ABB Relion REQ650, Applications Manual

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Section 10 Control
10.1 Synchrocheck, energizing check, and synchronizing
SESRSYN
10.1.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Synchrocheck, energizing check, and
synchronizing
SESRSYN
sc/vc
SYMBOL-M V1 EN
25
10.1.2 Application
10.1.2.1 Synchronizing
To allow closing of breakers between asynchronous networks a synchronizing
function 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 to be 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 measured voltage U-Line is higher than 80% of GblBaseSelLine and the
measured voltage U-Bus is higher than 80% of GblBaseSelBus .
• The voltage difference is smaller than 0.10 p.u, that is (measured U-Bus/
GblBaseSelBus ) - (measured U-Line/ GblBaseSelLine ) < 0.10.
• The difference in frequency is less than the set value of FreqDiffMax and larger
than the set value of FreqDiffMin . If the frequency is less than FreqDiffMin the
synchrocheck is used and the value of FreqDiffMin must thus be identical to the
value FreqDiffM resp FreqDiffA for synchrocheck function. The bus and line
1MRK 505 291-UEN A
Section 10
Control
183
Application manual