大型发电机定子槽楔厚板模型及松动特征量研究

Study on Stator Slot Wedge Based on Plank Model and Its Characteristic Parameters

大型发电机定子线棒在运行过程中受到100 Hz的电磁力,波纹板和槽楔构成的紧固系统在电磁力长期作用下逐渐失去紧固性能,加剧定子线棒主绝缘劣化,甚至引发停机事故。该文研究波纹板紧固结构在松动过程中振动特性的变化规律,通过厚板振动力学建立了槽楔振动特性的物理模型;通过数学分析提出振动响应第一峰值点作为反映槽楔松紧程度的特征参数,并研究了振动峰值与激振力及波纹板紧固力之间的关系,通过实验数据验证了楔块物理模型的正确性。研究了波纹板形变量逐渐变小过程中振动特征参数的变化规律。在一定激振力作用下,第一峰值点随波纹板形变量增大而减小;在波纹板相同形变下,一定范围内提高激振力可以提升测量灵敏度。

Stator bar is excited by 100 Hz electromagnetic force in generators during operation, leading to serious vibration, so the bars are usually fixed within stator slot via ripple spring and wedge. However, stator wedges are becoming loose during long period of vibration, which will accelerate the deterioration of stator bar main insulation even lead to power outage. So it＇s of vital importance to detect the looseness of stator wedge for the security of power systems. This paper is concerned with the relationship among vibration characteristics of stator wedge, ripples spring deformation and excitation force, which identify the looseness of wedge tighting system, and also first present the plank model, which was verified by looseness detection experiments. According to mathematic analysis, the condition of wedge tighting system can be effectively reflected by the first maximum amplitude. First maximum amplitude decreases as deformation of ripple spring grows, while measuring sensitivity can be improved by higher excitation force.