Operation Principle - ABB REL650 series Technical Manual

1MRK 506 335-UUS A
11.1.7
11.1.7.1
11.1.7.2
Technical manual

Operation principle

Basic functionality
The synchronism check 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 breaker-and-a-half circuit breaker arrangements,
the SESRSYN (25) 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 breaker-and-a-half
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.
Synchronism check
The voltage difference, frequency difference and phase angle difference values are
calculated by the SESRSYN function and are available for the synchronism check
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 = Enabled, 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.
Section 11
Control
353