Offshore Grid Access Solutions
Siemens DC Technology
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Offshore Grid Access Solutions
Siemens DC Technology
Whether it’s remote offshore wind power or oil and gas production, the high potential of energy resources far offshore calls for cost-effective, cutting-edge technology. The only feasible way for efficiently transmitting power to and from platforms that are more than 80 kilometers from the mainland is DC technology. As the market leader in grid access solutions with four platforms using innovative HVDC PLUS technology in operation Siemens has recently created the next generation of DC grid access technology for offshore wind farms.
The 2nd generation DC grid access is the largest single lever to achieve the target commonly set by the industry for the »Levelized Cost of Energy of Offshore Wind« in 2020 .Therefore Siemens not only offers cutting-edge technology but also life-cycle services for DC technology solutions.
Siemens HVDC (High Voltage Direct Current) solution is the access technology of choice for bi-directional power transmission and whenever black-start capability is necessary. For wind applications the collected wind power is converted via HVDC PLUS into DC current and transmitted to the shore. There it is reconverted into AC current for in feed into the grid. For power supply of oil and gas applications AC current is converted to DC at an onshore converter station. After transmission to the platform it is converted back to AC via an HVDC PLUS converter station.
HVDC PLUS is a space saving and highly reliable voltage source converter (VSC) featuring modular multilevel converter (MMC) functionalities. It is designed for energy transmission of 1,000 MW and more, which make it ideally suited for grid access of far offshore platforms. HVDC PLUS is fully suitable for AC voltage control. The advantages are especially apparent in connections with weak AC networks. Harmonic filters are no longer necessary, providing tremendous footprint advantages, especially for offshore applications. Even when space is limited, in combination with DC Compact Switchgear the HVDC PLUS allows for optimum grid connection.
Get to know the new cost-saving DC grid access solution for far offshore wind farms under development at Siemens. It is a breakthrough in simplifying today’s offshore AC/DC converters, making them smaller, easier to install and to maintain. Its core is an encapsulated Diode Rectifier Unit (DRU) – the diode rectifier is the simplest, most compact and robust AC/DC converter the electrical engineer can imagine. The DC switchgear is now encapsulated as well, the so called DC Compact Switchgear (DC CS), which provides additional space-savings. Thus platform size and weight can be reduced dramatically. The total top side volume is reduced by up to 80%. The weight is reduced from approx. 26.000 tons to only 9.000 tons. Combined with the benefits of DC cables like their high power density the new DC technology becomes the most cost-effective solution for large power offshore wind farms. The breakeven distance is reduced to about 80 kilometers.
The concept of the Siemens Grid Access Solution using Diode Rectifier Units (SGA-DRU) includes small, distributed DC platforms connected in series by a DC cable. A central DC transmission platform is not required. The SGA-DRU can also operate with a reduced number of DC platforms, and platforms can be bypassed. This allows stepwise construction and commissioning and offers outstanding availability. The new SGA-DRU concept does not require any AC Offshore Substations. The turbine strings can directly be connected to the DC platform with a modification of the wind turbine control.
Learn more about this new technology on this page or visit our social media channels.
The world's first efficient high voltage DC Technology in operation: BorWin2 link
Siemens has a proven track record of successful DC offshore grid access projects. BorWin2 was the first offshore grid connection worldwide to begin commercial operation with efficient high-voltage DC technology. Its installation marks a crucial milestone in the German wind power development. The link connects the wind farms Veja Mate and Global Tech 1 to the onshore grid and can transmit up to 800 MW of clean electricity, enough to supply around one million German households. The offshore platform is located around 100 kilometers off the German coast – northwest of the island of Borkum, after which the project was named.
The world’s largest voltage-sourced converter (VSC) offshore system : HVDC PLUS link SylWin1
Siemens supplied the world’s largest voltage-sourced converter (VSC) offshore system with a rating of 864 MW for the SylWin1 project. Siemens’ HVDC PLUS link connects the Dan Tysk wind farm to the German shore. The converter is installed on an offshore platform, where the voltage level is stepped up and converted to ±320 kV DC. The platform accommodates all electrical equipment required for the HVDC converter station: two transformers, four AC cable compensation reactors, and high-voltage gas-insulated switchgear (GIS).
Four times a year, the HDVC/FACTS Highlights newsletter informs about proof points in outstanding projects, new developments and innovative solutions. This issue the Newsletter looks into the next generation of offshore power transmission.
Embedding dispersed generators like offshore wind farms in the power systems requires a higher investment in access technology and greater complexity in electrical design. The grid stability and transmission distance are both challenges that have to be taken into account. Siemens customizes grid access technology to meet specific offshore demands.
We conduct studies to determine the most technically efficient and economically feasible system solution. Whether you need support regarding your project management, commissioning, operations or service and maintenance, Siemens offers services to solve all offshore grid access issues. The portfolio also includes trainings for your employees and individual fault analysis.
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