ABB RELION 670 Series Applications Manual page 139

1MRK 511 364-UUS A
OpModeSel is set to 3I0 and fi the function will operate if the residual current is larger than
When
the setting
The characteristic for this
ANSI06000652 V2 EN-US
Figure 60: Characteristic for RCADir = 0° and ROADir = 80°
DirMode is set Forward or Reverse to set the direction of the operation for the directional function
selected by the
All the directional protection modes have a residual current release level setting
set in % of
be detected.
All the directional protection modes have a residual voltage release level setting
set in % of
voltage to be detected.
tDef is the definite time delay, given in s, for the directional residual current protection.
tReset is the time delay before the definite timer gets reset, given in s. With a tReset time of few
cycles, there is an increased possibility to clear intermittent ground faults correctly. The setting
shall be much shorter than the set trip delay. In case of intermittent ground faults, the fault
current is intermittently dropping below the set value during consecutive cycles. Therefore the
definite timer should continue for a certain time equal to
dropped below the set value.
The characteristic angle of the directional functions
set equal to 0° in a high impedance grounded network with a neutral point resistor as the active
current component is appearing out on the faulted feeder only.
isolated network as all currents are mainly capacitive.
ROADir is Relay Operating Angle. ROADir is identifying a window around the reference direction in
order to detect directionality.
Application manual
INDirPU and the residual current angle is within the sector RCADir ± ROADir .
OpModeSel when RCADir = 0° and ROADir = 80° is shown in figure 60.
RCA = 0º
ROA = 80º
OpModeSel .
IBase . This setting should be chosen smaller than or equal to the lowest fault current to
VBase . This setting should be chosen smaller than or equal to the lowest fault residual
ROADir is set in degrees. For angles differing more than ROADir
Operate area
3I
0
V =-3V
ref 0
ANSI06000652-2-en.vsd
tReset even though the fault current has
RCADir is set in degrees. RCADir is normally
RCADir is set equal to -90° in an
Section 8
Current protection
INRelPU which is
VNRelPU which is
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