abstract according to increase in electricity consumption in one hand and power systemsreliability importance in another , fault location detection techniqueshave beenrecentlytaken to consideration. an algorithm based on collected data from both transmission line endsproposed in this thesis. in order to reducecapacitance effects of transmission line, distributed parametersof transmission line has been employed. fault locations can be easily derived from a simple procedure, in which drawbacks of reiterative algorithms do not appear. applying illustrated modifications, suggested in this thesis, algorithm has been developed to function in presence of transmission line compensators, including three important facts devicessuch as sssc, statcom and upfc. the proposed method was evaluated using detailed simulations to algorithm performance be ensured. simulations have been performed in matlab/simulink environment through following stages: • simulation of method in a non-compensated transmission line • simulation of stated method in presence of facts: o simulation of represented method in a seri-compensated transmission line withsssc o simulation of represented method in a shunt-compensated transmission line withstatcom o simulation of represented method in a shunt and seri-compensated transmission line withupfc.