Active Power Control with Undead-Band Voltage & Frequency Droop for HVDC Converters in Large Meshed DC Grids

A new control method for large meshed HVDC grids has been developed, which helps to keep the active power balance at the AC and the DC side. The method definition is kept wide, leaving the possibility for control parameter optimisation. Other known control methods can be seen as specific examples of the proposed method.

It can serve as a framework for the control of large DC grids, defining a common standard for the control scheme, but still leaving a lot of freedom for individual adjustments. The proposed method is based on a so called “undead”-band, meaning that control activity is reduced within the band, but not set to zero as with a regular dead-band.

It operates with a minimum of required communication. New converters can be added to the system without changing the control of the other individual converters. It is well suited to achieve high reliability standards due to the distributed control approach.