ABB RED615 Technical Manual page 346

Section 4
Protection functions
340
Table 323: Values of the Enable reference use setting
Enable reference use
Standalone
Reference use Communication
valid
Communication
invalid
The Enable reference use setting forces the function to use the DT
characteristics where the operating time is set with the Minimum
operate time setting.
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 Minimum operate time setting is used for restricting too fast an
operation 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 A, Curve parameter B, Curve parameter C,
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 Operating curve 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 Reset delay time setting is
exceeded. When the IDMT curves are selected, the Type of reset curve setting can
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 Reset delay time setting. With the reset curve type
"Inverse reset", the reset time depends on the current during the drop-off situation.
If the drop-off situation continues, the reset timer is reset and the START output is
deactivated.
The "Inverse reset" selection is only supported with ANSI or the
programmable types of the IDMT operating curves. If another
Functionality
In the standalone mode, depending on the value of the
Operating curve type setting, the time characteristics are
according to DT or IDMT. When the operation timer has
reached the value of the Operate delay time setting in
the DT mode or the value defined by the inverse time
curve, the OPERATE 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 the
operate time setting and simultaneously the enabling
signal from the Current comparison module is active, the
OPERATE signal is activated.
Function operates as in the standalone mode.
1YHT530004D05 D
Minimum
615 series
Technical Manual