A simple analytical method for accurate prediction of the leakage reactance and leakage energy in high-voltage transformers

Transformers are one of the most crucial pieces of equipment for the distribution and transmission of electric power. A high-voltage transformer plays a vital role to reduce power losses during the transmission of electricity. Leakage reactance plays a vital role in the working and stability of the transformer. The accurate prediction of the leakage reactance is a great asset to the transformer designers during the manufacturing stage to attain the dynamically optimum design of the transformer. In the literature, mostly given analytical techniques for leakage reactance calculations are applied to the transformers with the symmetric axial heights of the low-voltage, and high-voltage windings. Therefore, a proper analytical prediction for the leakage reactance in the transformer with asymmetric axial heights is needed to implement an optimized design. This paper proposes a new advanced method for an accurate calculation of the leakage reactance and leakage energies in different parts of the transformer with symmetrical and asymmetrical axial heights of the windings. Moreover, the finite element method and three different analytical methods are also compared with a new analytical technique for 5 real cases. For 2 cases, the proposed method's results are also verified by experimental tests. The method's accuracy in predicting the stored energy and leakage reactance of the high-voltage transformer is found to be more accurate and much simpler than the other analytical methods.