Undrained Shear Strength Assessments for Clay of the Offshore Wind Power Projects in Vietnam

2022 ◽  
pp. 188-196
Author(s):  
Kuanjun Wang ◽  
Mingyuan Wang ◽  
Kanmin Shen ◽  
Jianhua Lu ◽  
Ben He ◽  
...  
Keyword(s):  
Shear Strength ◽  
Wind Power ◽  
Undrained Shear Strength ◽  
Offshore Wind ◽  
Offshore Wind Power ◽  
Undrained Shear

scholarly journals On-Bottom Stability of Umbilicals and Power Cables for Offshore Wind Applications

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3635
Author(s):  
Guomin Ji ◽  
Muk Chen Ong
Keyword(s):  
Shear Strength ◽  
Stability Analysis ◽  
Friction Coefficient ◽  
Lateral Displacement ◽  
Interaction Model ◽  
Undrained Shear Strength ◽  
Offshore Wind ◽  
Power Cables ◽  
Sand Soil ◽  
Undrained Shear

With the increase in offshore wind farms, the demands for umbilicals and power cables have increased. The on-bottom stability of umbilicals and power cables under the combined wave and current loading is the most challenging design issue, due to their light weight and the complex fluid–cable–soil interaction. In the present study, the methodology for dynamic lateral stability analysis is first discussed; and the reliable hydrodynamic load model and cable–soil interaction model based on large experimental test data are described in detail. The requirement of the submerged weight of a cable w s to obtain on-bottom stability is investigated for three types of soil (clay, sand and rock), using the finite element program PONDUS, and the results are w s , r o c k > w s , c l a y > w s , s a n d under the same load conditions. Several different aspects related to optimization design of the on-bottom stability are explored and addressed. There is a significant benefit for the on-bottom stability analysis to consider the reduction factors, due to penetration for clay and sand soil. The on-bottom stability is very sensitive to the relative initial embedment z 0 / D for clay and sand soil, due to the small diameter of the cables, and therefore, reliable prediction of initial embedment is required. In the energy-based cable–soil interaction model, the friction coefficient μ and the development of penetration affect each other and the total effect of friction force F f and passive resistance F r is complicated. The effect of the friction coefficient μ on the on-bottom stability is different from engineering judgement based on the Coulomb friction model. The undrained shear strength of clay is an important parameter for the on-bottom stability of umbilicals and cables. The higher the undrained shear strength of the clay, the larger the lateral displacement. Meanwhile, the submerged weight of sand has a minor effect on the lateral displacement of cables. The method used in the present study significantly improves the reliability of the on-bottom stability analysis of umbilicals and power cables for offshore wind application.

scholarly journals Scenarios for offshore wind power production for Central California Call Areas

Wind Energy ◽  
2021 ◽  
Author(s):  
Yi‐Hui Wang ◽  
Ryan K. Walter ◽  
Crow White ◽  
Matthew D. Kehrli ◽  
Benjamin Ruttenberg
Keyword(s):  
Wind Power ◽  
Power Production ◽  
Offshore Wind ◽  
Central California ◽  
Offshore Wind Power

scholarly journals Evaluation of offshore wind power in the China sea

2021 ◽  
pp. 014459872199226
Author(s):  
Yu-chi Tian ◽  
Lei kou ◽  
Yun-dong Han ◽  
Xiaodong Yang ◽  
Ting-ting Hou ◽  
...  
Keyword(s):  
Wind Energy ◽  
Wind Power ◽  
Energy Development ◽  
Offshore Wind ◽  
Human Beings ◽  
Offshore Wind Power ◽  
Business Operation ◽  
Advantages And Disadvantages ◽  
Wind Energy Development ◽  
The Impact

With resource crisis and environmental crisis increasingly grim, many countries turn the focus to pollution-free and renewable wind energy resources, which are mainly used for offshore wind power generation, seawater desalination and heating, etc., on the premise that the characteristics of resources are fully grasped. In this study, the evaluation of offshore wind energy in offshore waters in China, as well as the advantages and disadvantages of existing studies were overviewed from four aspects: the spatial-temporal characteristics of wind energy, wind energy classification, the short-term forecast of wind energy and the long-term projection of wind energy, according to the research content and the future considerations about wind energy evaluation (evaluation of wind energy on islands and reefs, the impact of wind energy development on human health) were envisaged, in the hope of providing a scientific basis for the site selection and business operation ‘or military applications’ here (after business operation), etc. of wind energy development, ‘aritime navigation against environmental construction,’ here and also contributing to the sustainable development and health of human beings.

scholarly journals Miniaturization of an Offshore Platform with Medium-Frequency Offshore Wind Farm and MMC-HVDC Technology

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2058
Author(s):  
Zheren Zhang ◽  
Yingjie Tang ◽  
Zheng Xu
Keyword(s):  
Wind Power ◽  
Computer Aided Design ◽  
Wind Farm ◽  
Offshore Platform ◽  
Offshore Wind ◽  
Operating Frequency ◽  
Offshore Wind Farm ◽  
Medium Frequency ◽  
Offshore Wind Power ◽  
System Frequency

Offshore wind power has great development potential, for which the key factors are reliable and economical wind farms and integration systems. This paper proposes a medium-frequency wind farm and MMC-HVDC integration system. In the proposed scheme, the operating frequency of the offshore wind farm and its power collection system is increased from the conventional 50/60 Hz rate to the medium-frequency range, i.e., 100–400 Hz; the offshore wind power is transmitted to the onshore grid via the modular multilevel converter-based high-voltage direct current transmission (MMC-HVDC). First, this paper explains the principles of the proposed scheme in terms of the system topology and control strategy aspects. Then, the impacts of increasing the offshore system operating frequency on the main parameters of the offshore station are discussed. As the frequency increases, it is shown that the actual value of the electrical equipment, such as the transformers, the arm inductors, and the SM capacitors of the rectifier MMC, can be reduced, which means smaller platforms are required for the step-up transformer station and the converter station. Then, the system operation characteristics are analyzed, with the results showing that the power losses in the system increase slightly with the increase of the offshore AC system frequency. Based on time domain simulation results from power systems computer aided design/electromagnetic transients including DC (PSCAD/EMTDC), it is noted that the dynamic behavior of the system is not significantly affected with the increase of the offshore AC system frequency in most scenarios. In this way, the technical feasibility of the proposed offshore platform miniaturization technology is proven.

scholarly journals A Diode-MMC AC/DC Hub for Connecting Offshore Wind Farm and Offshore Production Platform

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3759
Author(s):  
Kai Huang ◽  
Lie Xu ◽  
Guangchen Liu
Keyword(s):  
Wind Power ◽  
Wind Farm ◽  
Offshore Wind ◽  
System Control ◽  
Dc Voltage ◽  
Offshore Wind Power ◽  
Offshore Production ◽  
Production Platform ◽  
In Series ◽  
Dc Voltage Control

A diode rectifier-modular multilevel converter AC/DC hub (DR-MMC Hub) is proposed to integrate offshore wind power to the onshore DC network and offshore production platforms (e.g., oil/gas and hydrogen production plants) with different DC voltage levels. The DR and MMCs are connected in parallel at the offshore AC collection network to integrate offshore wind power, and in series at the DC terminals of the offshore production platform and the onshore DC network. Compared with conventional parallel-connected DR-MMC HVDC systems, the proposed DR-MMC hub reduces the required MMC converter rating, leading to lower investment cost and power loss. System control of the DR-MMC AC/DC hub is designed based on the operation requirements of the offshore production platform, considering different control modes (power control or DC voltage control). System behaviors and requirements during AC and DC faults are investigated, and hybrid MMCs with half-bridge and full-bridge sub-modules (HBSMs and FBSMs) are used for safe operation during DC faults. Simulation results based on PSCAD/EMTDC validate the operation of the DR-MMC hub.

Sign in / Sign up

Export Citation Format

Share Document