[dw_GPP PQ diagram, 2, en_US]
Figure 7-175 Pickup Values and Characteristic Curves
Setting Notes for the Active Power Stage
Stage Type
In the following example, a drop of the active power below a threshold is to be monitored. In the 3-phase
circuit breaker (P, Q) function, work with the stage type Power P<.
Parameter: Measured value
•
Recommended setting value (_:6271:105) Measured value = positive seq. power
The Measured value parameter is used to specify which measured power value is evaluated. For 3-phase
measurement, Siemens recommends to evaluate the positive-sequence system power.
Parameter: Threshold
•
Recommended setting value (_:6271:3) Threshold = 0 %
The Threshold parameter is used to define the pickup threshold of the active power stage. In the example,
the pickup characteristic runs across the point of origin of the coordinates. Set the parameter Threshold to
0 %.
NOTE
If you use several settings groups, consider the following:
•
The dropout value of a stage must have the same sign in all settings groups.
•
Switching from a positive dropout value to a negative dropout value or vice versa is not allowed. As a
result, DIGSI reports an inconsistency.
•
If you want to change the sign of the dropout value of a stage in an additional settings group, instan-
tiate a new stage and enable it. If the new stage should not be effective in another settings group,
disable the stage there.
Parameter: Dropout ratio
•
Recommended setting value (_:6271:101) Dropout ratio = 1.05
A hysteresis of 5 % is sufficient for most applications. The setting value for the lower stage is therefore 1.05.
7.22.6
Protection and Automation Functions
7.22 Power Protection (P,Q), 3-Phase
SIPROTEC 5, High-Voltage Bay Controller, Manual 857
C53000-G5040-C015-9, Edition 11.2017
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