ABB RED615 Technical Manual page 694

Section 9
Control functions
688
A
U_Bus
SECRSYN
DARREC
GUID-27A9936F-0276-47A1-B646-48E336FDA95C V2 EN
Figure 370: Synchrocheck function SECRSYN checking energizing conditions
and synchronism
Connections
A special attention is paid to the connection of the IED. Furthermore it is checked
that the primary side wiring is correct.
A faulty wiring of the voltage inputs of the IED causes a malfunction in the
synchrocheck function. If the wires of an energizing input have changed places, the
polarity of the input voltage is reversed (180°). In this case, the IED permits the
circuit breaker closing in a situation where the voltages are in opposite phases. This
can damage the electrical devices in the primary circuit. Therefore, it is extremely
important that the wiring from the voltage transformers to the terminals on the rear
of the IED is consistent regarding the energizing inputs U_BUS (bus voltage) and
U_LINE (line voltage).
The wiring should be verified by checking the reading of the phase difference
measured between the U_BUS and U_LINE voltages. The phase difference
measured by the IED has to be close to zero within the permitted accuracy
tolerances. The measured phase differences are indicated in the LHMI. At the same
time, it is recommended to check the voltage difference and the frequency
differences presented in the monitored data view. These values should be within
the permitted tolerances, that is, close to zero.
Figure 371 shows an example where the synchrocheck is used for the circuit
breaker closing between a busbar and a line. The phase-to-phase voltages are
measured from the busbar and also one phase-to-phase voltage from the line is
measured.
U_Line U_Line
1YHT530004D05 D
G
B
U_Bus
SECRSYN
PLC
615 series
Technical Manual