Chaos exists widely in nonlinear dynamic systems, it behaves as chaotic oscillation, voltage collapse, etc. Power system in essence is a strong nonlinear system, with certain conditions there will be completely chaotic phenomena.The main research progress of chaotic control approaches and application and the prospect is outlined in this paper. This article also presents shortcomings and challenges of chaos studies in power system.

Doubly fed induction generator (DFIG) is receiving more attention nowadays due to growing power demand and environmental concerns. In this paper, five main issues of the DFIG associating with the grid-connection, low voltage ride-through (LVRT), maximum power point tracking (MPPT) control strategy, operation in unbalanced voltage condition, contribution to frequency regulation of grid and influence on power system stability are discussed.