Siemens 6MD85, Manual

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Checking the Closing Conditions in Synchronous Systems
[losynsyn-100611-01.tif, 1, en_US]
Figure 6-72 Closing Conditions when Switching Synchronous Systems
The frequency difference is very low in the synchronous systems operating mode. It is below the threshold
value
f-threshold ASYN<->SYN
. The status is signaled via the
State f-synchronous
indication.
The parameters ΔV and Δα are checked for issuing an activation release (see Figure 6-73 ). The indication
All
sync. conditio. OK
signals that both setting values (conditions) are reached. If the conditions remain
fulfilled over the set time delay (parameter
Delay close command
), the release for closing is given (see
also chapter 6.4.7.1 Description ).
Every condition fulfilled is signaled individually via the indications
Voltage difference OK
and
Angle
difference OK
.
If a condition is not fulfilled, detailed information on why the condition is not fulfilled is provided via indica-
tions. If the differential voltage is outside the setting limits, for example, the indication
V dif.too
large(V2<V1)
is issued. The indication indirectly contains information that the voltage V2 has to be
increased for a successful synchronization.
With the Expanded delta-f options stage type configured and an activated
(_:142) Limit dfdiff/dt
for asyn. op
parameter, the frequency difference rate of change is also checked. If the permissible
frequency change rate (parameter
(_:143) Max. value dfdiff/dt asyn
) is exceeded, the indication
(_:329) dfdiff/dt too large
is generated.
Control Functions
6.4 Synchronization Function
SIPROTEC 5, High-Voltage Bay Controller, Manual 381
C53000-G5040-C015-9, Edition 11.2017