汽轮发电机转子阻尼系统对小扰动特性的影响

Influence of rotor damping system of turbine generator on small disturbance characteristic

电力系统中的各种小扰动通常会导致系统发生低频振荡,而汽轮发电机转子阻尼系统对于抑制低频振荡具有重要作用。为了研究转子大齿导条、转子导电槽楔构成阻尼绕组和转子铁心对系统小扰动特性的影响,建立了能够反映实际转子阻尼结构影响的时步有限元模型。首先研究了忽略转子阻尼作用对小扰动仿真结果的影响;然后对比研究了阻尼绕组和转子铁心分别对小扰动特性的影响,分析了不同阻尼结构中阻尼电流的大小及其所产生的阻尼作用强弱;最后对比了转子槽楔采用铝合金和不锈钢时,材料电导率的大小对小扰动特性的影响。结果表明:小扰动过程中阻尼绕组中的阻尼电流大于转子铁心中的电流,因此其对小扰动特性的影响较大;转子槽楔采用铝合金时的阻尼作用要强于不锈钢槽楔的阻尼作用。研究结果可为电力系统仿真中如何合理准确地分析系统小扰动特性提供必要的理论基础。

The small disturbance in power system generally results in low frequency oscillation, which can be suppress by rotor damping system of turbine generator. In order to study the impact of rotor iron core and damping winding which consists of damping bars, rotor conductive slot wedge on small disturbance characteristic, we established time-step fi- nite element model of turbine generator. Firstly, we investigated the importance of the rotor damping system to small disturbance characteristic and find its impact is not negligible. Secondly, we compared the small disturbance character- istic affected by damping winding and rotor iron core respectively, and analized the value of current in rotor conductor and the damping strength of different damping structures. Finally, we studied the influence of rotor slot wedge material on small disturbance characteristic. The results show that the rotor slot wedge plays a leading role small disturbance characteristic, and the damping effects of rotor slot wedge made from aluminum alloy is stronger than that made from stainless steel. The result provides theoretical basis to analyze accurately the small disturbance characteristic in power system simulation.