Broken Conductor Detection - Siemens 7SC80 Manual

Phase Sequence of Voltage and Current
To detect swapped phase connections in the voltage and current input circuits, the phase sequence of the
phase-to-phase measured voltages and the phase currents are checked by monitoring the sequence of same
polarity zero crossing of the voltages.
Direction measurement with normal voltages, path selection for fault location, and negative sequence detec-
tion all assume a phase sequence of "abc". Phase rotation of measurement quantities is checked by verifying
the phase sequences. For that purpose, the phase-sequence monitoring uses the phase-to-phase voltages V
V , V .
B3 C1
Voltages: V before V
A2
Currents: Ι before Ι
A
Verification of the voltage phase rotation is done when each measured voltage is at least
|V |, |V |, |V | > 40 V
A2 B3 C1
Verification of the current phase rotation is done when each measured current is at least:
|Ι |, |Ι |, |Ι | > 0.5 Ι
A B C
For abnormal phase sequences, the messages
with the switching of this message
For applications in which an opposite phase sequence is expected, the protective relay should be adjusted via
a binary input or the respective parameter PHASE SEQ. (address 209). If the phase sequence is changed in
the relay, phases B and C internal to the relay are reversed, and the positive and negative sequence currents
are thereby exchanged (see also Section
values, and measured values are not affected by this.
2.12.1.5

Broken Conductor Detection

The broken conductor detection monitors the current and voltage transformer circuits.
The function can be switched on and off and is active even during a fault.
Broken conductor detection can be blocked via binary input
The broken conductor detection evaluates the measured phase currents Ιa, Ιb, Ιc and the voltages Va, Vb, and
Vc. The algorithm furthermore needs the arrangement of the transformers relating to the transmission tower
(Direction 1 or Direction 2). The direction can be set separately for the current and voltage trans-
formers. The following examples show 4 arrangement options.
[anschluss-drahtbrucherk-a, 1, en_US]
Figure 2-66
SIPROTEC Compact, 7SC80, Manual
E50417-G1140-C486-A8, Edition 07.2017
vor V and
B3 C1
before Ι .
B C
.
N
Fail Ph. Seq. .
2.24.2 Setting
Broken Conductor Detection - Current and Voltage Measurement Direction 1
Fail Ph. Seq. V or Fail Ph. Seq. I are issued, along
Notes). The phase-related messages, malfunction
> BLK 46BC .
Functions
2.12 Monitoring Functions
,
A2
229