低压穿越工况对大型DFIG绕组绝缘老化的影响

Influence of low voltage ride through on insulation aging of large doubly-fed induction generator

为了研究低压穿越对1.5 MW双馈感应式风力发电机(Doubly Fed Induction Generator,DFIG)绝缘老化的影响和使绕组绝缘性能降低的因素,文章对电老化、热老化和机械应力老化模型进行分析。综合PSCAD和Ansoft仿真得到的低压穿越过程中电流、电压、转速等物理量的变化,以及不同低穿程度下发电机铁耗和铜耗反映出的铁芯和绕组的生热情况,利用老化模型判断低压穿越对绕组的绝缘性能产生的影响,进而分析其对匝间短路的影响。分析结果表明,低压穿越会对绕组绝缘性能产生恶劣影响,极有可能造成发电机匝间短路故障或者使故障恶化。

In order to study the influence of low voltage ride through on the insulation aging of 1.5 MW doubly-fed in- duction generator and the factors that reduce the insulation performance of windings, the electrical aging, thermal ag- ing and mechanical stress aging mode/ are analyzed. The changes in physical quantities such as current, voltage, speed are obtained by PSCAD and Ansoft s^mulations during low voltage ride through conditions. The heat build-up of the core and winding is reflected by the iron and the copper consumption of the generator under different low voltage ride through degrees. Afterwards, the influence of low voltage ride through on the insulation performance of winding and the turn-to-turn short circuit is judged by the aging model. The analysis results show that the low voltage ride through has a bad influence on the insulation performance of the windings, and may cause the inter-turn short circuit fault or a deterioration of the generator.