Edwin Wiggelinkhuizen

A Novel Distributed Direct-Voltage Control Strategy for Grid Integration of Offshore Wind Energy Systems Through MTDC Network

Although HVDC transmission systems have been available since mid-1950s, almost all installations worldwide are point-to-point systems. In the past, the lower reliability and higher costs of power electronic converters, together with complex controls and need for fast telecommunication links, may have prevented the construction of multiterminal DC (MTDC) networks. The introduction of voltage-source converters for transmission purposes has renewed the interest in the development of supergrids for integration of remote renewable sources, such as offshore wind. The main focus of the present work is on the control and operation of MTDC networks for integration of offshore wind energy systems. After a brief introduction, this paper proposes a classification of MTDC networks. The most utilized control structures for VSC-HVDC are presented, since it is currently recognized as the best candidate for the development of supergrids, followed by a discussion of the merits and shortcomings of available DC voltage control methods. Subsequently, a novel control strategy-with distributed slack nodes-is proposed by means of a DC optimal power flow. The distributed voltage control (DVC) strategy is numerically illustrated by loss minimization in an MTDC network. Finally, dynamic simulations are performed to demonstrate the benefits of the DVC strategy.

Optimal power flow of VSC-based multi-terminal DC networks using genetic algorithm optimization

Europe is rapidly expanding its offshore wind energy capacity. Hence, the construction of a multi-terminal dc (MTDC) infrastructure to accommodate the generated electrical energy brings several advantages, but also comes with many challenges. Operation and control of a MTDC network is one of these challenges. This paper explains the operation and control of MTDC networks. Moreover, a study is carried on how to optimally operate and control an offshore VSC-based MTDC network. It focus on the development plans for an offshore transnational grid in the North Sea. A genetic algorithm (GA) will be employed to obtain an optimal power flow inside the offshore network. The MTDC grid is composed of 19 nodes, interconnecting 9 OWFs to 5 European countries. The optimal power flow results obtained from the genetic algorithm are tested in a simulation model for three case studies.

Multi-terminal network options for the interconnection of offshore wind farms: A case study between Britain and The Netherlands

The increasing global energy needs have led to the realization of interconnectors to strengthen regional electricity systems. As interconnectors are often placed offshore, combining those with wind farm grids can increase profitability compared to separate infrastructure and improve the grid integration, offering higher security of supply and controllability. However, a systematic approach for selecting the best transmission options for offshore multi-terminal networks is still missing in literature. This paper investigates options for interconnecting two offshore wind farms (OWFs) to two onshore asynchronous grids in a multi-terminal network. The options are presented for a case study comprising the Dutch and the British grid along with two OWFs in the coastal zone of each country. A review of the available technologies regarding high-voltage ac (HVac) and high-voltage dc (HVdc) transmission systems is given and, on this basis, six technical scenarios are identified and evaluated. For each scenario, the technical specifications are elaborated and a rough cost calculation is made. Based on the design possibilities for a four-terminal network, the technical bottlenecks and the most important research challenges for its realization are presented.

A Smart Grid simulation centre at the Institute for Energy and Transport — Integration of large amounts of offshore wind energy

In this paper the Smart Grid simulation centre facilities of the Institute for Energy and Transport (IET), Joint Research Centre (JRC) of the European Commissions (EC) are presented, providing a specific application of our work. The Smart Grid Simulation Centre is intended to combine electrical power components and communication/control equipment with system simulation tools. In this way the Centre can test grid elements and evaluate different operation scenarios under various conditions. As a specific activity the cooperation in accessing multiterminal grids is described in this paper.