A classification of DC node voltage control methods for HVDC grids

Abstract In a DC grid, contingencies such as converter outages give rise to a current imbalance that is reflected in the DC node voltages in the grid. This imbalance has to be accounted for by changing the currents flowing in and out of the DC system. These DC node voltages can be directly influenced by controlling the DC current of the HVDC converter at that node. Different control strategies can be applied to balance the currents in a DC grid after a contingency. In this paper, the different converter control strategies are introduced systematically, thereby aiming to provide a framework for classifying the different converter control strategies available in literature. It is discussed how all converter control strategies theoretically can be regarded as limiting cases of a voltage droop control. It is also explained how the different converter control concepts can be combined, leading to more advanced converter control schemes such as voltage margin control, dead-band droop control and undead-band droop control. Based on the introduced converter control strategies, different grid control strategies are introduced and classified. The application of the advanced converter control strategies results in advanced grid control strategies and the advantages of those are discussed.

[1]  T. Nakajima,et al.  A control system for HVDC transmission by voltage sourced converters , 1999, 1999 IEEE Power Engineering Society Summer Meeting. Conference Proceedings (Cat. No.99CH36364).

[2]  Ronnie Belmans,et al.  Modeling and Control of Multi-Terminal VSC HVDC Systems , 2012 .

[3]  Olav Bjarte Fosso,et al.  Dynamic active power control with improved undead-band droop for HVDC grids , 2012 .

[4]  Olav Bjarte Fosso,et al.  Active Power Control with Undead-Band Voltage & Frequency Droop for HVDC Converters in Large Meshed DC Grids , 2012 .

[5]  Magnus Korpås,et al.  WINDSPEED. Roadmap to the deployment of offshore wind energy in the Central and Southern North Sea , 2011 .

[6]  C D Barker,et al.  Autonomous converter control in a multi-terminal HVDC system , 2010 .

[7]  Oriol Gomis-Bellmunt,et al.  Methodology for Droop Control Dynamic Analysis of Multiterminal VSC-HVDC Grids for Offshore Wind Farms , 2011 .

[8]  Tore Undeland,et al.  Multi-Terminal VSC-HVDC System for Integration of Offshore Wind Farms and Green Electrification of Platforms in the North Sea , 2008 .

[9]  Boon-Teck Ooi,et al.  DC overvoltage control during loss of converter in multiterminal voltage-source converter-based HVDC (M-VSC-HVDC) , 2003 .

[10]  Janaka Ekanayake,et al.  Voltage–current characteristics of multiterminal HVDC-VSC for offshore wind farms , 2011 .

[11]  C D Barker,et al.  Further developments in autonomous converter control in a multi-terminal HVDC system , 2012 .

[12]  Andreas Sumper,et al.  Optimum voltage control for loss minimization in HVDC multi-terminal transmission systems for large offshore wind farms , 2012 .

[13]  Dirk Van Hertem,et al.  CIGRE TB 533 - Working Group B4.52 - HVDC Grid Feasibility Study , 2013 .

[14]  Wenyuan Wang,et al.  Droop Control Modelling and Analysis of Multi-terminal VSC-HVDC for Offshore Wind Farms , 2012 .

[15]  Olav Bjarte Fosso,et al.  Technical Aspects of the North Sea Super Grid , 2011 .

[16]  Dirk Van Hertem,et al.  VSC MTDC systems with a distributed DC voltage control - A power flow approach , 2011, 2011 IEEE Trondheim PowerTech.

[17]  Ronnie Belmans,et al.  A Distributed DC Voltage Control Method for VSC MTDC Systems , 2012 .

[18]  Kjetil Uhlen,et al.  Primary frequency control of remote grids connected by multi-terminal HVDC , 2010, IEEE PES General Meeting.

[19]  Dirk Van Hertem,et al.  Multi-terminal VSC HVDC for the European supergrid: Obstacles , 2010 .