ABB RELION REX640 Technical Manual page 525

1MRS759142 F
Table 584: Values of the Enable reference use setting
Enable reference use
Standalone
Reference use
If the communication for some reason fails, the function switches to use the
Operation curve type setting, and if DT is selected, Operate delay time is used. If the
IDMT curve is selected, the time characteristics are according to the selected curve
and the
time.
In case of a communication failure, the start duration may change substantially
depending on the user settings.
When the programmable IDMT curve is selected, the operation time characteristics
are defined with the
Curve parameter D and Curve parameter E parameters.
If a drop-off situation happens, that is, a fault suddenly disappears before the
operation delay is exceeded, the Timer reset state is activated. The functionality
of Timer in the reset state depends on the combination of the
type , Type of reset curve and Reset delay time settings. When the DT characteristic
is selected, the reset timer runs until the value of the
exceeded. When the IDMT curves are selected, the
be set to "Immediate", "Def time reset" or "Inverse reset". The reset curve type
"Immediate" causes an immediate reset. With the reset curve type "Def time reset",
the reset time depends on the
"Inverse reset", the reset time depends on the current during the drop-off situation
and the value of START_DUR. If the drop-off situation continues, the reset timer is
reset and the START output is deactivated.
The setting
REX640
Technical Manual
Communication
valid
Communication
invalid
Enable reference use setting forces the function to use the DT
The
characteristics where the operating time is set with the
operate time setting.
Minimum operate time setting is used for restricting too fast an operation
Curve parameter A , Curve parameter B , Curve parameter C ,
The "Inverse reset" selection is only supported with ANSI or the
programmable types of the IDMT operating curves. If another operating
curve type is selected, an immediate reset occurs during the drop-off
situation.
Time multiplier is used for scaling the IDMT operation and reset times.
Functionality
In the standalone mode, depending on the value
Operating curve type setting, the time char-
of the
acteristics are according to DT or IDMT. When the
operation timer has reached the value of the
ate delay time setting in the DT mode or the value
defined by the inverse time curve, the
output is activated.
When using the horizontal communication, the
function is forced to use the DT characteristics.
When the operation timer has reached the value of
Minimum operate time setting and simultane-
the
ously the enabling signal from the Current compari-
son module is active, the
ted.
Function operates as in the standalone mode.
Type of reset curve setting can
Reset delay time setting. With the reset curve type
Protection functions
OPERATE
signal is activa-
OPERATE
Minimum
Operating curve
Reset delay time setting is
Oper-
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