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.
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.
4.1.1.5 Measurement modes
The function operates on four alternative measurement modes: "RMS", "DFT",
"Peak-to-Peak" and "P-to-P + backup". The measurement mode is selected with the
setting
Measurement mode
.
Table 217: Measurement modes supported by PHxPTOC stages
Measurement mode PHLPTOC PHHPTOC PHIPTOC
RMS x x
DFT x x
Peak-to-Peak x x
P-to-P + backup x
For a detailed description of the measurement modes, see
Chapter 11.5
Measurement modes
in this manual.
Protection functions 1MRS757644 H
242 620 series
Technical Manual
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