Abstract: The symmetrical component method is a fundamental method for analyzing the asymmetric operation of three-phase symmetrical system in power system. This paper elaborated the fundamental principle of the method of symmetrical components. In addition, it introduced the idea of the three-phase asymmetric fault voltage source to the local short-circuit fault of the power system. Moreover, it used the Thevenin equivalent theorem and superposition theorem of the circuit to structure the series phase equivalent network based on a certain phase. By analyzing the boundary conditions of three asymmetric short-circuit faults, this research formulated the equivalent circuit of the compound sequence network that matched the different fault types. Therefore, it helped to solve the problem of asymmetric short-circuit current. In conclusion, an example proves the effectiveness of the symmetrical component method in solving the asymmetrical short-circuit current process of each winding of a power transformer.

    Key words: power transformer; symmetrical component method; asymmetric short-circuit current; single phase short-circuit grounding;two phase short-circuit; two phase short-circuit grounding; sequence component