Multiterminal grid for offshore wind

With the aim to investigate the best ways of integrating large scale offshore wind power by means of a transnational grid in the North Sea, we are working with ECN and TU Delft - in the context of the North Sea Transnational Grid (NSTG) project - to assess the challenges of operating multiterminal direct current transmission networks.

More specifically, aim of the cooperation is to test and validate new control strategies for AC/DC converters operating inside a multi-terminal DC (MTDC) grid.

For this validation a down-scaled MTDC grid will be built and tested in the JRC Smart Grid Simulation centre. First a stand-alone configuration will be tested consisting of three Voltage Source Converters (VSCs). Subsequently, a real-time digital simulator will be connected to perform testing of the VSC and its controls, interactively with the MTDC grid model in combination with real-time validation of the different models (f.i. wind farm models) and control strategies previously developed in the NSTG project.

For the testing phase, 3 voltage-source converters (VSC), each rated at 5 kVA, have been acquired. With the VSCs, it is possible to use PC-based controllers directly developed in Simulink™ together with the actual power hardware. This provides a straight-forward platform for obtaining practical results from the developed control strategies in the simulation phase. The advantage of using a real-time simulator in this scenario lies in the fact that it becomes possible to exchange signals with external devices, such as the VSCs, and use them in real-time, making this a valuable setup for PHIL (power-hardware-in-the-loop) testing.