14.9.2 ApplicationThe main objective of line protection and monitoring IEDs is fast, selective and reliableoperation for faults on a protected line section. Besides this, information on distance tofault is very important for those involved in operation and maintenance. Reliableinformation on the fault location greatly decreases the downtime of the protected lines andincreases the total availability of a power system.The fault locator is started with the input CALCDIST to which trip signals indicating in-line faults are connected, typically distance protection zone 1 and accelerating zone. Thedisturbance report must also be started for the same faults since the function uses pre- andpost-fault information from the trip value recorder function.Beside this information the function must be informed about faulted phases for correctloop selection . The following loops are used for different types of 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 to selectthe unit of length either, in kilometer or miles for the distance to fault. The distance to thefault, which is calculated with a high accuracy, is stored together with the recordeddisturbances. This information can be read on the local HMI, uploaded to PCM600 and isavailable on the station bus according to IEC 61850–8–1.The fault locator LMBRFLO function, supports kilometer and mile for theline length unit. The fault distance will be presented with the same unit asthe line length and is mapped to IEC61850 -8-1 communication protocol,where the fault distance is supposed to be in kilometer (km). Select the linelength unit to kilometer for compliance with IEC61850.The distance to fault can be recalculated on the local HMI by using the measuringalgorithm for different fault loops or for changed system parameters.14.9.3 Setting guidelinesThe parameters for the Fault locator function are set via the local HMI or PCM600.1MRK 506 334-UUS A Section 14Monitoring447Application manual
