Impact of integrating DFIG and direct drive synchronous wind turbine generator on power system stability

Abstract

This paper focuses on the small signal stability analysis of Doubly Fed Induction Generator (DFIG) and Direct Drive Synchronous Generator (DDSG) integrated power system. For this purpose, one synchronous generator in the IEEE 14 bus test system is first replaced by a DFIG, and then by a DDSG while the wind penetration is varied between 24–40%. PSAT, a Matlab based power system analysis toolbox is used to perform small signal stability analysis, where eigenvalues give the insight into system oscillations and damping. In order to improve the damping of the Wind Turbine Generator (WTG) integrated system, Power System Stabilizers (PSS) are designed for synchronous generators. The key observations include the capability of WTGs to increase system stability under certain conditions, DDSG providing better damping for a certain range of penetration, and DFIG providing stability for a larger range of wind penetration. The findings were verified using time domain analysis, where the frequency response of the synchronous generators were observed.