Characterization Leakage Inductance Behavior of Power Transformer Affected by Mechanical Faults

Winding mechanical faults are one of the main defects that mostly occurred in transformers and can put them out of service. Throughout the years, different methods have been investigated for calculating leakage inductance of power transformers. And its potential for diagnosing winding mechanical faults and diagnosing transformers faults and nowadays, this parameter is used as a transformer health index in practical measurements. Hence, an accurate study in this area is needed to verify the capability of this method in detecting and diagnosing of various transformer windings faults. In this study some most common forms of winding mechanical faults such as deformation and displacement and the effects of each of them on transformer windings leakage inductance have been studied by using finite element method (FEM), but the main objective of this study and desired future works, is to perform a systematic study on different types of transformers winding mechanical and electrical faults and so, verify the sensitivity and ability of the leakage inductance measurement in monitoring of the transformers status. In the end, an 8 MVA power transformer has been taken as a case study to clarify the capability of this method in assessing transformer winding condition. Obtained results from simulation reveal the fact that the leakage inductance has a higher sensitivity to winding radial deformation in comparison to winding axial displacement and therefore, the winding deformation will be reflected as well in leakage inductance.

Keywords:

Winding Deformation , Leakage Inductance , Short Circuit Impedance , Finite Element Method (FEM) , Electromagnetic Forces , Energy Method.