Adaptive droop control strategy for autonomous power sharing and DC voltage control in wind farm‐MTDC grids

Abstract

This study presents a novel adaptive droop control (ADC) strategy for power-sharing in a multi-terminal high-voltage DC grid while maintaining a desirable DC voltage level. The ADC scheme can share the power without burdening any power converters during one or more converter outages and huge power imbalance situations. To improve the effectiveness of the power sharing and DC voltage deviation control, the ADC is also implemented for wind farm converters. This is achieved through a derated mode operation of wind farms. The performance and effectiveness of the proposed control approach are evaluated in several case studies based on the specific type of converter outage under the various outage scenarios. The proposed method is validated on a five-terminal CIGRE B4 DC grid test system.

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

“…However, it is not mentioned in [19] that how WFs are operated such that they can provide support to the onshore AC grids. Whereas in [36], it is mentioned clearly the operation of WFs, i.e. derated mode of operation has been used along with WF‐VSCs operating in voltage droop to provide support to the MTDC grid.…”

“…derated mode of operation has been used along with WF‐VSCs operating in voltage droop to provide support to the MTDC grid. In this case, unlikely to the [36], the WF‐VSCs are operated in the frequency droop (Pf) instead of voltage droop control mode.…”

“…Further, the GS‐VSC1 is usually of large capacity and is operating as swing converter and is utilised to maintain a constant DC voltage across the MTDC grid during the steady state. However, it cannot maintain the DC voltage when the grid is subjected to sudden load change or contingencies [7, 36]. For instance, if the GS‐VSC1 (operating in constant DC‐voltage) outage has been considered to regulate the DC voltage along with frequency in the AC‐MTDC grids, it is essential to operate VSCs in the droop control.…”

Two-layer control structure for enhancing frequency stability of the MTDC system

“…Common control strategies for the MTDC system include masterslave control (MSC) [4], voltage margin strategy [5], and DC voltage droop control strategies [6][7][8][9][10][11][12][13][14]. The general disadvantage of MSCbased control strategies lays in the fact that the MTDC system will be paralyzed once the master converter stops working.…”

An Interaction Less Duo Control Strategy for Bi-polar Voltage Source Converter in Renewables Integrated Multi-Terminal HVDC (MTDC) Grids

“…A generalized droop control strategy proposed for improved dc voltage and powersharing in the MTDC grids [8]. A decentralized adaptive droop control strategy is proposed for enhanced dc voltage support in the MTDC grid [9]. In analogous to the frequency reserve, an over-and under-voltage reserve droop-based primary control is utilized to secure and enhance dc voltage regulation in the MTDC grid [10].…”