Paralleling Functions
The paralleling facility is the main function of the 7VE61 and 7VE63 devices. A high degree of reliability and
flexible adaptation to power system conditions allow different application areas. The following modes of oper-
ation are covered:
•
Synchrocheck
•
Switching Synchronous Systems
•
Switching Asynchronous Systems
•
Switching to dead line/dead busbar
Functional Description
When connecting generator and power system or two power systems, the synchronism check verifies that the
switching does not endanger the generator or the stability of the power system. For this purpose the voltage
vectors of the power system sections to be synchronised are checked within definite limits for compatibility.
Connection and definitions
Depending on the device variants, parametrization possibilities are provided for up to eight different synchro-
nizing functions. The following describes the function and mode of operation for the first synchronising func-
tion (SYNC Function group 1). The same applies to function groups 2 to 8.
For proper functioning of the parallel devices 7VE61 and 7VE63 special conditions must be adhered to on
connection to the voltage transformer circuits and the power breaker close coils.
Figure 2-3 shows a three-phase connection. The measuring voltage is the phase-to-phase voltage U
L12
which is
used for the synchronization function. The voltage inputs Ua and Ub can be connected on the side 1 and the
voltage inputs Ud and Ue on the side 2. Since the winding sense of the voltage inputs Ub and Ue is changed
opposite the other inputs, the connection of the corresponding second voltage input (Ub or Ue) takes place in
inverse polarity (also anti-parallel). The sum of these voltages rotated by 180° to each other on each side must
be zero. This allows a steady check of the measurement circuit as well as of the whole measuring channel of
the voltage transformer circuit up to the recording of the measuring values.
At each third measurement input, for three-phase power systems a second phase-to-phase voltage (voltage
U
L23
) can be connected which — together with each first voltage — allows the phase sequence to be checked.
For two or single-phase power systems (16.7 Hz) the third measurement input remains unused (see connec-
tion example in the appendix).
An den jeweils dritten Messeingang kann bei Dreiphasennetzen eine zweite verkettete Spannung (Spannung
U
L23
) angeschlossen werden, die – zusammen mit der jeweils ersten Spannung – die Kontrolle der Drehfelder
ermöglicht. Bei Zwei- oder Einphasennetzen (16,7 Hz) bleibt der dritte Messeingang unbenutzt (siehe
Anschlussbeispiel im Anhang A.3).
The device can also be connected to a V-connection (open delta connection) using two phase-phase voltages
(see connection example in the appendix).
2.2
2.2.1
2.2.1.1
Functions
2.2 Paralleling Functions
SIPROTEC 4, 7VE61 and 7VE63, Manual 35
C53000-G1176-C163-3, Edition 10.2017
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