Coordinated reactive power control for facilitating fault ride through of doubly fed induction generator- and fixed speed induction generator-based wind farms

This study proposes a coordinated control strategy for adjacent fixed speed induction generator (FSIG)-and doubly fed induction generator (DFIG)-based wind farms whereby the reactive power output of the DFIG is prioritised over active power after a fault on the network, in order to boost the FSIG terminal voltage and improve its fault ride-through capability. The simulation results show that the stability margin of an FSIG can be significantly greater when there is extra reactive power compensation available from a DFIG in the vicinity. It is also seen that the increase in FSIG active power output because of higher voltage can compensate for the reduction in DFIG active power. The effects of different reactive power levels and coupling impedance on stability improvement and active power generation are also investigated. It is shown that an optimal reactive power limit for the DFIG should be chosen which takes account of both the increase in stability and also of the active power generation from the DFIG and FSIG wind farms.