Forced Low Frequency Oscillation of Wind-Integrated Power Systems

• 1、Electrical Engrineering and Automation,Harbin Institute of Technology,Harbin 150001

Abstract：Due to a large number of wind generators integrated to power systems, some new problems for the grid such as the forced low frequency oscillation (LFO) may occur. In order to ensure the safety and stability of Wind-Integrated Power Systems, Analysis and control of the LFO is particularly important. Based on the per-unit value system, this paper established a 7-order model DFIG and analyzed the small signal linear mathematical model of One Machine Infinity Bus (OMIB) containing wind farms under various wind speed, calculated the characteristic root and participation factor, concluded that there are two forced low oscillation modes separately of high and low frequency in the system which are caused by shaft system and pitch angle control system respectively.What's more, this paper put forwar an improved MPPT strategy. Based on discrete model simulation, the validity of the conclusion is verified, which can provide basic theoretical analysis of forced LFO for future measures of prevention and control.

Keywords： Wind power generation 7-order model DFIG Per-unit value system Characteristic equations under various wind speed Two forced low oscillation modes Discrete model simulation