1 Connecting Belgium and Germany using HVDC: A Preliminary Study S. Cole, Member, IEEE, D. Van Hertem, Member, IEEE, R. Belmans, Fellow, IEEE Abstract—Although Belgium and Germany are neighbouring countries, there is no direct high-voltage line between them. A study that assessed the opportunity of an ac high-voltage line between the two countries was performed at request of Belgian, German, and Luxembourgian governments. The result of the technical study was that no substantial import capacity can be achieved. In this paper, the conclusions of a new study are presented. This study considers the connection of Belgium and Germany via an HVDC link. It is shown that HVDC can increase import capacity significantly. It would be the first HVDC land cable connection in the UCTE grid. Index Terms--HVDC Transmission, VSC HVDC, Power transmission. I. INTRODUCTION HE European electricity grid is highly meshed. In this meshed grid, the Belgian transmission system forms one of the most important electrical crossroads in Europe, with significant international power flows taking a large part of the available transmission capacity. The European community already identified the congestion problems on the France- Belgium-Netherlands-Germany borders to be one of the axes for priority projects [1]. The congestion limits the internal market operation within Belgium. In view of increasing import capacity, existing international connections are upgraded. Recently the second circuit of the Avelgem-Avelin connection with France was installed. A second connection with France, Aubange-Moulaine, will be upgraded in the future. International East-West connections are currently non-existent: although Germany and Belgium are neighbours, no direct connection exists between the two countries (Fig. 1). It is therefore requested by Belgian, German, and Luxembourgian governments to assess the opportunity of an interconnection between Belgium and Germany. From the point of view of the Belgian government, import Manuscript received March 9, 2007. The research performed at the KU Leuven is financially supported by the Belgian 'Fonds voor Wetenschappelijk Onderzoek (F.W.O.)-Vlaanderen'. Dirk Van Hertem is a doctoral research assistant of the F.W.O.-Vlaanderen. S. Cole (e-mail: stijn.cole@esat.kuleuven.be), D. Van Hertem (e-mail: dirk.vanhertem@esat.kuleuven.be), and R. Belmans (e-mail: ronnie.belmans@esat.kuleuven.be) are with the Electrical Engineering Department of University of Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium. R. Belmans is chairman of the board of directors of Elia, the Belgian TSO. capacity is of utmost importance. The Belgium government is interested whether the connection would substantially increase import capacity. This would also enhance competition in the Belgian market. II. PREVIOUS STUDY A joint study has been conducted by Elia, the Belgian transmission system operator, and RWE Transportnetz Strom, the German transmission system operator in the area adjacent to the Belgian grid, to assess the opportunity of the requested interconnection between Belgium and Germany. Only ac overhead 380 kV double circuits were considered in this study. Two trajectories were investigated. The first one from Brume (B) to Dalhem (D), 65 km, and the second one from Lixhe (B) to Oberzier (D), 60 km (Fig. 1). The result of the technical study was that no substantial import capacity can be achieved, regardless of the chosen trajectory. The capacity found was in the order of magnitude of 200 MW. Optimization of the flows by phase shifting transformers that will be installed elsewhere in the Belgian power system, was taken into account in the study. The reason for this very limited increase in import capacity is that the power in Europe primarily flows along North-South paths. Moreover, from environmental, planning and regulatory point of view, major difficulties can be expected. The variant Brume–Dalhem crosses the national park "Hohes Venn-Eifel", as well as many cities and villages. The Lixhe–Oberzier variant crosses the densely populated area around Aachen. For these reasons this investment was not considered beneficial, and was abandoned. Summarizing, it may be said that the construction of a connection Belgium – Germany was rejected for three reasons: • limited import capacity; • high environmental impact, e.g. crossing a national park; • expected permitting problems. Nevertheless, the connection as such is very important for the Belgian government. III. PRESENT STUDY Having the conclusions of the previous study in mind, T