ABB RELION Series, Техническое руководство

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When the user-programmable IDMT curve is selected, the operation time
characteristics are defined by the parameters
Curve parameter A , Curve parameter B ,
Curve parameter C , Curve parameter D and Curve parameter E .
If a drop-off situation happens, that is, a fault suddenly disappears before the operate
delay is exceeded, the timer reset state is activated. The functionality of the 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 set 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
START
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 operate and reset times.
The setting parameter Minimum operate time defines the minimum desired operate
time for IDMT. The setting is applicable only when the IDMT curves are used.
The Minimum operate 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 operate time setting. For more
information, see the IDMT curves for overcurrent protection section
in this manual.
The timer calculates the start duration value START_DUR, which indicates the
percentage ratio of the start situation and the set operating 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 OPERATE output is not
deactivated when blocking is activated. In the "Block all" mode, the whole function is
1MRS758755 A
Section 4
Protection functions
REC615 and RER615 397
Technical Manual