scholarly journals A Study on Directly Interconnected Offshore Wind Systems during Wind Gust Conditions

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 168
Author(s):  
Cathal W. O’Donnell ◽  
Mahdi Ebrahimi Salari ◽  
Daniel J. Toal
Keyword(s):  
High Voltage ◽  
Wind Farm ◽  
Low Frequency ◽  
Alternating Current ◽  
Offshore Wind ◽  
Wind Gust ◽  
Interconnected System ◽  
High Voltage Direct Current ◽  
Wind Generators ◽  
Wind Gusts

An investigation of the effects of wind gusts on the directly interconnected wind generators is reported, and techniques toward the mitigation of the wind gust negative influences have been proposed. Using a directly interconnected system approach, wind turbine generators are connected to a single synchronous bus or collection grid without the use of power converters on each turbine. This bus can then be transformed for transmission onshore using High Voltage Alternating Current, Low-Frequency Alternating Current or High Voltage Direct Current techniques with shared power conversion resources onshore connecting the farm to the grid. Analysis of the potential for instability in transient conditions on the wind farm, for example, caused by wind gusts is the subject of this paper. Gust magnitude and rise time/fall time are investigated. Using pitch control and the natural damping of the high inertial offshore system, satisfactory overall system performance and stability can be achieved during these periods of transience.

scholarly journals Research on hybrid multi-terminal high-voltage DC technology for offshore wind farm integration

2013 ◽  
Vol 1 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Peng Zhan ◽  
Chenghao Li ◽  
Jinyu Wen ◽  
Yu Hua ◽  
Meiqi Yao ◽  
...  
Keyword(s):  
High Voltage ◽  
Wind Farm ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Wind Farm Integration

scholarly journals Low-Cost Resistivity Meter for Groundwater Exploration Using High Voltage Experimentations

2019 ◽  
Vol 10 (3) ◽  
pp. 35-39
Author(s):  
Mirza Naseer Ahmad ◽  
Farhat Iqbal ◽  
Saad Maqbool ◽  
M Bilal Arshad
Keyword(s):  
High Voltage ◽  
Local Community ◽  
Low Cost ◽  
Low Frequency ◽  
Groundwater Exploration ◽  
Time Loss ◽  
High Voltage Direct Current ◽  
The Earth ◽  
Resistivity Meter ◽  
Multiplier Circuit

26 March, 2018 Accepted: 17 September, 2019Abstract: Resistivity survey is very well known for the exploration of groundwater and to determine the depth ofbedrock. Generally, in Pakistan local drillers rarely use resistivity meter due to high cost of commercially availableequipment. Therefore, most of the wells for groundwater are drilled without any feasibility survey, which causeseconomic and time loss. An inexpensive resistivity meter has been developed that can help the local community toconduct a survey for groundwater. This designed equipment is handy, portable, easy to operate and can bemanufactured locally. This equipment costs 500 US Dollars (USD), whereas commercially available equipment costs2500 to 50000 USD. The designed portable device comprises of a 12V DC battery, an inverter, multiplier circuit,DPDT switch and electrodes. A 12V DC battery is fed to an inverter to achieve AC supply of 220V. The achieved ACvoltage is rectified to DC-voltage which is further enhanced up-to 1300 volts using voltage multiplier circuit. This highDC voltage is called High Voltage Direct Current (HVDC). HVDC is switched at very low frequency of 1Hz.Automatic switching is being accomplished by means of DPDT relay and its control circuitry. HVDC at low frequencyis applied to the earth through electrodes to determine resistivity for different materials lying inside the ground with apenetration depth of 100 meters. This portable instrument would be useful to map surface lithological layers, determinequality of groundwater and bedrock level in accurate and inexpensive way.

scholarly journals A Multi-Terminal HVdc Grid Topology Proposal for Offshore Wind Farms

2020 ◽  
Vol 10 (5) ◽  
pp. 1833
Author(s):  
Ali Raza ◽  
Muhammad Younis ◽  
Yuchao Liu ◽  
Ali Altalbe ◽  
Kumars Rouzbehi ◽  
...  
Keyword(s):  
High Voltage ◽  
Wind Farm ◽  
Wind Farms ◽  
Offshore Wind ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Offshore Platforms ◽  
Offshore Wind Farms ◽  
Dc Fault ◽  
Grid Side

Although various topologies of multi-terminal high voltage direct current (MT-HVdc) transmission systems are available in the literature, most of them are prone to loss of flexibility, reliability, stability, and redundancy in the events of grid contingencies. In this research, two new wind farms and substation ring topology (2WF-SSRT) are designed and proposed to address the aforementioned shortcomings. The objective of this paper is to investigate MT-HVdc grid topologies for integrating large offshore wind farms with an emphasis on power loss in the event of a dc grid fault or mainland alternating current (ac)grid abnormality. Standards and control of voltage source converter (VSC) based MT-HVdc grids are defined and discussed. High voltage dc switch-gear and dc circuit topologies are appraised based on the necessity of dc cables, HVdc circuit breakers, and extra offshore platforms. In this paper, the proposed topology is analyzed and compared with the formers for number and ratings of offshore substations, dc breakers, ultra-fast mechanical actuators, dc circuits, cost, flexibility, utilization, and redundancy of HVdc links. Coordinated operation of various topologies is assessed and compared with respect to the designed control scheme via a developed EMTDC/PSCAD simulation platform considering three fault scenarios: dc fault on transmission link connecting the wind farm to mainland power converters, dc fault within substation ring of VSC-HVdc stations, and ultimate disconnection of grid side VSC station. Results show that 2WF-SSRT is a promising topology for future MT-HVdc grids.

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