ABB Relion 670 Series Applications Manual page 319

1MRK 511 401-UEN Rev. K
Section 15
15.1 Synchrocheck, energizing check, and synchronizing
SESRSYN
15.1.1 Identification
Function description
Synchrocheck, energizing check, and
synchronizing
15.1.2 Application
15.1.2.1 Synchronizing
To allow closing of breakers between asynchronous networks, a synchronizing feature is
provided. The breaker close command is issued at the optimum time when conditions across
the breaker are satisfied in order to avoid stress on the network and its components.
The systems are defined as asynchronous when the frequency difference between bus and line
is larger than an adjustable parameter. If the frequency difference is less than this threshold
value the system is defined to have a parallel circuit and the synchrocheck function is used.
The synchronizing function measures the difference between the U-Line and the U-Bus. It
operates and enables a closing command to the circuit breaker when the calculated closing
angle is equal to the measured phase angle and the following conditions are simultaneously
fulfilled:
• The voltages U-Line and U-Bus are higher than the set values for
UHighLineSynch of the respective base voltages GblBaseSelBus and GblBaseSelLine .
• The difference in the voltage is smaller than the set value of
• The difference in frequency is less than the set value of
set value of
used and the value of
FreqDiffA for synchrocheck function. The bus and line frequencies must also be within a
range of ±5 Hz from the rated frequency. When the synchronizing option is included also
for autoreclose there is no reason to have different frequency setting for the manual and
automatic reclosing and the frequency difference values for synchronism check should be
kept low.
• The frequency rate of change is less than set value for both U-Bus and U-Line.
• The difference in the phase angle is smaller than the set value of
• The closing angle is decided by the calculation of slip frequency and required pre-closing
time.
The synchronizing function compensates for the measured slip frequency as well as the circuit
breaker closing delay. The phase angle advance is calculated continuously. The calculation of
the operation pulse sent in advance is using the measured
time. To prevent incorrect closing pulses, a maximum closing angle between bus and line is set
Bay control REC670
Application manual
Control
IEC 61850
identification
SESRSYN
FreqDiffMin . If the frequency is less than FreqDiffMin the synchrocheck is
FreqDiffMin must thus be identical to the value FreqDiffM resp
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IEC 60617 ANSI/IEEE C37.2
identification device number
25
sc/vc
SYMBOL-M V1 EN-US
UHighBusSynch and
UDiffSynch .
FreqDiffMax and larger than the
CloseAngleMax .
SlipFrequency and the set tBreaker
Section 15
Control
IP14558-1 v4
M14889-1 v4
IP15111-1 v1
SEMOD171992-5 v10
313