| 摘要 |
Method for detection and location of a fault point on a power transmission line and device for carrying out the method. Method and device are based on voltage waves (u<+>] emitted from a measuring point towards a fault point and corresponding waves (u<->) reflected from the fault point, which are included in a travelling wave model of the transmission line. The invention comprises a measurement of the instantaneous values of the current and the voltage at the end point of the transmission line, for example at a station, at certain regular intervals. Based on these measured values and with the aid of the traveling wave model it is possible to calculate the voltage (u1, u2, ... un) at a number of control points (d1, d2, ... dn) along the transmission line. If the line is energized and the calculated control voltages at two control points have different signs during a time longer than a time corresponding to normal phase difference between the two voltages, there is a fault on the line between these two points. By interpolation it is possible, based on the distance between the two points and the calculated control voltages, to locate the fault point in case of low resistance faults. |
