Title :
New estimating techniques for multi-stress aging test of large generator stator winding insulation
Author :
Jiancheng, Song ; Bo, Yue ; Hengkun, Xie
Author_Institution :
State Key Lab. of Electr. Insulation for Power Equipment, Xi´´an Jiaotong Univ., China
Abstract :
The stator winding insulation of large generators suffers from combined stresses including thermal, mechanical, electrical and environmental stresses in service, resulting in gradual deterioration. In the present investigation, a multistress aging test model including electrical, thermal, mechanical vibration and thermal cycling factors is developed. According to the model, a multistress aging system is established and long-term aging tests of stator bar specimens in a 780 kW/6 kV motor have been carried out. Several new diagnostic parameters, such as dynamic increase rate of loss tangent, index of partial discharge magnitude, and second current rapid increase index, are put forward, which appear to be correlated with the deterioration of generator stator insulation. It has been verified that these parameters can be used to estimate the aging degree of stator winding insulation for power plants
Keywords :
AC generators; ageing; dielectric loss measurement; dynamic testing; environmental testing; insulation testing; machine insulation; partial discharge measurement; stators; thermal stresses; 6 kV; 780 kW; diagnostic parameters; dynamic increase rate of loss tangent; electrical stresses; environmental stresses; gradual deterioration; large generator stator winding insulation; long-term aging tests; mechanical stresses; multistress aging test; partial discharge magnitude index; power plants; second current rapid increase index; stator bar specimens; thermal cycling factors; thermal stresses; vibration; Aging; Dielectrics and electrical insulation; Insulation testing; Power generation; Stator windings; System testing; Thermal degradation; Thermal factors; Thermal stresses; Vibrations;
Conference_Titel :
Properties and Applications of Dielectric Materials, 2000. Proceedings of the 6th International Conference on
Conference_Location :
Xi´an
Print_ISBN :
0-7803-5459-1
DOI :
10.1109/ICPADM.2000.876388
