Setting Guidelines - ABB RELION 670 SERIES Applications Manual

Section 18
Monitoring
18.8.3
846
directional OC protection, and so on). 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, in
kilometers or miles as selected on the local HMI. LineLengthUnit setting is used to select
the unit of length either, in kilometer or miles for the distance to fault. The distance to the
fault, which is calculated with a high accuracy, is stored together with the recorded
disturbances. This information can be read on the local HMI, uploaded to PCM600 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 measuring
algorithm for different fault loops or for changed system parameters.

Setting guidelines

The 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 in
observed bay (protected line) and residual current from a parallel bay (line, which is
mutual coupled to protected line).
The Fault locator has close connection to the Disturbance report function. All external
analog inputs (channel 1-30), connected to the Disturbance report function, are available
to the Fault locator and the function uses information calculated by the Trip value
recorder. After allocation of analog inputs to the Disturbance report function, the user has
to point out which analog inputs to be used by the Fault locator. According to the default
settings the first four analog inputs are currents and next three are voltages in the observed
bay (no parallel line expected since chosen input is set to zero). Use the Parameter Setting
tool within PCM600 for changing analog configuration.
The measured phase voltages can be fine tuned with the parameters VAGain, VBGain and
VCGain to further increase the accuracy of the fault locator.
The list of parameters explains the meaning of the abbreviations. Figure
these system parameters graphically. Note, that all impedance values relate to their
primary values and to the total length of the protected line.
1MRK 506 369-UUS -
398 also presents
Line distance protection REL670 2.2 ANSI
Application manual