Input Impedance Based Nyquist Stability Criterion for Subsynchronous Resonance Analysis in DFIG Based Wind Farms

One of the problems encountered when a wind farm is radially connected to a series compensated transmission line is subsynchronous resonance (SSR). The aim of this paper is to investigate the risk of SSR condition in Doubly-Fed Induction Generator (DFIG) based wind farms that are radially connected to series compensated transmission lines. The IEEE First Benchmark Model (IEEE FBM) is adopted and the passivity of the system in the subsynchronous range is investigated. Impedance based Nyquist criterion is used to assess the impact of DFIG controller parameters, output power and compensation level. The obtained analytical results are verified using time-domain simulation in PSCAD/EMTDC.