Author(s): HU Junhui, QI Xiaoguang
Pages: 106-113
Year: 2015 Issue:  7
Journal: Advances of Power System & Hydroelectric Engineering
Keyword:  asymmetric short circuit; con-verter control; harmonic analysis;
Abstract: Double fed induction generator (DFIG) is the most widely used wind generator. Because of its special struc-tural design the operating characteristic of DFIG becomes much complicated during fault,especially under the low voltage ride through,and the output of DFIG has caused a series of effects on the safe operation of power grid and relay protection. At present a lot of research has focused on the short-current characteristic of DFIG,but the study of the harmonic current is rarely reported. This paper studies on the stator harmonic current and rotor harmonic current of DFIG during asymmetric fault with consideration of the effect of LVRT. From the perspective of electromagnetic transients,the analytic expressions of the DFIG stator harmonic current are derived in detail under the condition of Crowbar action. The generation mechanism of the harmonic current on the stator and rotor of DFIG caused by the converter control is researched under the condition of the crow-bar inaction. The conclusion made is verified by simulation.