Siemens 7VK512

-ETHOD OF OPERATION6+
6
#
' #

 3ELECTIVITY DURING AUTOMATIC RE
CLOSURE
&OR THE AUTO RECLOSURE SEQUENCE TO BE SUCCESSFUL
FAULTS ON ANY PART OF THE LINE MUST BE CLEARED FROM
BOTH LINE ENDS WITHIN THE SAME
SHORTEST POSSI
BLE
TIME 5SUALLY THEREFORE AN INSTANTANEOUS
STAGE OF THE SHORT
CIRCUIT PROTECTION IS SET TO OPERATE
BEFORE A RECLOSURE BY THE !2
UNIT
)F THE SHORT
CIRCUIT PROTECTION IS EQUIPPED WITH A
SO
CALLED 2!2 STAGE THEN THIS STAGE CAN BE ACTI
VATED BY 6+ THE OUTPUT SIGNAL
2!2 :ONE
2EL
IS AVAILABLE AS LONG AS THE 2!2 FUNCTION IS
READY FOR RECLOSE AFTER DISCONNECTION OF THE LINE
)F THE FEEDER PROTECTION INCORPORATES THE FACILITY TO AC
TIVATE ITS 2!2 STAGE ONLY IN CASE OF SINGLE
PHASE
FAULTS BUT NOT IN CASE OF THREE
PHASE FAULTS THE 2!2
FUNCTION OF 6+ CAN GIVE THE OUTPUT SIGNAL
2!2
P 0ROG
IN ADDITION TO 2!2 :ONE 2EL WHICH
MEANS THAT THE 2!2 FUNCTION WILL RECLOSE ONLY IN CASE
OF SINGLE
POLE TRIP BUT NOT AFTER THREE POLE TRIP THAT
IS THE CASE WHEN THE 2!2 FUNCTION IS PROGRAMMED TO
SINGLE
POLE AUTO RECLOSURE
)F THE FEEDER PROTECTION IS EQUIPPED WITH AN ADDITION
AL SO
CALLED $!2 STAGE THIS CAN BE ACTIVATED BY
6+ THROUGH THE OUTPUT SIGNAL
2!2 :ONE
2EL
WHICH IS PRESENT AS LONG AS THE $!2 FUNCTION
IS READY TO RECLOSE AFTER DISCONNECTION OF THE LINE
)F NO RECLOSURE IS EXPECTED EG CIRCUIT BREAKER NOT
READY FOR A TRIP
CLOSE CYCLE OR ACTION TIME EXPIRED
THEN THE ABOVE MENTIONED RELEASE SIGNALS ARE NOT IS
SUED 4HE FEEDER PROTECTION THEN HAS TO OPERATE AC
CORDING TO THE TIME GRADING PLAN IN ORDER TO ACHIEVE
SELECTIVITY
)T IS POSSIBLE TO BLOCK THE !2 FUNCTIONS IN COMMON OR
SEPARATE FOR 2!2 OR $!2 FROM EXTERNAL CRITERIA IE
FROM THE PLANT OR FROM OTHER PROTECTION DEVICES 4HE
RELEASE SIGNALS OF 6+ ARE NOT ISSUED IN THIS CASE
EITHER
4HE AUTO
RECLOSE FUNCTION PROVIDES AN ACTION TIME
FOR EACH OF 2!2 AND $!2 FUNCTION WHICH CAN SEPA
RATELY SET 4HE ACTION TIMES ARE STARTED WITH ANY FAULT
DETECTION OF A SHORT
CIRCUIT PROTECTION WHICH SHALL
TRIGGER THE !2 FUNCTION )F THE ACTION TIME HAS ELAPSED
BEFORE ANY TRIP SIGNAL IS GIVEN IT IS ASSUMED THAT THE
FAULT IS NOT ON THE PROTECTED LINE BUT ON A DIFFERENT
LINE AUTO
RECLOSURE IS NOT INITIATED
 !CTION TIMES AND RECLAIM TIMES
)T IS OFTEN APPROPRIATE TO PREVENT READINESS FOR RECLO
SURE WHEN THE FAULT HAS PERSISTED FOR A SPECIFIED
TIME FOR EXAMPLE WHEN IT CAN BE ASSUMED THAT THE
ARC HAS BURNT ITSELF IN TO SUCH AN EXTENT THAT THERE IS
NO CHANCE OF NATURAL QUENCHING DURING THE DEAD
TIME
4RIPPING AFTER FAULTS WHICH ARE CLEARED IN A DELAYED
TIME SHOULD FOR REASONS OF SELECTIVITY REFER FOREGO
ING SECTION NOT RESULT IN AN AUTO
RECLOSURE EITHER
4HE !2
FUNCTIONS OF 6+ ARE PROVIDED WITH SET
TABLE ACTION TIMES SEPARATE FOR 2!2 AND $!2 WHICH
ARE STARTED BY THE FAULT DETECTION SIGNAL OF THE FEEDER
PROTECTION )F AFTER EXPIRY OF THE ACTION TIME NO TRIP
PING SIGNAL HAS BEEN GIVEN RECLOSURE IS BLOCKED
4HE !2
FUNCTIONS OF 6+ ARE PROVIDED WITH
THREE SETTABLE RECLAIM TIMES WHICH DO NOT DISCRIMI
NATE BETWEEN 2!2 AND $!2 'ENERALLY THE RECLAIM
TIME IS THE TIME PERIOD DURING WHICH NO FURTHER RECLO
SURE ATTEMPT IS PERMITTED
4HE RECLAIM TIME 4
2%#,!)- IS STARTED AT EVERY RE
CLOSE COMMAND )F AUTO
RECLOSURE HAS BEEN SUC
CESSFUL
 ALL FUNCTIONS RESET TO THE QUIESCENT CONDITION
AFTER EXPIRY OF 4
2%#,!)- ANY FAULT OCCURRING AFTER
THE EXPIRY OF THE RECLAIM TIME IS CONSIDERED TO BE A
NEW SYSTEM FAULT 7HEN A RENEWED TRIP COMMAND IS
GIVEN WITHIN
THIS RECLAIM TIME THE NEXT AUTO RECLOSE
CYCLE IS STARTED IF MULTI
SHOT !2 IS PERMITTED IF NO
FURTHER !2 CYCLE IS PERMITTED A RENEWED TRIP COM
MAND WITHIN THE RECLAIM TIME IS FINAL !2 HAS BEEN
UNSUCCESSFUL
4HE LOCK
OUT TIME AFTER DYNAMIC BLOCKING 4",/#+
$9. IS THE TIME PERIOD DURING WHICH ANY FURTHER
CLOSE COMMAND BY THE 6+ RELAY IS BLOCKED AFTER
FINAL
DISCONNECTION 4HIS APPLIES FOR ALL CLOSING AT
TEMPTS WHICH ARE PERFORMED BY THE RELAY )F THIS TIME
IS SET TO 0 CLOSING IS LOCKED OUT UNTIL THE !2 FUNCTION
IS RESET BY ENERGIZATION OF THE BINARY INPUT
!2 2E
SET
 !FTER THE RESET SIGNAL ALL FUNCTIONS RESET TO THE
QUIESCENT CONDITION
! SPECIAL RECLAIM TIME 4",/#+ -# IS PROVIDED FOR
MANUAL CLOSING $URING THIS TIME AFTER MANUAL CLOSE
RECLOSURE IS BLOCKED ANY TRIP COMMAND WILL BE A FINAL
THREE
POLE TRIP