Patent ID: 7298149

Claim:
A method to locate a fault from one end of a section of a power line by means of measurements of current, voltage and angles between the phases at a first end of said section, the method comprising: calculating symmetrical components of currents for said current and voltage measurement at said first end, calculating a value of impedance for an extra link between the terminals with the impedance for the positive sequence equal to: ( Z _ 1 ⁢ LB & ⁢ AB = Z _ 1 ⁢ LB ⁢ Z _ 1 ⁢ AB Z _ 1 ⁢ LB + Z _ 1 ⁢ AB ) where ⁢ : Z 1AB =impedance for the positive sequence of the extra link, Z 1LA =positive-sequence impedance of the healthy line, determining a compensation for the shunt capacitance with the aid of an equation of the form: B 2 comp —1 ( d comp — 1 ) 2 +B 1 comp — 1 d comp — 1 +B 0 comp— 1 =0 where: B 2 comp — 1 =A 2 — Re comp — 1 A 00 — Im comp — 1 −A 2 — Im comp — 1 A 00 — Re comp — 1 B 1 comp — 1 =A 1 — Re comp — 1 A 00 — Im comp — 1 −A 1 — Im comp — 1 A 00 — Re comp — 1 B 0 comp — 1 =A 0 — Re comp — 1 A 00 — Im comp — 1 −A 0 — Im comp — 1 A 00 — Re comp — 1 determining the zero-sequence current from the healthy line of a section of parallel power lines, calculating a distance to a fault for the parallel line section, calculating the distance to the fault from said first end using a quadratic equation of the form: B 2 d 2 +B 1 d+B 0 =0 where: B 2 =A 2 — Re A 00 — Im −A 2 — Im A 00 — Re B 1 =A 1 — Re A 00 — Im −A 1 — Im A 00 — Re B 0 =A 0 — Re A 00 — Im −A 0 — Im A 00 — Re and locating the fault utilizing the calculated distances.