The power system is a complex system in both structure and operation. When a problem occurs, any element in the system affects the reliability of power supply, energy quality and causes huge economic loss. There are many causes of incidents on power transmission lines, including lightning strikes, aging insulation, trees falling into the lines, etc. Due to the long length of the lines running on complex terrain, this leads to incidents. When an incident occurs, the search process to locate the problem takes a lot of time, leading to a long troubleshooting time, affecting the uninterrupted power supply process. Therefore, the problem of detecting the type of fault and the location of the fault on power transmission lines is an urgent requirement. In current practice, determining the location of faults on power lines relies on impedance relays, however this method has large errors because it does not take into account the inductance value of the fault caused. In the tested models, mainly the power transmission line is modeled as a long line with typical parameters for the wave propagation process. Therefore, researching the Wavelet spectrum analysis method of the wave propagation process to determine the location of faults on power transmission lines to support the process of locating and fixing faults on power transmission lines, thereby reducing economic losses and improving the reliability and quality of energy supplied to consumers.