scholarly journals The Importance of Fault Prediction in a Tidal Turbine. Misalignment and Cracks in the Shaft

Proceedings ◽  
2018 ◽  
Vol 2 (22) ◽  
pp. 1368
Author(s):  
Beatriz F. Cal ◽  
Pedro Fraga
Keyword(s):  
Failure Prediction ◽  
Ocean Currents ◽  
Fault Prediction ◽  
Early Failure ◽  
Tidal Turbines ◽  
Early Appearance ◽  
Rapid Changes ◽  
Tidal Turbine

This study is focused on the early failure prediction of underwater Tidal Turbines. These types of turbines undergo strong torques due to ocean currents which also causes rapid changes in direction and speed which subjected to important loads and misalignments. The main objective of this study is therefore to analyse the response to the constant vibration produced by those misalignments and early appearance of cracks in this shaft.

scholarly journals Tidal Energy Utilization of Larantuka Strait by Dual Tidal Turbines to Increase National Energy Resilience

2019 ◽  
Vol 2 ◽  
pp. 73-77
Author(s):  
Eko Soejianto ◽  
Khansa Hanifa Zahra ◽  
Suci Nur Hidayah
Keyword(s):  
Renewable Energy ◽  
Energy Demand ◽  
Energy Resource ◽  
Electrical Energy ◽  
Tidal Energy ◽  
Ocean Currents ◽  
Energy Utilization ◽  
Tidal Turbines ◽  
Tidal Turbine ◽  
The Government

Currently, renewable energy can only support 5% of national energy needs. Meanwhile, in 2035 renewable energy targeted to sustain 14% of total national energy demand. The proper way for optimizing the renewable energy is needed to actualize the target. Tidal energy as one of the potentials that are still being developed and need more attention from the government. Tidal can be used for natural energy resource since it has zero emission, produce big energy, and has no impact to weather. Larantuka Strait located in Flores island, Nusa Tenggara Timur province can produce tidal velocity up to 2.859 m/s with water density as much as 1.025 gr/cc.  In utilizing this energy, we use new innovation by using dual tidal turbines which placed at the foot of Palmerah Bridge. The construction of Palmerah Bridge is built both by the government of Flores Island and Adonara Island. Dual tidal turbines are more efficient than singl e turbine by reason of tidal that has passed through the first turbine can be used again for the second turbine. The using of the generator is meant to convert kinetic energy that produced by dual tidal turbines. To convert ocean currents into electrical energy optimally, it is necessary to plan turbine designs that are in accordance with the conditions of ocean currents and the surrounding environment such as current velocity, wind influences and so on. Horizontal-axis tidal turbine (HATTs) is one of the technologies that are being developed and tested in prototype form by several companies, an efficient blade design is very important for the success of the HATTs. The amount of turbine needs, in this case, is 15 turbines with each turbine’s length is 10 meters. The turbines installed in bridge’s column along 800 meters. Estimate electricity can be generated by the turbine is 1.48 Mega Watt (MW).

scholarly journals Cross-Flow Tidal Turbines with Highly Flexible Blades—Experimental Flow Field Investigations at Strong Fluid–Structure Interactions

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 797
Author(s):  
Stefan Hoerner ◽  
Iring Kösters ◽  
Laure Vignal ◽  
Olivier Cleynen ◽  
Shokoofeh Abbaszadeh ◽  
...  
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Cross Flow ◽  
Speed Ratio ◽  
Fluid Structure Interactions ◽  
Dimensional Parameter ◽  
Fluid Structure ◽  
Passive Flow Control ◽  
Tidal Turbines ◽  
Tidal Turbine

Oscillating hydrofoils were installed in a water tunnel as a surrogate model for a hydrokinetic cross-flow tidal turbine, enabling the study of the effect of flexible blades on the performance of those devices with high ecological potential. The study focuses on a single tip-speed ratio (equal to 2), the key non-dimensional parameter describing the operating point, and solidity (equal to 1.5), quantifying the robustness of the turbine shape. Both parameters are standard values for cross-flow tidal turbines. Those lead to highly dynamic characteristics in the flow field dominated by dynamic stall. The flow field is investigated at the blade level using high-speed particle image velocimetry measurements. Strong fluid–structure interactions lead to significant structural deformations and highly modified flow fields. The flexibility of the blades is shown to significantly reduce the duration of the periodic stall regime; this observation is achieved through systematic comparison of the flow field, with a quantitative evaluation of the degree of chaotic changes in the wake. In this manner, the study provides insights into the mechanisms of the passive flow control achieved through blade flexibility in cross-flow turbines.

scholarly journals Rotor Loading Characteristics of a Full-Scale Tidal Turbine

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1035 ◽  
Author(s):  
Magnus Harrold ◽  
Pablo Ouro
Keyword(s):  
Turbulent Flows ◽  
Mechanical Loading ◽  
Full Scale ◽  
Design Stage ◽  
Flow Profile ◽  
Expected Return ◽  
Tidal Turbines ◽  
Theoretical Predictions ◽  
Tidal Turbine

Tidal turbines are subject to highly dynamic mechanical loading through operation in some of the most energetic waters. If these loads cannot be accurately quantified at the design stage, turbine developers run the risk of a major failure, or must choose to conservatively over-engineer the device at additional cost. Both of these scenarios have consequences on the expected return from the project. Despite an extensive amount of research on the mechanical loading of model scale tidal turbines, very little is known from full-scale devices operating in real sea conditions. This paper addresses this by reporting on the rotor loads measured on a 400 kW tidal turbine. The results obtained during ebb tidal conditions were found to agree well with theoretical predictions of rotor loading, but the measurements during flood were lower than expected. This is believed to be due to a disturbance in the approaching flood flow created by the turbine frame geometry, and, to a lesser extent, the non-typical vertical flow profile during this tidal phase. These findings outline the necessity to quantify the characteristics of the turbulent flows at sea sites during the entire tidal cycle to ensure the long-term integrity of the deployed tidal turbines.

A French Application Case of Tidal Turbine Certification

2016 ◽  
Author(s):  
Stéphane Paboeuf ◽  
Laura-Mae Macadré ◽  
Pascal Yen Kai Sun
Keyword(s):  
Renewable Energy ◽  
Water Current ◽  
Support Structure ◽  
Design Assessment ◽  
Certification Scheme ◽  
Tidal Turbines ◽  
Marine Energy ◽  
Certification Procedure ◽  
Tidal Turbine

Tidal turbines are emerging technologies offering great potential for the harnessing of a renewable and predictable oceanic resource. However, exploitation at sea comes with significant design, installation, grid connection, and maintenance operations challenges. Consequently, guidelines and standards are required to ensure safety, quality, performance and accelerate tidal turbines development and commercialisation. Standardisation is also a necessity to support and improve safety and confidence of a wide range of Marine Renewable Energy (MRE) stakeholders such as designers, project operators, investors, insurers or final users. There are undergoing developments on guidelines, standards and certification systems within the International Electrotechnical Commission (IEC) Technical Committee TC 114 “Marine energy - Wave, tidal and other water current converters” and the IEC Renewable Energy “Marine Energy - Operational Management Committee” (IECRE ME – OMC). However, as the tidal energy concepts are only at the demonstration stage, only few guidelines and no dedicated certification scheme has been published so far within this organization, which guarantee an international, independent, non-governmental and consensus-based elaboration process. The aim of this paper is to present a proposal of certification methodology, developed by Bureau Veritas for the design assessment of current and tidal turbines, and its application to a French case study. This certification procedure was developed within the French research project Sabella D10 funded by ADEME and is published in the Bureau Veritas guideline NI603 “Current & Tidal Turbines”. The suggested certification procedure addresses prototype, component, type and project certification. Main objective, scope, intermediary steps to be completed and resulting certificates will be detailed for each certification scheme, as well as their interactions. This methodology will be illustrated by the case study on the Sabella D10 prototype, a French tidal turbine installed in 2015 in the Fromveur Passage, off Ushant Island. Sabella D10 is a 1 MW tidal turbine fully submerged laid on the seabed with a horizontal axis and 6 blades. It is the first French tidal turbine producing electricity and connected to the electrical network. The Sabella D10 case study will focus on prototype certification and computations performed for support structure and blades. The paper will describe the load cases that have been considered, the review procedure for the support structure and the blades design assessment, including description of a streamlined method for basic design and a detailed method for final design. In conclusion, the next steps will be introduced to continue the certification developments of tidal and current turbines.

scholarly journals Passive acoustic methods for tracking the 3D movements of small cetaceans around marine structures

2020 ◽  
Author(s):  
Douglas Gillespie ◽  
Laura Palmer ◽  
Jamie Macaulay ◽  
Carol Sparling ◽  
Gordon Hastie
Keyword(s):  
Marine Mammals ◽  
New Technologies ◽  
Three Dimensional ◽  
Tidal Energy ◽  
Time Of Arrival ◽  
Marine Animals ◽  
Tidal Turbines ◽  
Wide Range ◽  
Tidal Turbine ◽  
Passive Acoustic

AbstractA wide range of anthropogenic structures exist in the marine environment with the extent of these set to increase as the global offshore renewable energy industry grows. Many of these pose acute risks to marine wildlife; for example, tidal energy generators have the potential to injure or kill seals and small cetaceans through collisions with moving turbine parts. Information on fine scale behaviour of animals close to operational turbines is required to understand the likely impact of these new technologies. There are inherent challenges associated with measuring the underwater movements of marine animals which have, so far, limited data collection. Here, we describe the development and application of a system for monitoring the three-dimensional movements of cetaceans in the immediate vicinity of a subsea structure. The system comprises twelve hydrophones and software for the detection and localisation of vocal marine mammals. We present data demonstrating the systems practical performance during a deployment on an operational tidal turbine between October 2017 and October 2019. Three-dimensional locations of cetaceans were derived from the passive acoustic data using time of arrival differences on each hydrophone. Localisation accuracy was assessed with an artificial sound source at known locations and a refined method of error estimation is presented. Calibration trials show that the system can accurately localise sounds to 2m accuracy within 20m of the turbine but that localisations become highly inaccurate at distances greater than 35m. The system is currently being used to provide data on rates of encounters between cetaceans and the turbine and to provide high resolution tracking data for animals close to the turbine. These data can be used to inform stakeholders and regulators on the likely impact of tidal turbines on cetaceans.

Assessment of Zooplankton Injury and Mortality Associated With Underwater Turbines for Tidal Energy Production

2013 ◽  
Vol 47 (4) ◽  
pp. 142-150 ◽  
Author(s):  
David R. Schlezinger ◽  
Craig D. Taylor ◽  
Brian L. Howes
Keyword(s):  
Size Distribution ◽  
Particle Density ◽  
Collaborative Work ◽  
Tidal Energy ◽  
Energy Potential ◽  
Marine Renewable Energy ◽  
Tidal Turbines ◽  
Video Images ◽  
Significant Difference ◽  
Tidal Turbine

AbstractCollaborative work between the UMASS-Marine Renewable Energy Center, the Town of Edgartown, and the Coastal Systems Program is focused on developing the tidal energy potential of Muskeget Channel. We have undertaken detailed oceanographic and environmental surveys to optimize in-stream turbine power generation and to quantify potential environmental effects. In 2011 and 2012, tidal turbine demonstration projects were conducted in Muskeget Channel to determine the combined effects of blade strikes, shear stress, turbulence, and cavitation on zooplankton. Single turbines may minimally impact zooplankton populations; however, full-scale projects may potentially alter zooplankton populations forming the base of coastal food webs. Static plankton tows were performed up- and downstream of the operating turbine axis. Integral flow meters allowed adjustment of tow duration to optimize zooplankton density in the concentrate. Samples were held at in situ temperatures, and sequential photomicrographs and video images were taken to determine particle density, size distribution, and the number of live organisms in samples taken up and down gradient of the operating tidal turbines within 3 h of collection. Statistical analysis showed no significant difference in the total number or size distribution of motile zooplankters, indicating tidal turbine operation did not cause significant mortality and suggested that impacts of commercial size tidal energy projects upon zooplankton populations in Muskeget Channel may be negligible.

scholarly journals Wake of a Ducted Vertical Axis Tidal Turbine in Turbulent Flows, LBM Actuator-Line Approach

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4273 ◽  
Author(s):  
Mikaël Grondeau ◽  
Sylvain Guillou ◽  
Philippe Mercier ◽  
Emmanuel Poizot
Keyword(s):  
Turbulent Flows ◽  
Vertical Axis ◽  
Tidal Currents ◽  
Eddy Simulation ◽  
Tidal Turbines ◽  
Tidal Turbine ◽  
Vertical Axis Tidal Turbine ◽  
Ambient Turbulence ◽  
The Cost ◽  
Boltzmann Method

Vertical axis tidal turbines are devices that extract the kinetic energy from tidal currents. Tidal currents can be highly turbulent. Since ambient turbulence affects the turbine hydrodynamic, it is critical to understand its influence in order to optimize tidal farms. Actuator Line Model (ALM) combined with Large Eddy Simulation (LES) is a promising way to comprehend this phenomenon. In this article, an ALM was implemented into a Lattice Boltzmann Method (LBM) LES solver. This implementation gives good results for predicting the wake of a vertical axis tidal turbine placed into a turbulent boundary layer. The validated numerical configuration was then used to compute the wake of a real size ducted vertical axis tidal turbine. Several upstream turbulence rates were simulated. It was found that the shape of the wake is strongly influenced by the ambient turbulence. The cost-to-precision ratio of ALM-LBM-LES compared to fully resolved LBM-LES makes it a promising way of modeling tidal farms.

Electronic Equipment Combination Fault Prediction Technology Research Based on LSSVM-HMM

2014 ◽  
Vol 687-691 ◽  
pp. 978-983
Author(s):  
Yan Ping Tian ◽  
Xiao Hui Ye ◽  
Ming Yin
Keyword(s):  
Failure Prediction ◽  
Prediction Method ◽  
Electronic Equipment ◽  
Condition Based Maintenance ◽  
Fault Prediction ◽  
Support Vector ◽  
Technology Research ◽  
State Prediction ◽  
Fault State ◽  
Fault Information

In order to solve the problem of complicated electronic equipment structure, inadequate fault information, hard to predict the fault and the existing failure prediction method cannot predict the state of the electronic equipment and other issues directly, we propose a combination failure prediction methods of least squares support vector machine (LSSVM) and hidden Markov model (HMM) based on Condition Based Maintenance (CBM). First, according to sensitivity analysis to determine the circuit elements to be changed to set the circuit by changing the parameters of the different components degraded state; secondly, create a combination failure prediction model; Finally, the circuit state prediction. The results show that the proposed method can directly predict the different states of the circuit, so as to realize the fault state prediction of the electronic equipment directly, the prediction accuracy can reach 93.3%.

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