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
Chapter 11.2.1 IDMT curves for overcurrent protection
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 blocked and the timers are reset. In the "Block OPERATE output" mode,
the function operates normally but the
OPERATE
output is not activated.
4.1.3.5
Measurement modes
The function operates on three alternative measurement modes: “RMS”, “DFT” and
“Peak-to-Peak” . The measurement mode is selected with the
Measurement mode
setting.
Table 270: Measurement modes supported by DPHxPDOC stages
Measurement mode
DPHLPDOC
DPHHPDOC
RMS
x
x
DFT
x
x
Peak-to-Peak
x
x
1MRS757644 H
Protection functions
620 series
Technical Manual
279
