Fault location using digital relay data

The most accurate and reliable fault location results are obtained using new algorithms that consider the fault data from both ends of the line together. Obviously, the data from the two ends must be brought together via data communications, either from one substation to the other or to a computer at a third site to which both substations can send the data. This might be a control center, relay engineer´s office, or maintenance depot, which are ideal locations for really accurate fault location displays to be presented. Some two-ended location algorithms require time synchronization of the data from the two ends, which is not widely available. This article presents new calculations that do not require any such synchronization of the records to achieve excellent accuracy. Following an overview of the technical problems in computing fault location from fault voltage and current signals, a sampling of the newest and most accurate techniques that are easily implemented in existing digital devices for calculating location from one-ended or two ended line fault data records is given