ABB 615 series Technical Manual page 410

Section 4
Protection functions
404
Timer
The PICKUP output is activated when Level detector sends the enabling signal.
Functionality and the time characteristics depend on the selected value of the Enable
reference use setting.
Table 388: 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 trip time
setting.
If the communication for some reason fails, the function switches to use the Operation
curve type setting, and if DT is selected, Trip delay time is used. If the IDMT curve is
selected, the time characteristics are according to the selected curve and the Minimum trip
time setting is used for restricting too fast an operation time.
In case of a communication failure, the pickup 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 trip 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
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
Trip delay time setting in the DT
reached the value of the
mode or the value defined by the inverse time curve, the
TRIP 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
and simultaneously the enabling signal from the Current
comparison module is active, the TRIP signal is activated.
Function operates as in the standalone mode.
1MAC059074-MB A
Minimum trip time setting
615 series ANSI
Technical Manual