Control methodologies for direct voltage and power flow in a meshed HVDC grid

Summary

Historically, HVDC (High Voltage Direct Current) technology has been used mainly for point-to-point transmission with one sending and one receiving converter station.  Although the connection of more than two HVDC converters in a multi-terminal HVDC configuration is feasible, there are only a few multi-terminal schemes in service today. The need for integrating large-scale renewable generation, the electrification of oil and gas platforms from onshore grids, and the integration of markets has resulted in a demand for new transmission capacity and interconnectors. To meet these needs, more multi-terminal and meshed HVDC grids are under consideration.

The control of power flow, frequency control and voltage control in AC (Alternating Current) systems is well understood, and a similar control scheme will also be needed in HVDC grids. In addition, an HVDC grid cannot be controlled and operated independently of the AC system. The stakeholders of an HVDC grid, such as the TSOs (Transmission System Operators), regulators and other market players, are likely to require that the HVDC grid facilitates efficient and secure operation of the combined AC and HVDC systems.

This brochure provides the requirements and the classification of different control methods, including the coordinated system control, in order to ensure system security and efficient operation of the combined AC and HVDC system in an electricity market environment. In addition, a range of power flow controlling devices is described for efficient utilization of overhead lines and cables in the HVDC grid. The main focus for the technical brochure is on static control characteristics.

Control methods in HVDC grids is a technical area in development, and as such this technical brochure should be seen as a first attempt to provide the requirements, classification and description of different methodologies for direct voltage control, power flow control and coordinated system control in a meshed HVDC grid.

Additional informations

Authors

PAILLET, Gamlin

Keywords

hvdc, power electronics