Monitored data values Description
ANGLE_RCA The angle difference between the operating
angle and Characteristic angle, that is, AN-
GLE_RCA = ANGLE – Characteristic angle.
I_OPER The current that is used for fault detection. If
the Operation mode setting is "Phase angle",
"Phase angle 80" or "Phase angle 88", I_OP-
ER is the measured or calculated residual cur-
rent. If the Operation mode setting is "IoSin",
I_OPER is calculated as follows I_OPER = Io x
sin(ANGLE). If the Operation mode setting is
"IoCos", I_OPER is calculated as follows I_OP-
ER = Io x cos(ANGLE).
Monitored data values are accessible on the LHMI or through tools via
communications.
Timer
Once activated, the timer activates the START output. 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
Operate delay time
in the
DT mode or the maximum value defined by the inverse time curve, the OPERATE
output is activated.
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
Chapter 11.2.1 IDMT curves for overcurrent protection
in this manual.
Protection functions 1MRS757644 H
392 620 series
Technical Manual
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