Impact of DFIG impedance model precision on stability analysis

Abstract

Impedance-based stability analysis (IBSA) is an effective method to analyze the interaction problem between the doubly-fed induction generator-based wind park (DFIG-WP) and series compensated or weakly tied AC grids. The analytical impedance model of DFIG has evolved over the years for better precision. This paper presents a precision comparison of those analytical models where the reference is obtained through EMT-level frequency scanning simulations. Moreover, representative IBSA is also performed with those models on typical test systems in which the DFIG adversely interacts with the series compensated grid and weakly tied AC grid in sub- and super-synchronous frequency ranges, respectively. The common modeling approach, which disregards the coupling between the rotor side converter (RSC) and grid side converter (GSC) at the DC-side, reduces the accuracy of IBSA and may lead to incorrect stability analysis results.

Keywords

• DFIG
• Impedance modeling
• Weak grid instability
• Series-capacitor SSO
• Stability analysis