The increasing complexity of the modern power system makes the transient as an important phenomenon. It required the fast fault detection. The fault has the fundamental components and higher order harmonics and time domain information. Analysis of these higher frequencies and noise are very helpful for the detection of the fault. For the proper planning and the operation of digital computation and simulation is necessary. These computer programs include short-circuit analysis, transients program, stability analysis, and power flow study. The extraction of the frequency component of voltage & current with the help of wavelet is presented. This frequency component directly gives the faulty transmission line resistance & reactance. The Mho relay characteristic is utilized for the analysis purpose. Calculated values of resistance & reactance are plotted in the graph. This paper proposed wavelet theory and its application in the development of transmission line protections. The proposed paper simulates a power system network in the PSCAD-a transient simulation and microcontroller program. The simulation of the protective relays under power disturbance is of particular interest in this work