The invention provides an analytical method of operation of a large
transformer with inconsistent three-phase parameters. The analytical method includes the following steps: carrying out analytical calculation on parameters of a large three-phase
transformer set, comparing the parameters with related indexes so as to analyze possibility of operation of the
transformer with the inconsistent three-phase parameters, reutilizing electromechanical-
electromagnetic simulation analog computation to analyze operation condition of the transformer set in a
power grid and effects on other devices, further verifying possibility of grid-connected operation of the transformer set, and lastly working out related operation types and
relay protection setting value adjusting schemes according to the result of analysis and emulation to conduct operation of the transformer set. According to the method, the effect of operation of the large transformer with the inconsistent three-phase parameters on the
power grid can be completely and accurately analyzed, and corresponding operation types and the setting value protection adjusting schemes can be provided, so that safety and stability of the
power grid in operation of the large transformer with the inconsistent three-phase parameters are guaranteed. The method can be applied to analysis of transformer accidental replacement and transformer back-up transformer applicability, and the like.