Siemens SIPROTEC 4 7VK61 - Setting Notes

Closing under asynchronous system conditions
Before releasing a closing command under asynchronous conditions, the following conditions are checked:
•
Is the busbar voltage above the setting value Live Volt. Thr., but below the maximum voltage
Umax?
•
Is the feeder voltage above the setting value Live Volt. Thr. but below the maximum voltage
Umax?
•
Is the voltage difference |U
sy1
– U
sy2
|within the permissible tolerance AR maxVolt.Diff or MC
maxVolt.Diff?
•
Are the two frequencies f
sy1
and f
sy2
within the permitted operating range f
N
± 3 Hz?
•
Is the frequency difference |f
sy1
– f
sy2
| within the permissible tolerance AR maxFreq.Diff or MC
maxFreq.Diff?
When the check has been terminated successfully, the device determines the next synchronizing time from
the angle difference and the frequency difference. The close command is issued at synchronization time
minus the operating time of the circuit breaker.
Measured values
The measured values of the synchronism check are displayed in separate boxes for primary and secondary
measured values and percentages.
The following is displayed:
•
Value of reference voltage U
sy1
•
Value of the voltage to be synchronized U
sy2
•
Frequency values f
sy1
and f
sy2
•
Differences of voltage, frequency and angle between U
sy1
and U
sys2
.
The primary measured values of the synchronism check are summarized in one of the preset default displays
(see Appendix D Default Settings and Protocol-dependent Functions).
Setting Notes
Preconditions
When setting the general power system data a number of parameters regarding the measured quantities and
the operating mode of the synchronism check function must be applied.
This concerns the following parameters:
203
Unom PRIMARY primary rated voltage of the voltage transformers of
the protection functions (phase-to-phase) in kV,
measuring point U
sy1
;
204 Unom SECONDARY secondary rated voltage of the protection functions
(phase-to-phase) in V, measuring point U
sy1
;
210 U4 transformer voltage measurement input U
4
must be set to Usy2
transf.;
212 Usy2 connection voltage connection of measuring point U
sy2
(e.g. U
L1–
L2
),
214 φ Usy2-Usy1 phase displacement between the voltages U
sy2
and
U
sy1
if a transformer is switched in between;
215 Usy1/Usy2 ratio ratio between the secondary voltage U
sy1
and voltage
U
sy2
under nominal condition;
2.4.2
Functions
2.4 Synchronism and voltage check (optional)
SIPROTEC 4, 7VK61, Manual 89
C53000-G1176-C159-5, Edition 05.2018