ABB RELION REF615R, Техническое руководство

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synchronism are not detected. This function is also used to prevent the reconnection of two
systems which are divided after islanding and a three-pole reclosing.
The Synchro check function block includes both the synchronism check function and the
energizing function to allow closing when one side of the breaker is dead.
Network and the generator running in parallel with the network are connected through the
line AB. When a fault occurs between A and B, the protection relay protection opens the
circuit breakers A and B, thus isolating the faulty section from the network and making the
arc that caused the fault extinguish. The first attempt to recover is a delayed autoreclosure
made a few seconds later. Then, the autoreclose function 79 gives a command signal to the
synchrocheck function to close the circuit breaker A. 25 performs an energizing check, as
the line AB is de-energized (
V_BUS
> Live bus value ,
V_LINE
< Dead line value ). After
verifying the line AB is dead and the energizing direction is correct, the protection relay
energizes the line (
V_BUS
->
V_LINE
) by closing the circuit breaker A. The PLC of the
power plant discovers that the line has been energized and sends a signal to the other
synchrocheck function to close the circuit breaker B. Since both sides of the circuit
breaker B are live (
V_BUS
> Live bus value ,
V_LINE
> Live bus value ), the synchrocheck
function controlling the circuit breaker B performs a synchrocheck and, if the network and
the generator are in synchronism, closes the circuit breaker.
G
25
79
25
PLC
A B
V_Bus
V_Bus
V_Line V_Line
52 52
GUID-3C69BD5D-5D9F-44C7-87C8-D25C70829B97 V2 EN
Figure 267: Synchrocheck function 79 checking energizing conditions and
synchronism
Connections
A special attention is paid to the connection of the protection relay. Furthermore it is
checked that the primary side wiring is correct.
A faulty wiring of the voltage inputs of the protection relay causes a malfunction in the
synchrocheck function. If the wires of an energizing input have changed places, the
Section 9
1MRS240050-IB C
Control functions
506 REF615R
Technical Manual