Fault section identification method for mixed line in AC transmission system

The increasing utilization of the mixed line requires more reliable technique to identify the fault section to overcome all the disadvantages of the existing schemes. Distance relay technique is not accurate and limited to one configuration of mixed line while the differential relay is more expensive since it requires more measurement hardware in the junction points and related communication channels along the whole length of the line. Based on the modern communication technology and digital signal processing technology development such as global positioning system (GPS) and high sampling frequency introduction in the signal processing domains, an accurate scheme with reasonable price is needed to identify fault section and configure the auto reclosing scheme to meet the increased demand on the mixed line.