A generalized approach for design of contingency versatile DC voltage droop control in multi-terminal HVDC networks

The non-deterministic nature of power fluctuations in renewable energy sources impose challenges to the design of DC voltage-droop controller in Multi-Terminal High-Voltage DC (MTDC) systems. Fixed droop control does not consider converters' capacity and system operational constraints. Consequently, an adaptive droop controller is counseled for appropriate power demand distribution. The previous adaptive droop control studies based on the converters' Available-Headroom (AH) have lacked the demonstration of the droop gain design during consecutive power disturbances. In this paper, the design of the adaptive DC voltage droop control is investigated with several approaches, based on the permitted converters' global and/or local AH and Loading Factor (LF). Modified adaptive droop control approaches are presented along with a droop gain perturbation technique to achieve the power-sharing based on the converters' AH and LF. In addition, the impact of MultiUpdated (MU), Single-Updated (SU), and Irregular-Updated (IU) droop gains is investigated. The main objective of the adaptive droop control design is to minimize the power-sharing burden on converters during power variations/consecutive disturbances while maintaining the constraints of the DC grid (i.e., voltage and power rating). The presented approaches are evaluated through case studies with a 4-terminal and 5-terminal radial MTDC networks.

Automated summary

The paper investigates the design of adaptive DC voltage droop control with different approaches based on permitted converters' global and/or local AH and Loading Factor (LF). It also presents modified adaptive droop control methods and a droop gain perturbation technique to achieve power-sharing based on converters' AH and LF. Additionally, the impact of Multi-Updated (MU), Single-Updated (SU), and Irregular-Updated (IU) droop gains is explored to minimize power-sharing burden on converters while maintaining DC grid constraints.