Research on Model Reduction of Direct Drive Wind Farm Subsynchronous Oscillation Analysis Based on Alternating Direction Implicit Balanced Truncation Method

Abstract

A reduced order model for subsynchronous oscillation analysis of direct drive wind farm was studied, and a balanced truncation method based on alternating direction implicit (ADI) was proposed. Firstly, the mathematical model of wind farm was built according to the mathematical representation of direct-driven permanent magnet synchronous wind turbine. The ADI method was used to solve the Lyapunov equation iteratively, and the controllable and observable Gramm matrixs were obtained. Then, the balanced truncation method was used to obtain the reduced order model. The time domain simulation waveform, Bode diagram, calculation time and subsynchronous oscillation mode of the full order model and the reduced order model were compared to verify the effectiveness of the proposed method. The simulation results show that the reduced order model has good consistency with the full order model, and the calculation speed is improved and the number of reduced order is greatly reduced.

Keywords

• direct drive wind farm
• alternating direction implicit (adi)
• subsynchronous oscillation
• model reduction
• balanced truncation method