Enhanced Frequency Response in VSC-Based MTDC Networks With Adaptive Frequency Droop Control and Direct Power Control

This paper presents an innovative adaptive frequency droop control technique for Voltage Source Converter (VSC)-based Multi-Terminal Direct Current (MTDC) systems. The primary objective is to enhance frequency stability and optimize power distribution in AC grids with significant wind power integration. Traditional fixed droop control methods are inadequate in adapting to changing grid conditions, leading to inadequate frequency responses, voltage instabilities, and reduced lifespan of the converter during disturbances. To address these issues, this work proposes an adaptive droop control strategy integrated with direct power control (DPC). This method dynamically adjusts droop coefficients based on the converters' current operational state. The proposed system enables healthy converters share the burden of power distribution more effectively based on their current state of operation during emergencies, thereby enhancing both frequency and voltage stability while preventing converter overload, malfunction, and subsequent load shedding. Furthermore, these adjustable droop controllers work in tandem with the primary frequency response of the wind farm (WF) that has significant level of penetration. The system's design is compatible with current wind farm control mechanisms, eliminating the need for further modifications or replacements of existing equipment.