distance to fault is very important for those involved in operation and maintenance.Reliable information on the fault location greatly decreases the downtime of theprotected lines and increases the total availability of a power system.The fault locator is started with the input CALCDIST to which trip signals indicatingin-line faults are connected, typically distance protection zone 1 and accelerating zoneor the line differential protection. The disturbance report must also be started for thesame faults since the function uses pre- and post-fault information from the trip valuerecorder function (TVR).Beside this information the function must be informed about faulted phases for correctloop selection (phase selective outputs from differential protection, distance protection,directional OC protection, and so on). The following loops are used for different typesof faults:• for 3 phase faults: loop A-B.• for 2 phase faults: the loop between the faulted phases.• for 2 phase-to-ground faults: the loop between the faulted phases.• for phase-to-ground faults: the phase-to-ground loop.LMBRFLO function indicates the distance to fault as a percentage of the line length, inkilometers or miles as selected on the local HMI. LineLengthUnit setting is used toselect the unit of length either, in kilometer or miles for the distance to fault. Thedistance to the fault, which is calculated with a high accuracy, is stored together withthe recorded disturbances. This information can be read on the local HMI, uploaded toPCM600 and is available on the station bus according to IEC 61850–8–1.The distance to fault can be recalculated on the local HMI by using the measuringalgorithm for different fault loops or for changed system parameters.17.8.3 Setting guidelines IP14835-1 v1M13769-3 v6The parameters for the Fault locator function are set via the local HMI or PCM600.The Fault locator algorithm uses phase voltages, phase currents and residual current inobserved bay (protected line) and residual current from a parallel bay (line, which ismutual coupled to protected line).The Fault locator has close connection to the Disturbance report function. All externalanalog inputs (channel 1-30), connected to the Disturbance report function, areavailable to the Fault locator and the function uses information calculated by the Tripvalue recorder. After allocation of analog inputs to the Disturbance report function, theuser has to point out which analog inputs to be used by the Fault locator. According tothe default settings the first four analog inputs are currents and next three are voltages1MRK 511 401-UUS A Section 17MonitoringBay control REC670 2.2 ANSI 541Application manual
