A power flow calculation method of DRU-based AC transmission systems for offshore wind power

Abstract

The VSC-HVDC transmission systems are the typical solution for integrating far offshore wind power. Using diode rectifier units （DRUs） at the rectifier stations can further enhance the system’s economic efficiency and reliability. Therefore， a steady-state power flow calculation method of AC system transmission system for offshore wind power， based on grid-forming （GFM） wind turbines and DRU， is proposed. The topology of the offshore wind power integration system using DRU is described， and the GFM control strategy of the wind turbines， utilizing Q-f（reactive power-frequency） droop control， is introduced. The proposed steady-state power flow calculation method iterates the power flow using the reactive power imbalance in AC bus at the DRU-based converter station and considers the Q-f droop control characteristics of the GFM wind turbines. The steady-state operational characteristics of AC transmission systems for offshore wind power， based on GFM wind turbines and DRU， are analyzed for both the low-frequency and intermediate-frequency AC transmission systems. The effectiveness of the proposed method is validated.

Keywords

• offshore wind power
• dru
• gfm wind turbine
• q-f control
• power flow calculation