ABB RELION 670 Series Applications Manual page 433

1MRK 504 152-UEN B
IEC06000652 V3 EN-US
Figure 264: 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
is set in % of
current to be detected.
All the directional protection modes have a residual voltage release level setting
is set in % of
residual 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 earth faults correctly. The
setting shall be much shorter than the set trip delay. In case of intermittent earth 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
fault current has dropped below the set value.
The characteristic angle of the directional functions
normally set equal to 0° in a high impedance earthed network with a neutral point resistor as
the active current component is appearing out on the faulted feeder only.
to -90° in an 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.
than ROADir from RCADir the function is blocked. The setting can be used to prevent
unwanted operation for non-faulted feeders, with large capacitive earth fault current
contributions, due to CT phase angle error.
INCosPhi> is the operate current level for the directional function when OpMode is set
3I0Cosfi . The setting is given in % of IBase . The setting should be based on calculation of the
active or capacitive earth fault current at required sensitivity of the protection.
Application manual
RCADir = 0º
ROADir = 80º
OpMode .
IBase . This setting should be chosen smaller than or equal to the lowest fault
UBase . This setting should be chosen smaller than or equal to the lowest fault
Operate area
3I
0
-3U
0
IEC06000652-3-en.vsd
RCADir is set in degrees. RCADir is
ROADir is set in degrees. For angles differing more
Section 8
Current protection
INRel> which
UNRel> which
tReset even though the
RCADir is set equal
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