Siemens SIPROTEC 7RW80 Manual page 70

Functions
2.5 Monitoring Functions
Figure 2-13
Phase sequence of the voltages
To detect swapped phase connections in the voltage input circuits, the direction of rotation of the phase-to-
phase voltages is checked. Therefore the sequence of the zero crossings of the currents (having the same
sign) is checked.
Phase rotation of measurement quantities is checked by verifying the phase sequences. Here, the phase se-
quence supervision requires the phase-phase voltages V
Voltages: V
A2
Verification of the voltage phase rotation is done when each measured voltage is at least
|V |, |V |, |V
A2 B3
For abnormal phase sequences, the messages „Fail Ph. Seq. V" or are issued, along with the switching
of this message „Fail Ph. Seq.".
For applications in which an opposite phase sequence is expected, the protective relay should be adjusted via
a binary input or a programmable setting PHASE SEQ. (Addresse 209). If the phase sequence is changed in
the device, phases B and C internal to the relay are reversed, and the positive and negative sequence currents
are thereby exchanged (see also Section 2.10.2). The phase-related messages, malfunction values, and mea-
sured values are not affected by this.
70
Voltage symmetry monitoring
before V before V
B3 C1
| > 40 V.
C1
, V , V .
A2 B3 C1
C53000-G1140-C233-1, Release date 10.2010
SIPROTEC, 7RW80, Manual