Ratio-Based Selective Inertial and Primary Frequency Support Through MTDC Grids With Offshore Wind Farms

Hybrid control strategy for effective frequency regulation and power sharing in multi‐terminal HVDC grids

“…A coordinated control strategy has opted for frequency regulation in AC grid through HVDC link connected OWF [21]. In both [22, 23], primary frequency, along with inertial support, has been taken through MTDC grids. However, the control methodology was almost same in providing frequency support.…”

“…The selection approach of participated and non‐participated VSC in both the cases depends on the distress signals generated after the contingencies. Further, Vennelaganti and Chaudhuri [22] and [23] used model predictive control and proposed modification in OWF control, respectively, to improve frequency dynamics in the AC‐MTDC grid. In the modular multilevel converter (MMC) based MTDC system, the GS‐VSC uses both supplementary and standard control strategies to support inertial emulation and frequency regulation [24].…”

“…To the best knowledge of the authors, this kind of approach is unique and novel in improving frequency regulation of the AC grid, and it is not used in any literature. Moreover, the proposed control is simple and most effective in frequency regulation than that of individual PVf or droop control methods, and other frequency regulation methods in [9, 11, 23, 24]. In [9, 11], the change of control modes from DC‐voltage to frequency regulation will result in switching disturbance and it may not be smooth while switching one mode to another.…”

“…In [9, 11], the change of control modes from DC‐voltage to frequency regulation will result in switching disturbance and it may not be smooth while switching one mode to another. Whereas in [23, 24], the supplementary control techniques increase the control complexity of the VSCs. These control techniques usually add auxiliary control loop into the existing control loop and also depend on the dedicated communication links which increase the cost of installation.…”

Selective Frequency Support Approach for MTDC Systems Integrating Wind Generation

“…This study concluded that the extent of support between asynchronous ac systems is highly dependent on droop-coefficient selection. [15], [16] suggested the addition of a distress signal to transmit information about the ac side disturbance in MTDC systems, activate the FD loop, and to achieve ratio-based reserve sharing. Based on the simplified mathematical models of the whole system, [15], [16] attempted the design and parameter setting of FD controllers, e.g., droop-coefficient selection.…”