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.
4.2.1.5 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 374: Measurement modes supported by EFxPTOC stages
Measurement mode EFLPTOC EFHPTOC EFIPTOC
RMS x x
DFT x x
Peak-to-Peak x x x
For a detailed description of the measurement modes, see
Chapter 11.5
Measurement modes
in this manual.
4.2.1.6 Timer characteristics
EFxPTOC supports both DT and IDMT characteristics. The user can select the timer
characteristics with the
Operating curve type
and
Type of reset curve
settings.
When the DT characteristic is selected, it is only affected by the
Operate delay time
and
Reset delay time
settings.
The protection relay provides 16 IDMT characteristics curves, of which seven comply
with the IEEE C37.112 and six with the IEC 60255-3 standard. Two curves follow the
Protection functions
1MRS757644 H
378 620 series
Technical Manual
To Next Page
Loading...
