Mathematical Model for Transformer Winding to Diagnose radial Deformation

The application of the transfer function is discussed at present as a method for on-site monitoring and diagnoses of power transformers with regard to mechanical damages of the winding. In order to be able to evaluate the measurements, the correlation between the characteristics of transfer functions and possible damages must be known. Radial deformation of transformer windings have been studied experimental and theoretical. The primary winding of the test transformer has 30 double disk coiis (1.2 MVA, 10 kV) and the secondary is a one layer winding with 23 turns (1.2 MVA, 400 V). A detailed mathematical model were developed for the test object and a comparison between measured and calculated results was carried out. A numerical method for the calculation of inductances is suggested, which is independent of the shape of the windings' turns. For the calculation of the earth capacitances or coupled capacitances a relationship is given. An independent simulation confirmed the accuracy of this relationship by using finite elements method. It is shown that the developed model can represent the behavior of transformer windings in the frequency domain in case of sound and deformed conditions.

کلیدواژه ها:

Transformer Monitoring ، Detailed Model ، Transfer Function