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1MRK 505 288-UEN A
10.1.7
10.1.7.1
10.1.7.2
Technical manual
Operation principle
Basic functionality
The synchrocheck function measures the conditions across the circuit breaker and
compares them to set limits. The output is only given when all measured quantities are
simultaneously within their set limits.
The energizing check function measures the bus and line voltages and compares them
to both high and low threshold detectors. The output is given only when the actual
measured quantities match the set conditions.
The synchronizing function measures the conditions across the circuit breaker, and
also determines the angle change occurring during the closing delay of the circuit
breaker, from the measured slip frequency. The output is given only when all
measured conditions are simultaneously within their set limits. The issue of the output
is timed to give closure at the optimal time including the time for the circuit breaker
and the closing circuit.
For single circuit breaker double bus and 1½ breaker circuit breaker arrangements, the
SESRSYN function blocks have the capability to make the necessary voltage
selection. For single circuit breaker double bus arrangements, selection of the correct
voltage is made using auxiliary contacts of the bus disconnectors. For 1½ breaker
circuit breaker arrangements, correct voltage selection is made using auxiliary
contacts of the bus/line disconnectors as well as the circuit breakers.
The internal logic for each function block as well as, the input and outputs, and the
settings with default setting and setting ranges is described in this document. For
application related information, please refer to the application manual.
Synchrocheck
The voltage difference, frequency difference and phase angle difference values are
calculated by the SESRSYN function and are available for the synchrocheck function
for evaluation. If the bus voltage is connected as phase-phase and the line voltage as
phase-neutral (or the opposite), this need to be compensated. This is done by selecting
the corresponding phases for the measurement in the settings for the SESRSYN
function. In addition the phase angle difference has to be compensated for by the
setting PhaseShift. The setting scales the line voltage and adjust the phase angle equal
to the bus voltage.
When the function is set to OperationSC = On, the measuring will start.
The function will compare the bus and line voltage values with internally preset values
that are set to be 80% of the UBase selected for GlbBaseSelBus and GlbBaseSelLine.
If both sides are higher than 80% of the Ubase values, the measured values are
compared with the set values for acceptable frequency, phase angle and voltage
difference: FreqDiff, PhaseDiffand UDiff. If a compensation factor is set due to the
Section 10
Control
167
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