Controlling the Power Flows

The multiDC Project

An internationally funded project under Innovation Fund Denmark framework of Grand Solutions

The project “MULTI-DC: Innovative Methods and Optimal Operation of Multiple HVDC Connections and Grids” (multiDC) applied in 2016 for funding under the Innovation Fund Denmark framework of “Grand Solutions”. Due to the high number of HVDC connections in the Nordic region, this call pursues new and advanced control solutions to fully employ the benefits HVDC connection has to offer. The specific objective of multiDC project is to develop innovative methods for the optimal coordination of multiple HVDC lines and HVDC grids in systems with high shares of renewables. To achieve this highly ambitious result, multiDC teamed up with established researchers, technology providers, and end customers

usemap SvK KTH HITACHI-ABB DTU Energinet Innovation Fund Denmark uLiege

Our focus

Dynamic Security

The increase of inverter-based generation is phasing out grid-connected generation units, which provide various system services, such as Short Circuit Capacity (SCC), frequency control and rotational energy. Moreover, the clustered renewable generation requires facilitation of huge power influx in a power system, which becomes increasingly challenging for TSOs to control. Due to high controllability and bulk power transmission capability, HVDC technology is a promising replacement to provide such services and help stabilizing the system. To ensure the feasibility of such transition, stability analysis needs to be conducted for low and zero inertia systems, and advanced converter control design should be employed.

Optimal operation

In the last decades, HVDC technology has become a common tool in the design of transmission grids. From a technical point of view, the full controllability of power converters gives the opportunity of supporting local AC networks by means of voltage control, frequency support and reactive power compensation. On the economic side, HVDC interconnectors facilitate the exchange of energy and ancillary services between countries. Thus, if HVDC and AC grids are operated in an optimal way, significant cost and energy savings can be achieved. The scope of this project is to benchmark current markets and to propose various path for their evolution in order to unleash the potential of HVDC lines.

Emergency Control

HVDC connections will play a key role in an efficient and secure operation of the future system, mainly due to their capability to bulk power transmission over long distances and for fast, flexible control. Today the operation of multi HVDC connections is not coordinated during disturbed system operation. This project’s primary goal is to enable HVDCs active participation in AC system frequency stability by developing advanced control actions. Moreover, these control actions should be carefully coordinated to avoid negative interaction with other stability types and operation factors in all interconnected systems. The aim is to use the current power system infrastructure, without implying large additional investment costs.

Implementation and testing

To analyse the North Sea Wind Power Hub offshore grid stability, and HVDC effective utilization in market operations and emergency control, an environment for testing must be established. This process is separated into two stages: online testing using powerful simulation tools, and hardware-in-the-loop implementation in state-of-art facilities across Denmark. The primary tool for online testing is DigSilent PowerFactory, used to develop Kriegers Flak interconnector, NSWPH, and detailed Nordic Test System models. Once our methods prove viable the implementation is taken to PowerLabDK Real-Time-Digital-Simulator, and, finally, reaches the transmission system operator’s SCADA control room.

Our Team

Jacob Østergaard
Jacob Østergaard
Head of Center of Electric Power and Energy at DTU
Project leader, Steering committee member and work-package leader
Spyros Chatzivasileiadis
Spyros Chatzivasileiadis
Associate professor at DTU
Co-leader of the project, work-package lead and PhD Supervision. Contribution to HVDC coordination for steady-state control and market operation.
Fitim Kryezi
Fitim Kryezi
Technical Project Manager/Power System Engineer at EnerginetDK
Steering committee member.
Robert Eriksson
Robert Eriksson
Senior Power System Analyst at SvK
Work-package leader and PhD Supervision. Contribution to HVDC coordination for power system stability and control.
Thierry Van Cutsem
Thierry Van Cutsem
Adjunct Professor at ULiége and Research Director of the Fund for Scientific Research (FNRS)
Work-package leader and PhD supervision. Contribution to HVDC coordination for power system stability and control.
Jenny Josefsson
Jenny Josefsson
R&D Project Manager DC Grids at ABB-Hitachi Grid Solutions
Mehrdad Ghandhari
Mehrdad Ghandhari
Professor at KTH
PhD supervisor. Contribution to coordinated HVDC emergency control.
Tilman Weckesser
Tilman Weckesser
Electrical Engineer at Danish Energy Association, Grid Technology
Work-package leader and PhD Supervision. Contribution to HVDC coordination for power system stability and control.
Qiuwei Wu
Qiuwei Wu
Associate Professor at DTU
WP leader
Andrea Tosatto
Andrea Tosatto
PhD student at DTU
Contribution to optimal operation and integration of HVDC.
Georgios Misyris
Georgios Misyris
PhD student at DTU
Contribution to HVDC coordination for power system stability and control.
Danilo Obradovic
Danilo Obradovic
PhD student at KTH
Contribution to coordinated HVDC emergency control.

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