A Vibration Method for Identifying the Looseness of Windings for Large Power Transformers

Abstract. The safe operation of large power transformers is very important for the electricity system, while the looseness of winding clamping pressure is one of the main failure reasons. To deal with this problem, a two-degree-of-freedom nonlinear mechanical model for one winding is proposed and analyzed to study the influence of clamping pressure looseness on the windings’ vibration characteristics. The simulation of this model studies the influence of clamping pressure changes on the winding's natural frequency and its amplitude. Based on this study, the vibration method under swept frequency with constant current is put forward to identify the looseness of the windings. The experiments were conducted on one real large power transformer, which testifies that this method is effective by exactly identifying the windings’ looseness.

[1]  Jin Zhijian,et al.  Estimation of the Clamping Pressures of Transformer Windings from Vibration Measurements , 2008 .

[2]  K. D. Srivastava,et al.  Review of condition assessment of power transformers in service , 2002 .

[3]  M. Duval,et al.  Dissolved gas analysis: It can save your transformer , 1989, IEEE Electrical Insulation Magazine.

[4]  B. Garcia,et al.  Transformer tank vibration modeling as a method of detecting winding deformations-part II: experimental verification , 2006, IEEE Transactions on Power Delivery.

[5]  C. K. Mechefske.  Correlation power transformer tank vibration characteristics to winding looseness , 1995 .

[6]  Victor V. Sokolov,et al.  EXPERIENCE WITH DETECTION AND IDENTIFICATION OF WINDING BUCKLING IN POWER TRANSFORMERS , 2006 .

[7]  Mukund R. Patel.  Dynamic Response of Power Transformers Under Axial Short Circuit Forces Part I - Winding and Clamp as Individual Components , 1973 .

[8]  E.P. Dick,et al.  Transformer Diagnostic Testing by Frequuency Response Analysis , 1978, IEEE Transactions on Power Apparatus and Systems.

[9]  B. Garcia,et al.  Transformer tank vibration modeling as a method of detecting winding deformations-part I: theoretical foundation , 2006, IEEE Transactions on Power Delivery.

[10]  James R. McDonald,et al.  The use of artificial neural networks for condition monitoring of electrical power transformers , 1998, Neurocomputing.

[11]  G.W.A. McDowell,et al.  Real time monitoring of movement of transformer winding , 1994 .

[12]  A. Garcia-Cerrada,et al.  Experiences learned from the on-line internal monitoring of the behaviour of a transformer , 1997, 1997 IEEE International Electric Machines and Drives Conference Record.

[13]  A.J. Vandermaar,et al.  Transformer winding movement monitoring in service - key factors affecting FRA measurements , 2004, IEEE Electrical Insulation Magazine.