ABB RELION REX640 Technical Manual page 463

1MRS759142 F
groups or the RCA_CTL input. Alternatively, the operating sector of the directional
earth-fault protection function can be extended to cover the operating sectors of
both neutral earthing principles. Such characteristic is valid for both unearthed and
compensated network and does not require any modification in case the neutral
earthing changes temporarily from the unearthed to compensated network or vice
versa.
The extended phase angle characteristic is created by entering a value of over 90
degrees for the
reverse angle in case Directional mode is set to "Reverse"). The Max forward angle
setting should be set to cover the possible measurement inaccuracies of current
and voltage transformers; a typical value is 80 degrees (
Directional mode is set to "Reverse").
Figure 261: Extended operation area in directional earth-fault protection
4.2.2.7 Measurement modes
The function operates on three alternative measurement modes: "RMS", "DFT" and
"Peak-to-Peak". The measurement mode is selected with the
setting.
Table 534: Measurement modes supported by DEFxPDEF stages
Measurement mode
RMS
DFT
Peak-to-Peak
REX640
Technical Manual
Min forward angle setting; a typical value is 170 degrees ( Min
DEFLPDEF
x
x
x
Protection functions
Max reverse angle in case
Measurement mode
DEFHPDEF
x
x
x
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