alternating Current-to-Alternating Current (AC-AC), Alternating Current-to-Direct Current-Alternating Current (AC-DC-AC) and/or Direct Current-to-Alternating Current (DC-AC)/Alternating Current-to-Direct Current (AC-DC) macroelectronic converter commutator (macro-commutator) wheel-hub motors/generators with the Application Specific Integrated Matrixer (ASIM) macroelectronic converter commutators (ASIM macrocommutators) and Application Specific Integrated Circuit (ASIC) microelectronic Neuro-Fuzzy (NF) computer (processor) controllers (ASIC NF microcontrollers) for environmentally-friendly tri-mode supercars (advanced ultralight hybrids) have been conceived by the first author and designed by both authors with the Cracow University of Technology’s Automotive Mechatronics Research and Development (R&D) Team. These electromechanical/mechanoelectrical wheel-hub motors/generators, respectively, for instance, can be composed of the outer rotor with the Interior Permanent Magnet (IPM) poles and the inner stator that has the three-phase armature winding. The macroelectronic converter commutator establishes the AC-AC cycloconverter, AC-DC rectifier-DC-AC inverter and/or DC-AC inverter/AC-DC rectifier ASIM macrocommutator. The microelectronic NF computer (processor) controller establishes the ASIC microcomputer-based NF microcontroller. By adopting continuous semiconductor bipolar electrical valves in the high-power ASIM, it has been able to increase the commutation (switching) frequency and reduce harmonic losses of the electromechanical/mechanoelectrical wheel-hub motors/generators, respectively.

Alginate/Bioglass® composite coatings on stainless steel deposited by direct current and alternating current electrophoretic deposition

2013 ◽  
Vol 233 ◽  
pp. 49-56 ◽  
Author(s):  
Qiang Chen ◽  
Luis Cordero-Arias ◽  
Judith A. Roether ◽  
Sandra Cabanas-Polo ◽  
Sannakaisa Virtanen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Electrophoretic Deposition ◽  
Direct Current ◽  
Composite Coatings ◽  
Alternating Current

scholarly journals Decision Support Tool for Offshore Wind Farm Vessel Routing under Uncertainty

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2190 ◽  
Author(s):  
Rafael Dawid ◽  
David McMillan ◽  
Matthew Revie
Keyword(s):  
Wind Farm ◽  
Real Life ◽  
Synthetic Data ◽  
Optimal Solution ◽  
Decision Support Tool ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Support Tool ◽  
Trade Offs ◽  
The Impact

This paper for the first time captures the impact of uncertain maintenance action times on vessel routing for realistic offshore wind farm problems. A novel methodology is presented to incorporate uncertainties, e.g., on the expected maintenance duration, into the decision-making process. Users specify the extent to which these unknown elements impact the suggested vessel routing strategy. If uncertainties are present, the tool outputs multiple vessel routing policies with varying likelihoods of success. To demonstrate the tool’s capabilities, two case studies were presented. Firstly, simulations based on synthetic data illustrate that in a scenario with uncertainties, the cost-optimal solution is not necessarily the best choice for operators. Including uncertainties when calculating the vessel routing policy led to a 14% increase in the number of wind turbines maintained at the end of the day. Secondly, the tool was applied to a real-life scenario based on an offshore wind farm in collaboration with a United Kingdom (UK) operator. The results showed that the assignment of vessels to turbines generated by the tool matched the policy chosen by wind farm operators. By producing a range of policies for consideration, this tool provided operators with a structured and transparent method to assess trade-offs and justify decisions.

Sign in / Sign up

Export Citation Format

Share Document