Operation Principle; Basic Functionality; Synchrocheck - ABB REG650 Technical Manual

Section 11
Control
11.1.7
11.1.7.1
11.1.7.2
286

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 arrangements, SESRSYN function blocks have the
capability to make the necessary voltage selection. The selection of correct voltage
is made using auxiliary contacts of the bus disconnectors.
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
measured in the IED centrally 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 with a
setting, which scales up the line voltage to a level equal to the bus voltage.
When the function is set to OperationSC = On, the measuring will start.
The function compares bus and line values with the set values for acceptable
frequency, phase angle and voltage difference: FreqDiffA, FreqDiffM, PhaseDiffA,
PhaseDiffM and UDiffSC. If a compensation factor is set due to the use of different
voltages on the bus and line, the factor is deducted from the line voltage before the
comparison of the phase angle values.
The frequency on both sides of the circuit breaker is also measured. The
frequencies must not deviate from the rated frequency more than +/-5Hz. The
frequency difference between the bus frequency and the line frequency is measured
and may not exceed the set value.
1MRK 502 034-UEN -
Technical Manual