基于FLUX 2D的大型同步发电机在额定运行下定子绕组匝间短路故障特性研究

Fault Characteristic Study Based on FLUX 2D for Large Synchronous Generators With Stator Winding Inter-turn Short Circuits Under Rated Operating Conditions

该文采用单一绕组分析和有限元分析相结合的方法,研究大型同步发电机在额定运行方式下定子绕组匝间短路故障特性。该方法同样适用于确定故障条件下的电流和转矩。对于内部故障情况的电磁瞬态仿真必须考虑到一些特殊措施,如单一绕组和电网之间正确的连接对于模拟内部故障是相当关键的。以往的结果表明,在内部磁场非对称的情况下,基于等效电路的经典算法是不适用的。该文通过对汽轮发电机匝间短路故障进行系统的研究,表明:其短路电流、相电流、转矩和径向力与短路的位置及匝数紧密相关。在一些短路情况下,发电机将产生很大的局部电流,该局部电流对同步发电机的影响甚至超过外部故障。此外,很大的径向力作用在转子上可能对整个转轴产生极大的危害。

This paper investigates the stator winding short circuit characteristics in synchronous generators under rated operating conditions by combing the single-winding analytical method and the finite element method（FEM）,which is still the effective method to determine currents and torques under specific fault conditions.Some special measures have to be considered in case of the electromagnetic transient process under the condition of inner faults,e.g.,the correct interconnection between sub-strands and the grid is of the particular importance for inner fault simulations.The previous results show that the traditional calculation method based on the equivalent networks fails in case of the inner asymmetry magnetic field.Based on the systematic investigation of a turbo generator with inter-turn short circuits,the results of this paper show the short circuit currents,phase currents,torques and the radial forces have strong correlations with the location and the turn number of faults.In some cases of inter-turn short circuits,the fault currents exceed that of the outer faults.Furthermore,strong radial forces acting on the magnet wheel might lead to the damages of the total shaft train.