双馈感应发电机(DFIG)在定子磁链或电压定向的矢量控制下,其功角动态行为均具有快变特性,致使DFIG对常规同步发电机(SG)的首摆稳定性和阻尼特性产生重要影响.研究发现,DFIG和SG的功角摇摆曲线可能存在两类交点,将其分别定义为主动交越点和被动交越点,交越性质决定了DFIG对SG稳定性影响的性质.大扰动时,SG的首摆期间有主动交越交点,DFIG降低了系统的暂态稳定性;后续摇摆期间有被动交越交点,DFIG起到了正阻尼作用.%When vector control strategy is employed, based on stator flux orientation or stator voltage orientation, the power angle of DFIG has a sensitive dynamic behavior. Due to this characteristic, the first swing stability and damping of conventional synchronous generator (SG) are greatly influenced by DFIG. It is found that two sorts of power angle curve crosses will be produced when DFIG and parallel SG are integrated into power grid. In this paper, the two angle curves crosses are defined as positive cross and passive cross, whose cross nature determines the effect of DFIG on the stability of SG. When a large disturbance happens in power grid, the positive cross will appear in the period of fist swing and transient stability of power system will be weakened. But, the passive cross will occur in the succeeding seconds and DFIG will accordingly enhance damping of SG.This work is supported by Special Fund of the National Basic Research Program of China (973) (No. 2004CB217904).
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