Stage Description
Logic of a Stage
[logiknsp-070312-01.tif, 2, en_US]
Figure 7-184
Logic Diagram of the Stage Negative-Sequence Protection with Definite-Time Characteristic
Curve
Method of Measurement
The fundamental phasors are calculated from the 3-phase phase currents. Based on this, the negative-
sequence system and the positive-sequence system are calculated. Following this, the negative-sequence
current is normalized to the reference current. The selection of the reference current is made in the FB
General.
Blocking of the Stage
When blocked, the picked-up protection stage will drop out.
In addition to the current blocking (see Current limitation Imax and Maximum phase current ),
the stages can be blocked in the following ways:
•
Via the binary input signal >Block stage from an external or internal source
•
When leaving the permissible frequency operating range
7.25.3
Protection and Automation Functions
7.25 Negative-Sequence Protection
872 SIPROTEC 5, High-Voltage Bay Controller, Manual
C53000-G5040-C015-9, Edition 11.2017
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