Harmonic instability analysis of distributed power stations considering dq-axis coupling and line distribution parameters

Abstract

To address the challenge of solving the zero-pole of transcendental equation for distributed power station with simultaneous consideration of two factors， i.e.， dq-axis coupling and line distribution parameter， an impedance model for distributed power station considering the two factors is established. This paper proposes a matrix-determinant zero-pole solution method for transcendental equation using Padé approximation and provides detailed steps for calculating the zero-pole distribution of the transfer function. Furthermore，it analyzes the impact of the two factors on harmonic instability analysis in the system under different scenarios. The research demonstrates that the proposed method can accurately analyze harmonic instability issues when these two factors are considered simultaneously. And ignoring one of the two factors may result in the misjudgment of stability， and considering the line distribution parameter is a necessary prerequisite for solving the amplification point of high-frequency harmonics. The effectiveness of the proposed method is verified by simulation.

Keywords

• distributed power station
• harmonic instability
• distribution parameters
• dq-axis coupling
• transcendent equation
• padé approximation