scholarly journals Communication-Less Frequency Support from Offshore Wind Farms Connected to HVdc via Diode Rectifiers

2020 ◽  
Author(s):  
Oscar Saborío-Romano ◽  
Ali Bidadfar ◽  
Jayachandra Naidu Sakamuri ◽  
Lorenzo Zeni ◽  
Ömer Göksu ◽  
...  
Keyword(s):  
Wind Farms ◽  
Sensitivity Study ◽  
Offshore Wind ◽  
Voltage Measurement ◽  
Estimation Errors ◽  
Offshore Wind Farms ◽  
Direct Voltage ◽  
Control Scheme ◽  
Static Performance ◽  
The Impact

Before diode rectifier (DR) technology for connecting offshore wind farms (OWFs) to HVdc is deployed, in-depth studies are needed to assess the actual capabilities of DR-connected OWFs to contribute to the secure operation of the networks linked to them. This study assesses the capability of such an OWF to provide communication-less frequency support (CLFS) to an onshore ac network. It is shown that the HVdc link’s offshore terminal direct voltage can be estimated from measurements at the OWF’s point of connection with the DR platform. Two different methods are proposed for implementing CLFS in the OWF active power controls. In Method 1, the estimated offshore terminal direct voltage is used for estimating the onshore frequency deviation. In Method 2, the actual offshore terminal direct voltage measurement is used instead. Unique features of the provision of CLFS from OWFs connected to HVdc via DRs are highlighted, and the dynamic and static performance of the CLFS control scheme is compared to that of the communication-based frequency support scheme. To assess the impact of parameter estimation errors on the provision of CLFS, a parametric sensitivity study is presented as well, and recommendations are given to increase accuracy.<br><br>The manuscript has been accepted for publication in IEEE Transactions on Sustainable Energy.

scholarly journals Communication-Less Frequency Support from Offshore Wind Farms Connected to HVdc via Diode Rectifiers

2020 ◽  
Author(s):  
Oscar Saborío-Romano ◽  
Ali Bidadfar ◽  
Jayachandra Naidu Sakamuri ◽  
Lorenzo Zeni ◽  
Ömer Göksu ◽  
...  
Keyword(s):  
Wind Farms ◽  
Sensitivity Study ◽  
Offshore Wind ◽  
Voltage Measurement ◽  
Estimation Errors ◽  
Offshore Wind Farms ◽  
Direct Voltage ◽  
Control Scheme ◽  
Static Performance ◽  
The Impact

Before diode rectifier (DR) technology for connecting offshore wind farms (OWFs) to HVdc is deployed, in-depth studies are needed to assess the actual capabilities of DR-connected OWFs to contribute to the secure operation of the networks linked to them. This study assesses the capability of such an OWF to provide communication-less frequency support (CLFS) to an onshore ac network. It is shown that the HVdc link’s offshore terminal direct voltage can be estimated from measurements at the OWF’s point of connection with the DR platform. Two different methods are proposed for implementing CLFS in the OWF active power controls. In Method 1, the estimated offshore terminal direct voltage is used for estimating the onshore frequency deviation. In Method 2, the actual offshore terminal direct voltage measurement is used instead. Unique features of the provision of CLFS from OWFs connected to HVdc via DRs are highlighted, and the dynamic and static performance of the CLFS control scheme is compared to that of the communication-based frequency support scheme. To assess the impact of parameter estimation errors on the provision of CLFS, a parametric sensitivity study is presented as well, and recommendations are given to increase accuracy.<br><br>The manuscript has been accepted for publication in IEEE Transactions on Sustainable Energy.

scholarly journals Communication-Less Frequency Support from Offshore Wind Farms Connected to HVdc via Diode Rectifiers

2019 ◽  
Author(s):  
Oscar Saborío-Romano ◽  
Ali Bidadfar ◽  
Jayachandra Naidu Sakamuri ◽  
Lorenzo Zeni ◽  
Ömer Göksu ◽  
...  
Keyword(s):  
Wind Farms ◽  
Sensitivity Study ◽  
Offshore Wind ◽  
Voltage Measurement ◽  
Estimation Errors ◽  
Offshore Wind Farms ◽  
Direct Voltage ◽  
Control Scheme ◽  
Static Performance ◽  
The Impact

Before diode rectifier (DR) technology for connecting offshore wind farms (OWFs) to HVdc is deployed, in-depth studies are needed to assess the actual capabilities of DR-connected OWFs to contribute to the secure operation of the networks linked to them. This study assesses the capability of such an OWF to provide communication-less frequency support (CLFS) to an onshore ac network. It is shown that the HVdc link’s offshore terminal direct voltage can be estimated from measurements at the OWF’s point of connection with the DR platform. Two different methods are proposed for implementing CLFS in the OWF active power controls. In Method 1, the estimated offshore terminal direct voltage is used for estimating the onshore frequency deviation. In Method 2, the actual offshore terminal direct voltage measurement is used instead. Unique features of the provision of CLFS from OWFs connected to HVdc via DRs are highlighted, and the dynamic and static performance of the CLFS control scheme is compared to that of the communication-based frequency support scheme. To assess the impact of parameter estimation errors on the provision of CLFS, a parametric sensitivity study is presented as well, and recommendations are given to increase accuracy.<br><br>The manuscript has been submitted to IEEE Transactions on Sustainable Energy.

An ecosystem approach for studying the impact of offshore wind farms: a French case study

2018 ◽  
Vol 77 (3) ◽  
pp. 1238-1246 ◽  
Author(s):  
Jean-Philippe Pezy ◽  
Aurore Raoux ◽  
Jean-Claude Dauvin
Keyword(s):  
Network Analysis ◽  
Wind Farm ◽  
Wind Farms ◽  
Sampling Strategy ◽  
Ecosystem Approach ◽  
Offshore Wind ◽  
Ecosystem Structure ◽  
Offshore Wind Farms ◽  
Ecopath Model ◽  
The Impact

Abstract The French government is planning the construction of offshore wind farms (OWF) in the next decade (around 2900 MW). Following the European Environmental Impact Assessment Directive 85/337/EEC, several studies have been undertaken to identify the environmental conditions and ecosystem functioning at selected sites prior to OWF construction. However, these studies are generally focused on the conservation of some species and there is no holistic approach for analysing the effects arising from OWF construction and operation. The objective of this article is to promote a sampling strategy to collect data on the different ecosystem compartments of the future Dieppe-Le Tréport (DLT) wind farm site, adopting an ecosystem approach, which could be applied to other OWFs for the implementation of a trophic network analysis. For that purpose, an Ecopath model is used here to derive indices from Ecological Network Analysis (ENA) to investigate the ecosystem structure and functioning. The results show that the ecosystem is most likely detritus-based, associated with a biomass dominated by bivalves, which could act as a dead end for a classic trophic food web since their consumption by top predators is low in comparison to their biomass. The systemic approach developed for DLT OWF site should be applied for other French and European installations of Offshore Wind Farm.

Seismic Design for Offshore Wind Farms – Lessons Learnt From the ACE Joint Industry Project

2021 ◽  
Author(s):  
Marcus Klose ◽  
Junkan Wang ◽  
Albert Ku
Keyword(s):  
Seismic Design ◽  
Wind Turbines ◽  
Wind Farms ◽  
The United States ◽  
Offshore Wind ◽  
Seismic Load ◽  
Support Structures ◽  
Offshore Wind Farms ◽  
Asian Pacific Region ◽  
The Impact

Abstract In the past, most of the offshore wind farms have been installed in European countries. In contrast to offshore wind projects in European waters, it became clear that the impact from earthquakes is expected to be one of the major design drivers for the wind turbines and their support structures in other areas of the world. This topic is of high importance in offshore markets in the Asian Pacific region like China, Taiwan, Japan, Korea as well as parts of the United States. So far, seismic design for wind turbines is not described in large details in existing wind energy standards while local as well as international offshore oil & gas standards do not consider the specifics of modern wind turbines. In 2019, DNV GL started a Joint Industry Project (JIP) called “ACE -Alleviating Cyclone and Earthquake challenges for wind farms”. Based on the project results, a Recommended Practice (RP) for seismic design of wind turbines and their support structures will be developed. It will supplement existing standards like DNVGL-ST-0126, DNVGL-ST-0437 and the IEC 61400 series. This paper addresses the area of seismic load calculation and the details of combining earthquake impact with other environmental loads. Different options of analysis, particularly time-domain simulations with integrated models or submodelling techniques using superelements will be presented. Seismic ground motions using a uniform profile or depth-varying input profile are discussed. Finally, the seismic load design return period is addressed.

scholarly journals Impact of Primary Frequency Control of Offshore HVDC Grids on Interarea Modes of Power Systems

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3879 ◽  
Author(s):  
Ali Bidadfar ◽  
Oscar Saborío-Romano ◽  
Vladislav Akhmatov ◽  
Nicolaos A. Cutululis ◽  
Poul E. Sørensen
Keyword(s):  
Power Systems ◽  
Frequency Control ◽  
Wind Farms ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
Dc Voltage ◽  
Simultaneous Use ◽  
Primary Frequency ◽  
Primary Frequency Control ◽  
The Impact

Offshore high-voltage DC (HVDC) grids are developing as a technically reliable and economical solution to transfer more offshore wind power to onshore power systems. It is also foreseen that the offshore HVDC grids pave the way for offshore wind participation in power systems’ balancing process through frequency support. The primary frequency control mechanism in an HVDC grid can be either centralized using communication links between HVDC terminals or decentralized by the simultaneous use of DC voltage and frequency droop controls. This paper investigates the impact of both types of primary frequency control of offshore HVDC grids on onshore power system dynamics. Parametric presentation of power systems’ electro-mechanical dynamics and HVDC controls is developed to analytically prove that the primary frequency control can improve the damping of interarea modes of onshore power systems. The key findings of the paper include showing that the simultaneous use of frequency and DC voltage droop controls on onshore converters results in an autonomous share of damping torque between onshore power systems even without any participation of offshore wind farms in the frequency control. It is also found that the resulting damping from the frequency control of offshore HVDC is not always reliable as it can be nullified by the power limits of HVDC converters or wind farms. Therefore, using power oscillation damping control in parallel with frequency control is suggested. The analytical findings are verified by simulations on a three-terminal offshore HVDC grid.

scholarly journals Current Source Converter Based Offshore Wind Farm: Configuration and Control

2021 ◽  
Author(s):  
Miteshkumar Nandlal Popat
Keyword(s):  
Wind Farm ◽  
Current Source ◽  
Wind Farms ◽  
Offshore Wind ◽  
Grid Integration ◽  
Offshore Wind Farm ◽  
Offshore Wind Farms ◽  
Control Scheme ◽  
Current Source Converter ◽  
Grid Side

Recently, offshore wind farms have emerged as the most promising sector in the global renewable energy industry. The main reasons for the rapid development of offshore wind farms includes much better wind resources and smaller environmental impact (e.g., audible noise and visual effect). However, the current state of the offshore wind power presents economic challenges significantly greater than onshore. In this thesis, a novel interconnecting method for permanent magnet synchronous generator (PMSG)-based offshore wind farm is proposed, where cascaded pulse-width modulated (PWM) current-source converters (CSCs) are employed on both generator- and grid-side. With the converters in cascade to achieve high operating voltages, the proposed method eliminates the need for bulky and very costly offshore converter substation which is usually employed in voltage source converter (VSC) high voltage DC (HVDC)-based counterparts. Related research in terms of control schemes and grid integration are carried out to adapt the proposed cascaded CSC-based offshore wind farm configuration. The large distance between generator- and grid-side CSC in the proposed wind farm configuration addresses significant challenges for the system control. In order to overcome the problem, a novel decoupled control scheme is developed. The active and reactive power control on the grid-side converters are achieved without any exchange of information from the generator-side controller. Therefore, the long distance communication links between the generator- and grid-side converters are eliminated and both controllers are completely decoupled. At the same time, the maximum power tracking control is achieved for the generator-side converters that enable full utilization of the wind energy. Considering inconsistent wind speed at each turbine, a coordinated control scheme is proposed for the cascaded CSC-based offshore wind farm. In proposed control strategy, the wind farm supervisory control (WFSC) is developed to generate the optimized dc-link current control. This enables all the turbines to independently track their own MPPT even with inconsistent wind speed at each turbine. Grid integration issues, especially the fault ride-through (FRT) capability for the cascaded CSC-based offshore wind farm are addressed. Challenges in implementing existing FRT methods to the proposed offshore wind farm are identified. Based on this, a new FRT strategy using inherent short circuit operating capability of the CSC is developed. Moreover, the mitigation strategy is developed to ensure the continuous operation of the cascaded CSC-based offshore wind farm when one or more turbines fail to operate. Simulation and experimental verification for various objectives are provided throughout the thesis. The results validate the proposed solutions for the main challenges of the cascaded current source converter based offshore wind farm.

scholarly journals Multi-Purpose Offshore-Platforms: Past, Present and Future Research and Developments

2017 ◽  
Author(s):  
Bernt J. Leira
Keyword(s):  
Wind Farms ◽  
Offshore Wind ◽  
Future Research ◽  
Offshore Platforms ◽  
Offshore Wind Farms ◽  
Ocean Renewable Energy ◽  
Transport Maritime ◽  
Optimal Coupling ◽  
Environmental Feasibility ◽  
The Impact

Energy, fisheries and transport infrastructures are increasingly being established offshore. Facilities such as offshore wind farms may occupy large areas and compete with other users of the maritime space. Accordingly, offshore platforms that can combine many functions within the same infrastructure could offer significant benefits. This applies to economy, optimization of spatial planning and minimization of the impact on the environment. In the present paper, some proposed innovative designs for multi-use offshore platforms are described. The technical, economical and environmental feasibility of designing, installing, operating, servicing and maintaining such platforms are discussed. The relevant platforms under consideration are targeted towards ocean renewable energy (in particular offshore wind), aquaculture and related transport maritime services. Innovative designs for multi-use offshore platforms that intend to allow optimal coupling of the various activities and services are highlighted. Issues such as safe and efficient installation, operation, maintenance and monitoring are also briefly discussed in the paper.

scholarly journals Coastal protection of the Romanian nearshore throughout hybrid wave and offshore wind farms

2018 ◽  
Vol 51 ◽  
pp. 01004
Author(s):  
Alina Raileanu ◽  
Florin Onea ◽  
Liliana Rusu
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Wave Model ◽  
Reference Points ◽  
Offshore Wind ◽  
Wave Transformation ◽  
The Black Sea ◽  
Coastal Protection ◽  
Offshore Wind Farms ◽  
The Impact

The objective of the present work is to estimate the influence of several hybrid wind and wave farm configurations on the wave conditions reported in the vicinity of the Saint George coastal area, in the Romanian nearshore of the Black Sea. Based on the wave data coming from a climatological database (ERA20C) and also on in situ measurements, it was possible to identify the most relevant wave patterns, which will be further considered for assessment. The numerical simulations were carried out with the SWAN (Simulating Waves Nearshore) wave model, which may provide a comprehensive picture of the wave transformation in the presence of the marine farms. Although the impact of the wind farm is not visible from the spatial maps, from the analysis of the values corresponding to the reference points, it was noticed that a maximum variation of 2% may occur for several wave parameters.

Wind Flow Conditions in Offshore Wind Farms: Validation and Application of a CFD Wake Model

Green ◽  
2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Annette Westerhellweg ◽  
Beatriz Cañadillas ◽  
Friederike Kinder ◽  
Thomas Neumann
Keyword(s):  
Wind Farm ◽  
Atmospheric Stability ◽  
Wind Farms ◽  
Offshore Wind ◽  
Wind Flow ◽  
Flow Conditions ◽  
Offshore Wind Farms ◽  
Speed Reduction ◽  
Wake Model ◽  
The Impact

AbstractSince August 2009, the first German offshore wind farm ‘alpha ventus’ is operating close to the wind measurement platform FINO1. Within the research project RAVE-OWEA the wind flow conditions in ‘alpha ventus’ were assessed in detail, simulated with a CFD wake model and compared with the measurements. Wind data measured at FINO1 have been evaluated for wind speed reduction and turbulence increase in the wake. Additionally operational data were evaluated for the farm efficiency. The atmospheric stability has been evaluated by temperature measurements of air and water and the impact of atmospheric stability on the wind conditions in the wake has been assessed. As an application of CFD models the generation of power matrices is introduced. Power matrices can be used for the continual monitoring of the single wind turbines in the wind farm. A power matrix based on CFD simulations has been created for ‘alpha ventus’ and tested against the measured data.

scholarly journals Modelling the impact of offshore wind farms on safety radars onboard oil and gas platforms

2017 ◽  
Vol 11 (12) ◽  
pp. 1714-1718
Author(s):  
Laith Danoon ◽  
Waleed Al‐Mashhadani ◽  
Anthony Brown
Keyword(s):  
Oil And Gas ◽  
Wind Farms ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
The Impact
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