The Frequency Regulation Of Doubly-Fed Induction Generator And Its Impacts On Small Signal Stability

As one of the most important new energy power generations around the world, wind power generation has made a great difference to the energy, economy and environment. With the increasing penetration of large scale wind power and the level of voltage and capacity, it might have some influences on power system inertia and its small signal stability. Based on the facts, this paper mainly focuses on the strategies of frequency regulation of doubly-fed induction generator (DFIG) which rotor side convertor is based on the stator voltage oriented strategy and its impacts on power system stability.This paper was organized as follows:Firstly, this paper expounded the background and value of this paper, and then summarized wind power technology, the frequency regulation strategies and small signal stability of wind farm at home and abroad, and then pointed out the shortages. Secondly, this paper analyzed the theory of DFIG variable speed constant frequency, provided the DFIG mathematic models and control strategies, and then established two machines model in DIgSILENT/Power Factory, studied the inertia of DFIG stepped in it. This paper studied the frequency regulation under SFO and SVO strategy and analyzed the influence of controller parameters, and then compared the two frequency strategies and the two vector strategies. Thirdly, this paper studied the torsional oscillation modal and the effects of parameters of shafting stiffness coefficient, shafting damping coefficient, inertia time constant and the frequency controller on it in the single machine infinite bus system based on characteristic root analyzing method and time-domain simulation method. Lastly, this paper studied the influence of DFIG joined in the two-areas-four-machines system in the aspects of the location, the capacity of DFIG, and that whether the synchronous generators installed PSS, the distances of DFIG tie-line, and the frequency controllers. The conclusions of this paper are useful.