It is not only important for the transient protection

but also has significant engineering meaning for the lightning current parameters collection to identify the lightning and short-circuit fault of transmission lines correctly. For the problem on identifying the lightning and short-circuit faults

this paper adopts a multi-resolution analysis of wavelet packet and finds that energy distribution of additional components of the transient currents differs when the data windows move. Defining K value as the principal component proportion

according to the differences among the K values of the different transient signals

the lightning and short-circuit fault can be identified by using the coefficient of variation of K values. The theory of the proposed method is intuitive

simple and EMTP simulations are provided its correctness.