Functions
2.4 Synchronism and voltage check (optional)
SIPROTEC, 7VK61, Manual
C53000-G1176-C159-3, Release date 05.2009
87
Closing under asynchronous system conditions
Before releasing a closing command at 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?
• Does the frequency difference |f
sy1
– f
sy2
| lie 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 A.4).
2.4.2
Setting Notes
Preconditions
When setting the general power system data (Power system data 1, refer to Section 2.1.3.1) a number of pa-
rameters 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 protective functions
(phase-to-phase) in kV, measuring point U
sy1
;
204
Unom SECONDARY
secondary rated voltage of the protective functions (phase-to-phase) in V,
measuring point U
sy1
;
210
U4 transformer
Voltage measuring 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;
Summary of Contents for Siprotec 7VK61
Page 8: ...Preface SIPROTEC 7VK61 Manual C53000 G1176 C159 3 Release date 05 2009 8 ...
Page 14: ...Contents SIPROTEC 7VK61 Manual C53000 G1176 C159 3 Release date 05 2009 14 ...
Page 316: ...Literature SIPROTEC 7VK61 Manual C53000 G1176 C159 3 Release date 05 2009 316 ...
Page 328: ...Glossary SIPROTEC 7VK61 Manual C53000 G1176 C159 3 Release date 05 2009 328 ...