/PERATING INSTRUCTIONS
3$
6
# ' #
3ETTINGS FOR BACKUP OVERCURRENT TIME PROTECTION
ADDRESS BLOCK
4HE BACKUP OVERCURRENT TIME PROTECTION OPERATES
INDEPENDENT OF THE DIFFERENTIAL PROTECTION ! PRECON
DITION IS THAT THE BACKUP PROTECTION HAS BEEN CONFI
GURED UNDER ADDRESS AS "!#+ 50 /#
%8
)34
REFER 3ECTION
4HE OVERCURRENT TIME PROTECTION IS EVEN OPERATIVE
WHEN THE PILOT WIRES ARE FAULTY
4HE PARAMETERS OF THE BACKUP OVERCURRENT TIME PRO
TECTION ARE SET IN BLOCK 4HE OUTPUT CURRENT OF THE
SUMMATION TRANSFORMER IS DECISIVE SINCE THE RELAY
CANNOT PROCESS THE INDIVIDUAL PHASE CURRENTS 4HIS
RESULTS IN DIFFERENT SENSITIVITY DEPENDING ON THE FAULT
TYPE WITH THE SAME SENSITIVITY FACTORS AS FOR THE DIFFER
ENTIAL PROTECTION !LL CURRENT VALUES ARE BASED ON THE
SYMMETRICAL THREEPHASE CURRENTS WITH STANDARD
CONNECTION ACCORDING TO &IGURE
!T FIRST THE HIGHSET OVERCURRENT STAGE ) IS SET UN
DER ADDRESSES AND 4HIS STAGE IS ALWAYS A
DEFINITE TIME STAGE INDEPENDENT ON WHICH CHARAC
TERISTIC IS SET FOR THE OVERCURRENT STAGE )T IS REFERRED TO
THE RATED LINE CURRENT AS SET UNDER ADDRESS
4HE OVERCURRENT STAGE CAN BE USED AS DEFINITE TIME
OVERCURRENT PROTECTION OR INVERSE TIME OVERCURRENT
PROTECTION 4HIS FUNCTION MODE CAN BE SELECTED IN
ADDRESS &OR INVERSE TIME A CHOICE CAN BE
MADE BETWEEN THREE TRIPPING TIME CHARACTERISTICS
DEFINED IN )%#
4HE PICKUP VALUE ) ADDRESS FOR DEFINITE TIME
OR )P ADDRESS FOR INVERSE TIME MUST BE SET
ABOVE THE MAXIMUM EXPECTED OVER LOAD CURRENT
APPROXIMATELY TIMES )T IS REFERRED TO THE RATED
LINE CURRENT AS SET UNDER ADDRESS
4OGETHER WITH THE HIGHCURRENT STAGE ) A TWO
STAGE OVERCURRENT TIME PROTECTION IS ACHIEVED 4HE
SETTING OF THE DELAY TIMES MUST BE IN ACCORDANCE
WITH THE GRADING PLAN OF THE GALVANICALLY INTERCON
NECTED SYSTEM
'ENERALLY IT MUST BE NOTED THAT THE SET TIMES FOR DEFI
NITE TIME STAGES ARE PURE DELAY TIMES WHICH DO NOT
INCLUDE THE INHERENT OPERATION TIME OF THE PROTECTION
FUNCTIONS
" ! # +
5 0
/ 6 % 2 # 5 2 2 % . 4
4 ) - %
"EGINNING OF BLOCK
"ACKUP OVERCURRENT TIME PROTECTION
" ! # + 5 0
/ #
/ & &
/ .
"ACKUP OVERCURRENT TIME PROTECTION CAN BE
/&&
SWITCHED OFF
OR
/.
SWITCHED ON
OR
",/#+ 42)0 2%,
TRIP RELAY IS BLOCKED BUT THE
PROTECTION IS OPERATIVE
" , / # +
4 2 ) 0
2 % ,
(IGH CURRENT PICKUP THRESHOLD ) REFERRED TO THE
RATED LINE CURRENT AS SET UNDER ADDRESS
3MALLEST SETTING VALUE
)
. LINE
,ARGEST SETTING VALUE
)
. LINE
)
) ) N , N
4
)
S
4IME DELAY FOR THE HIGHCURRENT STAGE )
3MALLEST SETTING VALUE
S
,ARGEST SETTING VALUE
S
AND
0
NO TRIP WITH ) STAGE
# ( ! 2 ! # 4
$ % & ) . ) 4 %
4 ) - %
. / 2 - ! ,
) . 6 % 2 3 %
#HARACTERISTIC OF THE OVERCURRENT STAGE
6 % 2 9
) . 6 % 2 3 %
% 8 4 2 % - % , 9
) . 6 % 2 3
$%&).)4% 4)-%
CHARACTERISTIC
./2-!, ).6%23%
TIME TYPE ! ACC )%#
%842%-%,9 ).6%23
E TIME TYPE # ACC )%#
6%29 ).6%23%
TIME TYPE " ACC )%#
Содержание 7SD502
Страница 148: ... PPENDIX 3 6 PPENDIX ENERAL DIAGRAMS ONNECTION DIAGRAMS 4ABLES ...
Страница 176: ... 3 6 ...
