Analysis of Parameters and Characteristics of Inter-turn Short-circuit Fault on Primary Side of Transformer

Transformer is the key equipment to transmit electric energy in the power system. A fault current generated by inter-turn short-circuit fault on the primary side of transformer will have a great impact on the transformer itself, the electric generator and the power grid. Besides, it makes an influence on the quality and stability of the electric energy of the power system. Aiming at the problem of calculating the inter-turn short-circuit current of transformer, by testing the measured data of steady and transient state of transformer, a simulation model in the 3D finite element software-FLUX is established. On the basis of this model, the inter-turn fault simulation is conducted with different turns and at different positions. Meanwhile, considering the relationship between the self and mutual inductance of windings and the number of turns and positions of short-circuit fault, a method for calculating fault current is put forward according to the circuit voltage equation. Compared with the simulation results obtained by FLUX, the validity of the calculation method is verified. By means of the post-processing function of the FLUX software, the change rules of the internal electromagnetic field after different types of transformer inter-turn short-circuit faults are finally studied by comparison. © 2019 Automation of Electric Power Systems Press.