SSR characteristics of a wind farm connected to series-compensated transmission system under all operation region of DFIG

In most literatures related to subsynchronous resonance (SSR) in doubly fed induction generator (DFIG) based wind farm connected to series-compensated transmission system, the research is on the basis that the wind turbine is operated within the maximum power point tracing (MPPT) operating region, so the obtained conclusions are not comprehensive, since there are other important operating regions of DFIG such as fixed speed operating region, constant power operating region and so on. Firstly, all operating regions of DFIG are analyzed; then taking actual parameters and operating modes of wind turbine in a certain wind farm located in North China as the prototype, a small-signal model and PSCAD simulation model of single machine infinite bus system composed of DFIG and infinite bus system are built, and then using eigenvalue analysis and time-domain simulation the SSR Characteristics of a wind farm connected to series-compensated transmission system under all operation region of DFIG are researched and the SSR stable area are attained. Simulation results show that under low wind speed the SSR phenomenon will occur whether the DFIG is operated in MPPT region or in other operating regions; with the increase of the wind speed the area of stable operation region of DFIG gradually increases. On this basis, several rational suggestions on the stable operation of actual wind farms are put forward.