ABB 615 series Technical Manual page 220

Section 4
Protection functions
214
Reset delay time value 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. The
PICKUP output is deactivated when the reset timer has elapsed.
The "Inverse reset" selection is only supported with ANSI or user
programmable types of the IDMT operating curves. If another operating
curve type is selected, an immediate reset occurs during the drop-off
situation.
The setting Time multiplier is used for scaling the IDMT trip and reset times.
The setting parameter Minimum trip time defines the minimum desired trip time for
IDMT. The setting is applicable only when the IDMT curves are used.
The Minimum trip time setting should be used with great care because the
operation time is according to the IDMT curve, but always at least the
value of the Minimum trip time setting. For more information, see the
IDMT curves for overcurrent protection
The timer calculates the pickup duration value PICKUP_DUR, which indicates the
percentage ratio of the pickup situation and the set trip time. The value is available in the
monitored data view.
Blocking logic
There are three operation modes in the blocking function. The operation modes are
controlled by the BLOCK input and the global setting in Configuration/System/Blocking
mode which selects the blocking mode. The BLOCK input can be controlled by a binary
input, a horizontal communication input or an internal signal of the protection relay's
program. The influence of the BLOCK signal activation is preselected with the global
setting Blocking mode.
The Blocking mode setting has three blocking methods. In the "Freeze timers" mode, the
operation timer is frozen to the prevailing value, but the TRIP output is not deactivated
when blocking is activated. In the "Block all" mode, the whole function is blocked and the
timers are reset. In the "Block TRIP output" mode, the function operates normally but the
TRIP output is not activated.
1MAC059074-MB A
section in this manual.
615 series ANSI
Technical Manual