Flashover analysis tool

A method of producing flashover analysis signal comprising processing a neutral current, three phase voltage profile, and a plurality of digital signals of a transmission line to identify a flashover fault caused by tree encroachment, crane, polluted insulator or lightning strike, by obtaining λ, the gradient of neutral current's root mean square value, whereby;

• if λ is not more than a threshold value, then the fault is a tree encroachment;
• if λ is more than a threshold value, then determine if voltage dip is less than a threshold value;
• if voltage dip is less than a threshold value then the fault is also a tree encroachment;
• if voltage dip is not less than a threshold value, then determine if a persistent fault is found;
• if a permanent fault is found then the fault is caused by crane;
• if there is no persistent fault, then determine if Δtf is more than a threshold value;
• if Δtf is more than a threshold value then the fault is caused by polluted insulator;
• and
• if Δtf is not more than a threshold value, then the fault is caused by lightning strike;
• wherein the above-mentioned steps are not restricted by order and Δtf is the time interval between the last current distortion and a flashover.