Study on impedance-traveling wave assembled algorithm in one-terminal fault location system for transmission lines

Considering roundly reliability and accuracy of one- terminal fault location system for transmission lines, an impedance-traveling wave assembled algorithm, which combines measurement impedance method with traveling wave method, is presented. At first, it uses measurement impedance method to calculate roughly fault distance. Then regions of reflected waves from fault point and opposite bus to detective bus are confirmed respectively through the distance. At last, exact time of reflected wave from fault point to detective bus and that of reflected wave from opposite bus to detective bus are identified respectively in corresponding regions, and fault location is implemented according to the result detected. It has complementarities of both methods, because measurement impedance method guarantees reliability and traveling wave method improves accuracy. Results of simulation are that located errors are within 100 m if fault location based on traveling wave algorithm is available. It is improved that assembled algorithm proposed is correct.