Abstract
During the power transmission of doubly-fed induction generator (DFIG), due to the influence of series compensating capacitance and long-distance transmission, DFIG is prone to sub-synchronous oscillation, which damages the stability of the system. By establishing the mathematical model of DFIG system, the cause of sub-synchronous oscillation and its influence on the control strategy of DFIG system are discussed. In order to solve the problem of performance degradation of traditional phase-locked loop (PLL) under sub-synchronous oscillation, an improved PLL is proposed to replace the traditional PLL. Aiming at the problem that the control of rotor side converter(RSC) and grid side converter(GSC) in doubly-fed wind power generation system under sub-synchronous oscillation is disturbed by harmonic signals, a control method of adding a quasi resonant controller in the control link of RSC and GSC to suppress sub-synchronous oscillation is proposed, and the feasibility of the method is verified by simulation and experiment. Finally, based on the research process of RSC direct resonance control, the sub-synchronous oscillation suppression strategy based on harmonic current extraction is proposed for the frequency adaptability of the quasi resonant controller. The actual performance of the sub-synchronous oscillation suppression strategy is verified through simulation and experiment. The experimental results show that the strategy is effective.
Highlights
The proportion of new energy generation in the power system is increasing day by day, and the use of power electronic equipment is more extensive, which makes the influence of new energy grid connection on the stability of the power grid is increasing [1]-[4]
The control of a doubly-fed induction generator (DFIG) depends on a large number of power electronic devices, which greatly enhances the interaction between power electronic components and line dynamic components, leading to the generation of Subsynchronous Oscillation (SSO) in the system [10]
This method simplified parameter adjustment and reduced control cost, but the variation of SSO oscillation frequency was not considered in the research process; [26] proposed to feed POD control signal to Grid side converter (GSC) as auxiliary control, so as to effectively alleviate Subsynchronous Control Interaction (SSCI) in DFIG and increase the damping of the system, but this method did not consider the optimization of Rotor side converter (RSC) control; [27] proposed to use Kalman fifilter (KF), the state estimation of the sub-synchronous component in the series compensation circuit is carried out, and a KF - damping controller is designed
Summary
The proportion of new energy generation in the power system is increasing day by day, and the use of power electronic equipment is more extensive, which makes the influence of new energy grid connection on the stability of the power grid is increasing [1]-[4]. In order to suppress SSO generated in wind power system, [25] proposed a control strategy based on stator side analog resistance by studying the influence of line series compensation degree on SSO This method simplified parameter adjustment and reduced control cost, but the variation of SSO oscillation frequency was not considered in the research process; [26] proposed to feed POD control signal to GSC as auxiliary control, so as to effectively alleviate SSCI in DFIG and increase the damping of the system, but this method did not consider the optimization of RSC control; [27] proposed to use Kalman fifilter (KF), the state estimation of the sub-synchronous component in the series compensation circuit is carried out, and a KF - damping controller is designed. The main factors affecting the oscillation frequency are the parameter control strategy of the controller, the series compensation degree of the transmission line, the line impedance and so on
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
